is voyager 2 past pluto

Voyager 1 and 2: The Interstellar Mission

An image of Neptune taken by the Voyager 2 spacecraft. Image credit: NASA

NASA has beautiful photos of every planet in our solar system. We even have images of faraway Neptune , as you can see in the photo above.

Neptune is much too distant for an astronaut to travel there with a camera. So, how do we have pictures from distant locations in our solar system? Our photographers were two spacecraft, called Voyager 1 and Voyager 2!

An artist’s rendering of one of the Voyager spacecraft. Image credit: NASA

The Voyager 1 and 2 spacecraft launched from Earth in 1977. Their mission was to explore Jupiter and Saturn —and beyond to the outer planets of our solar system. This was a big task. No human-made object had ever attempted a journey like that before.

The two spacecraft took tens of thousands of pictures of Jupiter and Saturn and their moons. The pictures from Voyager 1 and 2 allowed us to see lots of things for the first time. For example, they captured detailed photos of Jupiter's clouds and storms, and the structure of Saturn's rings .

Image of storms on Jupiter taken by the Voyager 1 spacecraft. Image credit: NASA

Voyager 1 and 2 also discovered active volcanoes on Jupiter's moon Io , and much more. Voyager 2 also took pictures of Uranus and Neptune. Together, the Voyager missions discovered 22 moons.

Since then, these spacecraft have continued to travel farther away from us. Voyager 1 and 2 are now so far away that they are in interstellar space —the region between the stars. No other spacecraft have ever flown this far away.

Where will Voyager go next?

Watch this video to find out what's beyond our solar system!

Both spacecraft are still sending information back to Earth. This data will help us learn about conditions in the distant solar system and interstellar space.

The Voyagers have enough fuel and power to operate until 2025 and beyond. Sometime after this they will not be able to communicate with Earth anymore. Unless something stops them, they will continue to travel on and on, passing other stars after many thousands of years.

Each Voyager spacecraft also carries a message. Both spacecraft carry a golden record with scenes and sounds from Earth. The records also contain music and greetings in different languages. So, if intelligent life ever find these spacecraft, they may learn something about Earth and us as well!

A photo of the golden record that was sent into space on both Voyager 1 and Voyager 2. Image credit: NASA/JPL-Caltech

More about our universe!

Where does interstellar space begin?

Searching for other planets like ours

Play Galactic Explorer!

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Bound for Pluto, Carrying Memories of Triton

A captured ice moon, neptune’s moon triton was the last stop on voyager 2’s tour of the outer planets. it is one of the coldest objects in the solar system and a big brother of pluto, which nasa will visit next year..

By Dennis Overbye

• Nov. 5, 2014

On Aug. 25, 1989, the Voyager 2 spacecraft slipped over the north pole of Neptune , then the most distant planet in the solar system, swerved south at Neptune’s big moon Triton and left the known worlds forever.

Today Voyager 2 is 10 billion miles from the Sun and bumping through the magnetic frontier between the solar system and interstellar space, but planetary scientists are still poring over the data from its last planetfall, at Triton, for clues to what they might expect the next time humanity encounters a new world. That will happen July 14 next year when the New Horizons probe goes past Pluto and its icy moons, of which five are currently known. Pluto, of course, was once upon a time the smallest and most distant planet in the solar system, and the only one that has never been visited.

It turns out, however, that Pluto and Triton are probably long-lost brothers. And so at the end of Voyager’s 12-year-long cosmic picture show, scientists might have seen a preview of coming attractions.

Triton, Neptune’s largest moon and one of the largest in the solar system, is the only one that goes around its planet backward, in the opposite direction of Neptune’s rotation – retrograde, in astronomical lingo. Which means it couldn’t have formed out of the swirling blob of gas and dust from which Neptune presumably condensed back at the dawn of the solar system.

Astronomers have concluded, therefore, that Triton is a stranger from outside Neptune’s system; the moon was kidnapped, they theorize, from the Kuiper Belt, a vast ring of icy debris left over from the formation of the solar system.

It was Pluto’s similarity to Kuiper Belt objects, including an egg-shaped orbit that sometimes took it inside Neptune’s orbit, that helped seal its demise as a planet. In 2006, in a controversial vote of the International Astronomical Union, Pluto was downgraded to the status of a dwarf planet.

The worlds out there in the outer solar system are basically compositions in ice. Triton is one of the brightest and whitest objects known, reflecting 95 percent of the sunlight that hits it. Strengthening the case for brotherhood, Triton and Pluto are basically the same size. Earlier this year Voyager scientists compiled a movie of Voyager 2’s encounter with Triton.

Triton was a fitting capstone to the Voyager adventures, at least here in the solar system. Voyager 2 and its twin, Voyager 1, were launched in 1977 to take advantage of a rare once-in-175-year alignment of Jupiter, Saturn, Uranus and Neptune to tour the outer solar system. In addition to cameras and other gear, each carried a gold record (and instructions on how to play it) with sights and sounds of Earth, including a kiss, as greetings for whoever or whatever was Out There.

Voyager 1 departed the tour early, having detoured to inspect Saturn’s misty moon Titan, and then headed for the stars. Voyager 2 kept going past Uranus and Neptune before looping outward past Triton. The Voyagers cruised on, during wars, recessions, the inauguration of the space shuttle, the crack cocaine epidemic and Ronald Reagan’s “morning in America.” At every planetfall the Voyager scientists, like a graying tribe, reassembled at the Jet Propulsion Laboratory in Pasadena, Calif., for a refresher course on nature’s repertoire.

The result was a cavalcade of discoveries, the biggest being the diversity of the moons that had been hitherto points of light in the telescopes of ground-based astronomers, now revealed as minature planetary systems in their own right, pulsing with surprise and energy: There were sulfur volcanoes on Jupiter’s moon Io, an ocean hiding under the ice of Europa, clouds of nitrogen and methane on smoggy Titan. Today astronomers agree that the leading candidates besides that old standby Mars for harboring life outside Earth – at least in our solar system – are moons of Saturn or Jupiter: the ocean of Europa, jets of water squirting from Saturn’s moon Enceladus, or even in the methane snowdrifts and lakes of Titan.

To that list we might want to add Triton, whose internal energies are pumped up by tidal forces from Neptune. Voyager recorded nitrogen geysers and a landscape that seems formed by water flowing like lava and tectonic shifts. Some of its surface looks like a cantaloupe.

Pluto and its biggest moon, Charon, are now locked in a tidal embrace, keeping the same faces toward each other, meaning that tidal forces in the past could have warmed both bodies and created interior oceans. If so, are those oceans still there?

Where there are heat and liquid water, as the NASA mantra goes, there is always the chance of life as we barely know it.

The never-ending tour continues next summer.

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NASA Marks Milestones for Voyager and New Horizons' Mission to Pluto

The planets were literally aligned on Monday for NASA's celebration of its Voyager mission to the outer planets and its upcoming New Horizons mission to Pluto and beyond.

Monday marked 25 years since the Voyager 2 probe made its flyby of the planet Neptune, and the day also marked a milestone for the New Horizons spacecraft, which was launched eight and a half years ago .

"Today we crossed the orbit of Neptune ... outbound for Pluto to make a little bit of history," said Alan Stern, a planetary scientist at the Southwest Research Institute who heads up the $728 million New Horizons mission. New Horizons is due to fly past Pluto and its moons next July 14, on Bastille Day.

Stern said he considered the flyby to be on a par with Voyager's encounter with Neptune in 1989, in that it would mark the first close-up view of a new frontier in the solar system. To mark the occasion, the New Horizons team released a picture of Neptune and its largest moon, Triton , taken in July from a distance of nearly 2.5 billion miles (4 billion kilometers).

The planet and moon look like little more than specks in New Horizons' picture — and so do Pluto and its largest moon, Charon , which are still about 240 million miles (385 million kilometers) away. But the controversial dwarf planet is due to loom much larger in the coming months.

By next May, the views from New Horizons' high-resolution LORRI camera should outdo the Hubble Space Telescope, Stern said. And during next July's 30,000-mph flyby, the pictures of Pluto are expected to be far better than anything Voyager sent back from Neptune.

During a news briefing at NASA Headquarters in Washington on Monday, Stern paid tribute to Voyager's project scientist, Ed Stone. "We stand on the shoulders of giants, giants like Ed Stone and his Voyager science team, who pioneered how to do the exploration of the deep outer solar system," he said.

Stern also praised the more than 2,000 members of what he called the "New Horizons Corps of Discovery." Thanks to technological advances in the past 25 years, New Horizons' mission cost is about a fifth of Voyager's price tag, Stern said. He noted that the piano-sized probe's seven scientific instruments weigh less than the camera on NASA's Cassini orbiter, and that they draw "less than one-half the power of a 60-watt light bulb." The power is provided by a plutonium-fueled generator that's expected to run for decades.

Focusing on the solar system's icy ring

New Horizons is the first mission to focus on the Kuiper Belt, a ring of icy material that lies more than 2.7 billion miles (4.5 billion kilometers) from the sun.

In preparation for the flyby, the New Horizons team has been using Hubble to survey Pluto's vicinity for moons and debris, as well as for potential targets beyond Pluto in the Kuiper Belt. The effort has turned up four new moons , plus several prospects for a follow-up flyby. Stern said it would take several months to determine whether any of the Kuiper Belt targets were within the spacecraft's fuel range.

New Horizons will be programmed to take pictures of Pluto and all of its five known moons, with the tiny moon Nix looming as a particularly promising target. The probe's instruments will also analyze Pluto's ultra-thin atmosphere and watch for phenomena ranging from planetary rings to clouds and ice geysers. Although there are no pictures that show Pluto's surface in detail, scientists expect it to have the weird-looking "cantaloupe terrain" that Voyager's cameras saw on Triton 25 years ago.

"This is just mouth-watering," Stern said. "It's a scientific wonderland that we look forward to exploring."

Veterans of the twin Voyager missions said they were looking forward to the Pluto flyby as well. "The one thing I'd be surprised about at Pluto is if we weren't truly surprised," said Jeffrey Moore, a planetary scientist at NASA Ames Research Center.

Stern said there'd be booklets and "Plutopalooza" party kits to publicize New Horizons' mission. He promised that during the height of the mission, pictures from Pluto would be posted to the Web on the same day they're received. "We're going to take you along on all of this journey," he said.

Revisiting the question of Pluto's planethood

This week marks yet another anniversary for Pluto's fans and detractors: Eight years ago, the International Astronomical Union voted to reclassify the icy world as a dwarf planet , and declared that such bodies were not planets per se because they did not "clear the neighborhood around their orbits."

Pluto was once seen as a misfit in the solar system, but astronomers have found more objects like it in recent years. So far, the IAU has designated four other worlds as dwarf planets: Eris, Makemake and Haumea, which are beyond Pluto's orbit, plus Ceres in the main asteroid belt. Stern said at least eight more objects (Quaoar, Sedna , Orcus, Ixion, Varuna, 2002 AW197 , Pallas and Vesta ) may well be round enough to fit the IAU's dwarf-planet definition.

"More dwarf planets than all the giants and terrestrials combined," he noted. "You might ask yourself, who are the misfits now?"

During the briefing, a NASA moderator read out a Pluto-centric question submitted via Twitter by William Shatner , who portrayed Captain Kirk in the popular "Star Trek" TV series and several movies.

@NASAGoddard What can we do to get it's planetary status back? There can't be just 8 planets in our solar system. — William Shatner (@WilliamShatner) August 25, 2014

"It's silly that it comes down to whether you think a dwarf planet is a planet or not. That's kind of semantics," Voyager veteran David Grinspoon, a researcher at the Planetary Science Institute, replied.

The University of Colorado's Fran Bagenal jumped in, saying, "Dwarf planets are planets — come on!"

Grinspoon (who has criticized the IAU's ruling in the past) noted that Pluto would probably pass the "Captain Kirk Test" for planethood — that is, a judgment by Kirk and Spock that what they were seeing on the Starship Enterprise's viewscreen was a planet rather than something else. But he said the semantics weren't as important as the prospect of learning about a new planetary frontier.

"We're exploring this new realm of the solar system that we haven't explored before, the realm of dwarf planets," Grinspoon said. "Dwarf planets are this amazing new kind of body that we're about to learn a lot more about. Take us into orbit, Captain. Beam us up to Pluto."

25 Years After Neptune: Reflections on Voyager

August 25, 1989: Neptune is in view. It is the middle of the night and everything is happening fast at NASA's Jet Propulsion Laboratory in Pasadena, California. Voyager team members have had little or no sleep. Vice President Dan Quayle is on the scene and Chuck Berry, of "Johnny B. Goode" fame, is prepping for an outdoor party. This will be "the last picture show" of the grand tour of the solar system by NASA's Voyager mission.

Fast forward to August 25, 2014: New Horizons, the first mission sent to explore dwarf planet Pluto and other icy objects within the Kuiper Belt, is less than one year away from its arrival. And today, New Horizons will cross Neptune's orbit -- the very day that Voyager 2 flew past Neptune 25 years ago.

In celebration of this anniversary, scientists from both missions reflected on Voyager 2's Neptune encounter.

The Encounter - Coming in Close

The Voyager team remembers how extraordinary it was to visit Neptune.

"We had been lucky enough to be in the right place at the right time with the right team, and this was the first and only opportunity we would have for a long time for an up-close and personal view with Neptune and the outer parts of our solar system," said Ralph McNutt, a member of the New Horizons science team who was a plasma data team member on Voyager 2.

New Horizons Principal Investigator Alan Stern, now based at the Southwest Research Institute in Boulder, was a graduate student at the University of Colorado, Boulder, at the time of the encounter.

"As much as anything, just seeing this world unfold from the point of light it had been to become a real place was just enthralling," Stern said.

The Exhilaration at JPL

JPL, which manages the Voyager mission, was an exciting place to be in 1989.

Tom Spilker, who was a member of the Voyager 2 radio science team and who has since moved on from JPL, recalls: "I got this overwhelming feeling inside, as if I was standing in the bow of Captain Cook's expedition into the Gulf of Alaska for the very first time. We were going to places where no one had ever gone before -- we were explorers."

Stern describes JPL as the place where "all the action was" in August of 1989.

"I do remember Carl Sagan calling me at the Goddard Space Flight Center, while I was making collaborative measurements of Neptune's moon Triton with the International Ultraviolet Explorer satellite to say, 'Hey, you're not in the thick of it, but let me tell you what the press doesn't know yet.' He did this so I would feel like an insider," Stern said.

Discoveries

As the spacecraft delivered images of Neptune, scientists uncovered some unexpected findings.

"The Voyager 2 flyby of Neptune was just another example of the surprises we had time after time as Voyager was flying by each of the outer planets," said Ed Stone, project scientist for Voyager at the California Institute of Technology in Pasadena.

The "Great Dark Spot" on Neptune was the first big surprise.

"This dark spot is very similar to the Great Red Spot on our solar system's largest planet, Jupiter, which is a very large storm," Stone said. Because Neptune is six times farther from the sun than Jupiter, it receives a fraction of the energy that Jupiter does -- this dark spot was a complete surprise.

Voyager scientists were also amazed to see that Triton, a moon of Neptune, has active geysers.

"The Triton flyby was my favorite moment partly because it was a bookend. The journey really started with the discovery of volcanoes on Io with Voyager 1, 10 years earlier -- the first bookend. We finished the planetary part of the mission with another bookend, the flyby of Triton, where we discovered a much colder, smaller world that was also geologically active," Stone said.

In the spirit of the Voyager 2 missions to Uranus and Neptune, New Horizons is going where no spacecraft has gone before.

"New Horizons will certainly provide us with new and exciting discoveries, just as Voyager did with its planetary flybys," said Suzanne Dodd of JPL, project manager for Voyager.

Stern summed up the two missions nicely: "The Voyager and New Horizons missions have very important similarities. They are both historic missions of exploration to the very frontier of human knowledge: Voyager with the middle zone of the solar system and the giant planets, and New Horizons with the Kuiper Belt and Pluto. Both excite the public about not only the field of planetary science, but also about exploration and some of the things that our nation and NASA do that really do go down in the history books."

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. The Voyager spacecraft were built and continue to be operated by JPL. Caltech manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.

For more information about Voyager, visit:

http://www.nasa.gov/voyager

Http://voyager.jpl.nasa.gov.

New Horizons was designed, built and is operated by the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. New Horizons, which launched in 2006, is the first mission in NASA's New Frontiers Program of medium-class spacecraft exploration projects.

For more information about New Horizons, visit:

http://www.nasa.gov/newhorizons

Http://pluto.jhuapl.edu/, related terms, explore more.

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Kuiper Belt

Where Will the New Horizons Probe Go After Pluto?

The historic flyby may be over, but the spacecraft should still go on to study even smaller bodies on its path through the Kuiper belt

Victoria Jaggard

Space exploration is often an exercise in delayed gratification. When the New Horizons spacecraft started its voyage to Pluto in 2006, Twitter had just made its public debut. Now, almost a decade later, social media is awash with gorgeous close-ups of the Pluto system, which is turning out to be more textured and complex than anyone imagined.

The closest part of the spacecraft's visit was brief, just a swoop past Pluto's sunlit face that lasted mere hours. But on-board instruments managed to capture a mountain of data that scientists will be sifting through for years, including signs of large impact craters, multicolored terrain and a dusting of Plutonian atmosphere on the poles of the large moon Charon. The first taste of high-resolution data from the flyby is expected to debut this afternoon.

"New Horizons has sent back and will continue to return the most detailed measurements ever taken of Pluto and its system," NASA administrator Charlie Bolden said in the euphoric moments after the team received word that New Horizons had safely completed its close flyby. "It's a historic win for science and for exploration." So with mission scientists hard at work on Earth, what will New Horizons do now that Pluto is in its rear-view mirror?

For the rest of its operational life, the spacecraft will be barreling on through a region of space called the Kuiper belt, a reservoir of cold, icy bodies on the outskirts of the solar system. In late August, mission managers will select a potential follow-up target : a small Kuiper belt object (KB) in the right orbital spot for a possible rendezvous. These objects are some of the oldest, most pristine nubbins of ice and rock in the solar system—leftovers from the process that formed our cosmic neighborhood some 4.6 billion years ago.

"This would be totally unexplored territory. We've never been close to any of these smaller objects in the Kuiper belt," says mission scientist John Spencer of the Southwest Research Institute. "In the Kuiper belt, the original building blocks of the solar system are still out there, many in the locations where they formed. We can see that record in these smaller objects."

Pluto is also a KBO—the largest one known —and that's actually why it's not as good of a record of the solar system's past, says Casey Lisse , a mission scientist at the Johns Hopkins University Applied Physics Laboratory (APL). "Pluto is so big that it has altered itself from when it first formed, it densified and contracted," he says. "How we see that is because it's round—it's big enough to have coalesced by its own self gravity to round out the rough edges." If we want to study the most primordial things in the outer solar system, we need to visit much smaller bodies.

Finding the right targets for an extended mission took a combination of grit and luck. "We would not come close to one by random chance—we definitely needed a target," says Spencer. But if Pluto was just a pixelated orb of light even to the powerful eye of the Hubble Space Telescope, how could anyone hope to find images of more distant objects a fraction of its size?

To the scientists' relief, in October 2014 the search team announced that they had spotted three promising options about a billion miles beyond the Pluto system. Two of the objects are brighter and so are probably bigger; early estimates put them both around 34 miles wide. The third option is smaller, maybe about 15 miles wide, but it would be easier to reach after the Pluto encounter.

"One criteria for selecting the target will be fuel," says Curt Niebur , lead program scientist for NASA's New Frontiers program, which funded the New Horizons mission. A course correction requires a big burn of fuel, so the team has to decide on a target and orient the spacecraft by late October or early November to ensure a safe arrival in 2018.

No matter which KBO makes the cut, New Horizons would then give us an unprecedented look at the landscape in this frigid frontier. "We'll only fly close to one KBO, but we'll observe maybe a dozen from a distance," says Spencer. "We'll be looking for moons, looking at the brightness from different angles, so we'll be exploring other objects, but not in nearly the detail as the main target."

This follow-up mission is not yet a given: the Pluto flyby was the primary point of New Horizons, and the team must apply for more funding to extend their science to a small KBO. On the off-chance that the extension doesn't come through, the New Horizons science team will still be collecting information about the waning breezes of the solar wind in this distant region of space, akin to the magnetic and plasma data being still being collected by the two Voyager probes . Voyager 2 may even serve as a guide for New Horizons as it explores the heliosphere, the bubble of solar material that cocoons our solar system as we hurtle through the galaxy.

Launched in August 1977, Voyager 2 sped past Uranus and Neptune before continuing deeper into the heliosphere. It even crossed near Pluto's orbit in 1989, but aiming for a visit would have meant flying through Neptune—obviously, not an option. Now Voyager 2 is about 9.9 billion miles from Earth, in the outer part of the solar bubble called the heliosheath, and it's still transmitting data. New Horizons will be following a similar path into the mysterious fringes of the solar system.

"It's very fortuitous that New Horizons is in about same heliospheric longitude as Voyager 2," says mission scientist Ralph McNutt at APL. "Even though Voyager 2 is a lot farther out, we kind of have an upstream monitor." As with the Voyager probes, the data returned from New Horizons should help scientists better understand what happens when the solar wind starts to fade and interstellar space takes over—important clues to how the heliosphere shields us from damaging high-energy particles known as galactic cosmic rays. New Horizons probably won't make it to the very edge of the bubble before it runs out of fuel, but it will contribute valuable science for decades to come.

"We should have power until the 2030s, so we can get into the outer part of the heliosphere," says Spencer. "As long as we can continue to get good data—and persuade NASA to pay for it—we will keep getting the data, because we will be in a unique environment that we've never been in before." 

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Victoria Jaggard | | READ MORE

Victoria Jaggard is the science editor for Smithsonian.com. Her writing has appeared in Chemical & Engineering News , National Geographic , New Scientist and elsewhere.

• NO PLACE LIKE HOME

Mission to Pluto Is Like a Next-Gen Voyager

Yesterday, a cosmic coincidence brought together two spacecraft. One, a veteran cosmic explorer, is hurtling ever outward toward the hinterlands of the solar system. The curtain is still waiting to rise on the other, a relative youngster that will soon be stepping into the spotlight.

On August 25, the Pluto-destined New Horizons spacecraft crossed Neptune’s orbit — 25 years to the day after its elder sibling, Voyager 2 , swooped in for a close look at the big, blue ice giant and its curious, geyser-spewing moon.

That cosmic collusion of events helps mark the passing of a torch from one generation of space explorers to another, scientists said during a press conference commemorating the occasion.

A quarter-century ago, Voyager 2 beamed the first good images of Neptune back to Earthly eyes. Now, of course, Neptune isn’t anywhere near where it was then. But that didn’t stop New Horizons from snapping a quick photo as it zoomed over Neptune’s invisible footsteps. From 4 billion kilometers away, the giant planet and its weird moon Triton appear as nothing more than a few tiny pixels, a bit brighter than the inky black background.

For many, exploring the Pluto system will be the modern equivalent of the Voyager mission, says New Horizons principal investigator

“This is the first opportunity in a generation to really explore a new planetary system for the first time,” he said. “When I was growing up, we had the privilege of seeing the first orbiter at Mars, and the first landers. And then, the first missions to Jupiter, to Saturn and Uranus and Neptune. And they were enthralling. And they were mind-blowing in terms of the richness of nature. But there hasn’t been anything like this yet in a long time.”

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I think it’s safe to say that the spotlight will be firmly fixed on New Horizons when it pulls up next to Pluto in July 2015 and sends those first detailed images of the dwarf planet back to Earth. It’ll be like sending a long-awaited interplanetary postcard to millions of people at once.

Pluto is the most farflung system we will have explored. That enormous distance means we know relatively little about the tiny planet, which is faint and hard to see, even for the most powerful telescopes. “Even with all of our modern technology, everything we know about the Pluto system today would probably fit on one piece of paper,” Stern said, gesturing to a regular old piece of paper.

The same could probably be said for several of the giant planets in the 1980s. Putting the issues of politics and funding aside, these are stories of discovery on the grandest scale, of visiting new worlds and revealing new vistas.

Erupting Ice

Take Neptune, for example. Until Voyager arrived in 1989, the planet was a small blue smear in the sky. But Voyager saw much more than that. Fragments of rings gracefully hugged the space near the planet’s equator. A storm the size of Earth left a large, dark blue blotch on the cerulean surface (the Great Dark Spot had disappeared by the time Hubble aimed its eye at Neptune five years later). Methane clouds high in Neptune’s atmosphere hovered in relief above the otherwise smooth, gassy world. “The planet also had the highest speed winds of any that we had seen in the solar system — over 1,000 milers per hour,” says Voyager project scientist Ed Stone . “We were surprised to find such an active atmosphere so far from the sun.”

And then there was Neptune’s strange little moon, Triton . Before Voyager arrived, teams had no idea what they would find. Unlike some of the other outer planet moons, Triton was not formed in the same neighborhood as Neptune. Instead, it grew up far, far away, in a region known as the Kuiper Belt. That distant band of rocky objects is home to the likes of Pluto and its dwarfy brethren.

“Triton was captured by Neptune and probably had geologic activity early in its history. But we had no idea, really, what it was going to look like,” Stone says. “There were many surprises ahead for us.”

The flyby revealed an active world with strange surface features (dubbed “cantaloupe terrain”), fractures, icy lava and geysers strewing dark material across the moon’s bright polar cap.   “Even at the most remote edges, we have an active, alive surface on this cold little moon,” Stone says.

Now, a new animation using re-processed images from Voyager recreates that early flyby.

( Dr. P. Schenk and J. Blackwell, Lunar and Planetary Institute, Houston )

In the intervening 25 years, astronomers have discovered that several of the outer solar system’s icy moons are also erupting. Saturn has its famous little spitter, Enceladus, and Jupiter’s moon Europa is also releasing plumes of water vapor. The Jovian moon Io, of course, is the most volcanically active object in the solar system – another Voyager discovery – and New Horizons has snapped the photos to prove it .

Tiny Planet, Huge Mysteries

Now, some scientists say, it’s possible Pluto is erupting as well.

“The biggest surprise at Neptune was the plumes on Triton,” says JPL’s   Bonnie Buratti , a team member on both the Voyager and New Horizons missions. “I would be surprised at Pluto if we didn’t see something like that.”

Pluto is a Kuiper Belt object, just like Triton. The best images we have of Pluto so far – though they’re just blurry pixels – reveal that the frosty features on the world’s surface are shifting. That suggests some kind of active process is going on out there, Buratti says, even at the freezing fringe of the solar system.

“We have been watching Pluto as a little pinpoint of light in the sky that we see from a telescope,” she says. “And it looks like the frost patterns are changing. I think the polar caps are sublimating away and we’re going to see plumes. I would be surprised if we did not see the same types of plumes on Pluto that we saw on Triton.”

The New Horizons mission will begin to reveal the characteristics of the objects populating the Kuiper Belt, which wasn’t discovered until the 1990s. In it are trillions of comets and who-knows-how-many dwarf planets. Lots. They’re the most common type of body in the solar system, and yet we know nothing about them, Stern says.

“We didn’t know they were there. We thought Pluto was a misfit,” he said. “There are many of them, in fact — more dwarf planets than all the giants and terrestrials combined. You might ask yourself, who’s the misfit now?”

In December, New Horizons will emerge from hibernation as it begins its final approach to the faraway system. The probe is already snapping photos, and last month released an animation of Pluto and its largest moon Charon , circling one another like perpetual planetary dance partners. When it arrives in the system in July, it will map the planet’s surface, study its many moons, and gather as much data as possible before continuing in the footsteps of Voyager and plunging headlong into the unknown.

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News | October 5, 2018

Nasa voyager 2 could be nearing interstellar space.

NASA's Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system. Launched in 1977, Voyager 2 is a little less than 11 billion miles (about 17.7 billion kilometers) from Earth, or more than 118 times the distance from Earth to the Sun.

Since 2007 the probe has been traveling through the outermost layer of the heliosphere -- the vast bubble around the Sun and the planets dominated by solar material and magnetic fields. Voyager scientists have been watching for the spacecraft to reach the outer boundary of the heliosphere, known as the heliopause. Once Voyager 2 exits the heliosphere, it will become the second human-made object, after Voyager 1, to enter interstellar space.

Since late August, the Cosmic Ray Subsystem instrument on Voyager 2 has measured about a 5 percent increase in the rate of cosmic rays hitting the spacecraft compared to early August. The probe's Low-Energy Charged Particle instrument has detected a similar increase in higher-energy cosmic rays.

Cosmic rays are fast-moving particles that originate outside the solar system. Some of these cosmic rays are blocked by the heliosphere, so mission planners expect that Voyager 2 will measure an increase in the rate of cosmic rays as it approaches and crosses the boundary of the heliosphere.

In May 2012, Voyager 1 experienced an increase in the rate of cosmic rays similar to what Voyager 2 is now detecting. That was about three months before Voyager 1 crossed the heliopause and entered interstellar space.

However, Voyager team members note that the increase in cosmic rays is not a definitive sign that the probe is about to cross the heliopause. Voyager 2 is in a different location in the heliosheath -- the outer region of the heliosphere -- than Voyager 1 had been, and possible differences in these locations means Voyager 2 may experience a different exit timeline than Voyager 1.

The fact that Voyager 2 may be approaching the heliopause six years after Voyager 1 is also relevant, because the heliopause moves inward and outward during the Sun's 11-year activity cycle. Solar activity refers to emissions from the Sun, including solar flares and eruptions of material called coronal mass ejections. During the 11-year solar cycle, the Sun reaches both a maximum and a minimum level of activity.

"We're seeing a change in the environment around Voyager 2, there's no doubt about that," said Voyager Project Scientist Ed Stone, based at Caltech in Pasadena. "We're going to learn a lot in the coming months, but we still don't know when we'll reach the heliopause. We're not there yet -- that's one thing I can say with confidence."

The Voyager spacecraft were built by NASA's Jet Propulsion Laboratory in Pasadena, California, which continues to operate both. JPL is a division of Caltech. The Voyager missions are a part of the NASA Heliophysics System Observatory, managed by the Heliophysics Division of the Science Mission Directorate in Washington.

• https://www.nasa.gov/voyager
• https://voyager.jpl.nasa.gov

News Media Contacts Calla Cofield Jet Propulsion Laboratory, Pasadena, Calif. 626-808-2469 [email protected] Jia-Rui Cook Jet Propulsion Laboratory, Pasadena, Calif. 818-354-0724 [email protected] Karen Fox NASA Headquarters, Washington 301-286-6284 [email protected]

News Release: 2018-232

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Why did it take us so long to send a mission to Pluto?

The Grand Tour could have included Pluto

In 1964, Jet Propulsion Laboratory (JPL) scientist Gary Flandro noticed that a so-called “grand tour” of the outer solar system would be possible in the late 1970s given the impending alignment of Jupiter, Saturn, Uranus, and Neptune. Such an alignment is exceptionally rare and occurs only once every 175 years . In keeping with tradition and recognizing the difficulties inherent in using unmanned probes, two missions were planned to increase the chances of success should one mission fail: Voyager 1 and 2. Of key importance, Pluto (at that time formally considered a planet) was also in relative alignment and within reach of flyby explorations by both probes, albeit years after they would reach and survey the giant planets. These outer solar system explorations were made possible by the gravity assists that mission planners were incorporating into the flight plan: these maneuvers would use both the gravity and relative movement of each planet visited by the probes to alter their path and velocity to send them on their way to the next planet in line from the Sun. According to the original plans, both probes would, in turn, visit Pluto.

The Voyagers’ targets rule out a Pluto flyby

By the late 1980s, scientists including Alan Stern and Fran Bagenal had created the Pluto Underground , whose goal was to promote (aggressively) the idea of a mission to explore Pluto in detail. There was some time pressure to undertake such a mission — thanks to its highly eccentric orbit and its position along it, planetary scientists were concerned that Pluto’s atmosphere would “freeze out” and snow down to the surface as it moved away from the Sun, possibly as early as 2010. Furthermore, Pluto’s axis is oriented such that its north pole was inclined towards the Sun and if a spacecraft arrived too late, the southern hemisphere of the planet would be difficult to observe. Funding and administrative problems dogged plans for a Pluto mission, and the year 2000 came and went without any concrete mission on the books.

New Horizons is born

An updated list of space missions: Current and upcoming voyages

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Nasa’s snake-like eels robot impresses in early testssssssss.

NASA is taking astronaut applications. Here’s how to apply

It’s hard to grow food in space. These sensors can help.

NASA Pluto-Bound Spacecraft Crosses Neptune's Orbit

NASA's New Horizons spacecraft has crossed the orbit of Neptune, as it prepares to rendezvous with Pluto less than a year from now.

NASA's Pluto-bound New Horizons spacecraft has traversed the orbit of Neptune. This is its last major crossing en route to becoming the first probe to make a close encounter with distant Pluto on July 14, 2015.

The sophisticated piano-sized spacecraft, which launched in January 2006, reached Neptune's orbit -- nearly 2.75 billion miles (4.4. billion kilometers) from Earth -- in a record eight years and eight months. New Horizons' milestone matches precisely the 25th anniversary of the historic encounter of NASA's Voyager 2 spacecraft with Neptune on Aug. 25, 1989.

"It's a cosmic coincidence that connects one of NASA's iconic past outer solar system explorers, with our next outer solar system explorer," said Jim Green, director of NASA's Planetary Science Division, NASA Headquarters in Washington. "Exactly 25 years ago at Neptune, Voyager 2 delivered our 'first' look at an unexplored planet. Now it will be New Horizons' turn to reveal the unexplored Pluto and its moons in stunning detail next summer on its way into the vast outer reaches of the solar system."

New Horizons now is about 2.48 billion miles (nearly 4 billion kilometers) from Neptune -- nearly 27 times the distance between Earth and our sun -- as it crosses the giant planet's orbit at 7:04 p.m. PDT (10:04 p.m. EDT) Monday. Although the spacecraft will be much farther from the planet than Voyager 2's closest approach, New Horizons' telescopic camera was able to obtain several long-distance "approach" shots of Neptune on July 10.

"NASA's Voyager 1 and 2 explored the entire middle zone of the solar system where the giant planets orbit," said Alan Stern, New Horizons principal investigator at the Southwest Research Institute in Boulder, Colorado. "Now we stand on Voyager's broad shoulders to explore the even more distant and mysterious Pluto system."

Several senior members of the New Horizons science team were young members of Voyager's science team in 1989. Many remember how Voyager 2's approach images of Neptune and its planet-sized moon Triton fueled anticipation of the discoveries to come. They share a similar, growing excitement as New Horizons begins its approach to Pluto.

"The feeling 25 years ago was that this was really cool, because we're going to see Neptune and Triton up-close for the first time," said Ralph McNutt of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, who leads the New Horizons energetic-particle investigation and served on the Voyager plasma-analysis team. "The same is happening for New Horizons. Even this summer, when we're still a year out and our cameras can only spot Pluto and its largest moon as dots, we know we're in for something incredible ahead."

Voyager's visit to the Neptune system revealed previously unseen features of Neptune itself, such as the Great Dark Spot, a massive storm similar to, but not as long-lived, as Jupiter's Great Red Spot. Voyager also, for the first time, captured clear images of the ice giant's ring system, too faint to be clearly viewed from Earth. "There were surprises at Neptune and there were surprises at Triton," said Ed Stone, Voyager's long-standing project scientist from the California Institute of Technology in Pasadena. "I'm sure that will continue at Pluto."

Many researchers feel the 1989 Neptune flyby -- Voyager's final planetary encounter -- might have offered a preview of what's to come next summer. Scientists suggest that Triton, with its icy surface, bright poles, varied terrain and cryovolcanoes, is a Pluto-like object that Neptune pulled into orbit. Scientists recently restored Voyager's footage of Triton and used it to construct the best global color map of that strange moon yet -- further whetting appetites for a Pluto close-up.

"There is a lot of speculation over whether Pluto will look like Triton, and how well they'll match up," McNutt said. "That's the great thing about first-time encounters like this -- we don't know exactly what we'll see, but we know from decades of experience in first-time exploration of new planets that we will be very surprised."

Similar to Voyager 1 and 2's historic observations, New Horizons also is on a path toward potential discoveries in the Kuiper Belt, which is a disc-shaped region of icy objects past the orbit of Neptune, and other unexplored realms of the outer solar system and beyond.

"No country except the United States has the demonstrated capability to explore so far away," said Stern. "The U.S. has led the exploration of the planets and space to a degree no other nation has, and continues to do so with New Horizons. We're incredibly proud that New Horizons represents the nation again as NASA breaks records with its newest, farthest and very capable planetary exploration spacecraft."

Voyager 1 and 2 were launched 16 days apart in 1977, and one of the spacecraft visited Jupiter, Saturn, Uranus and Neptune. Voyager 1 now is the most distant human-made object, about 12 billion miles (19 billion kilometers) away from the sun. In 2012, it became the first human-made object to venture into interstellar space. Voyager 2, the longest continuously operated spacecraft, is about 9 billion miles (15 billion kilometers) away from our sun.

New Horizons is the first mission in NASA's New Frontiers program. APL manages the mission for NASA's Science Mission Directorate at NASA Headquarters. APL also built and operates the New Horizons spacecraft.

The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory in Pasadena, California. The Voyager missions are part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate.

To view the Neptune images taken by New Horizons and learn more about the mission, visit:

http://www.nasa.gov/newhorizons

For more information about the Voyager spacecraft, visit:

http://www.nasa.gov/voyager

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