ESA /NASA's Hubble telescope finds Kuiper belt targets for New Horizons Pluto mission

This is an artist's impression of a Kuiper Belt object (KBO), located on the outer rim of our solar system at a staggering distance of 4 billion miles from the Sun. 

Unlike asteroids, KBOs have not been significantly heated by the Sun, and so are thought to represent a pristine, well preserved, deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago. 

A Hubble survey uncovered three KBOs, ranging from 27 to 35 miles across, that are potentially reachable by NASA's New Horizons spacecraft after it passes by Pluto in mid-2015. 

The Sun appears as a bright star at image center in this graphic, which represents the view from the KBO. 

The Earth and other inner planets are too close to the Sun to be seen in this illustration. 

The bright "star" to the left of the Sun is the planet Jupiter, and the bright object below the Sun is the planet Saturn. 

Two bright pinpoints of light to the right of the Sun, midway to the edge of the frame, are the planets Uranus and Neptune, respectively. 

The planet positions are plotted for late 2018 when the New Horizons probe reaches a distance of 4 billion miles from the Sun. The Milky Way appears in the background. 

Credit: NASA, ESA, and G. Bacon (STScI)

NASA's New Horizons Spacecraft showing the Scientific Instrument Payload.

Credit: Nasa

Peering out to the dim, outer reaches of our solar system, ESA /NASA's Hubble Space Telescope has uncovered three Kuiper Belt objects (KBOs) the agency's New Horizons spacecraft could potentially visit after it flies by Pluto in July 2015.

The KBOs were detected through a dedicated Hubble observing program by a New Horizons search team that was awarded telescope time for this purpose.

The NASA New Horizons Mission Timeline. (Click on the image to see the full HD imnage)

Credit: Nasa

"This has been a very challenging search, and it's great that in the end Hubble could accomplish a detection, one NASA mission helping another," said Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, principal investigator of the New Horizons mission.

The Kuiper Belt is a vast rim of primordial debris encircling our solar system. KBOs belong to a unique class of solar system objects that has never been visited by spacecraft and which contain clues to the origin of our solar system.

The KBOs that Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the size of Pluto.

Unlike asteroids, KBOs have not been heated by the Sun, and are thought to represent a pristine, well preserved, deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago.

The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto.

The New Horizons team started to look for suitable KBOs in 2011 using some of the largest ground-based telescopes on Earth.

They found several dozen KBOs, but none were reachable within the fuel supply available aboard the New Horizons spacecraft.

"We started to get worried that we could not find anything suitable, even with Hubble, but in the end the space telescope came to the rescue," said New Horizons science team member John Spencer of SwRI.

"There was a huge sigh of relief when we found suitable KBOs; we are 'over the moon' about this detection."

Following an initial proof of concept of the Hubble pilot observing program in June, the New Horizons team was awarded telescope time by the Space Telescope Science Institute for a wider survey in July.

When the search was completed in early September, the team identified one KBO that is "definitely reachable" and two other potentially accessible KBOs that will require more tracking over several months to know whether they too are accessible by the New Horizons spacecraft.

This was a needle-in-a-haystack search for the New Horizons team because the elusive KBOs are extremely small, faint, and difficult to pick out against myriad background stars in the constellation Sagittarius, which is in the present direction of Pluto.

The three KBOs identified are each a whopping 1 billion miles beyond Pluto. Two of the KBOs are estimated to be as large as 34 miles (55 kilometers) across, and the third is perhaps as small as 15 miles (25 kilometers).

New Horizons has One Last Sleep til Pluto

On Aug. 25, New Horizons crossed the orbit of Neptune-the last planetary orbit crossing during cruise.

Now the spacecraft is outbound for Pluto.

On Aug. 29 the team put New Horizons into hibernation for the final time, prior to its encounter with Pluto.

This last hibernation lasts 99 days and ends on Dec. 6.

After seven-plus years of hibernating through most of the 2.5-billion mile journey from Jupiter to Pluto and the inner reaches of the Kuiper Belt, the spacecraft has reached the final, short leg of cruise.

New Horizons will be re-awakened for the last time in just 10 weeks. Once this has been done, 'encounter' preparations will begin, and six weeks later, the Pluto encounter itself will begin.

At that time, the New Horizons team will have good cause to celebrate. They will have reached the outer end of our Solar System, twenty-five years after first wondering if Pluto might someday be explored.

This summer's eighth and final "pre-Pluto" spacecraft and payload Active Check Out (ACO-8) lasted from June through late August. All spacecraft subsystems-both prime and backup-were checked out and were found to be operating successfully.

Additionally, the team performed their first course-correction since 2010, uploaded the final autonomy system software for the encounter, checked out all seven payload instruments, conducted some final instrument calibrations, and performed their first optical navigation campaign to home in on Pluto using New Horizons' Long Range Reconnaissance Imager (LORRI).

Those activities went well, and so did many others, including more sampling of the heliospheric plasma and dust environment with PEPSSI, SWAP and Student Dust Counter instruments.

The only real anomaly of the entire ACO-8 was a failed startup of a single Alice ultraviolet spectrometer observation.

That observation was to study the distribution of interplanetary hydrogen near Neptune's orbit; it failed because Alice was much colder than was planned, and onboard software "safed" (or turned off) Alice's high-voltage power supply when it took too long to get to its set point voltages.

The team have now learned that they need to adjust some timing settings for future power-ons when Alice will be as cold or even colder, On its approach to Pluto.

Additionally, ACO-8 was the subject of a recent news story from New Horizons: While testing the methods to be used to search for hazards in the Pluto system on approach, the spacecraft detected Pluto's little moon Hydra.

The team didn't think it would be possible to see Hydra until early in 2015, when the spacecraft was much closer, but science team members John Spencer and Hal Weaver found Hydra in the July hazard-sequence test.

The New Horizons team sees the early detection of Hydra as good news, because it anticipates their ability to detect currently unknown moons and rings close to Pluto.

New Horizons: Awaiting New Results on Pluto's Atmosphere

Artist's impression of Pluto, with its wispy atmosphere.

Data from New Horizons' Alice ultraviolet spectrograph will answer a full range of questions about the composition and structure of that atmosphere.

What is Pluto's atmosphere like? It seems like I've been wondering about that for decades!

We've known so little for so long about Pluto's atmosphere, other than it's low-pressure, made mostly of molecular nitrogen (with a little methane and carbon monoxide mixed in) and may be quite extended, it's nice to realise that we'll know a whole lot more after New Horizons visits in summer 2015.

Alice UV spectrograph

My professional interests on New Horizons lie with Pluto's upper atmosphere, what it's made of, how it interacts with space, and how it is processed by sunlight into different gases and aerosols.

A problem in planning atmospheric observations for New Horizons during the flyby is that we really don't know what to expect.

Only a few models have been made that try to predict the composition of Pluto's atmosphere, and they don't agree very much with each other because of the many present uncertainties.

So our plans generally include a lot of survey-type observations, where we try not to assume too much about what we will detect, but are ready for anything.

The best example of this is the Pluto solar occultation observation.

Just Joking!

The Alice ultraviolet spectrograph will watch the Sun set (and then rise again) as New Horizons flies through Pluto's shadow, about an hour after closest approach.

Watching how the different colours of sunlight fade (and then return) as New Horizons enters (and leaves) the shadow will tell us nearly all we could ask for about composition (all gases have unique absorption signatures at the ultraviolet wavelengths covered by Alice) and structure (how those the absorption features vary with altitude will tell us about temperatures, escape rates and possibly about dynamics and clouds).

When the New Horizons data start coming down, these are the data I'll be waiting for the most!

New Horizons: Team spot Charon, the tiny moon of Pluto

Artist’s conception of the New Horizons spacecraft flying past Pluto and Charon, one of the dwarf planet’s moons. 

Credit: Johns Hopkins University/APL 

The New Horizons team spotted Charon, the tiny moon of Pluto in July, about six months ahead of when they expected to.

You can check it out in the images below.

The find is exciting in itself, but it also bodes well for the spacecraft's search for orbital debris to prepare for its close encounter with the system in July 2015.

Most of Pluto's moons were discovered while New Horizons was under development, or already on its way.

Mission planners are thus concerned that there could be moons out there that aren't discovered yet, moons that could pose a danger to the spacecraft if it ended up in the wrong spot at the wrong time.

That's why the team is engaging in long-range views to see what else is lurking in Pluto's vicinity.

"We're thrilled to see it, because it shows that our satellite-search techniques work, and that our camera is operating superbly, but it's also exciting just to see a third member of the Pluto system come into view, as proof that we're almost there," stated science team member John Spencer, of the Southwest Research Institute.

Hydra was spotted using the spacecraft's Long Range Reconnaissance Imager (LORRI), which took 48 images of 10 seconds apiece between July 18 and July 20.

Then the team used half the images, the ones that show Hydra better, to create the images you see above.

The spacecraft was still 267 million miles (430 million kilometers) from Pluto when the images were taken.

Another moon discovered around the same time as Hydra, Nix, is still too close to be seen given it's so close to Pluto, but just wait.

Meanwhile, scientists are busily trying to figure out where to send New Horizons after Pluto.

In July, researchers using the Hubble Space Telescope began a full-scale search for a suitable Kuiper Belt Object, which would be one of trillions of icy or rocky objects beyond Neptune's orbit.

Flying past a KBO would provide more clues as to how the Solar System formed, since these objects are considered leftovers of the chunks of matter that came together to form the planets.

Watch the difference: Pluto’s moon Hydra stands out in these images taken by the New Horizons spacecraft on July 18 and 20, 2014. 

Credit: NASA /Johns Hopkins University Applied Physics Laboratory /Southwest Research Institute

New Horizons crossed the orbit of Neptune

Artist's concept of NASA's New Horizons probe flying past the dwarf planet Pluto on July 14, 2015. 

New Horizons crossed the orbit of Neptune on Aug. 25, 2014, 25 years to the day after NASA's Voyager 2 spacecraft flew by the distant blue planet.

Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

A speedy NASA probe has crossed the orbit of Neptune, notching one more spaceflight milestone on its way toward a historic flyby of Pluto next summer.

New Horizons, which is scheduled to zoom through the Pluto system on July 14, 2015, passed Neptune's orbit today (Aug. 25), 25 years to the day after NASA's Voyager 2 probe executed the first-ever flyby of faraway Neptune and its icy moon Triton.

New Horizons team members took the opportunity provided by this spaceflight coincidence to pay tribute to Voyager 2, the only probe ever to visit the "ice giant" planets Uranus and Neptune.

NASA Probe Sees Pluto and Its Moon Charon - Video

A NASA spacecraft hurtling toward a 2015 rendezvous with Pluto has captured an amazing video of the dwarf planet and its largest moon, Charon.

The New Horizons probe used its onboard telescope to record a video of Charon and Pluto locked in their orbital dance.

The movie is composed of 12 individual images taken from July 19 through July 24, almost exactly one year before the spacecraft's flyby of the distant dwarf planet, which is scheduled for July 14, 2015.

"The image sequence showing Charon revolving around Pluto set a record for close-range imaging of Pluto, they were taken from 10 times closer to the planet than the Earth is," New Horizons principal investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado, said in a statement. "But we'll smash that record again and again, starting in January, as approach operations begin."

"We are really excited to see our target and its biggest satellite in motion from our own perch, less than a year from the historic encounter ahead!" he added.

New Horizons was about 265 million miles (426 million kilometers) from Pluto when it took the 12 photos, researchers said.

New Horizons baseline spacecraft design. 

Image Credit: The Boeing Company

What is beneath the cracked surface of Pluto's moon Charon?

An artist’s concept of Pluto as viewed from the surface of one its moons. 

Pluto is the large disk at the center of the image. Charon is the smaller disk to the right. 

Credit: NASA, ESA and G. Bacon (STScI)

Is there evidence of an ocean-past or present-waiting to surprise us on Charon?

It isn't impossible. In fact, it might be likely.

What used to be the smallest planet in our solar system has, comparatively, the biggest moon.

Pluto, now classified as a dwarf planet, has a moon, Charon, almost 1/8th its own mass and almost half its physical volume.

Our Moon, by comparison, has about 1% of the Earth's mass and only 2% of its volume.

Charon is so large compared to Pluto that some astronomer's consider the two to be a sort of binary dwarf-planet system, as opposed to a moon-and-planet system.

Both Charon and our Moon are believed to have formed in the same way: when they were knocked off their parent planets.

Enormous collisions liquified parts of the Earth and Pluto. The debris was thrown into orbit where it later cooled.

In the process of cooling into solid bodies around the Earth and Pluto, the Moon and Charon became locked to their parent planets' orbits.

That locking of the planets to moons results in tides: here on Earth, on the Moon, and, we believe, on Pluto and Charon.

An analysis by scientists at Goddard suggests that tides on Pluto and Charon could have been especially high as Charon cooled.

This is because the part of Pluto knocked into orbit didn't get very far. Charon formed incredibly close to Pluto: only 19,000 km (12,000 miles) away.

By comparison, our Moon is currently 384,000 km (238,855 mi) from Earth. Initially, the orbit might not have been very circular, either: it might have been more eccentric or elliptical-shaped.

Eccentrically-moving, close-by Charon would have pulled on Pluto, and Pluto would have pulled back, resulting in heating of both planets and, maybe, an ocean under Charon's ice shell.

Alyssa Rhoden

Depending on exactly how Charon's orbit evolved, particularly if it went through a high-eccentricity phase, there may have been enough heat from tidal deformation to maintain liquid water beneath the surface of Charon for some time," said Alyssa Rhoden of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

"Using plausible interior structure models that include an ocean, we found it wouldn't have taken much eccentricity (less than 0.01) to generate surface fractures like we are seeing on Europa."

Artist impression of the New Horizons spacecraft as it approached Jupiter en route to Pluto. 

Credit: NASA

On icy moons like Europa and Enceladus, tidal forces exerted by their parent planets cause massive surface cracks to form.

Those cracks are easily appreciated by passing spacecraft. According to Rhoden and colleagues' model, Charon's surface should be similarly cracked.

We expect to see evidence of this fractured surface geology as the New Horizons spacecraft approaches Pluto. New Horizons will pass directly over Pluto and Charon, briefly, on July 15th 2015.

Charon was discovered thirty-five years ago, in 1978, but well-photographed for the first time by New Horizons in 2013.

With the 2015 close-up just around the corner, scientists are working swiftly to make best use of surface photographs returned by the spacecraft.

New Horizons will give us the ability to resolve objects as small as a football field on part of the surface of Pluto and Charon.

With pictures of that detail and models such as this one, we may be able to look backwards in time to determine details about both bodies, such as how thick their ice shells were when they formed.

Studying patterns of fractures in Charon's surface is critical to building accurate models of the ice shell and layers beneath.

"Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon's interior and how easily it deforms, and how its orbit evolved," said Rhoden.

"By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity."

The oceans of certain icy moons with surface fractures are considered to be places where extraterrestrial life might be found.

Like Charon, Europa and Enceladus are very cold and very distant from the sun. In all three cases, the formation and maintenance of life would depend upon a reliable energy source as well as elements that can participate in the chemistry of life, such as carbon, nitrogen, and phosphorus.

New Horizons Long Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon. 

When these images were taken on July 1 and July 3, 2013, the New Horizons spacecraft was still about 550 million miles (880 million kilometers) from Pluto.

On July 14, 2015, the spacecraft is scheduled to pass just 7,750 miles (12,500 kilometers) above Pluto’s surface, where LORRI will be able to spot features about the size of a football field. 

Credit: NASA /Johns Hopkins University Applied Physics Laboratory /Southwest Research Institute (SRI)

It is unknown if a potential ocean on Charon may have harbored these ingredients or if the ocean there existed for long enough for life to form.

The same questions apply to any ancient ocean on any moon in our Solar System or any other. The first step on Charon is to find the fractures, and then go looking for the warmth that liquid water.

"Since it's so easy to get fractures, if we get to Charon and there are none, it puts a very strong constraint on how high the eccentricity could have been and how warm the interior ever could have been," said Rhoden.

"This research gives us a head start on the New Horizons arrival, what should we look for and what can we learn from it. We're going to Pluto and Pluto is fascinating, but Charon is also going to be fascinating."

Pluto: Three possible models of Dwarf Planet ahead of New Horizons visit

Interior structure models assumed for Pluto.

Two space researchers, Amy Barr, with Brown University and Geoffrey Collins with Wheaton College, have published a paper in the journal Icarus in which they describe three possible interior models of the former planet Pluto.

They suggest the possibilities include: 

1. an undifferentiated rock/ice mixture, 
2. a differentiated rock/ice mixture, and an ocean covered with ice. 
3. The third possibility suggests the likelihood, they claim, of tectonic action on the dwarf planet.

Pluto

A close up view of the planet by space probe New Horizons due to arrive next year, should help clarify which scenario is most likely.

Amy Barr

Scientists believe that Pluto came to exist as it does today, in part due to a collision billions of years ago that led also to the formation of its moon Charon.

Charon

When celestial bodies collide, not only do they knock each other around, they produce heat—heat, the researchers suggest that could still be evident today.

Barr and Collins are leading towards a theory that suggests that shortly after impact, Pluto and Charon were much closer together, the gravity attraction between them would have caused both to be egg shaped.

As time passed, melted ice from the impact would have created an icy crust on top of an ocean on Pluto, and then, as Charon moved farther away, the attractive pull would have diminished, causing ice plates to form and crack against one another, a form of tectonics.

Geoffrey Collins

If that were the case, the two add, then in all likelihood, when New Horizons begins sending back images, they should see evidence of such tectonic action—plate edges thrust into the air, for example.

There's just one catch, Pluto circles the sun in an elliptical orbit, thus sometimes it's much closer to the sun than other times.

When near, it has a defined atmosphere, when far away however, its atmosphere actually freezes to its surface, something that could hide ridges in the ice and thus evidence of both tectonic activity and an ocean beneath the crust of ice.

New Horizons

Artist concept of New Horizons spacecraft.

Johns Hopkins University Applied Physics Laboratory (JHUAPL) /Southwest Research Institute (SwRI)

Since New Horizons will arrive during a time when its atmosphere is frozen to the surface, it might be difficult to determine which of the three proposed models actually describes the relationship between its exterior and interior.

Barr and Collins are optimistic that even in such a scenario, ridges should be apparent, proving that beneath Pluto's icy surface, lies an ocean, one that future researchers might one day sample.

More information: Tectonic Activity on Pluto After the Charon-Forming Impact, Icarus, Available online 4 April 2014. dx.doi.org/10.1016/j.icarus.2014.03.042 . Available on Arxiv: xxx.lanl.gov/abs/1403.6377

NASA New Horizons: Volcanic Eruption Plume on Jupiter's moon Io - Video

Incredible footage of an eruption on Io, Jupiter’s third moon, considered the most volcanic place in the solar system, has been released by the US space agency.

The video, taken by the New Horizons spacecraft, pictures a drama that unfolded more than 6.2 million km away from Earth back in 2007. NASA only made it public on Tuesday.

Some 400 active volcanoes are situated on Io and they produce plumes as high as 500 kilometers above Io’s surface.

The latest eruption captured by the spacecraft saw plumes over 300 kilometers in height, according to NASA’s website.

The reason for the extreme volcanic activity on Io is that it’s “locked in a perpetual tug of war between the imposing gravity of Jupiter and the smaller, consistent pulls of its neighboring moons,” NASA explains.

As a result, Io’s orbit is distorted and it stretches.

This causes friction and intense heat inside the moon, which in turn triggers eruptions across its surface.

Controversial New Horizons Stamp

New Horizons' flight to explore the Pluto system in July 2015 will be a historic accomplishment for the U.S. space program, for planetary science, and indeed for all humankind.

Plans for the flyby are well under way - and now, so is an effort to petition the U.S. Postal Service to commemorate the historic achievements of New Horizons on a stamp.

The mission team launches that petition today, in early 2012, and plans to submit the petitioners' names and a formal proposal to the U.S. post office knowing it often takes three years or longer for a proposal to result in an actual stamp.

"You can help make this happen," says New Horizons Principal Investigator Alan Stern. "We're asking people to sign the petition, because the post office considers not just the merits of a new stamp proposal, but also whether it is supported by a significant number of people.

This is a chance for us all to celebrate what American space exploration can achieve though hard work, technical excellence, the spirit of scientific inquiry, and the uniquely human drive to explore."

The Southwest Research Institute's Dan Durda, a space scientist and artist whose works appear on the New Horizons website and many other venues, has designed a concept for a new Pluto stamp - which would be the successor to the 1990 U.S. postage stamp that labeled Pluto as "Not Yet Explored."

You can help by signing the petition urging the post office's Citizen Stamp Advisory Committee to recommend a New Horizons stamp to the postmaster general.

Pluto's Hidden Ocean - New Horizons

An artist's concept of the New Horizons spacecraft as it visits Pluto in 2015.

Instruments will map Pluto and its moon, Charon, providing detail not only on the surface of the dwarf planet, but also about its shape, which could reveal whether or not an ocean lies beneath the ice. 

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

When NASA's New Horizons cruises by Pluto in 2015, the images it captures could help astronomers determine if an ocean is hiding under the frigid surface, opening the door to new possibilities for liquid water to exist on other bodies in the solar system.

New research has not only concluded such an ocean is likely, but also has highlighted features the spacecraft could identify that could help confirm an ocean's existence.

Pluto's outer surface is composed of a thin shell of nitrogen ice, covering a shell of water ice.

Planetary scientists Guillaume Robuchon and Francis Nimmo, both of the University of California at Santa Cruz, wanted to find out whether or not an ocean could exist underneath this icy shell, and what visible signs such an ocean might produce on the surface.

The pair modeled the thermal evolution of the dwarf planet and studied the behavior of the shell to see how the surface would be affected by the presence of an ocean below.

Searching the surface
Ironically, the easiest feature to identify would appear if no ocean existed. As spherical bodies spin, their angular momentum tends to push material towards the equator, forming a bulge.

If Pluto boasts a liquid layer, the ice would flow, reducing such a protrusion. Thus, the appearance of a "frozen-in"primordial bulge, left over from when Pluto spun more rapidly, would signify a lack of ocean.

"If the bulge is present, it will be about 6 miles (10 km) high, so it should be readily detectable," Nimmo said. New Horizons project scientist Hal Weaver agreed on the last point.

"New Horizon imaging will measure the shape of Pluto very accurately."

New Horizons Web Site

The computer-generated images below are simulated views of New Horizons' location in the solar system.

The images were created using the Satellite Tool Kit (STK) software, which was developed by Analytical Graphics, Inc. Images are updated every hour.

Click here to follow New Horizons as it passes each planet's orbit, starting with our own Moon.


This image shows New Horizons' current position.

The green segment of the line shows where New Horizons has traveled since launch; the red indicates the spacecraft's path toward Jupiter, Pluto and beyond.

Positions of stars with magnitude 12 or brighter are shown from this perspective, which is above the Sun and "north" of Earth's orbit.

For more information follow this link New Horizons Web Site

NASA: Recent Pics of Jupiter's Moons

Jupiter's Moons

Jupiter's Moons
On Jan. 7, 1610, Galileo Galilei's improvements to the telescope enabled humanity to see Jupiter's four largest moons for the first time. Io, Europa, Ganymede and Callisto--the so-called Galilean satellites--were seen by the Long Range Reconnaissance Imager on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter.

Io is notable for its active volcanism, which New Horizons studied extensively. On the other hand, Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa's surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it.

New Horizons spied Ganymede from 2.2 million miles away. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior.

Scientists are using the infrared spectra New Horizons gathered of Callisto's ancient, cratered surface to calibrate spectral analysis techniques that will help them to understand the surfaces of Pluto and its moon Charon when New Horizons passes them in 2015.

Image Credit: NASA/JHU-APL/Southwest Research Institute