time taken to travel to mars from earth

How long does it take to get to Mars?

We explore how long it takes to get to Mars and the factors that affect a journey to the Red Planet.

• Distance to Mars
• Traveling at the speed of light

Fastest spacecraft so far

Mars travel time q&a with an expert.

• Travel time calculation problems
• Past mission's travel times

Additional resources

Ever wondered how long does it take to get to Mars? 

The answer depends on several factors, ranging from the position of Earth and Mars to the technology that would propel you there. According to NASA , a one-way trip to the Red Planet would take about nine months . If you wanted to make it a round-trip , all in all, it would take about 21 months as you will need to wait about three months on Mars to make sure Earth and Mars are in a suitable location to make the trip back home. 

We take a look at how long a trip to the Red Planet would take using available technology and explore some of the factors that would affect your travel time.

Related: Curiosity rover: 15 awe-inspiring photos of Mars (gallery) 

How far away is Mars?

To determine how long it will take to reach Mars, we must first know the distance between the two planets.

Mars is the fourth planet from the sun, and the second closest to Earth (Venus is the closest). But the distance between Earth and Mars is constantly changing as they travel around the sun .

In theory, the closest that Earth and Mars would approach each other would be when Mars is at its closest point to the sun (perihelion) and Earth is at its farthest (aphelion). This would put the planets only 33.9 million miles (54.6 million kilometers) apart. However, this has never happened in recorded history. The closest recorded approach of the two planets occurred in 2003 when they were only 34.8 million miles (56 million km) apart.

The two planets are farthest apart when they are both at their farthest from the sun, on opposite sides of the star. At this point, they can be 250 million miles (401 million km) apart.

The average distance between Earth and Mars is 140 million miles (225 million km).

Related: What is the temperature on Mars?

How long would it take to travel to Mars at the speed of light?

Light travels at approximately 186,282 miles per second (299,792 km per second). Therefore, a light shining from the surface of Mars would take the following amount of time to reach Earth (or vice versa):

• Closest possible approach: 182 seconds, or 3.03 minutes
• Closest recorded approach: 187 seconds, or 3.11 minutes
• Farthest approach: 1,342 seconds, or 22.4 minutes
• On average: 751 seconds, or just over 12.5 minutes

The fastest spacecraft is NASA's Parker Solar Probe , as it keeps breaking its own speed records as it moves closer to the sun. On Nov 21, 2021, the Parker Solar Probe reached a top speed of 101 miles (163 kilometers) per second during its 10th close flyby of our star, which translates to a phenomenal 364,621 mph (586,000 kph). According to a NASA statement , when the Parker Solar Probe comes within 4 million miles (6.2 million kilometers) of the solar surface in December 2024, the spacecraft's speed will top 430,000 miles per hour (692,000 kph)!

So if you were theoretically able to hitch a ride on the Parker Solar Probe and take it on a detour from its sun-focused mission to travel in a straight line from Earth to Mars, traveling at the speeds the probe reaches during its 10th flyby (101 miles per second), the time it would take you to get to Mars would be:

• Closest possible approach: 93 hours 
• Closest recorded approach: 95 hours  
• Farthest approach: 686 hours (28.5 days)  
• On average: 384 hours (16 days)  

We asked Michael Khan, ESA Senior Mission Analyst some frequently asked questions about travel times to Mars. 

Michael Khan is a Senior Mission Analyst for the European Space Agency (ESA). His work involves studying the orbital mechanics for journeys to planetary bodies including Mars.

How long does it take to get to Mars & what affects the travel time?

The time it takes to get from one celestial body to another depends largely on the energy that one is willing to expend. Here  "energy" refers to the effort put in by the launch vehicle and the sum of the maneuvers of the rocket motors aboard the spacecraft, and the amount of propellant that is used. In space travel, everything boils down to energy. Spaceflight is the clever management of energy.

Some common solutions for transfers to the moon are 1) the Hohmann-like transfer and 2) the Free Return Transfer. The Hohmann Transfer is often referred to as the one that requires the lowest energy, but that is true only if you want the transfer to last only a few days and, in addition, if some constraints on the launch apply. Things get very complicated from there on, so I won't go into details.

Concerning transfers to Mars, these are by necessity interplanetary transfers, i.e., orbits that have the sun as central body. Otherwise, much of what was said above applies: the issue remains the expense of energy. An additional complication lies in the fact that the Mars orbit is quite eccentric and also its orbit plane is inclined with respect to that of the Earth. And of course, Mars requires longer to orbit the sun than the Earth does. All of this is taken into account in a common type of diagram called the "pork chop plot", which essentially tells you the required dates of departure and arrival and the amount of energy required.

The "pork chop plot" shows the trajectory expert that opportunities for Mars transfers arise around every 25-26 months, and that these transfers are subdivided into different classes, one that is a bit faster, with typically around 5-8 months and the other that takes about 7-11 months. There are also transfers that take a lot longer, but I’m not talking about those here. Mostly, but not always, the second, slower one turns out to be more efficient energy-wise. A rule of thumb is that the transfer to Mars takes around as long as the human period of gestation, approximately 9 months. But that really is no more than an approximate value; you still have to do all the math to find out what applies to a specific date.

Why are journey times a lot slower for spacecraft intending to orbit or land on the target body e.g. Mars compared to those that are just going to fly by?

If you want your spacecraft to enter Mars orbit or to land on the surface, you add a lot of constraints to the design problem. For an orbiter, you have to consider the significant amount of propellant required for orbit insertion, while for a lander, you have to design and build a heat shield that can withstand the loads of atmospheric entry. Usually, this will mean that the arrival velocity of Mars cannot exceed a certain boundary. Adding this constraint to the trajectory optimisation problem will limit the range of solutions you obtain to transfers that are Hohmann-like. This usually leads to an increase in transfer duration.

The problems with calculating travel times to Mars

The problem with the previous calculations is that they measure the distance between the two planets as a straight line. Traveling through the farthest passing of Earth and Mars would involve a trip directly through the sun, while spacecraft must of necessity move in orbit around the solar system's star.

Although this isn't a problem for the closest approach, when the planets are on the same side of the sun, another problem exists. The numbers also assume that the two planets remain at a constant distance; that is, when a probe is launched from Earth while the two planets are at the closest approach, Mars would remain the same distance away over the length of time it took the probe to travel. 

Related: A brief history of Mars missions

In reality, however, the planets are moving at different rates during their orbits around the sun. Engineers must calculate the ideal orbits for sending a spacecraft from Earth to Mars. Like throwing a dart at a moving target from a moving vehicle, they must calculate where the planet will be when the spacecraft arrives, not where it is when it leaves Earth. 

It's also not possible to travel as fast as you can possibly go if your aim is to eventually orbit your target planet. Spacecraft need to arrive slow enough to be able to perform orbit insertion maneuvers and not just zip straight past their intended destination. 

The travel time to Mars also depends on the technological developments of propulsion systems.

According to NASA Goddard Space Flight Center's website, the ideal lineup for a launch to Mars would get you to the planet in roughly nine months. The website quotes physics professor Craig C. Patten , of the University of California, San Diego:

"It takes the Earth one year to orbit the sun and it takes Mars about 1.9 years (say 2 years for easy calculation) to orbit the sun. The elliptical orbit which carries you from Earth to Mars is longer than Earth's orbit but shorter than Mars' orbit. Accordingly, we can estimate the time it would take to complete this orbit by averaging the lengths of Earth's orbit and Mars' orbit. Therefore, it would take about one and a half years to complete the elliptical orbit.

"In the nine months it takes to get to Mars, Mars moves a considerable distance around in its orbit, about three-eighths of the way around the sun. You have to plan to make sure that by the time you reach the distance of Mar's orbit, Mars is where you need it to be! Practically, this means that you can only begin your trip when Earth and Mars are properly lined up. This only happens every 26 months. That is, there is only one launch window every 26 months."

The trip could be shortened by burning more fuel — a process not ideal with today's technology, Patten said.

Evolving technology can help to shorten the flight. NASA's Space Launch System (SLS) will be the new workhorse for carrying upcoming missions, and potentially humans, to the red planet. SLS is currently being constructed and tested, with NASA now targeting a launch in March or April 2022 for its Artemis 1 flight, the first flight of its SLS rocket.

Robotic spacecraft could one day make the trip in only three days. Photon propulsion would rely on a powerful laser to accelerate spacecraft to velocities approaching the speed of light. Philip Lubin, a physics professor at the University of California, Santa Barbara, and his team are working on Directed Energy Propulsion for Interstellar Exploration (DEEP-IN). The method could propel a 220-lb. (100 kilograms) robotic spacecraft to Mars in only three days, he said.

"There are recent advances which take this from science fiction to science reality," Lubin said at the 2015 NASA Innovative Advanced Concepts (NIAC) fall symposium . "There's no known reason why we cannot do this." 

How long did past missions take to reach Mars?

Here is an infographic detailing how long it took several historical missions to reach the Red Planet (either orbiting or landing on the surface). Their launch dates are included for perspective. 

Explore NASA's lunar exploration plans with their Moon to Mars overview . You can read about how to get people from Earth to Mars and safely back again with this informative article on The Conversation . Curious about the human health risks of a mission to the Red Planet? You may find this research paper of particular interest.  

Bibliography

• Lubin, Philip. " A roadmap to interstellar flight. " arXiv preprint arXiv:1604.01356 (2016). 
• Donahue, Ben B. " Future Missions for the NASA Space Launch System. " AIAA Propulsion and Energy 2021 Forum . 2021. 
• Srinivas, Susheela. " Hop, Skip and Jump—The Moon to Mars Mission. " (2019). 

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: [email protected].

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Nola Taylor Tillman is a contributing writer for Space.com. She loves all things space and astronomy-related, and enjoys the opportunity to learn more. She has a Bachelor’s degree in English and Astrophysics from Agnes Scott college and served as an intern at Sky & Telescope magazine. In her free time, she homeschools her four children. Follow her on Twitter at @NolaTRedd

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How Long Does It Take to Get to Mars?

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All eyes are on the red planet lately. Thanks to a number of missions in the past few years – including the Perseverance Rover that touched down Feb. 22, 2021 – Mars is increasingly interesting to astronomers, astrophysicists and future astronauts. NASA plans to put astronauts on Mars in the future, and Elon Musk keeps claiming he'll do it first , but before we strap in and blast off, it helps to know exactly how long it takes to get to there.

Mars completes one turn around the sun every 687 Earth days . This means that the distance between Earth and Mars changes every day, and the two planets are aligned closely to one another roughly every 26 months . Additionally, because both Earth and Mars have elliptical orbits (and Mars' is more elliptical than Earth's), some of our close approaches are closer than others. The most recent notable close approach was Oct. 6, 2020, when Mars was just 38.57 million miles (62.07 million kilometers) from Earth.

So how long does it take to travel the almost 40 million miles to Mars? That depends on your speed. For example, the Perseverance rover traveled at a speed of about 24,600 mph (about 39,600 kph) and the journey took seven months , but that's because of where the Earth and Mars were at the time Perseverance was launched and where they were when it landed. If you could travel as fast as the New Horizons spacecraft (which is famous for visiting Pluto back in 2015), you could potentially reach Mars in as little as 39 days depending on the alignment of the planets and the 36,000 mph (58,000 kph) speed that New Horizons reached. Historically, spacecraft have taken anywhere between 128 days (Mariner 7 on a flyby) and 333 days (Viking 2 Orbiter/Lander, the second U.S. landing on Mars) .

Since no human has traveled to Mars yet, we don't have exact numbers on how fast it's possible to go – because remember, you need to slow down as you get closer to Mars. The best estimates are that human missions to Mars will be timed to take advantage of a good planetary alignment. Most estimates put the travel time in the range of 150-300 days – that's five to 10 months – and the average is usually around seven months , just like the Perseverance rover.

The two fastest travel times from Earth to Mars are for the Viking 6 and Viking 7 spacecraft, which took 155 and 128 days respectively . Both of these spacecraft were on flyby missions to image Mars, so they didn't need to slow down as they approached Mars as orbiters, landers and rovers need to do.

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The cruise phase begins after the spacecraft separates from the rocket, soon after launch. The spacecraft departs Earth at a speed of about 24,600 mph (about 39,600 kph). The trip to Mars will take about seven months and about 300 million miles (480 million kilometers). During that journey, engineers have several opportunities to adjust the spacecraft’s flight path, to make sure its speed and direction are best for arrival at Jezero Crater on Mars. The first tweak to the spacecraft’s flight path happens about 15 days after launch.

Track the Spacecraft's Flight

The trip to mars.

• Checking spacecraft health and maintenance
• Monitoring and calibrating the spacecraft and its onboard subsystems and instruments
• Performing attitude correction turns (slight spins to keep the antenna pointed toward Earth for communications, and to keep the solar panels pointed toward the Sun for power)
• Conducting navigation activities, such as trajectory correction maneuvers, to determine and correct the flight path and train navigators before atmospheric entry. The last three correction maneuvers are scheduled during approach.
• Preparing for entry, descent, and landing (EDL) and surface operations , a process which includes tests of communications, including the communications to be used during EDL.

The mission is timed for launch when Earth and Mars are in good positions relative to each other for landing on Mars. That is, it takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits. As Earth and Mars orbit the Sun at different speeds and distances, once about every 26 months, they are aligned in a way that allows the most energy-efficient trip to Mars.

Fine-Tuning the Flight Path to Mars

This site is maintained by the Mars Communications Team at NASA's Jet Propulsion Laboratory for NASA's Science Mission Directorate

Mars Communications Manager : Claire Powell

NASA Official : Debra Hernandez

Site Manager : Melody Ho

Editor : Jane Platt

CL# : 19-6952

Want to travel to Mars? Here’s how long the trip could take.

Nuclear engines or not, you're gonna need a lot of PTO to get to the Red Planet.

By Eva Botkin-Kowacki | Published Feb 21, 2023 6:00 AM EST

Despite what Star Trek’s warp-speed journeys would have us believe, interplanetary travel is quite the hike. Take getting to Mars. Probes sent to the Red Planet by NASA and other space agencies spend about seven months in space before they arrive at their destination. A trip for humans would probably be longer—likely on the timescale of a few years. 

There are a lot of things that a human crew needs to survive that robots don’t, such as food, water, oxygen, and enough supplies for a return—the weight of which can slow down a spacecraft. With current technology, NASA calculations estimate a crewed mission to Mars and back, plus time on the surface , could take somewhere between two and three years. “Three years we know for sure is feasible,” says Michelle Rucker, who leads NASA’s Mars Architecture Team in the agency’s ​​ Human Exploration and Operations Mission Directorate .

But NASA aims to shorten that timeline, in part because it would make a Mars mission safer for humans—we still don’t know how well the human body can withstand the environment of space for an extended period. (The record for most consecutive days in space is 437.) The agency is investing in projects to develop new propulsion technologies that might enable more expeditious space travel. 

A crooked path to Mars

In a science-fictional world, a spacecraft would blast off Earth and head directly to Mars. That trajectory would certainly make for a speedier trip. But real space travel is a lot more complicated than going from point A to point B.

“If you had all the thrust you want, you could ignore the fact that there happens to be gravity in our universe and just plow all the way through the solar system,” says Mason Peck , a professor of astronautics at Cornell University who served as NASA’s chief technologist from 2011 to 2013. “But that’s not a scenario that’s possible right now.”

Such a direct trajectory has several challenges. As a spacecraft lifts off Earth, it needs to escape the planet’s gravitational pull, which requires quite a bit of thrust. Then, in space, the force of gravity from Earth, Mars, and the sun pulls the spacecraft in different directions. When it is far enough away, it will settle into orbit around the sun. Bucking that gravity requires fuel-intensive maneuvers.

[Related: Signs of past chemical reactions detected on Mars ]

The second challenge is that the planets do not stay in a fixed place. They orbit the sun, each at its own rate: Mars will not be at the same distance from Earth when the spacecraft launches as the Red Planet will be, say, seven months later. 

As such, the most fuel-efficient route to Mars follows an elliptical orbit around the sun, Peck says. Just one-way, that route covers hundreds of millions of miles and takes over half a year, at best. 

But designing a crewed mission to the Red Planet isn’t just about figuring out how fast a spacecraft can get there and back. It’s about “balance,” says Patrick Chai, in-space propulsion lead for NASA’s Mars Architecture Team . “There are a whole bunch of decisions we have to make in terms of how we optimize for certain things. Where do we trade performance for time?” Chai says. “If you just look at one single metric, you can end up making decisions that are really great for that particular metric, but can be problematic in other areas.”

One major trade-off for speed has to do with how much stuff is on board. With current technology, every maneuver to shorten the trip to Mars requires more fuel. 

If you drive a car, you know that in order to accelerate the vehicle, you step on the gas. The same is true in a spacecraft, except that braking and turning also use fuel. To slow down, for instance, a spacecraft fires its thrusters in the opposite direction to its forward motion.

But there are no gas stations in space. More fuel means more mass on board. And more mass requires more fuel to propel that extra mass through the air… and so on. Trimming a round-trip mission down to two years is when this trade-off starts to become exponentially less efficient, Rucker says. At least, that’s with current technology.

New tech to speed up the trip

NASA would like to be able to significantly reduce that timeline. In 2018, the space agency requested proposals for technological systems that could enable small, uncrewed missions to fly from Earth to Mars in 45 days or less . 

At the time, the proposals didn’t gain much traction. But the challenge inspired engineers to design innovative propulsion systems that don’t yet exist. And now, NASA has begun to fund the development of leading contenders. In particular, the space agency has its eye on nuclear propulsion.

Spacecraft currently rely largely on chemical propulsion. “You basically take an oxidizer and a fuel, combine them, and they combust, and that generates heat. You accelerate that heated product through a nozzle to generate thrust,” explains NASA’s Chai. 

Engineers have known for decades that a nuclear-based system could generate more thrust using a significantly smaller amount of fuel than a chemical rocket. They just haven’t built one yet—though that might be about to change.

One of NASA’s nuclear investment projects aims to integrate a nuclear thermal engine into an experimental spacecraft. The Demonstration Rocket for Agile Cislunar Operations , or DRACO, program, is a collaboration with the Defense Advanced Research Projects Agency (DARPA), and aims to demonstrate the resulting technology as soon as 2027 .

[Related: Microbes could help us make rocket fuel on Mars ]

The speediest trip to Mars might come from another project, however. This concept, the brainchild of researchers at the University of Florida and supported by a NASA grant, seeks to achieve what Chai calls the “holy grail” of nuclear propulsion: a combination system that pairs nuclear thermal propulsion with an electric kind. 

“We did some preliminary analysis, and it seems like we can get pretty close to [45 days],” says the leader of that project, Ryan Gosse, a professor of practice in the University of Florida’s in-house applied research program, Florida Applied Research in Engineering (FLARE). One caveat: That timeline is for a light payload and no humans on board. However, if the project is successful, the technology could potentially be scaled up in the future to support a crewed mission.

There are two types of nuclear propulsion, and both have their merits. Nuclear thermal propulsion, which uses heat, can generate a lot of thrust quickly from a small amount of fuel. Nuclear electric propulsion, which uses charged particles, is even more fuel-efficient but generates thrust much more slowly.

“While you’re in deep space, the electric propulsion is really great because you have all the time in the world to thrust. The efficiency, the miles per gallon, is far, far superior than the high-thrust,” Chai says. “But when you’re around planets, you want that oomph to get you out of the gravity well.”

The challenge, however, is that both technologies currently require different types of nuclear reactors, says Gosse. And that means two separate systems, which reduces the efficiency of having a nuclear propulsion system. So Gosse and his team are working to develop technology that can use the one system to generate both types of propulsion.

NASA’s Mars architecture team is also working with a bimodal concept that uses a chemical propulsion system to maneuver around planets and solar-powered electric propulsion to do the thrusting in deep space.

“What we are developing is different tools for the toolbox,” says NASA’s Rucker. “One tool isn’t going to be enough to do all of the exploration that we want to do. So we’re working on all of these.”

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• How Long Would It Take To Travel To Mars?

Humanity has dreamed of travelling to Mars for decades. As of yet, the only place humans have set foot on (other than Earth) is the moon . The moon presented humanity with one of its greatest challenges, yet in 1969, NASA overcame the challenge when the astronauts of Apollo 11 set foot on the lunar surface. Ever since the Apollo Program ended, NASA has slowly been developing the technology required to send humans to Mars. One of the primary purposes of the International Space Station has been to study the long term effects of space travel on the human body. In order for humans to eventually travel to Mars, they will need to survive in space for extended periods of time, yet just how long would it take to travel to Mars?

Distance To Mars

Mars is the second closest planet to Earth after Venus , yet it is still very far away. On average, the distance between Mars and Earth is about 140 million miles (225 million kilometres). To traverse that distance would likely take several months to years depending on how fast of a rocket you have. However, the distance between Mars and Earth actually changes. Both Mars and Earth orbit the sun in ellipses, meaning the  distance between them and the sun changes during their orbits. When the Earth is at furthest point from the sun and Mars is at its closest approach, the two planets are at their closest distance. When Mars and Earth happen to align in just the right way, the distance between them can be 34 million miles (54.6 million kilometres). That is significantly lower than the average distance between the two planets, and so it would make sense to send humans to Mars when the two planets are at their closest approach to each other. Unfortunately, this alignment does not happen often. The closest distance between Earth and Mars ever recorded was in 2003, when the two planets came within 35 million miles (56 million kilometres) of each other. An event such as this will only occur every couple hundred years, with the next closest approach predicted to happen in the year 2237. 

Mars and Earth rarely lineup so that the distance between them is at its minimum, but astronomers still take advantage of the fact that, at some points in their orbits, Mars and Earth are much closer together than on average. Every 26 months, Mars and Earth line up in such a way that it is most efficient to send spacecraft to the Red Planet. This means that there is one launch window to Mars every 26 months. 

Speed Of A Rocket

The distance to Mars itself is not the only factor that will determine how long it takes to travel to Mars. The speed at which a spacecraft moves will also determine the length of the trip. Past missions to Mars have generally taken anywhere from 128 days to nearly one full year. With current technology and rocket designs, NASA estimates that the first rockets carrying humans to Mars will achieve speeds of about 24,600 miles per hour (39,600 kilometres per hour). Moving at these speeds, it would take approximately seven months to reach the surface of Mars.

What If You Went Faster?

Assuming the technology is advanced enough, how quickly could you reach Mars? Currently, the fastest human-made object is the Parker Solar Probe, which has achieved speeds of 364,660 miles per hour (586,860 kilometers kilometres per hour). Moving at this speed, it would take about two weeks to reach Mars while it’s at its average distance from Earth. Travelling to Mars within only two weeks would be astonishing, yet unfortunately it would not be possible with current technology. The Parker Solar Probe has been able to attain such extreme speeds by slingshotting itself around the sun multiple times. In the far future, if humanity ever develops the technology to travel near the speed of light , we could travel to Mars in less than five minutes. For now, the first astronauts to travel to Mars will have to wait several months in space before arriving at the Red Planet. 

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How long does it take to get to Mars, and how far is it? Nasa Perseverance rover’s landing mission explained

It took around seven months for nasa's perseverance rover to reach the red planet.

Nasa’s Perseverance rover has landed safely on Mars, starting a new mission to look for signs of ancient life.

The rover left Earth at the end of July last year, and after a tense few moments ahead of landing, it confirmed its successful arrival.

But just how far away is Mars and how long does it take it get there?

How far away is Mars?

The distance between Earth and Mars is not always the same, as both planets are on constant orbits around the Sun.

The Nasa Perseverance travelled around 293 million miles (471 million kilometers) to get to Mars.

According to Nasa , the closest the two planets can theoretically be to each other is 33.9 million miles (54.6 million kilometers).

The closest recorded distance to Mars was in 2003 when Mars was recorded as 34.8 million miles (56 million km) – but the next time they are expected to come this close is the year 2287.

The last Mars “close approach” was in October 2020, when Mars was 38.6 million miles (62.07 million kilometers) from Earth.

Close approaches, which happen around every 26 months, are a good time to plan missions to Mars, Nasa said, as Earth and Mars are closest together on their orbits.

The furthest the two planets can be from each other is around 250 million miles (401 million km) apart.

How long does it take to get to Mars?

The time it takes to get to Mars varies, as of course, it’s not a staightforward journey.

It took the Perseverance around 7 months to get to Mars.

Past missions to Mars, including flybys, have varied in time, taking between 128 days and around 330 days to make the journey.

According to Space.com , travelling at the speed of light, (186,282 miles per second/299,792 km per second) it would take a minimum of just over three minutes to reach Mars.

On average, a light shined on to the red planet’s surface would take around 12 and a half minutes to reach it’s destination.

How did the Nasa Perserverance rover landed on the red planet?

Nasa’s Mars Perseverance rover launched on July 30, 2020, from the Cape Canaveral Air Force Station, Florida in the US.

It travelled for around seven months before landing safely on the surface of the red planet on February 18, 2021 just before 9pm (GMT).

Confirmation of the safe landing took more than 11 minutes to reach Earth and was met by jubilation from Nasa scientists, after a few tense minutes.

I’m safe on Mars. Perseverance will get you anywhere. #CountdownToMars — NASA's Perseverance Mars Rover (@NASAPersevere) February 18, 2021

Steve Jurczyk, Nasa’s acting administrator, said: “It’s amazing to have Perseverance join Curiosity on Mars and what a credit to the team.

“Just what an amazing team to work through all the adversity and all the challenges that go with landing a rover on Mars, plus the challenges of Covid.

“And just an amazing accomplishment.”

The rover has since sent back pictures of the planet’s rocky surface, and more footage is expected from the robot soon.

The mission’s goal is to search for signs of ancient life and collect samples for a future return to Earth from diverse environments on Mars.

Perseverance will gather rock and soil samples using its drill, and will store the sample cores in tubes on the Martian surface ready for a return mission to bring around 30 samples to Earth in the early 2030s.

It will also include testing out new technologies and try out the Ingenuity Mars Helicopter.

Additional reporting by PA.

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How long does it take to get to Mars?

How long would it take to drive or walk to Mars, and how long does it take actual space missions?

Jenny Winder

How long to get to Mars?

If you could jump in a car and travel at 161 kph (100 mph), it would take about 14,583 days or 40 years to reach Mars, but if you wanted some exercise, you could walk (at 6kph or 3.7 mph) and get there in 1,065 years!

Earth and Mars travel around the Sun at different speeds and distances, so the distance between us varies considerably.

Yet a day on Mars is remarkably similar to a day on Earth.

At our furthest distance, we are on opposite sides of the Sun (called a solar conjunction) when we are about 401 million km (249 million miles) apart.

The average distance between Earth and Mars is 225 million km (140 million miles)

The two planets are closest when we are both on the same side of the Sun (called opposition ) at about 56 million km (34.7 million miles) apart. This happens every two years and is our launch window to the Red Planet.

The first successful mission to Mars, Viking 1, launched on 20 August 1975 and landed on Mars on 19 June 1976, ten months later.

The rovers Spirit and Opportunity took just 6 months to reach Mars in 2003 and 2004.

The Curiosity rover launched on 26 November 2011 and landed on Mars on 5 August 2012.

Perseverance rover launched on 30 July 2020 and landed on Mars on 18 February 2021.

Various space agencies are working towards a crewed mission to Mars.

NASA is working towards a 9-month journey, while SpaceX hopes to cut the trip to 6 months.

The time it takes to get from Earth to Mars is mainly dependent on the propulsion method used.

A photon propulsion system is currently in development that would use a powerful laser to accelerate spacecraft to near the speed of light , cutting the journey to just three days!

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How NASA and SpaceX Will Get People From Earth to Mars and Safely Back Again

By Chris James, The University of Queensland April 25, 2021

This artist’s concept depicts astronauts and human habitats on Mars. NASA’s Mars Perseverance rover carries a number of technologies that could make Mars safer and easier to explore for humans. Credit: NASA

There are many things humanity must overcome before any return journey to Mars is launched.

The two major players are NASA and SpaceX , which work together intimately on missions to the International Space Station but have competing ideas of what a crewed Mars mission would look like.

Size matters

The biggest challenge (or constraint) is the mass of the payload (spacecraft, people, fuel, supplies, etc.) needed to make the journey.

We still talk about launching something into space being like launching its weight in gold.

The payload mass is usually just a small percentage of the total mass of the launch vehicle.

For example, the Saturn V rocket that launched Apollo 11 to the Moon weighed 3,000 tonnes.

But it could launch only 140 tonnes (5% of its initial launch mass) to low Earth orbit, and 50 tonnes (less than 2% of its initial launch mass) to the Moon.

Mass constrains the size of a Mars spacecraft and what it can do in space. Every maneuver costs fuel to fire rocket motors, and this fuel must currently be carried into space on the spacecraft.

SpaceX’s plan is for its crewed Starship vehicle to be refueled in space by a separately launched fuel tanker. That means much more fuel can be carried into orbit than could be carried on a single launch.

Concept art of SpaceX’s Dragon landing on Mars. Credit: SpaceX

Time matters

Another challenge, intimately connected with fuel, is time.

Missions that send spacecraft with no crew to the outer planets often travel complex trajectories around the Sun. They use what are called gravity assist maneuvers to effectively slingshot around different planets to gain enough momentum to reach their target.

This saves a lot of fuel, but can result in missions that take years to reach their destinations. Clearly, this is something humans would not want to do.

Both Earth and Mars have (almost) circular orbits and a maneuver known as the Hohmann transfer is the most fuel-efficient way to travel between two planets. Basically, without going into too much detail, this is where a spacecraft does a single burn into an elliptical transfer orbit from one planet to the other.

A Hohmann transfer between Earth and Mars takes around 259 days (between eight and nine months) and is only possible approximately every two years due to the different orbits around the Sun of Earth and Mars.

A spacecraft could reach Mars in a shorter time (SpaceX is claiming six months) but — you guessed it — it would cost more fuel to do it that way.

Mars and Earth have few similarities. Credit: NASA/JPL-Caltech

Safe landing

Suppose our spacecraft and crew get to Mars. The next challenge is landing.

A spacecraft entering Earth is able to use the drag generated by interaction with the atmosphere to slow down. This allows the craft to land safely on the Earth’s surface (provided it can survive the related heating).

But the atmosphere on Mars is about 100 times thinner than Earth’s. That means less potential for drag, so it isn’t possible to land safely without some kind of aid.

Some missions have landed on airbags (such as NASA’s Pathfinder mission) while others have used thrusters (NASA’s Phoenix mission). The latter, once again, requires more fuel.

Life on Mars

A Martian day lasts 24 hours and 37 minutes but the similarities with Earth stop there.

The thin atmosphere on Mars means it can’t retain heat as well as Earth does, so life on Mars is characterized by large extremes in temperature during the day/night cycle.

Mars has a maximum temperature of 30℃ (86ºF), which sounds quite pleasant, but its minimum temperature is -140℃ (-220ºF), and its average temperature is -63℃ (-81ºF) . The average winter temperature at the Earth’s South Pole is about -49℃ (-56ºF) .

So we need to be very selective about where we choose to live on Mars and how we manage temperature during the night.

The gravity on Mars is 38% of Earth’s (so you’d feel lighter) but the air is principally carbon dioxide (CO₂) with several percent of nitrogen, so it’s completely unbreathable. We would need to build a climate-controlled place just to live there.

SpaceX plans to launch several cargo flights including critical infrastructure such as greenhouses, solar panels and — you guessed it — a fuel-production facility for return missions to Earth.

Life on Mars would be possible and several simulation trials have already been done on Earth to see how people would cope with such an existence.

This illustration shows NASA astronauts working on the surface of Mars. A helicopter similar to the Ingenuity Mars Helicopter is airborne at left. Ingenuity is being carried aboard the Perseverance rover; it was recently deployed to the Martian surface to test whether future helicopters could accompany robotic and human missions. Credit: NASA

Return to Earth

The final challenge is the return journey and getting people safely back to Earth.

Apollo 11 entered Earth’s atmosphere at about 40,000km/h (25,000 mph), which is just below the velocity required to escape Earth’s orbit.

Spacecraft returning from Mars will have re-entry velocities from 47,000km/h to 54,000km/h (29,000 mph to 34,000 mph), depending on the orbit they use to arrive at Earth.

They could slow down into low orbit around Earth to around 28,800km/h (17,900 mph) before entering our atmosphere but — you guessed it — they’d need extra fuel to do that.

If they just barrel into the atmosphere, it will do all of the deceleration for them. We just need to make sure we don’t kill the astronauts with G-forces or burn them up due to excess heating.

These are just some of the challenges facing a Mars mission and all of the technological building blocks to achieve this are there. We just need to spend the time and the money and bring it all together.

And we need to return people safely back to Earth, mission accomplished. Credit: NASA

Written by Chris James, Lecturer, Centre for Hypersonics, The University of Queensland.

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17 comments on "how nasa and spacex will get people from earth to mars and safely back again".

The main issue being ignored is the need for artificial gravity in route. Without artificial gravity in route the astronauts will have to crawl out of the spaceship once on Mars. A fully functioning astronaut is one who has been conditioned to the gravity on Mars, or Earth, during the journey. Treadmills be damned, use a revolving capsule to live and work in during the trip. Go into microgravity as required but not all of the time.

One way to get to Mars faster would be to go towards the moon, swing around the moon. Then use the Earth for gravity assist to Mars. Might then have to wait for the right time for the position of the moon.

Why? Why go there? Won’t we just start messing with the climate there, ruining the environment there like we’re doing here?

Not to mention all of the stellar and cosmic radiation that the crew would likely absorb in transit and on the surface.

So Chris, has the ‘Cabin Fever’ problem been addressed? You do know what I mean by that don’t you? Astronauts all cooped up and nowhere to go; to get away from each other, take a space stroll, some solitude, alone time. Anything to keep from killing each other. Eh?

No mention of the radiation issues. Both in deep space and on Mars. You may survive the mission only to be riddled with cancer on your return.

However…

“Space is the natural habitat of humans. A planet, is after all, is a object in space.” – Frank Herbert

So….. where’s the Boring tunneler? Clearly Elon’s companies on Earth are just a trial run and funding source for Mars. They’ll have an entire subterranean city and solar+storage farm built before anyone steps foot on the Red Planet.

Wouldn’t it be more secure to live be on Mars underground? Elon Musk’s borer would make short work of it. Especially if it could be done remotely.

Improve earth.stop spoiling earth.Lets make earth heaven again

What about if we all stop for a moment and better think about how to save our own planet earth 🌎 which is suffering due to our negligence! Let’s make our own paradise and then if you want to leave in Jupiter! Go ahead and do it! But let’s save our own planet first! Stop destroying it.

What about if we all stop for a moment and better think about how to save our own planet earth 🌎 which is suffering due to our negligence! Let’s make our own paradise and then if you want to live in Jupiter! Go ahead and do it! But let’s save our own planet first! Stop destroying it. Spending millions of dollars in stupid stuff while our beautiful sea lions’ home have been destroy due to climate change! WHAT ABOUT IF WE THINK FIRST HOW WE CAN RECOVER OUR MOTHER EARTH 🌎 FIRST!!!

I think this will never happen as there is no signs in any religion discussing life expect this planet. This will not happen.

If humans are sent to Mars it should be with the intention of it being permanent. Not like it was going to the moon and then not going back now going on 50 plus years. Just make the commitment like Kennedy did and do it! Life’s a dance, you learn as you go.

I agree there are lots of issues with traveling to Mars

Well the climate change is because of Joe Biden so lets thank him for killing all our precious animals effected by this stupid Presidential decision on f’ing with our climate change acting like there ain’t nothing at risk with trying to change it. honestly Trump is our only saviour and I’m Mexican and had family taken by immigration but Trump has more potential than Biden ever will. Biden is hurting us Mexican more than Trump ever had. by taking the jobs we came to the US 🇺🇸 for in the first place climate change is not what we need. And our presence on Mars should and will help the chance at further life on Mars even though death is a possibility and will happen but it will also help transforming Mars to a liveable planet in the process.

There are so many issues going there. The landing might be one of the trickiest since they need a lot of supplies with them. Enough food (edible and healthy), oxygen and water. And also having enough fuel to go back. I do not see this happening any time soon.

why cracking heads for what is not necessary knowing that death will still come. pls use your time For God.

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SpaceX: Here’s the Timeline for Getting to Mars and Starting a Colony

SpaceX is aiming for a much faster timeframe, with a series of 10 launches to start a city by 2050. Here’s how it looks.

Elon Musk has a grand plan for getting humanity out of the confines of Earth, setting off to the moon, Mars, and even further reaches of the solar system. Musk has regularly estimated that humans could establish a city on Mars as early as 2050.

As CEO of SpaceX, he has led the development of the Starship. The rocket is designed to refuel and relaunch using liquid hydrogen and methane, unlike the rocket propellant used in the Falcon 9 and Falcon Heavy. That means astronauts will be able to set up refueling depots around the solar system, hopping from planet to planet. Still under development, the Starship could see its first commercial flight as early as 2021 .

Many plans for a Mars settlement expect a community in matters of decades. The United Arab Emirates aims for a city of 600,000 by 2117. Astrobiologist Lewis Dartnell told Inverse in October that “while the first human mission to land on Mars will likely take place in the next two decades, it will probably be more like 50-100 years before substantial numbers of people have moved to Mars to live in self-sustaining towns.”

SpaceX is aiming for a much, much faster timeframe, with a series of 10 launches to start a city by 2050. Here’s how it looks:

SpaceX’s Mars Plan: 2019

The company is set to hold the first “hop tests” for its Mars-bound Starship this year, seeing if the rocket can jump a few hundred kilometers. SpaceX has been developing a test facility in Boca Chica, Texas, shipping over 300,000 cubic yards of locally-sourced soil. In July 2018, the firm took shipment of a 95,000-gallon liquid oxygen tank, around the same capacity as 20 tanker trucks. It’s also completed a 600-kilowatt solar array and two ground station antennas that may also prove useful for Crew Dragon missions. In October 2018, it took shipment of the final major ground tank system to support the initial flights.

CEO Elon Musk previously described these tests as “fly out, turn around, accelerate back real hard and come in hot to test the heat shield because we want to have a highly reusable heat shield that’s capable of absorbing the heat from interplanetary entry velocities.” The tests were originally set to take place in the first few weeks of 2019, but a storm blew over the “hopper” test vehicle.

The firm completed its first hop test firing in April, reaching a few centimeters off the ground. More are expected later this year.

SpaceX's final Starship Hopper

Assuming all goes well, it’s onto the next stage. In January, Musk claimed that the first orbital Starship prototype may arrive as early as June, which could help accelerate testing and move select plans to an earlier stage of the schedule.

SpaceX’s Mars Plan: 2020

As the United States holds its next presidential election, SpaceX will be working on the next stage of Starship tests. This year’s tests cover the booster, as well as high altitude, high-velocity flights. The team is expected to conduct a number of test flights before actually placing anyone on board. An orbital Starship could make its flight debut at this time.

SpaceX’s Mars Plan: 2021

The Starship is set to embark on its first commercial flight. Jonathan Hofeller, SpaceX vice president of commercial sales, revealed at a conference in Indonesia that the plan is to host the first flight around this time.

The Starship’s first voyage could see it send a commercial satellite into space for one of three telecoms firms. That sounds like a job for the Falcon 9 and Falcon Heavy, but if all goes well it could prove the Starship’s viability for future missions and help fund its further development.

“You could potentially recapture a satellite and bring it down if you wanted to,” Hofeller said. “It’s very similar to the [space] shuttle bay in that regard. So we have this tool, and we are challenging the industry: what would you do with it?”

SpaceX’s Mars Plan: 2022

This could be the first year that SpaceX reaches Mars. At the International Astronautical Congress in Adelaide, Australia, in September 2017, Musk suggested this year as the point at which at least two unmanned ships could make their way to Mars. The two planets will be at an ideal point to send a rocket in 2022, a phenomenon that occurs roughly every two years.

SpaceX previously released concept art of the Starship on its way to distant planets, based around the older design rather than the more recent stainless steel iteration pictured above:

The Starship.

“I feel fairly confident that we can complete the ship and prepare the ship for launch in about five years,” he said. “Five years feels like a long time to me.”

The ships would place power, mining and life support infrastructure for future flights. They would also confirm water resources and identify hazards. Each ship would carry around 100 tons of supplies.

However, in February, Musk suggested that SpaceX has more pressing missions:

SpaceX’s Mars Plan: 2023

This is the year when SpaceX is expected to send Japanese billionaire Yukazu Maezawa , alongside six to eight artists, on a trip around the moon using the Starship. While not specifically a Mars-focused mission, its success would bode well for a future manned mission. Based on Musk’s February comments, this could be the first major mission for the Starship.

The path that Starship will take when on the Lunar Mission.

SpaceX’s Mars Plan: 2024

It’s time for another election for president of the United States. It’s also the next time that the Earth and Mars are suitably aligned to send a rocket.

There’s a high chance that, based on Musk’s previous comments, SpaceX will not send two cargo ships to Mars in 2022 as previously suggested. If this prediction holds true, this will be the next ideal moment that SpaceX can send the cargo ships and lay the groundwork for a further mission.

If SpaceX has sent the two cargo ships by this stage, the next step will be the manned mission. The plan is to send two cargo ships, alongside two crew ships taking the first people to Mars. They will be tasked with setting up a propellant production plant, combining Martian water, ice, and carbon dioxide to create methane and liquid oxygen to fuel the ships and come back home. The humans would be tasked with collecting one tonne of ice every day to fuel the plant.

The first humans will also likely have to use solar-powered hydroponics to feed the plants and grow more food. Musk said in a February interview that the technology, which allows plants to grow without soil, is already in use on Earth and the same techniques could immediately apply to the Mars colony.

The Starship on Mars.

In short, it’s not going to be a leisurely visit. Musk stated at the South by Southwest Festival in Austin, Texas in March this year, that Mars and the moon “are often thought of as some escape hatch for rich people, but it won’t be that at all.”

SpaceX’s Mars Plan: 2025

This is the earliest point at which Musk thinks a Mars colony could take shape . The CEO has predicted a timeframe of “7 to 10 years” before the first bases take shape.

This will expand on the work left behind by the first humans. Paul Wooster, principal Mars development engineer for SpaceX, explained that “the idea would be to expand out, start off not just with an outpost, but grow into a larger base, not just like there are in Antarctica, but really a village, a town, growing into a city and then multiple cities on Mars.” The larger cities would offer habitats, greenhouses, life support, and enable new experiments that help to answer some of the big questions about life on Mars.

A potential future Mars city.

SpaceX’s Mars Plan: 2026

This could be the next time that SpaceX sends more ships to Mars. Musk explained on Twitter that the company could use 10 orbital synchronizations to complete a city by the year 2050. With the two planets set to align in February 2027, this could be about the right time to complete another launch.

SpaceX’s Mars Plan: Beyond

By the end of the next decade, SpaceX expects to have some sort of settlement on Mars. Musk has said there’s a 70 percent chance he’ll visit Mars himself in his lifetime, perhaps paying a visit to this developing colony. That is, depending on how the first settlements go — Musk said in 2016 that “probably people will die,” but “ultimately, it will be very safe to go to Mars, and it will be very comfortable.”

Mars could perhaps serve as a base for more ambitious missions, with Musk describing the Starship as “really intended as an interplanetary transport system that’s capable of getting from Earth to anywhere in the solar system as you establish propellant depots along the way.”

Leaving for further adventures.

Beyond transforming humanity into a space-faring civilization, it could also preserve the species. SpaceX president Gwynne Shotwell said in April that “if something were to happen on Earth, you need humans living somewhere else…I think you need multiple paths to survival, and this is one of them.”

Related video: Elon Musk Predicts Our Future On Mars At SXSW 2018

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Time delay between Mars and Earth

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Spacecraft event time vs. Earth receive time

A photo of the Mars Express delay display on the control system, showing us the critical numbers of one-way light time, two-way light time and the distance from Earth.

One of the most difficult things about operating a spacecraft around Mars (not to mention the different time zones ), compared with the Earth, is that it’s so far away!

Mars is so far away in fact that it takes radio signals quite a long time to get from the spacecraft back to Earth. During Curiosity EDL, this delay will be 13 minutes, 48 seconds, about mid-way between the minimum delay of around 4 minutes and the maximum of around 24 minutes.

This makes it a challenge to operate Mars Express because it’s hard to have a conversation with the spacecraft, or react if anything happens on board. If there is a problem and the spacecraft tells us, we won’t know for 13 minutes, and then even if we react straight away it’ll be another 13 minutes before our instructions get back to Mars – there’s a lot that can happen in half an hour at Mars (for example a whole Curiosity landing)!

To keep Mars Express flying safely, we load all the commands for the mission in advance and built in lots of autonomy to let the spacecraft take care of itself – you could say that for the Curiosity landing we’re running completely on autopilot!

The delay is nothing to do with the spacecraft or the hardware on the ground – it can’t be improved by a faster computer or a more powerful radio. In fact it is obeying the fundamental speed limit of the universe – the speed of light.

At 1,079,000,000 km/hour, light is pretty quick; you could get from here to the Moon in a little over a second! But that just underlines how far away Mars is.

All light (or electromagnetic radiation, which includes radio signals) travels up to this speed, and radio waves from Earth to Mars Express and back are no exception. Take a look at the Wikipedia article on the speed of light and you’ll see how, in 1905, Einstein came upon the concept of this cosmic speed limit.

Above all, for tomorrow’s coverage of the Curiosity landing it makes it challenging for us to work out when to tell you what’s happening (as you’ve seen in our three column timeline )!

At ESOC, we talk about two different times – Spacecraft Event Time (SCET) and Earth Received Time (ERT). The former is what’s actually happening at Mars right now, although we won’t hear about it until over 13 minutes later, a time we call ERT.

The delay between the two is usually called the One-Way Light Time (OWLT) and the time for a message to go to Mars and come back is the Two-Way Light Time (TWLT), or round-trip time.

During all our coverage we’ll follow NASA’s lead and generally communicate events here and on Twitter to you in ERT because that’s when we’ll actually know what’s happened. If we do communicate something in SCET we’ll let you know so you (and us too) don’t get confused – it’s all part of the fun of exploring the Solar System!

Written by Thomas Ormston

Discussion: 68 comments

The distance from earth to sun is higher than that to Mars. It takes 8 minutes to suns light to reach earth. Why then signal takes 13 minutes to reach earth?

That’s because the light from the sun is photonic whereas the radio signals are electromagnetic radiation (sort of light), they don’t travel at the same speed as light.

Em, don’t radio waves travel at the speed of light in vacuum？

Yes radio signal is fast but light travels faster

Orbital distance is lower. Orbits are different. Therefore, whilst light speed = radio speed. distance travelled depends on orbital location distance!

Both travel at the speed of light, it takes 13 minutes for us to send a signal and get a signal back, it goes both ways so it takes a while. To just send a signal there, it takes 6 minutes and 30 seconds.

No, all parts of the electromagnetic spectrum travel at the speed of light in a vacuum; they simply have different wavelengths/frequencies.

No, all waves travel at the same speed. It takes light eight minutes on a one way trip, 16 minutes on a two way trip. Please learn to into physics

A “photon” is the carrier particle for both visible light AND radio waves, both of which are forms of electromagnetic energy, just at different frequencies. “Photonic energy” (which I’ve never heard of) would be synonymous with electromagnetic energy. Light, heat, gamma, radio, microwaves, ultraviolet – all are mediated by photon particles, but possess properties of waves as well, hence the “frequency” characteristic. Easiest to think of them as waves while they are traveling, but particles when they strike something.

And those numbers only apply to light traveling in vacuum. Light passing through matter travels measurably slower. I think some lab recently performed an experiment in which they “stopped light” inside a substance by slowing it waaaaaay down somehow. Don’t know how they did it, I didn’t read the whole thing.

would it stand to reason then, that certain frequencies of electromagnetic energy travel “faster” as they interact less with most forms of matter and thus have less interference when traveling large distances than other wavelengths traveling the same path and distance?

for example, inferred light compared to gamma-radiation, inferred light would have a higher chance of interacting with a medium compared to gammarays delaying the wavelength as it passes through minuscule amounts of matter. Could one say this would result in gammarays having a faster “net speed” on average?

Incorrect. Allow me to quote directly from the article you just read since you seem to have missed it.

“At 1,079,000,000 km/hour, light is pretty quick; you could get from here to the Moon in a little over a second! But that just underlines how far away Mars is.

All light (or electromagnetic radiation, which includes radio signals) travels up to this speed, and radio waves from Earth to Mars Express and back are no exception.”

The time from Earth to Mars varies between 4 and 24 minutes because earth (and mars) are both orbiting the sun, not each other. The distance between them therefore can change quite dramatically depending on where we are in our respective orbits.

When Mars is directly behind Earth at the closest possible point, it is only four minutes away. When it is at the farthes point opposite us behind the Sun, it is 24 minutes away. The Sun meanwhile, which we orbit, remains at roughly 8 minutes away since our orbit around the Sun is very nearly circular.

One more note, assuming Mars is also a circular orbit (which it is not) you could assume that the distance from mars to the sun is roughly 12 minutes and implying that the maximum distance would be 8 + 12 which would only be 20 minutes.

However this is not the case since Mars’ orbit is somewhat eliptical and in a slightly different plane from Earths orbit as well making it possible for them to be as distant as 24 minutes.

Just came across this: Radio signals are electromagnetic waves, such as light or X-ray. The speed of electromagnetic waves in vacuum, is 300000km/sec (approximately).

In order to calculate the time of travel with this speed from Earth to Mars, we need to know the distance.

When the Mars and the Earth are at the opposite sides of the Sun, the distance is the largest: approximately: 378 million km. The time needed for an electromagnetic wave to cover this distance is approximately: 21 minute.

The closest distance between Mars and Earth is 78 million km, the time in this case is: 4.3 min.

So the time of travel between Earth and Mars is between 4.3 minutes and 21 minutes, depending on the actual distance between the two planets.

Shab, you are calculating as if it is 2D plane, while DoctorZuber already mentioned the earth and mars elipses are of different plane.

So when Mars is at the exact opposite of Earth and the Sun is directly in between. Would it be possible for radio to even transmit to Earth Via right thru the sun?

You are wrong. It is because the earth is often much further from Mars than Mars is from the sun.

Usually I mean. The distances vary greatly, of course.

yo wassup guys whats lite

Guys guys guys u are over anylizing everything. It’s cause mars is further from earth than the sun sometimes cause of orbits

Yes they do. (Buy better science books.)

No, it takes 13 minutes round trip. Half that from Earth to Mars (depending on relative positions of both planets in their orbits). To my knowledge, there is no such thing as “photonic.” Light is electromagnet waves (or photons depending on the nature of the experiment you use to determine that – see “double slit light experiments”). All electromagnet waves travel at the same speed in space.

The article gives you the clue doesn’t it? Since the orbit of Mars is elliptical (not circular!), the epihelion and perihelion (i.e. shortest distance and the furthest Mars is from Earth) differs periodically.

The distance between the Earth and the Sun is based on our orbit and is relatively constant (about 92,960,00 miles). Since both the Earth and Mars orbit the sun at different distances and speed, the distance between us constantly changes. At times Mars is on the other side of the Sun from us and other times it is on the same side. When Mars is closest to Earth it can be as close as 34,000,000 miles, but when they are the furthest apart they can be almost 250,000,000 miles apart.

Hi, We gotta come to a common term for distance. Metric is proven to be easy and base of all science. When please switch to metric and use kilo meter. thanks

Just multiply miles by 1.8 to get equivalent kilometers. Or kilometers by .6 to get miles. Now you should be covered unless someone here starts talking about rods or leagues or something weird like that.

Actually, 1 mile = 1.625 km.

Just to assure accuracy for the people visiting. If you decide that you would like to do any maths related to this subject, here are the actual conversion values for U.S. and Metric measurements of distance:

1 mile = 1.609334 km (1.609 is close enough) 1km = 0.621371192 mile (0.621 is OK also)

No, we won’t use metric exclusively. Metric isn’t simpler, and miles are well established not only in the USA but in the UK too, and the UK helps to fund the ESA and the EU, so the ESA and the EU should use the BOTH measurement systems, instead of trying to impose metric on everyone.

Metric has been established in the UK for decades. School science has used SI and not Imperial for decades. Trying to use both systems would waste time and risk dangerous errors.

Meters are part of the SI system of units ( https://en.wikipedia.org/wiki/International_System_of_Units ). It becomes very complicated to use any standard derived unit such as Newton (Force) expressed by miles and pounds.

Further, 1 cubic decimeter equals 1 liter of water weighing 1kg which can also come in quite handy in everyday life. This is quite a trick in inches, fluid ounces, and pound 😉

No we don’t. You can use your metric system and we can use our British/American system.

We don’t speak one language, and we don’t need one system of measurement.

It’s good to be fluent in multiple systems.

There is a good reason to stick to metric when discussing scientific matters. Several space missions have failed disasterously due to mix-ups translating between the two 😛

Please not distance from earth to mars is about 225 million km (not miles).

the change in distances are also one reason they have to plan specific dates when launching satellites to Mars or any other planets.

It’s more like very different because mars also orbits the sun, but slower than earth, sometimes it is from our view behind the sun and other cases behind us

That is incorrect. Distance to sun 96 million miles. Distance to Mars, 140 million.

The distance to Mars varies because the Earth and Mars are both orbiting the sun, but not at the same speed or the same distance from the sun. Sometimes we are on the opposite side of the sun from Mars, and the sun is therefore closer to us than Mars is.

dude, shit happens

If the earth is on one side of the sun and mars is on the other side, then the distance from the earth to mars is greater than from the earth to the sun. Seems pretty straight forward. All electromagnetic radiation travels at the speed of light. Gladson is wrong.

Both earth and mars are in orbit around the sun. We make the trip in 265 earth days. Mars requires 669 earth days. Mars mean orbital radius to the sun is 1.6 times that of earth. We can be MUCH closer to Mars than the sun, or 2.6 times as far away, depending on our relative orbital positions.

Round trip radio time depends on where earth and mars are relative to the sun. If we are at our closest point to mars, R/T transit time is 4 minutes. If we are at opposite sides of the sun, R/T time is 24 minutes.

365 earth days

It varies, because Earth and Mars orbit the sun at different speeds. Sometimes they are on the same side of the sun and, at closest approach, light only takes about 3 minutes to travel between the two. Sometimes they are on opposite sides of the sun and it takes up to about 22 minutes. As to the other responses, the difference between speed of light and radio waves is negligible over these short distances.

Depends on the positionsame of earth and Mars. If we are on the same side of sun we are closer. If the planets are on opposite sides of sun. The sun is closer. The sun distance from Earth is relatively constant. Mars is not.

It’s a two way signal. Query and Response.

Because mars can be on the complete opposite side of the sun compared to the earth

Varges, we are not necessarily the same side of the sun at the same time – so the longest time is for when Earth and Mars are 180 degrees opposite each other and both at aphelion, and the shortest would be when we are both the same side, with Mars at perihelion and Earth at aphelion.:

o —————O——————-o o——-o————O

Now you are making sense, but at that point how much longer will it take the suns light to reach mars?

How much time could we have cut from our journey to mars if we timed it accordingly?

Well, you have to remember that both Earth and Mars are moving at different speeds while the rocket is en route. Google “hohmann transfer” for details on that if you’re interested.

Glad you didn’t bring in Einstein’s curved space theory! If you had then they’d be even more confused about how the Sun depresses Space/Time and therefore the distance light travels when Mars is on the opposite side of the sun as Earth then the curvilinear distance is actually greater than a straight line and the time for the message to get to Mars actually increases by the lending effect

Should be “Lensing effect!”

How do you determine the exact time when the sun spot is intitially emitted.

This is extremely important and could be cause fundament change in physics since Maxwell’s theory is justified by the relation between the velocity of light and the radio induction effect.

Nobody is suggesting that there need to be fundamental changes in physics here. I’m not sure where you would get that idea.

I don’t understand. Didn’t Khan do this and end up getting the enterprise destroyed at one point?

12 minutes and 60 seconds? 13 minutes!

I just want to establish some facts here for those who are confused about physics. 1) Electromagnetic radiation and light are the same thing. That includes visible light, radio waves, and so forth. There is no such thing as “Photonic energy”. 2) All light, regardless of frequency, travels at the same speed in a vacuum, known as the “speed of light”. The speed of light in matter can vary, but in this case that is not important since all the space between mars, the earth, and the sun is vacuum. There is no air in space.

If earth and Mars are traveling in different orbits around our sun ,their distances between them is continually changing and so will be the communication speed and all this makes it even more complicated on a permanent basis to figure this out (just a bit to much for my math capabilities) I really appreciate the skills of the modern scientists to make this all possible. You are all the frontiersmen and women of humanity……thanks!

I was having a discussion with my Circuits professor about the speed of communication to the Rover being faster than light. My professor and I wondered how that was possible. Thanks for all the great Info.

Bulldog6 Through quantum entanglement that would be possible however it has only been preformed on particles, scientists are yet to find a way for this to be used in a wave which is what would need to be done to communicate with the Rover at faster than light communication. For now communication with the Mars Rover happens at the speed of light until a better understanding of quantum entanglement comes into existence.

Can we discuss then through a light system rather than a radio system ?

Can We transmit using light? a laser light pointing to space satellites, and satellites to satellites by laser light ( like station to station ) then to the nearest satellites to the earth or mars…

using few laser light pointing at the same time to transmitt few data in the same time.. speed up the tranmittion.

laser light on going straight line.. so .. i guess not easy to aim..pointing from satellites to satellites.. or mars to satellites…..

its something like using scope on the satellite watch on top of the rover.. its kind like back to human early using light as signal.. but just by fire and now using laser gun which very command now..

Radio signals are a light wave and travel at the same speed as the light emitted from a laser. The advantage to radio waves is that they are more broad than a beam of light emitted from a laser so pin point accuracy is not needed to get a message from Earth to the rovers on Mars’ surface

Since we have established that light and radio waves go at the same speed, it would make no differences.

transmission time would still be the same

Wait until the planets about a hundred light years away pick up our 1960-2017 broadcasts. They will probably shoot us with some kind of deadly weapon.Earlier broadcasts before 1960 will probably be fine, even pleasant, but anything after 1960, especially 2008 on, we are going to be in big trouble with superior species

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There are many things humanity must overcome before any return journey to Mars is launched.

The two major players are NASA and SpaceX, which work together intimately on missions to the International Space Station but have competing ideas of what a crewed Mars mission would look like.

Size matters

The biggest challenge (or constraint) is the mass of the payload (spacecraft, people, fuel, supplies etc) needed to make the journey.

We still talk about launching something into space being like launching its weight in gold.

The payload mass is usually just a small percentage of the total mass of the launch vehicle.

Read more: Buried lakes of salty water on Mars may provide conditions for life

For example, the Saturn V rocket that launched Apollo 11 to the Moon weighed 3,000 tonnes.

But it could launch only 140 tonnes (5% of its initial launch mass) to low Earth orbit, and 50 tonnes (less than 2% of its initial launch mass) to the Moon.

Mass constrains the size of a Mars spacecraft and what it can do in space. Every manoeuvre costs fuel to fire rocket motors, and this fuel must currently be carried into space on the spacecraft.

SpaceX’s plan is for its crewed Starship vehicle to be refuelled in space by a separately launched fuel tanker. That means much more fuel can be carried into orbit than could be carried on a single launch.

Time matters

Another challenge, intimately connected with fuel, is time.

Missions that send spacecraft with no crew to the outer planets often travel complex trajectories around the Sun. They use what are called gravity assist manoeuvres to effectively slingshot around different planets to gain enough momentum to reach their target.

This saves a lot of fuel, but can result in missions that take years to reach their destinations. Clearly this is something humans would not want to do.

Both Earth and Mars have (almost) circular orbits and a manoeuvre known as the Hohmann transfer is the most fuel-efficient way to travel between two planets. Basically, without going into too much detail, this is where a spacecraft does a single burn into an elliptical transfer orbit from one planet to the other.

A Hohmann transfer between Earth and Mars takes around 259 days (between eight and nine months) and is only possible approximately every two years due to the different orbits around the Sun of Earth and Mars.

A spacecraft could reach Mars in a shorter time (SpaceX is claiming six months ) but — you guessed it — it would cost more fuel to do it that way.

Safe landing

Suppose our spacecraft and crew get to Mars. The next challenge is landing.

A spacecraft entering Earth is able to use the drag generated by interaction with the atmosphere to slow down. This allows the craft to land safely on the Earth’s surface (provided it can survive the related heating).

But the atmosphere on Mars is about 100 times thinner than Earth’s. That means less potential for drag, so it isn’t possible to land safely without some kind of aid.

Some missions have landed on airbags (such as NASA’s Pathfider mission) while others have used thrusters (NASA’s Phoenix mission). The latter, once again, requires more fuel.

• Life on Mars

A Martian day lasts 24 hours and 37 minutes but the similarities with Earth stop there.

The thin atmosphere on Mars means it can’t retain heat as well as Earth does, so life on Mars is characterised by large extremes in temperature during the day/night cycle.

Mars has a maximum temperature of 30°C, which sounds quite pleasant, but its minimum temperature is -140°C, and its average temperature is -63°C . The average winter temperature at the Earth’s South Pole is about -49°C .

So we need to be very selective about where we choose to live on Mars and how we manage temperature during the night.

The gravity on Mars is 38% of Earth’s (so you’d feel lighter) but the air is principally carbon dioxide (CO₂) with several percent of nitrogen, so it’s completely unbreathable. We would need to build a climate-controlled place just to live there.

SpaceX plans to launch several cargo flights including critical infrastructure such as greenhouses, solar panels and — you guessed it — a fuel-production facility for return missions to Earth.

Life on Mars would be possible and several simulation trials have already been done on Earth to see how people would cope with such an existence.

Return to Earth

The final challenge is the return journey and getting people safely back to Earth.

Apollo 11 entered Earth’s atmosphere at about 40,000km/h, which is just below the velocity required to escape Earth’s orbit.

Spacecraft returning from Mars will have re-entry velocities from 47,000km/h to 54,000km/h, depending on the orbit they use to arrive at Earth.

Read more: Dear diary: the Sun never set on the Arctic Mars simulation

They could slow down into low orbit around Earth to around 28,800km/h before entering our atmosphere but — you guessed it — they’d need extra fuel to do that.

If they just barrel into the atmosphere, it will do all of the deceleration for them. We just need to make sure we don’t kill the astronauts with G-forces or burn them up due to excess heating.

These are just some of the challenges facing a Mars mission and all of the technological building blocks to achieve this are there. We just need to spend the time and the money and bring it all together.

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Problem Set

Let's go to mars calculating launch windows.

This activity is related to a Teachable Moment from Oct. 31, 2016. See " When Computers Were Human. "

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This activity is designed for students familiar with advanced algebra concepts. In this lesson, students will:

• Use algebraic computations to determine the relative positions of Earth and Mars during which an optimal (low-energy) transfer of a spacecraft can occur.
• Combine this information with planetary-position data to determine the next launch opportunity to Mars.

Graph paper, quadrille ruled (one piece per student)

8.5-by-11-inch or larger piece of thick cardboard (per student)

Two push-pins (per student)

String, approximately 30 cm (per student)

Planetary heliocentric longitudes for appropriate years (search for “planetary heliocentric longitudes” along with the applicable years)

When a spacecraft is launched from Earth, its forward velocity combined with the gravitational pull of Earth cause it to travel in a curved path. As the spacecraft heads toward another planet, the gravitational pull of that planet factors in to the path the spacecraft takes. The more a spacecraft can “coast” with engines off, the lower the cost of the mission (rocket fuel is not cheap!).

Think of a quarterback throwing a football to a receiver. The initial impulse (throw) is all the football gets as far as power is concerned. The football follows a curved path into the hands of the receiver. Likewise, the quarterback throws the football to where the receiver is going to be, not necessarily to where the receiver is currently. So, the quarterback throws the football downfield as the receiver is running in that direction. In a perfectly thrown pass, the receiver’s running speed will bring him or her to the exact spot where the football arrives at hand-level.

Launching to Mars is similar to this. A spacecraft is given an initial impulse (launch) toward Mars and then shuts off its engines and coasts (obeying Newton’s First Law) until it gets close to its target. Depending on the mission, the spacecraft may slow down – to get into orbit or land – by using the Martian atmosphere or retro-rockets that fire opposite to the direction of travel (obeying Newton’s Third Law).

Though a spacecraft could follow a variety of curved paths from Earth to Mars, one path called the Hohmann transfer orbit uses the least energy and is thereby considered to be the most efficient.

The Hohmann transfer is an elliptical orbit with the sun at one focus of the ellipse that intersects the orbit of the target planet. Launch occurs when Earth is at Hohmann perihelion (the point of the Hohmann orbit that is closest to the sun). Arrival occurs when Mars is at Hohmann aphelion (the point of the Hohmann orbit that is farthest from the sun).

Depending on mission objectives and spacecraft characteristics, engineers will use variations on the Hohmann transfer orbit to get spacecraft to Mars. These variations can make travel time more or less lengthy than a standard Hohmann transfer.

To make sure the spacecraft and Mars arrive at the same place at the same time, the spacecraft must launch within a particular window of time. This window is called the “launch window” and, depending on the target, can be a few minutes or as much as a few weeks in length.

If a spacecraft is launched too early or too late, it will arrive in the planet’s orbit when the planet is not there.

When launched within the proper launch window, the spacecraft will arrive in the planet’s orbit just as the planet arrives at that same place. At this point, the spacecraft is positioned for either going into orbit about the planet or landing on the planet.

Calculating orbit trajectories and launch windows is a complex task involving a variety of parameters that may or may not be constantly changing. In order to make this task accessible to high-school students, some variable parameters have been stabilized and some assumptions have been made. This problem, with these simplifications, allows students to generate an approximation of the launch window to Mars.

• Explain to students that launching to Mars requires a spacecraft to travel in an elliptical orbit about the sun such that the spacecraft and Mars will arrive in the same place at the same time. Their task in this exercise is to determine when we should next launch to Mars.
• The orbits of Earth and Mars are circular and centered on the sun. (Earth’s orbit is more circular than Mars’ orbit, but they are both slightly elliptical.)
• Earth and Mars travel at constant speeds. (They do not. See Kepler’s Second Law).
• The orbits of Earth and Mars are in the same plane. (They are close but slightly out of plane with one another).

Use string and a pushpin to draw a circular orbit.

Use string and two pushpins to draw the elliptical Hohmann transfer orbit.

• Have students use Kepler’s Third Law, the Law of Harmony, to determine the period of the Hohmann transfer orbit and then the travel time to Mars along this orbit. Kepler’s Third Law states that the square of the period of any planet is proportional to the cube of the semi-major axis of its orbit. An equation can represent this relationship: P 2 =ka 3 with k being the constant of proportionality Using Earth as an example, we can measure P in years and a in astronomical units so P = 1 year and a = 1 AU. Thus, P 2 =ka 3 →k=1 => P 2 =a 3 P 2 = (1.26 AU) 3 => P ~ 1.41 years ~ 517 days The full period of this Hohmann transfer orbit is 517 days. Travel to Mars encompasses half of one orbit, so approximately 259 days.
• Using the planetary heliocentric longitudes, approximately when is the next opportunity for a launch to Mars?
• Must a spacecraft be launched at an exact moment in the launch window? What happens if it is launched early or late?
• Research: What is the average length of a launch window to Mars?
• Approximately when was the most recent opportunity for a launch to Mars? What countries took advantage of that opportunity and launched to Mars at that time? What is the current status of those missions? Were they successful?
• Have students create a spreadsheet that will subtract heliocentric longitudes for Earth and Mars to simplify launch window calculations.
• Relative to Mars, where is Earth in its orbit when the spacecraft arrives?

Explore More

• Meet JPL engineer Sue Finley – Finley started at JPL in 1958 as a human computer and still works at the laboratory.
• Women at JPL website  
• JPL History
• JPL 80th Anniversary Article
• JPL Timeline
• JPL 80th Anniversary Video Playlist
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Goddard institute for space studies, goddard space flight center sciences and exploration directorate earth sciences division, mars24 sunclock — time on mars, frequently asked questions.

(Updated 2023-03-01)

1. Why is there a difference of some seconds/minutes between the Mars 2020 Perseverance / InSight / MSL Curiosity / Mars Phoenix mission time and Local Mean Solar Time (LMST) at the landing site?

When each of these projects was planned, a mission clock was specified based on the LMST at the longitude targeted for landing. In each of these cases the probe touched down at a different longitude, but the definition of the mission clock did not change.

For Mars 2020 Perseverance , a landing site was selected at longitude 77.43°E. The rover touched down roughly 1 km to the southeast, at about 77.45°E. The resulting difference between LMST at the targeted and actual landing coordinates is about 5 seconds.

For InSight , a landing site was selected at longitude 135.97°E. However, the lander touched down about 0.35° west at 135.6234°E. The difference in LMST between these two longitudes is about 83 seconds.

For MSL Curiosity , a landing site at longitude 137.42°E was first planned. The targeted landing site was altered slightly to 137.40°E while MSL was in-flight to Mars. The rover then touched down about 0.04° "long" of the altered coordinates at 137.4416°E. The difference in LMST between the originally targeted coordinates and the actual landing site is about 5 seconds.

For Mars Phoenix , the planned landing site used in specifying a mission clock was at longitude 233.35°E. However, while the probe was in flight to Mars, the project decided to shift the landing to 233.98°E. But Phoenix touched down well long, about 0.25° east at 234.25°E. The end result was a difference of about three and a half minutes between the mission clock and LMST at the originally planned landing site.

For each of these Mars landers, the discrepancy between the mission clock and LMST was not important to mission operations. Moreover, making changes to mission timekeeping tools would require more effort than any benefit that might be gained. Thus, the science and engineering teams saw no need to re-define the original mission clock.

2. Why was there a difference of many minutes between MER Spirit and Opportunity mission time and Local Mean Solar Time (LMST) at their landing sites?

During mission planning, the Mars Exploration Rover team specified that the mission clock for each MER rover should 1) use mean Mars time units as the clock ticks, but 2) be roughly aligned with Local True Solar Time (LTST) at the middle of the nominal planned mission duration of 90 sols (i.e., on about sol 45 of their respective missions). This second requirement has two effects, first due to the large difference (roughly 50 minutes) between LMST and LTST on Mars in January 2004, and then subtracting an offset of either 10 minutes or 13 minutes from that difference. There would be some additional minor adjustment due to the rovers touching down off-target from the exact longitude planned. The end result is that both rovers used mission clocks roughly 40 minutes behind LMST at their landing sites.

The difference between LMST and LTST was so large because when Spirit landed on Mars, the planet was at the point in its orbit where the difference between LMST and LTST — what the technical notes call the Equation of Time — was near its maximum value. The difference was somewhat less but still significant when Opportunity landed.

3. Why do the mission times for Spirit and Opportunity differ by 12 hours plus/minus a minute and 10 seconds?

As noted above, the mission times defined by the planners for the Mars Exploration Rover project were defined so that at about the middle of each rover's planned mission, its particular mission clock would approximately sync up with Local True Solar Time at the lander sites. This means that the mission times were calculated separately and had no direct relation to each other.

Unfortunately, although the mission times for the two landers turned out to be very close to being 12 Mars hours apart — which is roughly what one expects; the two landers are almost on opposite sides of the planet — mission planners did not decide to simplify matters and define mission clocks in which the time of sol would make the difference exactly 12 Mars-hours.

4. How do I set Mars24 to show me what Mars looks like from Earth?

Perform the following steps in the settings window:

• Select the sunclock display and set it to use the "Orthographic" map projection.
• Set the "center of map" to use the landmark pop-up menu.
• Select "Sub-Earth point" in the landmark pop-up menu.
• Select an appropriate input in the source map pop-up menu.

If you watch the sunclock for a few minutes, you will see slight shifts in the graphics as Mars rotates within the view.

If you are trying to compare the resulting image to what you might see through a telescope, keep in mind that the display does not account for the time it takes light to get from Mars to Earth. Depending on where the two planets are in their orbits, this can take 3-20 minutes, and during that time Mars will rotate from one to five degrees.

Remember also that Mars24 sunclock uses stock images with enhanced and/or false color and enhanced contrast. The "realistic" images included in Mars24 also do not include any seasonal effects that alter the appearance of Mars, such as dust storms and growth/contraction of the polar caps. So even if you had a super high resolution telescope like the Hubble, Mars would still not look like the Mars24 display.

5. Why does the table on the panorama display say that the Sun had an elevation of -0.2° at sunrise and sunset? Shouldn't it be 0.0°?

On Mars, just like on Earth, the Sun is not so far away that it is a pinpoint light source. Depending on where Mars is in its orbit, the Sun has an apparent radius between 0.16° and 0.19°. Mars24 defines sunrise and sunset as occurring when the edge of the Sun crosses the horizon, which is to say, when the center of the Sun is at some elevation between -0.16° and -0.19°. Rounded off to a single digit after the decimal character, this is displayed as -0.2°.

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• go to mars24 website.

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Watch CBS News

What time the 2024 solar eclipse started, reached peak totality and ended

By Sarah Maddox

Updated on: April 9, 2024 / 5:04 AM EDT / CBS News

The 2024 solar eclipse will be visible across North America today. As the moon's position between the Earth and sun casts a shadow on North America, that shadow, or umbra, will travel along the surface from west to east at more than 1,500 miles per hour along the path of totality . 

That means the eclipse will start, peak and end at different times — as will the moments of total darkness along the path of totality — and the best time to view the eclipse depends on where you are located. Some places along the path will have more totality time than others.

In Texas, the south-central region had clouds in the forecast , but it was better to the northeast, according to the National Weather Service. The best eclipse viewing weather was expected in New Hampshire, Vermont and Maine, as well as in Canada's New Brunswick and Newfoundland.

What time does the 2024 total solar eclipse start?

The total solar eclipse will emerge over the South Pacific Ocean before the shadow falls across North America, beginning in parts of Mexico. The path of totality , where onlookers can witness the moon fully blocking the sun (through eclipse viewing glasses for safety ), is expected to first make landfall near the city of Mazatlán around 9:51 a.m. MT. 

The total solar eclipse will cross over the U.S.-Mexico border into Texas, where it will emerge over Eagle Pass at 12:10 p.m. CT and then peak at about 1:27 p.m. CT.

In Dallas, NASA data shows the partial eclipse will first become visible at 12:23 p.m. CT and peak at 1:40 p.m. CT. The next states in the path of totality are Oklahoma and Arkansas, where the eclipse begins in Little Rock at 12:33 p.m. CT. 

Cleveland will see the beginning of the eclipse at 1:59 p.m. ET. Darkness will start spreading over the sky in Buffalo, New York, at 2:04 p.m. ET. Then, the eclipse will reach northwestern Vermont, including Burlington, at 2:14 p.m. ET. Parts of New Hampshire and Maine will also follow in the path of totality before the eclipse first reaches the Canadian mainland  at 3:13 p.m. ET.

Although the experience won't be exactly the same, viewers in all the contiguous U.S. states outside the path of totality will still be able to see a partial eclipse. Some places will see most of the sun blocked by the moon, including Washington, D.C., where the partial eclipse will start at 2:04 p.m. ET and peak at about 3:20 p.m. ET.

In Chicago, viewers can start viewing the partial eclipse at 12:51 p.m. CT, with the peak arriving at 2:07 p.m. CT.  In Detroit, viewers will be able to enjoy a near-total eclipse beginning at 1:58 p.m. ET and peaking at 3:14 p.m. ET.

New York City will also see a substantial partial eclipse, beginning at 2:10 p.m. ET and peaking around 3:25 p.m. ET.

In Boston it will begin at 2:16 p.m. ET and peak at about 3:29 p.m. ET.

The below table by NASA shows when the eclipse will start, peak and end in 13 cities along the eclipse's path.

What time will the solar eclipse reach peak totality?

Millions more people will have the chance to witness the total solar eclipse this year than during the last total solar eclipse , which was visible from the U.S. in 2017. 

The eclipse's peak will mean something different for cities within the path of totality and for those outside. Within the path of totality, darkness will fall for a few minutes. The longest will last more than 4 minutes, but most places will see between 3.5 and 4 minutes of totality. In cities experiencing a partial eclipse, a percentage of the sun will be obscured for more than two hours.

Mazatlán is set to experience totality at 11:07 am PT. Dallas will be able to see the moon fully cover the sun at 1:40 p.m. CT. Little Rock will start to see the full eclipse at 1:51 p.m. CT, Cleveland at 3:13 p.m. ET and Buffalo at 3:18 p.m. ET. Totality will reach Burlington at 3:26 p.m. ET before moving into the remaining states and reaching Canada around 4:25 p.m.

Outside the path of totality, 87.4% of the sun will be eclipsed in Washington, D.C. at 3:20 p.m. ET, and Chicago will have maximum coverage of 93.9% at 2:07 p.m. CT. New York City is much closer to the path of totality this year than it was in 2017; it will see 89.6% coverage at 3:25 p.m. EDT. 

Detroit is another city that will encounter a near-total eclipse, with 99.2% maximum coverage at 3:14 p.m. ET. Boston will see 92.4% coverage at 3:29 p.m. ET.

What time will the solar eclipse end?

The eclipse will leave continental North America from Newfoundland, Canada, at 5:16 p.m. NT, according to NASA.

At the beginning of the path of totality in Mazatlán, the eclipse will be over by 12:32 p.m. PT, and it will leave Dallas at 3:02 p.m. CT. The eclipse will end in Little Rock at 3:11 p.m. CT, Cleveland at 4:29 p.m. CDT and Buffalo at 4:32 p.m. ET. Burlington won't be far behind, with the eclipse concluding at 4:37 p.m. ET.

Meanwhile, the viewing will end in Chicago at 3:21 p.m. CT, Washington, D.C. at 4:32 p.m. ET, and New York City at 4:36 p.m. ET. 

In Detroit, the partial eclipse will disappear at 4:27 p.m. ET, and in Boston, it will be over at 4:39 p.m. ET.

How long will the eclipse last in total?

The total solar eclipse will begin in Mexico at 11:07 a.m. PT and leave continental North America at 5:16 p.m. NT. From the time the partial eclipse first appears on Earth to its final glimpses before disappearing thousands of miles away, the celestial show will dazzle viewers for about 5 hours, according to timeanddate.com . 

The length of the total solar eclipse at points along the path depends on the viewing location. The longest will be 4 minutes and 28 seconds, northwest of Torreón, Mexico. Near the center of the path, totality takes place for the longest periods of time, according to NASA.

Spectators will observe totality for much longer today than during the 2017 eclipse , when the longest stretch of totality was 2 minutes and 32 seconds.

The moon's shadow seen on Earth today, called the umbra, travels at more than 1,500 miles per hour, according to NASA. It would move even more quickly if the Earth rotated in the opposite direction.

What is the longest a solar eclipse has ever lasted?

The longest known totality was 7 minutes and 28 seconds in 743 B.C. However, NASA says this record will be broken in 2186 with a 7 minute, 29 second total solar eclipse. The next total solar eclipse visible from parts of the U.S. won't happen until Aug. 23, 2044.

Sarah Maddox has been with CBS News since 2019. She works as an associate producer for CBS News Live.

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White House directs NASA to create unified time standard for the Moon and other celestial bodies

NASA will establish a unified standard of time for the Moon and other celestial bodies, as the White House aims to set international norms in space. 

The directive comes amid a growing lunar race among nations and private companies.

The head of the White House Office of Science and Technology Policy (OSTP) instructed the space agency to work with other parts of the US government to devise a plan by the end of 2026,  in a memo seen by Reuters.

The setting would be called Coordinated Lunar Time (LTC). 

The differing gravitational force on the Moon and on other celestial bodies change how time unfolds relative to how it is perceived on Earth. 

The LTC would provide a time-keeping benchmark for lunar spacecraft and satellites that require extreme precision for their missions, NASA's space communications and navigation chief Kevin Coggins says. 

"The same clock that we have on Earth would move at a different rate on the Moon," Mr Coggins said. 

"Think of the atomic clocks at the US Naval Observatory [in Washington]. They're the heartbeat of the nation, synchronising everything," Mr Coggins said.

"You're going to want a heartbeat on the Moon."

Under its Artemis program, NASA is aiming to send astronaut missions to the Moon in the coming years and establish a scientific lunar base that could help set the stage for future missions to Mars.

Dozens of companies, spacecraft and countries are involved in the effort.

An OSTP official said without a unified lunar time standard it would be challenging to ensure the data that transfers between spacecraft are secure and that communications between Earth, lunar satellites, bases and astronauts are synchronised.

Discrepancies in time also could lead to errors in mapping and locating positions on or orbiting the Moon, the official said.

On Earth, most clocks and time zones are based on Coordinated Universal Time, or UTC.

This internationally recognised standard relies on a vast global network of atomic clocks placed in different locations around the world.

They measure changes in the state of atoms and generate an average that ultimately makes up a precise time.

Deployment of atomic clocks on the lunar surface may be needed, according to the OSTP official.

While the US is the only country to have put astronauts on the Moon, others have lunar ambitions.

Countries have their eyes on potential mineral resources on the Moon, and lunar bases could help support future crewed missions to Mars and elsewhere.

In 2023, China said it aims to put its first astronauts on the Moon by 2030.

In January, Japan became the fifth country to put a spacecraft on the Moon.

India last year became the first country to land a spacecraft near the unexplored lunar south pole, and it has announced plans to send an astronaut to the Moon by 2040.

"US leadership in defining a suitable standard — one that achieves the accuracy and resilience required for operating in the challenging lunar environment — will benefit all space faring nations," the OSTP memo stated.

Defining how to implement Coordinated Lunar Time will require international agreements, the memo added.

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BREAKING: Trump says Arizona abortion ruling went too far

Your last-minute guide to Monday's total solar eclipse

A total solar eclipse will cross North America on Monday , offering millions a rare opportunity to see afternoon skies temporarily darken as the moon blocks the face of the sun.

Tune into NBC News NOW as Lester Holt hosts a two-hour special at 2 p.m. ET Monday from Indianapolis Motor Speedway.

The eclipse's path fortuitously cuts across Mexico, 15 U.S. states and a small part of eastern Canada. In all other states in the continental U.S., viewers will be treated to a partial solar eclipse, with the moon appearing to take a bite out of the sun and obscuring part of its light.

Here’s everything you need to know about the rare celestial event.

What is a solar eclipse?

Solar eclipses occur when the sun, moon and Earth align. The moon passes between Earth and sun, temporarily blocking the sun’s light and casting a shadow on Earth.

A total solar eclipse is when the moon fully obscures the sun, whereas a partial solar eclipse means it blocks just a portion of the sun’s face.

Solar eclipses occur only with the new moon. Because the moon’s orbit around Earth is tilted, the three bodies don’t always line up in a way that creates an eclipse.

“Imagine if the moon’s orbit were in the plane of Earth’s orbit around the sun — if that were the case, then every new moon, you’d have a total solar eclipse and every full moon, you’d have a lunar eclipse,” Neil DeGrasse Tyson, director of the Hayden Planetarium at the American Museum of Natural History, told NBC News. “So, because things don’t always align, it lends to the rarity of the event and the specialness of the event.”

Where and when will the eclipse be visible?

This year’s eclipse will follow a slightly wider path over more populated areas of the continental U.S. than other total solar eclipses have in the recent past.

NASA estimates that 31.6 million people live within what’s known as the path of totality, where the total solar eclipse will be visible. An additional 150 million people live within 200 miles of the path, according to the agency.

The path travels through Texas, Oklahoma, Arkansas, Missouri, Illinois, Kentucky, Indiana, Ohio, Pennsylvania, New York, Vermont, New Hampshire and Maine. Tiny parts of Michigan and Tennessee will also be able to witness totality if conditions are clear.

After the eclipse crosses into Canada, it will pass over southern Ontario, Quebec, New Brunswick, Prince Edward Island and Cape Breton, at the eastern end of Nova Scotia.

Those outside the path of totality can still take part in the astronomical event by viewing a partial solar eclipse — visible throughout all 48 states of the contiguous U.S. — or a NASA livestream.

The timing, including how long totality lasts, depends on the location, but some spots will see the moon fully cover the sun for up to 4 minutes and 28 seconds.

Below is a list of timings for some cities along the path of totality, as  provided by NASA . A number of other resources, including NationalEclipse.com  and  TimeandDate.com , can also help people plan.

• Dallas: Partial eclipse begins at 12:23 p.m. CT and totality at 1:40 p.m.
• Little Rock, Arkansas: Partial eclipse begins at 12:33 p.m. CT and totality at 1:51 p.m.
• Cleveland: Partial eclipse begins at 1:59 p.m. ET and totality at 3:13 p.m.
• Buffalo, New York: Partial eclipse begins at 2:04 p.m. ET and totality at 3:18 p.m.
• Lancaster, New Hampshire: Partial eclipse begins at 2:16 p.m. ET and totality at 3:27 p.m.

How to safely view a solar eclipse

It is never safe to gaze directly at the sun, even when it is partly or mostly covered by the moon. Special eclipse glasses or  pinhole projectors  are required to safely view solar eclipses and prevent eye damage. Failing to take the proper precautions can result in severe eye injury,  according to NASA .

Eclipse glasses are thousands of times darker than normal sunglasses and specially made to enable wearers to look at the sun during these kinds of celestial events.

Sky-watchers should also never view any part of the sun through binoculars, telescopes or camera lenses unless they have specific solar filters attached. Eclipse glasses should not be used with these devices, as they will not provide adequate protection.

However, during the few minutes of totality, when the moon is fully blocking the sun, it is safe to look with the naked eye.

Beware of fake eclipse glasses. On legitimate pairs, the lenses should have a silver appearance on the front and be black on the inside. The manufacturer’s name and address should be clearly labeled, and they should not be torn or punctured. Check, as well, for the ISO logo and the code “IS 12312-2” printed on the inside.

If you don’t have eclipse glasses, you can make a homemade pinhole projector, which lets sunlight in through a small hole, focuses it and projects it onto a piece of paper, wall or other surface to create an image of the sun that is safe to look at. 

All you need is two pieces of white cardboard or plain white paper, aluminum foil and a pin or thumbtack. Cut a 1- to 2-inch square or rectangle out of the center of a piece of white paper or cardboard. Tape aluminum foil over that cut-out shape, then use a pin or thumbtack to poke a tiny hole in the foil.

During the eclipse, place a second piece of white paper or cardboard on the ground as a screen and hold the projector with the foil facing up and your back to the sun. Adjusting how far you hold the projector from the second piece of paper will alter the size of the image on the makeshift screen.

What to look for while viewing the total solar eclipse

For people along the path of totality, there are some fun milestones to keep track of as the total solar eclipse unfolds.

As the eclipse progresses and the sun gets thinner in the sky, it will start to get eerily dark, according to Tyson.

When the last beams of sunlight are about to become obscured, look out for the “diamond ring effect”: The sun’s atmosphere will appear as an illuminated halo, and the last light still visible will look like the diamond of a giant ring.

As the sunlight decreases even further, an effect known as Baily’s beads will be created by the moon’s rugged terrain. Tiny “beads” of light will be visible for only a few seconds around the dark moon, as the last bits of sunlight peer through the moon’s mountains and valleys.

When the moon is fully blocking the sun, it is safe to remove eclipse glasses and look at the total solar eclipse with the naked eye.

Some lucky sky-watchers may even catch a glimpse of a comet .

Comet 12P/Pons-Brooks — nicknamed the “ devil comet ” because an eruption last year left it with two distinct trails of gas and ice in the shape of devil horns — is currently visible from the Northern Hemisphere as it swings through the inner solar system.

The comet can be seen in the early evenings by gazing toward the west-northwest horizon. During the eclipse, when skies darken during totality, it may be possible to see the comet near Jupiter, but its visibility will depend on whether it’s in the middle of an outburst and thus brighter than normal.

Most likely, all eyes will be on the alignment of the moon and sun.

“Most people won’t even notice,” Tyson said. “But if you know to look, it’s there.”

When is the next solar eclipse?

The next total solar eclipse will be in 2026, but it will mostly pass over the Arctic Ocean, with some visibility in Greenland, Iceland, Portugal and northern Spain. In 2027, a total solar eclipse will be visible in Spain and a swath of northern Africa.

The next total solar eclipse visible from North America will be in 2033, but only over Alaska. Then in 2044, a total solar eclipse will cross Montana, North Dakota, South Dakota, parts of Canada and Greenland.

The next total solar eclipse to cross the continental U.S. coast-to-coast in will occur in 2045. The path of totality for that eclipse will cut through California, Nevada, Utah, Colorado, New Mexico, Oklahoma, Kansas, Texas, Arkansas, Missouri, Mississippi, Louisiana, Alabama, Georgia and Florida.

Denise Chow is a reporter for NBC News Science focused on general science and climate change.

Lucas Thompson is a content producer for the NBC News Climate Unit.

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What to Know When You’ve Felt an Earthquake

And what else to be aware of when the Earth moves.

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By Camille Baker

If you just felt the ground shaking, you might be wondering what happened or how to react the next time an earthquake strikes. Here are the answers to some common questions about earthquakes.

What causes them?

To understand earthquakes, imagine the Earth as an egg, said Mark Benthien, the communications director for the Statewide California Earthquake Center, a research organization.

The egg’s shell represents the Earth’s crust, and “if you look at it from a worldwide view, there are 12 or so major egg pieces of the crust that are called plates,” Mr. Benthien said. Pieces of the egg’s shell — tectonic plates — move around slowly, about as quickly as your fingernails grow, building up pressure between them.

Most earthquakes occur when the force of the moving tectonic plates exceeds the friction between them. When this happens, the pressure releases suddenly and plates move into, past or away from one another. The pressure is released as seismic waves that pass through the earth, causing the ground to shake.

In rare cases, an earthquake can also occur in the interior of a tectonic plate.

Earthquakes can also be caused by human action , such as the disposal of waste fluids as part of the process of oil production.

Can earthquakes be predicted?

No. It is not possible to predict where or when an earthquake might happen.

However, national seismic hazard maps from the U.S. Geological Survey describe how many strong earthquakes are likely to happen in the next 10,000 years in the United States. More earthquakes with damaging shaking are likely to occur along the West Coast, along Alaska’s south coast and in parts of Hawaii, Puerto Rico and the Virgin Islands.

Globally, earthquakes are most likely near the “Ring of Fire,” which spans the Pacific Ocean at the edges of tectonic plates.

You can prepare ahead of time.

Should people worry about earthquakes before they happen? “It’s not that they should be worried, but they should act,” said Mr. Benthien, who leads the Earthquake Country Alliance, an earthquake coordination organization.

The group suggests securing items in your home ahead of time. Fasten down bookcases and other furniture, as well as your television and even your hot water heater. “As our buildings are built better and better, these aspects are really the cause of the most injuries — not the buildings collapsing, but just all this stuff flying around,” Mr. Benthien said.

You should also prepare at least one kit of supplies to use in the aftermath of an earthquake. Among other things, your emergency kit should include a fire extinguisher, extra doses of medications you may be taking, first-aid supplies, food and water, according to the U.S.G.S .

Earthquake early warning systems such as ShakeAlert can also sometimes provide precious seconds of advance warning before shaking strikes your area, said Robert-Michael de Groot, a coordinator for the program, which is run by the U.S.G.S. This gives you more time to react and avoid injury. “ShakeAlert asks you to do what you already do, but do it sooner,” he said. (Here’s how to sign up for U.S.G.S. early warning systems.)

What should I do if an earthquake happens?

The next time you feel the ground shaking, follow these three steps : Drop to the ground, cover your body to prevent injuries — by crawling under a table, for example — and hold on, according to the Earthquake Country Alliance. If you use a wheelchair or walker, remain seated, bend over and cover your head and neck.

Experts used to advise people to stand under a doorway during an earthquake, but they don’t do that anymore, Dr. de Groot said. “There was a time when the doorway was structurally more stable, stronger than the rest of other parts of the house,” he said. “That really isn’t the case anymore.”

No matter where you are when an earthquake strikes, Dr. de Groot said, stay alert and take protective measures. “If you’re driving on the highway at 70 miles an hour, you may not be able to drop, cover and hold on,” he said. “But there’s an idea about having that situational awareness and knowing how to protect yourself no matter where you are.”

“So staying in your place, dropping, is actually the most important part,” he said, advising people to stay low on the ground, and find a way to protect themselves, wherever they are.

Camille Baker is a news assistant working for The Times’s Data team, which analyzes important data related to weather and elections. More about Camille Baker