posted 01-12-2006 03:01 PM               

NASA's New Horizons

In 1930, the Lowell Observatory in Arizona announced the discovery of a small, odd world, roaming beyond the known planets in a region barely visible through the most powerful telescopes.

Seventy-five years later that historic find – Pluto – remains almost as much of a mystery as it was then. No spacecraft has ever visited it, and not even the Hubble Telescope can spot details on its rocky, icy surface.

Yet with the New Horizons mission, NASA looks to unlock one of the solar system's last, great planetary secrets.

"The United States has made history by being the only nation to reach every planet from Mercury to Neptune with a space probe," said New Horizons principal investigator Alan Stern, of the Southwest Research Institute, Boulder, Colo. "With New Horizons, the U.S. can complete the reconnaissance of the solar system and round out our knowledge of the planets."

New Horizons will cross the span of the solar system – in record time – and conduct flyby studies of Pluto and its moon, Charon, in 2015. The seven science instruments on the piano-sized probe will shed light on the bodies' surface properties, geology, interior makeup and atmospheres.

It will mark humankind's first voyage into the "third zone" of the solar system known as the Kuiper Belt, populated by smaller, icy objects different than the rocky inner planets or the outer gas giants.

posted 01-19-2006 02:06 PM               

New Horizons launches to Pluto

NASA's New Horizons spacecraft launched aboard an Atlas V rocket today at 2:00 p.m. EST from Complex 41 at Cape Canaveral Air Force Station in Florida. The unmanned probe is headed for a distant rendezvous with the planet Pluto in July 2015.

Credit: collectSPACE.com/Robert Z. Pearlman

Two consecutive launch attempts earlier this week were foiled by high winds at the launch site and a power outage at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., which operates the spacecraft now that the mission is underway.

As the first spacecraft to visit Pluto and its moon Charon, New Horizons looks to unlock one of the solar system's last, great planetary secrets. The New Horizons spacecraft will cross the entire span of the solar system and conduct flyby studies of Pluto and Charon. The seven science instruments on the piano-sized probe will shed light on the bodies' surface properties, geology, interior makeup and atmospheres.

The first 13 months of the mission include spacecraft and instrument checkouts, instrument calibrations and trajectory correction maneuvers.

There will also be rehearsals for an encounter with Jupiter in spring 2007, in which the giant planet will provide a slingshot-like gravity boost that could save New Horizons up to three years of flight time. This encounter will be followed by an approximately eight-year cruise to Pluto.

posted 10-19-2008 09:01 AM               

1,000 Days on the Road to Pluto - Time Flies and So Does New Horizons

It's hard to believe, but Oct. 15 will be the 1,000th day of flight for New Horizons. And in that time we've traveled so far that only four other spacecraft - Pioneers 10 and 11 and Voyagers 1 and 2 - have ventured farther. Can you believe it's been this long? Sometimes it seems so, but other times, it seems like we just blasted off from Florida on that cool afternoon of Jan. 19, 2006.

Of course, it's been a busy 1,000 days for everyone involved. After an exciting launch day none of us will ever forget, we spent the first four months of flight checking out our spacecraft systems and making the initial course corrections to put us right down the middle of the pike to our Jupiter flyby aim point.

posted 10-28-2008 12:40 AM               

To Pluto, with postage

Have you heard the one about the two men looking to launch a probe to Pluto who went to Burger King to find a part for their spacecraft?

posted 07-10-2009 08:29 AM               

Rise and Shine: New Horizons Wakes for Annual Checkout

New Horizons is up from the longest nap of its cruise to Pluto, as operators "woke" the spacecraft from hibernation yesterday for its annual series of checkouts and tests.

The actual wake-up call went in months ago; the commands for New Horizons to power up and reawaken its hibernating systems were radioed to its computer before it entered hibernation on Dec. 16, 2008. During hibernation, as the spacecraft traveled almost 200 million miles toward its goal -- the Pluto system -- New Horizons sent back weekly status reports as well as biweekly engineering telemetry reports.

Then at 6:30 a.m. EDT on July 7, operators at the Johns Hopkins University Applied Physics Lab (APL) in Laurel, Md., contacted the craft through NASA's Deep Space Network and began downloading data on its health.

"Everything is working normally," says Alice Bowman, New Horizons mission operations manager at APL. "You're a little anxious because you have to turn on a lot of computer processors - they'd been off for 202 days - and you always take a chance when you turn something off in space. But the systems look good."

Tagged "ACO-3," New Horizons' third annual checkout offers the team a chance to flight-test some spacecraft updates, such as new software that manages the solid-state data recorders. The team will also turn on and check each of the seven science instruments, as well as the power, propulsion, and guidance and control systems.

Mission Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colo., says this ACO differs from the first two. "The ACOs have now become a summer event, switching from the fall to allow the team to get into the rhythm of spring planning and summer activity necessary for the July 2015 encounter at Pluto," he says.

"The second and even more significant difference between past wakeups and this one is that we're going to minimize activities in this ACO to save time for our mission planners, who are working hard to finish their Pluto encounter close-approach sequencing job by next year," he continues. "And the minimal wakeup also saves us fuel, since we won't be de-spinning the spacecraft, conducting complex pointed observations with our scientific instruments, and then spinning up again to prepare for the next hibernation cycle."

The only busy scientific instrument on the spacecraft over the past eight months was the Venetia Burney Student Dust Counter (VBSDC), which quietly collected information on the number of dust particles along New Horizons' path through the outer solar system. During the spacecraft's trek through hibernation - which covered 1.91 astronomical units, or more than 177 million miles - VBSDC was calibrated to gain information on the amount of background noise that can affect the science data and to test the sensitivity of its internal electronics. That dust counter data will be sent back to Earth this week.

"Students will analyze that data over the coming months and compare it to earlier measurements made closer to the Sun," says Andrew Poppe, lead graduate student on the SDC team at the University of Colorado, Boulder. "This will really improve our understanding of the dust environment in the outer solar system."

New Horizons is now 1.19 billion miles (nearly 1.92 billion kilometers) from Earth, speeding away from the Sun at just over 10 miles per second. At that distance, radio signals (traveling at light speed) from home need an hour and 46 minutes to reach the spacecraft. The spacecraft is scheduled to complete ACO-3 and re-enter hibernation on August 27.

The hibernation period from December 16, 2008 to July 7, 2009 was the longest planned before New Horizons reaches Pluto. The previous record was 91 days, from June 3 - September 2, 2008. Hibernation periods of approximately 136 days are planned for 2012 and 2014.

posted 07-02-2010 01:30 PM               

Course Correction Keeps New Horizons on Path to Pluto

A short but important course-correction maneuver kept New Horizons on track to reach the "aim point" for its 2015 encounter with Pluto.

The deep-space equivalent of a tap on the gas pedal, the June 30 thruster-firing lasted 35.6 seconds and sped New Horizons up by just about one mile per hour. But it was enough to make sure that New Horizons will make its planned closest approach 7,767 miles (12,500 kilometers) above Pluto at 7:49 a.m. EDT on July 14, 2015.

Reflections: What "pushed" New Horizons slightly off course? According to mission navigation team members from KinetX, Inc., it was a tiny amount of force created from thermal photons from New Horizons' radioisotope thermoelectric generator (RTG) power source - reflecting off the backside of the spacecraft's high-gain antenna.

Commands for the preprogrammed maneuver were transmitted to the spacecraft's computers on June 24; the burn went off as planned Wednesday at 3 p.m. EDT. New Horizons was more than 1.49 billion miles (2.4 billion kilometers) from Earth at the time of the maneuver; at that distance, nearing the orbit of Uranus, a radio signal from the spacecraft needs more than 2 hours, 13 minutes to reach Earth.

Mission operators at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., received confirmation of the successful firing through NASA's Deep Space Network antenna station near Madrid, Spain.

• The New Horizons propulsion system uses hydrazine, an efficient "monopropellant" fuel used on many satellites. (Monopropellant means the fuel burns without the help of a separate oxidizer.) For extra efficiency the fuel on New Horizons is heated before it's burned.

• This was the fourth trajectory correction maneuver, or "TCM," since New Horizons launched on January 19, 2006.

posted 03-18-2011 03:46 PM               

Later, Uranus: New Horizons Passes Another Planetary Milestone

New Horizons is ready to put another planet - or at least the planet's orbit - in its rearview mirror. The Pluto-bound spacecraft crosses the path of Uranus around 6 p.m. EDT on March 18, more than 1.8 billion miles from Earth.

"New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that," says Principal Investigator Alan Stern, of the Southwest Research Institute. "Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration."

New Horizons is headed for a rendezvous with planet Pluto and its three moons in July 2015 and, soon after, possible encounters with smaller bodies in the distant Kuiper Belt. The fastest spacecraft ever launched, New Horizons has already covered serious space since lifting off in January 2006 -- traversing 20 times the distance between Earth and the sun, including a flight through the Jupiter system in 2007 for a gravity-assisted speed boost and scientific observations of the giant planet and its largest moons.

"This mission is a marathon," says Project Manager Glen Fountain, of the Johns Hopkins University Applied Physics Laboratory. "The New Horizons team has been focused on keeping the spacecraft on course and preparing for Pluto. So far, so good, and we are working to keep it that way."

When has New Horizons passed the other planetary orbits? Check here.

No pictures of Uranus are planned -- the gas giant is 2.4 billion miles from New Horizons and the spacecraft is currently in electronic sleep mode -- but the mission team on Earth is busy enough, putting final touches on its Pluto-encounter plan and, in April, starting a search for potential flyby targets in the Kuiper Belt. Preparations are also under way for the annual spacecraft systems checkout this spring.

Next planetary milestone on New Horizons' voyage is the orbit of Neptune, which it crosses on Aug. 25, 2014 -- exactly 25 years after Voyager 2 made its historic exploration of that giant planet.

posted 12-03-2011 11:24 PM               

New Horizons Becomes Closest Spacecraft to Approach Pluto

NASA's New Horizons mission reached a special milestone Friday (Dec. 2, 2011) on its way to reconnoiter the Pluto system, coming closer to Pluto than any other spacecraft.

It's taken New Horizons 2,143 days of high-speed flight – covering more than a million kilometers per day for nearly six years – to break the closest-approach mark set by NASA's Voyager 1 in January 1986. Pluto wasn't on Voyager's mission path, but after making historic flybys of Jupiter in 1979 and Saturn in 1980, the intrepid probe came about 983 million miles (1.58 billion kilometers) from Pluto as it raced to the solar system's outskirts.

Now New Horizons, which is healthy, on course and closer to Pluto than Voyager ever came, will continue to set proximity-to-Pluto records every day until its closest approach — about 7,767 miles (12,500 kilometers) from the planet — on July 14, 2015.

"We've come a long way across the solar system," says Glen Fountain, New Horizons project manager at the Johns Hopkins University Applied Physics Laboratory. "When we launched [on Jan. 19, 2006] it seemed like our 10-year journey would take forever, but those years have been passing us quickly. We're almost six years in flight, and it's just about three years until our encounter begins."

From New Horizons' current distance to Pluto – as far as Earth is (on average) from Saturn – Pluto remains just a faint point of light. But by the time New Horizons sails through the Pluto system in mid-2015, the planet and its moons will be so close that the spacecraft's cameras will spot features as small as a football field.

"What a cool milestone!" says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. "Although we're still a long way — 1.5 billion kilometers from Pluto — we're now in new territory as the closest any spacecraft has ever gotten to Pluto, and getting closer every day by over a million kilometers.

"I wonder how long it will be until the next Pluto spacecraft — perhaps a future orbiter or lander — crosses this distance marker?" he continues. "It could be decades."

New Horizons is currently in hibernation, with all but its most essential systems turned off, speeding away from the Sun at more than 34,500 miles (55,500 kilometers) per hour. Operators at the Applied Physics Lab will "wake" the spacecraft in January for a month of testing and maintenance activities.

posted 07-10-2013 02:21 PM               

New Horizons Camera Spots Pluto's Largest Moon

NASA's Pluto-bound New Horizons spacecraft, using its highest-resolution telescopic camera, has spotted Pluto's Texas-sized, ice-covered moon Charon for the first time. This represents a major milestone on the spacecraft's 9.5-year journey to conduct the initial reconnaissance of the Pluto system and the Kuiper Belt and, in a sense, begins the mission's long-range study of the Pluto system.

The largest of Pluto's five known moons, Charon orbits about 12,000 miles (more than 19,000 kilometers) away from Pluto itself. As seen from New Horizons, that's only about 0.01 degrees away.

Above: New Horizons LOng Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon, cleanly separated from Pluto itself. (NASA/JHU-APL/SwRI)

"The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these 'discovery' images from New Horizons look great!" says New Horizons Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. "We're very excited to see Pluto and Charon as separate objects for the first time from New Horizons."

The spacecraft was still 550 million miles from Pluto – farther than the distance from Earth to Jupiter – when its LOng Range Reconnaissance Imager (LORRI) snapped a total of six images: three on July 1 and three more on July 3. LORRI's excellent sensitivity and spatial resolution revealed Charon at exactly the predicted offset from Pluto, 35 years after the announcement of Charon's discovery in 1978 by James Christy of the Naval Observatory.

"In addition to being a nice technical achievement, these new LORRI images of Charon and Pluto should provide some interesting science too," says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. New Horizons is viewing Pluto and Charon at solar phase angles (the angles between the Sun, Pluto and spacecraft) much larger than can be achieved from observatories located on or near the Earth, potentially yielding important information about the surface properties of Charon and Pluto – perhaps the existence of an overlying layer of fine particles, for example.

"We're excited to have our first pixel on Charon," Stern continues, "but two years from now, near closest approach, we'll have almost a million pixels on Charon –and I expect we'll be about a million times happier too!"

posted 06-16-2014 11:49 AM               

NASA Hubble to Begin Search Beyond Pluto for a New Horizons Mission Target

After careful consideration and analysis, the Hubble Space Telescope Time Allocation Committee has recommended using Hubble to search for an object the Pluto-bound NASA New Horizons mission could visit after its flyby of Pluto in July 2015.

The planned search will involve targeting a small area of sky in search of a Kuiper Belt object (KBO) for the outbound spacecraft to visit. The Kuiper Belt is a vast debris field of icy bodies left over from the solar system's formation 4.6 billion years ago. A KBO has never been seen up close because the belt is so far from the sun, stretching out to a distance of 5 billion miles into a never-before-visited frontier of the solar system.

"I am pleased that our science peer-review process arrived at a consensus as to how to effectively use Hubble's unique capabilities to support the science goals of the New Horizons mission," said Matt Mountain, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

Fully carrying out the KBO search is contingent on the results from a pilot observation using Hubble data.

The space telescope will scan an area of sky in the direction of the constellation Sagittarius to try and identify any objects orbiting within the Kuiper Belt. To discriminate between a foreground KBO and the clutter of background stars in Sagittarius, the telescope will turn at the predicted rate that KBOs are moving against the background stars. In the resulting images, the stars will be streaked, but any KBOs should appear as pinpoint objects.

If the test observation identifies at least two KBOs of a specified brightness it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full moon.

Astronomers around the world apply for observing time on the Hubble Space Telescope. Competition for time on the telescope is extremely intense and the requested observing time significantly exceeds the observing time available in a given year. Proposals must address significant astronomical questions that can only be addressed with Hubble's unique capabilities, and are beyond the capabilities of ground-based telescopes. The proposals are peer reviewed annually by an expert committee, which looks for the best possible science that can be conducted by Hubble and recommends to the Space Telescope Science Institute director a balanced program of small, medium, and large investigations.

Though Hubble is powerful enough to see galaxies near the horizon of the universe, finding a KBO is a challenging needle-in-haystack search. A typical KBO along the New Horizons trajectory may be no larger than Manhattan Island and as black as charcoal.

Even before the launch of New Horizons in 2006, Hubble has provided consistent support for this edge-of-the-solar system mission. Hubble was used to discover four small moons orbiting Pluto and its binary companion object Charon, providing new targets to enhance the mission’s scientific return. And Hubble has provided the most sensitive search yet for potentially hazardous dust rings around the Pluto. Hubble also has made a detailed map of the dwarf planet's surface, which astronomers are using to plan New Horizon's close-up reconnaissance photos.

In addition to Pluto exploration, recent Hubble solar system observations have discovered a new satellite around Neptune, probed the magnetospheres of the gas-giant planets, found circumstantial evidence for oceans on Europa, and uncovered several bizarre cases of asteroids disintegrating before our eyes. Hubble has supported numerous NASA Mars missions by monitoring the Red Planet's seasonal atmospheric changes. Hubble has made complementary observations in support of the Dawn asteroid mission, and comet flybys. In July 1994, Hubble documented the never-before-seen string of comet collisions with Jupiter that resulted from the tidal breakup of comet Shoemaker-Levy 9.

"The planned search for a suitable target for New Horizons further demonstrates how Hubble is effectively being used to support humankind's initial reconnaissance of the solar system," said Mountain. "Likewise, it is also a preview of how the powerful capabilities of the upcoming James Webb Space Telescope will further bolster planetary science. We are excited by the potential of both observatories for ongoing solar system exploration and discovery."

posted 08-07-2014 09:07 PM               

New Horizons Spies Charon Orbiting Pluto

Like explorers of old peering through a shipboard telescope for a faint glimpse of their destination, NASA's New Horizons spacecraft is taking a distant look at the Pluto system – in preparation for its historic encounter with the planet and its moons next summer.

"Filmed" with New Horizons' best onboard telescope – the Long Range Reconnaissance Imager (LORRI) – this movie covers Pluto and almost one full rotation of its largest moon, Charon. The 12 images that make up the movie were taken July 19-24, from a distance ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface.

New Horizons snapped this image sequence as part of the mission's first optical navigation campaign. The mission team uses these "op nav" images – which focus on Pluto's position against a backdrop of stars – to fine-tune the distance that New Horizons will fly past Pluto and its moons. New Horizons is aiming for a precise close-approach point near Pluto in July 2015, so these and images to come – which help navigators and mission designers to get a better fix on Pluto's position – are critical to planning the encounter operations.

Pluto's four smaller satellites (Nix, Hydra, Styx and Kerberos) are too faint to be seen in these distant images, but will begin to appear in images taken next year as the spacecraft speeds closer to its target.

"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," says New Horizons mission Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colo. "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," he adds, "less than a year from the historic encounter ahead!"

As August begins, New Horizons is near the end of its final pre-Pluto annual systems checkout and instrument calibration before Pluto arrival. The New Horizons mission operations team at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, will put the spacecraft back into hibernation on August 29 – just four days after New Horizons crosses the orbit of Neptune on August 25.

That final "rest" lasts only until December 6, when New Horizons will stay wake for two years of Pluto encounter preparations, flyby operations, and data downlinks. Distant-encounter operations begin January 4, 2015.

posted 08-25-2014 03:34 PM               

NASA's New Horizons probe crosses orbit of Neptune 25 years after Voyager 2

An interplanetary crossing on Monday (Aug. 25) evoked a crossover in space history, as NASA's New Horizons spacecraft traversed the orbit of Neptune on its way to Pluto and beyond, 25 years to the day after the Voyager 2 probe became the first to encounter the eighth planet from the sun.

Voyager 2's flyby of Neptune a quarter of a century ago marked the final destination on its "grand tour" of the outer planets, whereas Monday's milestone for New Horizons is only the start of its approach to its first and primary target. New Horizons will come closest to the dwarf planet Pluto on July 14, 2015.

"It's a cosmic coincidence that connects one of NASA's iconic past ... explorers with our next outer solar system explorer," said Jim Green, director of planetary science at NASA Headquarters. "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."

posted 10-15-2014 12:56 PM               

NASA's Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission

Peering out to the dim, outer reaches of our solar system, 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.

"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).

The New Horizons spacecraft, launched in 2006 from Florida, is the first mission in NASA's New Frontiers Program. Once a NASA mission completes its prime mission, the agency conducts an extensive science and technical review to determine whether extended operations are warranted.

The New Horizons team expects to submit such a proposal to NASA in late 2016 for an extended mission to fly by one of the newly identified KBOs. Hurtling across the solar system, the New Horizons spacecraft would reach the distance of 4 billion miles from the Sun at its farthest point roughly three to four years after its July 2015 Pluto encounter. Accomplishing such a KBO flyby would substantially increase the science return from the New Horizons mission as laid out by the 2003 Planetary Science Decadal Survey.

posted 12-07-2014 01:54 AM               

On Pluto's Doorstep, NASA's New Horizons Spacecraft Awakens for Encounter

After a voyage of nearly nine years and three billion miles —the farthest any space mission has ever traveled to reach its primary target – NASA's New Horizons spacecraft came out of hibernation today for its long-awaited 2015 encounter with the Pluto system.

Operators at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., confirmed at 9:53 p.m. (EST) that New Horizons, operating on pre-programmed computer commands, had switched from hibernation to "active" mode. Moving at light speed, the radio signal from New Horizons – currently more than 2.9 billion miles from Earth, and just over 162 million miles from Pluto – needed four hours and 26 minutes to reach NASA's Deep Space Network station in Canberra, Australia.

"This is a watershed event that signals the end of New Horizons crossing of a vast ocean of space to the very frontier of our solar system, and the beginning of the mission's primary objective: the exploration of Pluto and its many moons in 2015," said Alan Stern, New Horizons principal investigator from Southwest Research Institute, Boulder, Colo.

Since launching on January 19, 2006, New Horizons has spent 1,873 days — about two-thirds of its flight time — in hibernation. Its 18 separate hibernation periods, from mid-2007 to late 2014, ranged from 36 days to 202 days in length. The team used hibernation to save wear and tear on spacecraft components and reduce the risk of system failures.

"Technically, this was routine, since the wake-up was a procedure that we'd done many times before," said Glen Fountain, New Horizons project manager at APL. "Symbolically, however, this is a big deal. It means the start of our pre-encounter operations."

The wake-up sequence had been programmed into New Horizons' onboard computer in August, and started aboard the spacecraft at 3 p.m. EST on Dec. 6. About 90 minutes later, New Horizons began transmitting word to Earth on its condition, including the report that it is back in "active" mode.

The New Horizons team will spend the next several weeks checking out the spacecraft, making sure its systems and science instruments are operating properly. They'll also continue to build and test the computer-command sequences that will guide New Horizons through its flight to and reconnaissance of the Pluto system.

With a seven-instrument science payload that includes advanced imaging infrared and ultraviolet spectrometers, a compact multicolor camera, a high-resolution telescopic camera, two powerful particle spectrometers and a space-dust detector, New Horizons will begin observing the Pluto system on Jan. 15.

New Horizons' closest approach to Pluto will occur on July 14, but plenty of highlights are expected before then, including, by mid-May, views of the Pluto system better than what the mighty Hubble Space Telescope can provide of the dwarf planet and its moons.

"New Horizons is on a journey to a new class of planets we've never seen, in a place we've never been before," says New Horizons Project Scientist Hal Weaver, of APL. "For decades we thought Pluto was this odd little body on the planetary outskirts; now we know it's really a gateway to an entire region of new worlds in the Kuiper Belt, and New Horizons is going to provide the first close-up look at them."

The Johns Hopkins Applied Physics Laboratory manages the New Horizons mission for NASA's Science Mission Directorate. Alan Stern, of the Southwest Research Institute (SwRI) is the principal investigator and leads the mission; SwRI leads the science team, payload operations, and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. APL designed, built and operates the New Horizons spacecraft.

A Musical Wake-Up

New Horizons joins the astronauts on four space shuttle missions who "woke up" to English tenor Russell Watson's inspirational "Where My Heart Will Take Me" – in fact, Watson himself recorded a special greeting and version of the song to honor New Horizons! The song was played in New Horizons mission operations upon confirmation of the spacecraft's wake-up on Dec. 6.

The Sleeping Spacecraft: How Hibernation Worked

During hibernation mode, much of the New Horizons spacecraft was unpowered. The onboard flight computer monitored system health and broadcast a weekly beacon-status tone back to Earth. Onboard sequences sent in advance by mission controllers woke New Horizons two or three times each year to check out critical systems, calibrate instruments, gather some science data, rehearse Pluto-encounter activities, and perform course corrections.

New Horizons pioneered routine cruise-flight hibernation for NASA. Not only has hibernation reduced wear and tear on the spacecraft's electronics, it also lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions.

posted 01-15-2015 04:46 PM               

New Horizons Begins First Stages of Pluto Encounter

NASA's New Horizons spacecraft has begun its long-awaited, historic encounter with Pluto, entering the first of several approach phases that will culminate with the first close-up flyby of the Pluto system six months from now.

"NASA's first mission to distant Pluto will also be humankind's first close up view of this cold, unexplored world in our solar system," said Jim Green, director of NASA's Planetary Science Division at NASA Headquarters, Washington. "The New Horizons team worked very hard to prepare for this first phase, and they did it flawlessly."

New Horizons launched in January 2006 and, after a voyage of more than 3 billion miles, will soar close to Pluto, inside the orbits of its five known moons, this July 14. The fastest spacecraft ever launched, New Horizons awoke from its final hibernation period in early December. Since then, the mission's science, engineering and spacecraft operations teams have configured the piano-sized probe for distant observations of the Pluto system, starting with a long-range photo shoot that begins Jan. 25.

Snapped by New Horizons' telescopic Long-Range Reconnaissance Imager, known as LORRI, those pictures will give mission scientists a continually improving look at the dynamics of those moons. And they'll play a critical role in navigating the spacecraft as it covers the remaining 135 million miles (220 million kilometers) to Pluto.

"We've completed the longest journey any craft has flown from Earth to reach its primary target, and we are ready to begin exploring!" said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado.

Over the next few months, LORRI will take hundreds of pictures of Pluto against star fields to refine the team's estimates of New Horizons' distance to Pluto. Though the Pluto system will resemble little more than bright dots in the camera's view until May, mission navigators will use those data to design course-correction maneuvers that aim the spacecraft toward its flyby target point this summer. The first such maneuver could occur as early as March.

"We need to refine our knowledge of where Pluto will be when New Horizons flies past it," said Mark Holdridge, the New Horizons encounter mission manager from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. "The flyby timing also has to be exact, because the computer commands that will orient the spacecraft and point the science instruments are based on precisely knowing the time we pass Pluto — which these images will help us determine."

Spacecraft operators also track New Horizons using radio signals from NASA's Deep Space Network. But the "optical navigation" campaign that begins this month marks the first time pictures from New Horizons will be used to help pinpoint Pluto's location.

This first approach phase, which lasts until spring, also includes a significant degree of other science. New Horizons will take essentially continuous data on the interplanetary environment where the Pluto system orbits, with its two charged-particle sensors measuring the high-energy particles streaming from the Sun, and its dust counter tallying dust-particle concentrations in the inner reaches of the Kuiper Belt — the unexplored outer region of the solar system that includes Pluto and potentially thousands of similar icy, rocky small planets.

More intensive Pluto studies begin in the spring, when the cameras and spectrometers aboard New Horizons can provide resolutions better than the most powerful telescopes on Earth. Eventually, New Horizons will obtain images good enough to map Pluto and its moons better than has ever been achieved by any previous first planetary reconnaissance mission.

posted 02-04-2015 03:34 PM               

NASA Spacecraft Returns New Images of Pluto En Route to Historic Encounter

NASA's New Horizons spacecraft returned its first new images of Pluto on Wednesday, as the probe closes in on the dwarf planet. Although still just a dot along with its largest moon, Charon, the images come on the 109th birthday of Clyde Tombaugh, who discovered the distant icy world in 1930.

"My dad would be thrilled with New Horizons," said Clyde Tombaugh's daughter Annette Tombaugh, of Las Cruces, New Mexico. "To actually see the planet that he had discovered, and find out more about it -- to get to see the moons of Pluto-- he would have been astounded. I'm sure it would have meant so much to him if he were still alive today."

New Horizons was more than 126 million miles (nearly 203 million kilometers) away from Pluto when it began taking images. The new images, taken with New Horizons' telescopic Long-Range Reconnaissance Imager (LORRI) on Jan. 25 and Jan. 27, are the first acquired during the spacecraft's 2015 approach to the Pluto system, which culminates with a close flyby of Pluto and its moons on July 14.

"This is our birthday tribute to Professor Tombaugh and the Tombaugh family, in honor of his discovery and life achievements -- which truly became a harbinger of 21st century planetary astronomy," said Alan Stern, New Horizons principal investigator at the Southwest Research Institute (SwRI) in Boulder, Colorado. "These images of Pluto, clearly brighter and closer than those New Horizons took last July from twice as far away, represent our first steps at turning the pinpoint of light Clyde saw in the telescopes at Lowell Observatory 85 years ago, into a planet before the eyes of the world this summer."

Over the next few months, LORRI will take hundreds of pictures of Pluto, against a starry backdrop, to refine the team's estimates of New Horizons' distance to Pluto. As in these first images, the Pluto system will resemble little more than bright dots in the camera's view until late spring. However, mission navigators can still use such images to design course-correcting engine maneuvers to direct the spacecraft for a more precise approach. The first such maneuver based on these optical navigation images, or OpNavs, is scheduled for March 10.

"Pluto is finally becoming more than just a pinpoint of light," said Hal Weaver, New Horizons project scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. "LORRI has now resolved Pluto, and the dwarf planet will continue to grow larger and larger in the images as New Horizons spacecraft hurtles toward its targets. The new LORRI images also demonstrate that the camera's performance is unchanged since it was launched more than nine years ago."

Closing in on Pluto at about 31,000 mph, New Horizons already has covered more than 3 billion miles since it launched on Jan. 19, 2006. Its journey has taken it past each planet's orbit, from Mars to Neptune, in record time, and it is now in the first stage of an encounter with Pluto that includes long-distance imaging as well as dust, energetic particle and solar wind measurements to characterize the space environment near Pluto.

"The U.S. has led the exploration of the planets and continues to do so with New Horizons," said Curt Niebur, New Horizons program scientist at NASA Headquarters in Washington. "This mission will obtain images to map Pluto and its moons better than has ever been achieved by any previous planetary mission."

posted 02-18-2015 11:54 AM               

85 Years after Pluto's Discovery, New Horizons Spots Small Moons Orbiting Pluto

Exactly 85 years after Clyde Tombaugh's historic discovery of Pluto, the NASA spacecraft set to encounter the icy planet this summer is providing its first views of the small moons orbiting Pluto.

The moons Nix and Hydra are visible in a series of images taken by the New Horizons spacecraft from Jan. 27-Feb. 8, at distances ranging from about 125 million to 115 million miles (201 million to 186 million kilometers). The long-exposure images offer New Horizons' best view yet of these two small moons circling Pluto, which Tombaugh discovered at Lowell Observatory in Flagstaff, Arizona, on Feb. 18, 1930.

"Professor Tombaugh's discovery of Pluto was far ahead its time, heralding the discovery of the Kuiper Belt and a new class of planet," says Alan Stern, New Horizons principal investigator from Southwest Research Institute, Boulder, Colorado. "The New Horizons team salutes his historic accomplishment."

Assembled into a seven-frame movie, the new images provide the spacecraft's first extended look at Hydra (identified by a yellow diamond) and its first-ever view of Nix (orange diamond). The right-hand image set has been specially processed to make the small moons easier to see.

"It's thrilling to watch the details of the Pluto system emerge as we close the distance to the spacecraft's July 14 encounter," says New Horizons science team member John Spencer, also from Southwest Research Institute. "This first good view of Nix and Hydra marks another major milestone, and a perfect way to celebrate the anniversary of Pluto's discovery."

These are the first of a series of long-exposure images that will continue through early March, with the purpose of refining the team's knowledge of the moons' orbits. Each frame is a combination of five 10-second images, taken with New Horizons' Long-Range Reconnaissance Imager (LORRI) using a special mode that combines pixels to increase sensitivity at the expense of resolution. At left, Nix and Hydra are just visible against the glare of Pluto and its large moon Charon, and the dense field of background stars. The bright and dark streak extending to the right of Pluto is an artifact of the camera electronics, resulting from the overexposure of Pluto and Charon. As can be seen in the movie, the spacecraft and camera were rotated in some of the images to change the direction of this streak, in order to prevent it from obscuring the two moons.

The right-hand images have been processed to remove most of Pluto and Charon's glare, and most of the background stars. The processing leaves blotchy and streaky artifacts in the images, as well as a few other residual bright spots that are not real features, but makes Nix and Hydra much easier to see. Celestial north is inclined 28 degrees clockwise from the "up" direction in these images.

Nix and Hydra were discovered by New Horizons team members in Hubble Space Telescope images taken in 2005. Hydra, Pluto's outermost known moon, orbits Pluto every 38 days at a distance of approximately 40,200 miles (64,700 kilometers), while Nix orbits every 25 days at a distance of 30,260 miles (48,700 kilometers). Each moon is probably between 25-95 miles (approximately 40- 150 kilometers) in diameter, but scientists won't know their sizes more precisely until New Horizons obtains close-up pictures of both of them in July. Pluto's two other small moons, Styx and Kerberos, are still smaller and too faint to be seen by New Horizons at its current range to Pluto; they will become visible in the months to come.

posted 04-14-2015 12:48 PM               

NASA's New Horizons Spacecraft Nears Historic July 14 Encounter with Pluto

NASA's New Horizons spacecraft is three months from returning to humanity the first-ever close up images and scientific observations of distant Pluto and its system of large and small moons.

Above: This image of Pluto and its largest moon, Charon, was taken by the Ralph color imager aboard NASA's New Horizons spacecraft on April 9 and downlinked to Earth the following day. It is the first color image ever made of the Pluto system by a spacecraft on approach. The image is a preliminary reconstruction, which will be refined later by the New Horizons science team. Clearly visible are both Pluto and the Texas-sized Charon. The image was made from a distance of about 71 million miles (115 million kilometers)-roughly the distance from the Sun to Venus. At this distance, neither Pluto nor Charon is well resolved by the color imager, but their distinctly different appearances can be seen. As New Horizons approaches its flyby of Pluto on July 14, it will deliver color images that eventually show surface features as small as a few miles across. Credit: NASA/JHU APL/SwRI

"Scientific literature is filled with papers on the characteristics of Pluto and its moons from ground based and Earth orbiting space observations, but we've never studied Pluto up close and personal," said John Grunsfeld, astronaut, and associate administrator of the NASA Science Mission Directorate at the agency's Headquarters in Washington. "In an unprecedented flyby this July, our knowledge of what the Pluto systems is really like will expand exponentially and I have no doubt there will be exciting discoveries."

The fastest spacecraft ever launched, New Horizons has traveled a longer time and farther away – more than nine years and three billion miles – than any space mission in history to reach its primary target. Its flyby of Pluto and its system of at least five moons on July 14 will complete the initial reconnaissance of the classical solar system. This mission also opens the door to an entirely new "third" zone of mysterious small planets and planetary building blocks in the Kuiper Belt, a large area with numerous objects beyond Neptune's orbit.

The flyby caps a five-decade-long era of reconnaissance that began with Venus and Mars in the early 1960s, and continued through first looks at Mercury, Jupiter and Saturn in the 1970s and Uranus and Neptune in the 1980s.

Reaching this third zone of our solar system – beyond the inner, rocky planets and outer gas giants – has been a space science priority for years. In the early 2000s the National Academy of Sciences ranked the exploration of the Kuiper Belt – and particularly Pluto and its largest moon, Charon – as its top priority planetary mission for the coming decade.

New Horizons – a compact, lightweight, powerfully equipped probe packing the most advanced suite of cameras and spectrometers ever sent on a first reconnaissance mission – is NASA's answer to that call.

"This is pure exploration; we're going to turn points of light into a planet and a system of moons before your eyes!" said Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI) in Boulder, Colorado. "New Horizons is flying to Pluto – the biggest, brightest and most complex of the dwarf planets in the Kuiper Belt. This 21st century encounter is going to be an exploration bonanza unparalleled in anticipation since the storied missions of Voyager in the 1980s."

Pluto, the largest known body in the Kuiper Belt, offers a nitrogen atmosphere, complex seasons, distinct surface markings, an ice-rock interior that may harbor an ocean, and at least five moons. Among these moons, the largest – Charon - may itself sport an atmosphere or an interior ocean, and possibly even evidence of recent surface activity.

"There's no doubt, Charon is a rising star in terms of scientific interest, and we can't wait to reveal it in detail in July," said Leslie Young, deputy project scientist at SwRI.

Pluto's smaller moons also are likely to present scientific opportunities. When New Horizons was started in 2001, it was a mission to just Pluto and Charon, before the four smaller moons were discovered.

The spacecraft's suite of seven science instruments – which includes cameras, spectrometers, and plasma and dust detectors – will map the geology of Pluto and Charon and map their surface compositions and temperatures; examine Pluto's atmosphere, and search for an atmosphere around Charon; study Pluto's smaller satellites; and look for rings and additional satellites around Pluto.

Currently, even with New Horizons closer to Pluto than the Earth is to the Sun, the Pluto system resembles little more than bright dots in the distance. But teams operating the spacecraft are using these views to refine their knowledge of Pluto's location, and skillfully navigate New Horizons toward a precise target point 7,750 miles (12,500 kilometers) from Pluto's surface. That targeting is critical, since the computer commands that will orient the spacecraft and point its science instruments are based on knowing the exact time and location that New Horizons passes Pluto.

"Our team has worked hard to get to this point, and we know we have just one shot to make this work," said Alice Bowman, New Horizons mission operations manager at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, which built and operates the spacecraft. "We've plotted out each step of the Pluto encounter, practiced it over and over, and we're excited the 'real deal' is finally here."

The spacecraft's work doesn't end with the July flyby. Because it gets one shot at its target, New Horizons is designed to gather as much data as it can, as quickly as it can, taking about 100 times as much data on close approach as it can send home before flying away. And although the spacecraft will send select, high-priority datasets home in the days just before and after close approach, the mission will continue returning the data stored in onboard memory for a full 16 months.

"New Horizons is one of the great explorations of our time," said New Horizons Project Scientist Hal Weaver at APL. "There's so much we don't know, not just about Pluto, but other worlds like it. We're not rewriting textbooks with this historic mission – we'll be writing them from scratch."

posted 04-29-2015 07:06 PM               

NASA's New Horizons Detects Surface Features, Possible Polar Cap on Pluto

For the first time, images from NASA's New Horizons spacecraft are revealing bright and dark regions on the surface of faraway Pluto — the primary target of the New Horizons close flyby in mid-July.

The images were captured in early to mid-April from within 70 million miles (113 million kilometers), using the telescopic Long-Range Reconnaissance Imager (LORRI) camera on New Horizons. A technique called image deconvolution sharpens the raw, unprocessed images beamed back to Earth. New Horizons scientists interpreted the data to reveal the dwarf planet has broad surface markings — some bright, some dark — including a bright area at one pole that may be a polar cap.

"As we approach the Pluto system we are starting to see intriguing features such as a bright region near Pluto's visible pole, starting the great scientific adventure to understand this enigmatic celestial object," says John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "As we get closer, the excitement is building in our quest to unravel the mysteries of Pluto using data from New Horizons."

Also captured in the images is Pluto's largest moon, Charon, rotating in its 6.4-day long orbit. The exposure times used to create this image set — a tenth of a second — were too short for the camera to detect Pluto's four much smaller and fainter moons.

Since it was discovered in 1930, Pluto has remained an enigma. It orbits our sun more than 3 billion miles (about 5 billion kilometers) from Earth, and researchers have struggled to discern any details about its surface. These latest New Horizons images allow the mission science team to detect clear differences in brightness across Pluto's surface as it rotates.

"After traveling more than nine years through space, it's stunning to see Pluto, literally a dot of light as seen from Earth, becoming a real place right before our eyes," said Alan Stern, New Horizons principal investigator at Southwest Research Institute in Boulder, Colorado. "These incredible images are the first in which we can begin to see detail on Pluto, and they are already showing us that Pluto has a complex surface."

The images the spacecraft returns will dramatically improve as New Horizons speeds closer to its July rendezvous with Pluto.

"We can only imagine what surprises will be revealed when New Horizons passes approximately 7,800 miles (12,500 kilometers) above Pluto's surface this summer," said Hal Weaver, the mission's project scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

posted 05-13-2015 08:01 AM               

NASA's New Horizons Spots Pluto's Faintest Known Moons

It's a complete Pluto family photo – or at least a photo of the family members we've already met.

For the first time, NASA's New Horizons spacecraft has photographed Kerberos and Styx – the smallest and faintest of Pluto's five known moons. Following the spacecraft's detection of Pluto's giant moon Charon in July 2013, and Pluto's smaller moons Hydra and Nix in July 2014 and January 2015, respectively, New Horizons is now within sight of all the known members of the Pluto system.

"New Horizons is now on the threshold of discovery," said mission science team member John Spencer, of the Southwest Research Institute in Boulder, Colorado. "If the spacecraft observes any additional moons as we get closer to Pluto, they will be worlds that no one has seen before."

Drawing ever closer to Pluto in mid-May, New Horizons will begin its first search for new moons or rings that might threaten the spacecraft on its passage through the Pluto system. The images of faint Styx and Kerberos shown here are allowing the search team to refine the techniques they will use to analyze those data, which will push the sensitivity limits even deeper.

Kerberos and Styx were discovered in 2011 and 2012, respectively, by New Horizons team members using the Hubble Space Telescope. Styx, circling Pluto every 20 days between the orbits of Charon and Nix, is likely just 4 to 13 miles (approximately 7 to 21 kilometers) in diameter, and Kerberos, orbiting between Nix and Hydra with a 32-day period, is just 6 to 20 miles (approximately 10 to 30 kilometers) in diameter. Each is 20 to 30 times fainter than Nix and Hydra.

The images detecting Kerberos and Styx shown here were taken with New Horizons' most sensitive camera, the Long Range Reconnaissance Imager (LORRI), from April 25-May 1. Each observation consists of five 10-second exposures that have been added together to make the image in the left panel. Images were extensively processed to reduce the bright glare of Pluto and Charon and largely remove the dense field of background stars (center and right panels). This reveals the faint satellites, whose positions and orbits - along with those of brighter moons Nix and Hydra - are given in the right panel.

"Detecting these tiny moons from a distance of more than 55 million miles is amazing, and a credit to the team that built our LORRI long-range camera and John Spencer's team of moon and ring hunters," added New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute.

Kerberos is visible in all of the images, though is partially obscured in the second image. Styx is not visible in the first image, only in subsequent ones; on April 25 it was obscured by electronic artifacts in the camera – the black and white streaks extending to the right of the extremely overexposed images of Pluto and Charon in the center of the frame. These artifacts point in different directions in different images due to the varying orientation of the spacecraft. Other unlabeled features in the processed images include the imperfectly removed images of background stars and other residual artifacts.

Although Styx and Kerberos are more visible in some frames than others, perhaps due to brightness fluctuations as they rotate on their axes, their identity is confirmed by their positions being exactly where they are predicted to be (in the center of the circles in the right panel).

posted 05-27-2015 02:37 PM               

NASA's New Horizons Sees More Detail as It Draws Closer to Pluto

What a difference 20 million miles makes! Images of Pluto from NASA's New Horizons spacecraft are growing in scale as the spacecraft approaches its mysterious target. The new images, taken May 8-12 using a powerful telescopic camera and downlinked last week, reveal more detail about Pluto's complex and high contrast surface.

Above: These images show Pluto in the latest series of New Horizons Long Range Reconnaissance Imager (LORRI) photos, taken May 8-12, 2015, compared to LORRI images taken one month earlier. In the month between these image sets, New Horizons' distance to Pluto decreased from 68 million miles (110 million kilometers) to 47 million miles (75 million kilometers), as the spacecraft speeds toward a close encounter with the Pluto system in mid-July.

The April images are shown on the left, with the May images on the right. All have been rotated to align Pluto's rotational axis with the vertical direction (up-down), as depicted schematically in the center panel. Between April and May, Pluto appears to get larger as the spacecraft gets closer, with Pluto's apparent size increasing by approximately 50 percent.

Pluto rotates around its axis every 6.4 Earth days, and these images show the variations in Pluto's surface features during its rotation. These images are displayed at four times the native LORRI image size, and have been processed using a method called deconvolution, which sharpens the original images to enhance features on Pluto. Deconvolution can occasionally add "false" details, so the finest details in these pictures will need to be confirmed by images taken from closer range in the next few weeks.

All of the images are displayed using the same linear brightness scale.

The images were taken from just under 50 million miles (77 million kilometers) away, using the Long-Range Reconnaissance Imager (LORRI) on New Horizons. Because New Horizons was approximately 20 million miles closer to Pluto in mid-May than in mid-April, the new images contain about twice as many pixels on the object as images made in mid-April.

A technique called image deconvolution sharpens the raw, unprocessed pictures beamed back to Earth. In the April images, New Horizons scientists determined that Pluto has broad surface markings – some bright, some dark – including a bright area at one pole that may be a polar cap. The newer imagery released here shows finer details. Deconvolution can occasionally produce spurious details, so the finest details in these images will need confirmation from images to be made from closer range in coming weeks.

"As New Horizons closes in on Pluto, it's transforming from a point of light to a planetary object of intense interest," said NASA's Director of Planetary Science Jim Green. "We're in for an exciting ride for the next seven weeks."

"These new images show us that Pluto's differing faces are each distinct; likely hinting at what may be very complex surface geology or variations in surface composition from place to place," added New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. "These images also continue to support the hypothesis that Pluto has a polar cap whose extent varies with longitude; we'll be able to make a definitive determination of the polar bright region's iciness when we get compositional spectroscopy of that region in July."

The images New Horizons returns will dramatically improve in coming weeks as the spacecraft speeds closer to its July 14 encounter with the Pluto system, covering about 750,000 miles per day.

"By late June the image resolution will be four times better than the images made May 8-12, and by the time of closest approach, we expect to obtain images with more than 5,000 times the current resolution," said Hal Weaver, the mission's project scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

posted 06-03-2015 01:41 PM               

NASA's Hubble Finds Pluto's Moons Tumbling in Absolute Chaos

If you lived on one of Pluto's moons, you might have a hard time determining when, or from which direction, the sun will rise each day. Comprehensive analysis of data from NASA's Hubble Space Telescope shows that two of Pluto's moons, Nix and Hydra, wobble unpredictably.

"Hubble has provided a new view of Pluto and its moons revealing a cosmic dance with a chaotic rhythm," said John Grunsfeld, associate administrator of NASA's Science Mission Directorate in Washington. "When the New Horizons spacecraft flies through the Pluto system in July we'll get a chance to see what these moons look like up close and personal."

Above: This set of computer modeling illustrations of Pluto's moon Nix shows how the orientation of the moon changes unpredictably as it orbits the "double planet" Pluto-Charon. Credits: NASA/ESA/M. Showalter (SETI)/G. Bacon (STScI)

The moons wobble because they're embedded in a gravitational field that shifts constantly. This shift is created by the double planet system of Pluto and Charon as they whirl about each other. Pluto and Charon are called a double planet because they share a common center of gravity located in the space between the bodies. Their variable gravitational field sends the smaller moons tumbling erratically. The effect is strengthened by the football-like, rather than spherical, shape of the moons. Scientists believe it's likely Pluto's other two moons, Kerberos and Styx, are in a similar situation.

The astonishing results, found by Mark Showalter of the SETI Institute in Mountain View, California and Doug Hamilton of the University of Maryland at College Park, will appear in the June 4 issue of the journal Nature.

"Prior to the Hubble observations, nobody appreciated the intricate dynamics of the Pluto system," Showalter said. "Our research provides important new constraints on the sequence of events that led to the formation of the system."

Showalter also found three of Pluto's moons are presently locked together in resonance, meaning there is a precise ratio for their orbital periods.

"If you were sitting on Nix, you would see that Styx orbits Pluto twice for every three orbits made by Hydra," noted Hamilton.

Hubble data also reveal the moon Kerberos is as dark as a charcoal briquette, while the other frozen moons are as bright as sand. It was predicted that dust blasted off the moons by meteorite impacts should coat all the moons, giving their surfaces a homogenous look, which makes Kerberos' coloring very surprising.

NASA's New Horizons spacecraft, which will fly by the Pluto system in July, may help settle the question of the asphalt-black moon, as well as the other oddities uncovered by Hubble. These new discoveries are being used to plan science observations for the New Horizons flyby.

The turmoil within the Pluto-Charon system offers insights into how planetary bodies orbiting a double star might behave. For example, NASA's Kepler space observatory has found several planetary systems orbiting double stars.

"We are learning chaos may be a common trait of binary systems," Hamilton said. "It might even have consequences for life on planets if found in such systems."

Above: This illustration shows the scale and comparative brightness of Pluto's small satellites. The surface craters are for illustration only and do not represent real imaging data. Credits: NASA/ESA/A. Feild (STScI)

Clues to the Pluto commotion first came when astronomers measured variations in the light reflected off Nix and Hydra. Analyzing Hubble images of Pluto taken from 2005 to 2012, scientists compared the unpredictable changes in the moons' brightness to models of spinning bodies in complex gravitational fields.

Pluto's moons are believed to have been formed by a collision between the dwarf planet and a similar-sized body early in the history of our solar system. The smashup flung material that consolidated into the family of moons observed around Pluto today. Its binary companion, Charon, is almost half the size of Pluto and was discovered in 1978. Hubble discovered Nix and Hydra in 2005, Kerberos in 2011, and Styx in 2012. These little moons, measuring just tens of miles in diameter, were found during a Hubble search for objects that could be hazards to the New Horizons spacecraft as it passes the dwarf planet in July.

Researchers say a combination of Hubble data monitoring and New Horizon's brief close-up look, as well as future observations with NASA's James Webb Space Telescope will help settle many mysteries of the Pluto system. No ground-based telescopes have yet been able to detect the smallest moons.

"Pluto will continue to surprise us when New Horizons flies past it in July," Showalter said. "Our work with the Hubble telescope just gives us a foretaste of what's in store."

posted 06-11-2015 07:48 PM               

Different Faces of Pluto Emerging in New Images from New Horizons

The surface of Pluto is becoming better resolved as NASA's New Horizons spacecraft speeds closer to its July flight through the Pluto system.

A series of new images obtained by the spacecraft's telescopic Long Range Reconnaissance Imager (LORRI) during May 29-June 2 show Pluto is a complex world with very bright and very dark terrain, and areas of intermediate brightness in between. These images afford the best views ever obtained of the Pluto system.

New Horizons scientists used a technique called deconvolution to sharpen the raw, unprocessed pictures that the spacecraft beams back to Earth; the contrast in these latest images has also been stretched to bring out additional details. Deconvolution can occasionally produce artifacts, so the team will be carefully reviewing newer images taken from closer range to determine whether some of the tantalizing details seen in the images released today persist. Pluto's non-spherical appearance in these images is not real; it results from a combination of the image-processing technique and Pluto's large variations in surface brightness.

Since April, deconvolved images from New Horizons have allowed the science team to identify a wide variety of broad surface markings across Pluto, including the bright area at one pole that scientists believe is a polar cap.

"Even though the latest images were made from more than 30 million miles away, they show an increasingly complex surface with clear evidence of discrete equatorial bright and dark regions—some that may also have variations in brightness," says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. "We can also see that every face of Pluto is different and that Pluto's northern hemisphere displays substantial dark terrains, though both Pluto's darkest and its brightest known terrain units are just south of, or on, its equator. Why this is so is an emerging puzzle."

"We're squeezing as much information as we can out of these images, and seeing details we've never seen before," said New Horizons Project Scientists Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. "We've seen evidence of light and dark spots in Hubble Space Telescope images and in previous New Horizons pictures, but these new images indicate an increasingly complex and nuanced surface. Now, we want to start to learn more about what these various surface units might be and what's causing them. By early July we will have spectroscopic data to help pinpoint that."

New Horizons is approximately 2.9 billion miles (4.7 billion kilometers) from Earth and just 24 million miles (39 million kilometers) from Pluto. The spacecraft and payload are in good health and operating normally.

posted 06-19-2015 05:43 PM               

Pluto and its Moon Charon, Now in Color

The first color movies from NASA's New Horizons mission show Pluto and its largest moon, Charon, and the complex orbital dance of the two bodies, known as a double planet.

"It's exciting to see Pluto and Charon in motion and in color," says New Horizons Principal Investigator Alan Stern of the Southwest Research Institute (SwRI), Boulder, Colorado. "Even at this low resolution, we can see that Pluto and Charon have different colors—Pluto is beige-orange, while Charon is grey. Exactly why they are so different is the subject of debate."

New Horizons will make its closest approach to Pluto on July 14, zipping by about 7,800 miles (12,500 kilometers) above the surface. It's the first mission to Pluto and the Kuiper Belt, a relic of solar system formation beyond Neptune. Sending a spacecraft on this almost 3-billion mile journey will help us answer basic questions about the surface properties, atmospheres, and moons of the Pluto system.

These near-true color movies were assembled from images made in three colors — blue, red and near-infrared – by the Multicolor Visible Imaging Camera on the instrument known as Ralph, a "Honeymooners" reference that classic TV fans can appreciate. The images were taken on nine different occasions from May 29-June 3.

Although the two movies were prepared from the same images, they display the Pluto-Charon pair from different perspectives. One movie is "Pluto-centric", meaning that Charon is shown as it moves in relation to Pluto, which is digitally centered in the movie. (The North Pole of Pluto is at the top.) Pluto makes one turn around its axis every 6 days, 9 hours and 17.6 minutes—the same amount of time that Charon rotates in its orbit. Looking closely at the images in this movie, one can detect a regular shift in Pluto's brightness—due to the brighter and darker terrains on its differing faces.

The second movie is barycentric, meaning that both Pluto and Charon are shown in motion around the binary's barycenter – the shared center of gravity between the two bodies as they do a planetary jig. Because Pluto is much more massive than Charon, the barycenter (marked by a small "x" in the movie) is much closer to Pluto than to Charon.

As New Horizons closes in its intended target, the best is yet to come. "Color observations are going to get much, much better, eventually resolving the surfaces of Charon and Pluto at scales of just kilometers," said Cathy Olkin, New Horizons deputy project scientist from SwRI. "This will help us unravel the nature of their surfaces and the way volatiles transport around their surfaces. I can't wait; it's just a few weeks away!"

posted 07-01-2015 09:01 AM               

New Horizons Update: Methane Detected; New Images of Pluto and Charon; Sunrise/Sunset Observations

Yes, there is methane on Pluto, and, no, it doesn't come from cows. The infrared spectrometer on NASA's Pluto-bound New Horizons spacecraft has detected frozen methane on Pluto's surface; Earth-based astronomers first observed the chemical compound on Pluto in 1976.

"We already knew there was methane on Pluto, but these are our first detections," said Will Grundy, the New Horizons Surface Composition team leader with the Lowell Observatory in Flagstaff, Arizona. "Soon we will know if there are differences in the presence of methane ice from one part of Pluto to another."

Methane (chemical formula CH4) is an odorless, colorless gas that is present underground and in the atmosphere on Earth. On Pluto, methane may be primordial, inherited from the solar nebula from which the solar system formed 4.5 billion years ago. Methane was originally detected on Pluto's surface by a team of ground-based astronomers led by New Horizons team member Dale Cruikshank, of NASA's Ames Research Center, Mountain View, California.

Come fly with New Horizons on its approach to Pluto

Images from New Horizons show the view from aboard the spacecraft closes in on the Pluto system for a July 14 flyby.

This time-lapse approach movie was made from images from the Long Range Reconnaissance Imager (LORRI) camera aboard New Horizons spacecraft taken between May 28 and June 25, 2015. During that time the spacecraft distance to Pluto decreased almost threefold, from about 35 million miles to 14 million miles (56 million kilometers to 22 million kilometers). The images show Pluto and its largest moon, Charon, growing in apparent size as New Horizons closes in. As it rotates, Pluto displays a strongly contrasting surface dominated by a bright northern hemisphere, with a discontinuous band of darker material running along the equator. Charon has a dark polar region, and there are indications of brightness variations at lower latitudes.

"Alice" practices for sunset and sunrise observations of Pluto's atmosphere

The New Horizons spacecraft has made a critical observation in preparation for its upcoming observations of Pluto's tenuous atmosphere. Just hours after its flyby of Pluto on July 14, the spacecraft will observe sunlight passing through the planet's atmosphere, to help scientists determine the atmosphere's composition. "It will be as if Pluto were illuminated from behind by a trillion-watt light bulb," said Randy Gladstone, a New Horizons scientist from Southwest Research Institute, San Antonio. On June 16, New Horizons' Alice ultraviolet imaging spectrograph successfully performed a test observation of the sun from 3.1 billion miles away (5 billion kilometers), which will be used to interpret the July 14 observations.

This spectrum of the Sun obtained by New Horizons' Alice instrument will be used to interpret the spacecraft's observations.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. The Southwest Research Institute, based in San Antonio, leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama.

posted 07-01-2015 05:01 PM               

NASA's New Horizons Spacecraft Stays the Course to Pluto

NASA's New Horizons spacecraft is getting a final "all clear" as it speeds closer to its historic July 14 flyby of Pluto and the dwarf planet's five moons.

Above: These images show the difference between two sets of 48 combined 10-second exposures with New Horizons' Long Range Reconnaissance Imager (LORRI) camera, taken at 8:40 UTC and 10:25 UTC on June 26, 2015, from a range of 21.5 million kilometers (approximately 13 million miles) to Pluto. The known small moons, Nix, Hydra, Kerberos and Styx, are visible as adjacent bright and dark pairs of dots, due to their motion in the 105 minutes between the two image sets. Credits: NASA/JHU-APL/SwRI

After seven weeks of detailed searches for dust clouds, rings, and other potential hazards, the New Horizons team has decided the spacecraft will remain on its original path through the Pluto system instead of making a late course correction to detour around any hazards. Because New Horizons is traveling at 30,800 mph (49,600 kph), a particle as small as a grain of rice could be lethal.

"We're breathing a collective sigh of relief knowing that the way appears to be clear," said Jim Green, director of planetary science at NASA. "The science payoff will be richer as we gather data from the optimal flight path, as opposed to having to conduct observations from one of the back-up trajectories."

Mission scientists have been using the spacecraft's most powerful telescopic camera, the Long Range Reconnaissance Imager (LORRI), to look for potential hazards, such as small moons, rings, or dust, since mid-May. The decision on whether to keep the spacecraft on its original course or adopt a Safe Haven by Other Trajectory, or "SHBOT" path, had to be made this week since the last opportunity to maneuver New Horizons onto an alternate trajectory is July 4.

"Not finding new moons or rings present is a bit of a scientific surprise to most of us," said principal investigator Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado. "But as a result, no engine burn is needed to steer clear of potential hazards. We presented these data to NASA for review and received approval to proceed on course and plan. We are 'go' for the best of our planned Pluto encounter trajectories."

New Horizons formed a hazard analysis team in 2011, after the discovery of Pluto's fourth moon, Kerberos, raised concerns the cratering of these moons by small debris from the outer area of the solar system known as the Kuiper Belt, could spread additional hazardous debris into New Horizons' path. Mission engineers re-tested spare spacecraft blanketing and parts back on Earth to determine how well they would stand up to particle impacts, and scientists modeled the likely formation and locations of rings and debris in the Pluto system. By the time New Horizons' cameras were close enough to Pluto to start the search last month, the team had already estimated the chances of a catastrophic incident at far less than one percent.

The images used in the latest searches that cleared the mission to stay on its current course were taken June 22, 23 and 26. Pluto and all five of its known moons are visible in the images, but scientists saw no rings, new moons, or hazards of any kind. The hazards team determined that satellites as faint as about 15 times dimmer than Pluto's faintest known moon, Styx, would have been seen if they existed beyond the orbit of Pluto's largest and closest moon, Charon.

If any rings do exist, the hazard team determined they must be extremely faint, reflecting less than one 5-millionth of the incoming sunlight.

"The suspense – at least most of it – is behind us," says John Spencer, of SwRI, who leads the New Horizons hazard analysis team. "As a scientist I'm a bit disappointed that we didn't spot additional moons to study, but as a New Horizons team member I am much more relieved that we didn't find something that could harm the spacecraft. New Horizons already has six amazing objects to analyze in this incredible system."

posted 07-02-2015 10:13 AM               

New Horizons Color Images Reveal Two Distinct Faces of Pluto, Series of Spots that Fascinate

New color images from NASA's New Horizons spacecraft show two very different faces of the mysterious dwarf planet, one with a series of intriguing spots along the equator that are evenly spaced. Each of the spots is about 300 miles (480 kilometers) in diameter, with a surface area that's roughly the size of the state of Missouri.

Scientists have yet to see anything quite like the dark spots; their presence has piqued the interest of the New Horizons science team, due to the remarkable consistency in their spacing and size. While the origin of the spots is a mystery for now, the answer may be revealed as the spacecraft continues its approach to the mysterious dwarf planet.

"It's a real puzzle — we don't know what the spots are, and we can't wait to find out," said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder. "Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon."

New Horizons team members combined black-and-white images of Pluto and Charon from the spacecraft's Long-Range Reconnaissance Imager (LORRI) with lower-resolution color data from the Ralph instrument to produce these views. We see the planet and its largest moon in approximately true color, that is, the way they would appear if you were riding on the New Horizons spacecraft. About half of Pluto is imaged, which means features shown near the bottom of the dwarf planet are at approximately at the equatorial line.

posted 07-04-2015 09:48 PM               

New Horizons Team Responds to Spacecraft Anomaly

The New Horizons spacecraft experienced an anomaly the afternoon of Saturday (July 4) that led to a loss of communication with Earth. Communication has since been reestablished and the spacecraft is healthy.

The mission operations center at the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, lost contact with the unmanned spacecraft — now 10 days from arrival at Pluto — at 1:54 p.m. EDT, and regained communications with New Horizons at 3:15 p.m. EDT, through NASA's Deep Space Network.

During that time the autonomous autopilot on board the spacecraft recognized a problem and — as it's programmed to do in such a situation — switched from the main to the backup computer. The autopilot placed the spacecraft in "safe mode," and commanded the backup computer to reinitiate communication with Earth. New Horizons then began to transmit telemetry to help engineers diagnose the problem.

A New Horizons Anomaly Review Board (ARB) was convened at 4 p.m. EDT to gather information on the problem and initiate a recovery plan. The team is now working to return New Horizons to its original flight plan. Due to the 9-hour, round trip communication delay that results from operating a spacecraft almost 3 billion miles (4.9 million kilometers) from Earth, full recovery is expected to take from one to several days; New Horizons will be temporarily unable to collect science data during that time.

Status updates will be issued as new information is available.

posted 07-05-2015 08:48 PM               

NASA's New Horizons Plans July 7 Return to Normal Science Operations

NASA's New Horizons mission is returning to normal science operations after a July 4 anomaly and remains on track for its July 14 flyby of Pluto.

The investigation into the anomaly that caused New Horizons to enter "safe mode" on July 4 has concluded that no hardware or software fault occurred on the spacecraft. The underlying cause of the incident was a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby. No similar operations are planned for the remainder of the Pluto encounter.

"I'm pleased that our mission team quickly identified the problem and assured the health of the spacecraft," said Jim Green, NASA's Director of Planetary Science. "Now – with Pluto in our sights – we're on the verge of returning to normal operations and going for the gold."

Preparations are ongoing to resume the originally planned science operations on July 7 and to conduct the entire close flyby sequence as planned. The mission science team and principal investigator have concluded that the science observations lost during the anomaly recovery do not affect any primary objectives of the mission, with a minimal effect on lesser objectives. "In terms of science, it won't change an A-plus even into an A," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder.

Adding to the challenge of recovery is the spacecraft's extreme distance from Earth. New Horizons is almost 3 billion miles away, where radio signals, even traveling at light speed, need 4.5 hours to reach home. Two-way communication between the spacecraft and its operators requires a nine-hour round trip.

posted 07-06-2015 03:09 PM               

Latest Images of Pluto from New Horizons

These are the most recent high-resolution views of Pluto sent by NASA's New Horizons spacecraft, including one showing the four mysterious dark spots on Pluto that have captured the imagination of the world. The Long Range Reconnaissance Imager (LORRI) obtained these three images between July 1 and 3 of 2015, prior to the July 4 anomaly that sent New Horizons into safe mode.

The left image shows, on the right side of the disk, a large bright area on the hemisphere of Pluto that will be seen in close-up by New Horizons on July 14. The three images together show the full extent of a continuous swath of dark terrain that wraps around much of Pluto's equatorial region. The western end of the swath (right image) breaks up into a series of striking dark regularly-spaced spots, each hundreds of miles in size, which were first detected in New Horizons images taken in late June.

Intriguing details are beginning to emerge in the bright material north of the dark region, in particular a series of bright and dark patches that are conspicuous just below the center of the disk in the right image. In all three black-and-white views, the apparent jagged bottom edge of Pluto is the result of image processing. The inset shows Pluto's orientation, illustrating its north pole, equator, and central meridian running from pole to pole.

The color version of the July 3 LORRI image was created by adding color data from the Ralph instrument gathered earlier in the mission.

posted 07-07-2015 08:07 PM               

New Horizons Map of Pluto: The Whale and the Donut

This is the latest map of Pluto created from images taken from June 27 to July 3 by the Long Range Reconnaissance Imager (LORRI) on New Horizons, combined with lower-resolution color data from the spacecraft's Ralph instrument. The center of the map corresponds to the side of Pluto that will be seen close-up during New Horizons' July 14 flyby.

Above: This map of Pluto, made from images taken by the LORRI instrument aboard New Horizons, shows a wide array of bright and dark markings of varying sizes and shapes. Perhaps most intriguing is the fact that all of the darkest material on the surface lies along Pluto's equator. The color version was created from lower-resolution color data from the spacecraft's Ralph instrument. (NASA/JHUAPL/SWRI)

This map gives mission scientists an important tool to decipher the complex and intriguing pattern of bright and dark markings on Pluto's surface. Features from all sides of Pluto can now be seen at a glance and from a consistent perspective, making it much easier to compare their shapes and sizes.

The elongated dark area informally known as "the whale," along the equator on the left side of the map, is one of the darkest regions visible to New Horizons. It measures some 1,860 miles (3,000 kilometers) in length.

Directly to the right of the whale's "head" is the brightest region visible on the planet, which is roughly 990 miles (1,600 kilometers) across. This may be a region where relatively fresh deposits of frost — perhaps including frozen methane, nitrogen and/or carbon monoxide — form a bright coating.

Continuing to the right, along the equator, we see the four mysterious dark spots that have so intrigued the world, each of which is hundreds of miles across. Meanwhile, the whale's "tail," at the left end of the dark feature, cradles a bright donut-shaped feature about 200 miles (350 kilometers) across. At first glance it resembles circular features seen elsewhere in the solar system, from impact craters to volcanoes. But scientists are holding off on making any interpretation of this and other features on Pluto until more detailed images are in hand.

Of course, higher-resolution images in the days to come will allow mission scientists to make more accurate maps, but this map is a tantalizing preview.

"We're at the 'man in the moon' stage of viewing Pluto," said John Spencer of the Southwest Research Institute, Boulder, Colorado, deputy leader of the Geology, Geophysics and Imaging team. "It's easy to imagine you're seeing familiar shapes in this bizarre collection of light and dark features. However, it's too early to know what these features really are."

posted 07-08-2015 02:03 PM               

NASA's New Horizons: A "Heart" from Pluto as Flyby Begins

After a more than nine-year, three-billion-mile journey to Pluto, it's show time for NASA's New Horizons spacecraft, as the flyby sequence of science observations is officially underway.

Above: This image of Pluto from New Horizons' Long Range Reconnaissance Imager (LORRI) was received on July 8, and has been combined with lower-resolution color information from the Ralph instrument. (NASA-JHUAPL-SWRI)

In the early morning hours of July 8, mission scientists received this new view of Pluto — the most detailed yet returned by the Long Range Reconnaissance Imager (LORRI) aboard New Horizons. The image was taken on July 7, when the spacecraft was just under 5 million miles (8 million kilometers) from Pluto, and is the first to be received since the July 4 anomaly that sent the spacecraft into safe mode.

This view is centered roughly on the area that will be seen close-up during New Horizons' July 14 closest approach. This side of Pluto is dominated by three broad regions of varying brightness. Most prominent are an elongated dark feature at the equator, informally known as "the whale," and a large heart-shaped bright area measuring some 1,200 miles (2,000 kilometers) across on the right. Above those features is a polar region that is intermediate in brightness.

"The next time we see this part of Pluto at closest approach, a portion of this region will be imaged at about 500 times better resolution than we see today," said Jeff Moore, Geology, Geophysics and Imaging Team Leader of NASA's Ames Research Center. "It will be incredible!"

posted 07-09-2015 04:59 PM               

Pluto and Charon: New Horizons' Dynamic Duo

They're a fascinating pair: Two icy worlds, spinning around their common center of gravity like a pair of figure skaters clasping hands. Scientists believe they were shaped by a cosmic collision billions of years ago, and yet, in many ways, they seem more like strangers than siblings.

Above: New Horizons was about 3.7 million miles (6 million kilometers) from Pluto and Charon when it snapped this portrait late on July 8, 2015. Most of the bright features around Pluto's edge are a result of image processing, but the bright sliver below the dark "whale," which is also visible in unprocessed images, is real. Color information obtained earlier in the mission from the Ralph instrument has been added. (NASA-JHUAPL-SWRI)

A high-contrast array of bright and dark features covers Pluto's surface, while on Charon, only a dark polar region interrupts a generally more uniform light gray terrain. The reddish materials that color Pluto are absent on Charon. Pluto has a significant atmosphere; Charon does not. On Pluto, exotic ices like frozen nitrogen, methane, and carbon monoxide have been found, while Charon's surface is made of frozen water and ammonia compounds. The interior of Pluto is mostly rock, while Charon contains equal measures of rock and water ice.

"These two objects have been together for billions of years, in the same orbit, but they are totally different," said Principal Investigator Alan Stern of the Southwest Research Institute (SwRI), Boulder, Colorado.

Charon is about 750 miles (1200 kilometers) across, about half the diameter of Pluto — making it the solar system's largest moon relative to its planet. Its smaller size and lower surface contrast have made it harder for New Horizons to capture its surface features from afar, but the latest, closer images of Charon's surface show intriguing fine details.

Newly revealed are brighter areas on Charon that members of the mission's Geology, Geophysics and Imaging team (GGI) suspect might be impact craters. If so, the scientists would put them to good use. "If we see impact craters on Charon, it will help us see what's hidden beneath the surface," said GGI leader Jeff Moore of NASA's Ames Research Center. "Large craters can excavate material from several miles down and reveal the composition of the interior."

In short, said GGI deputy team leader John Spencer of SwRI, "Charon is now emerging as its own world. Its personality is beginning to really reveal itself."

posted 07-10-2015 06:02 PM               

New Image of Pluto: 'Houston, We Have Geology'

It began as a point of light. Then, it evolved into a fuzzy orb. Now – in its latest portrait from NASA's New Horizons spacecraft – Pluto is being revealed as an intriguing new world with distinct surface features, including an immense dark band known as the "whale."

As the newest black and white image from New Horizons' Long Range Reconnaissance Imager (LORRI) appeared on the morning of July 10, members of the science team reacted with joy and delight, seeing Pluto as never before. There will no doubt be many similar moments to come. New images and data are being gathered each day as New Horizons speeds closer to a July 14 flyby of Pluto, following a journey of three billion miles.

"We're close enough now that we're just starting to see Pluto's geology," said New Horizons program scientist Curt Niebur, NASA Headquarters in Washington, who's keenly interested in the gray area just above the whale's "tail" feature. "It's a unique transition region with a lot of dynamic processes interacting, which makes it of particular scientific interest."

New Horizons' latest image of Pluto was taken on July 9, 2015 from 3.3 million miles (5.4 million kilometers) away, with a resolution of 17 miles (27 kilometers) per pixel. At this range, Pluto is beginning to reveal the first signs of discrete geologic features. This image views the side of Pluto that always faces its largest moon, Charon, and includes the so-called "tail" of the dark whale-shaped feature along its equator. (The immense, bright feature shaped like a heart had rotated from view when this image was captured.)

"Among the structures tentatively identified in this new image are what appear to be polygonal features; a complex band of terrain stretching east-northeast across the planet, approximately 1,000 miles long; and a complex region where bright terrains meet the dark terrains of the whale," said New Horizons principal investigator Alan Stern. "After nine and a half years in flight, Pluto is well worth the wait."

posted 07-11-2015 07:01 PM               

New Horizons' Last Portrait of Pluto's Puzzling Spots

Three billion miles from Earth and just two and a half million miles from Pluto, NASA's New Horizons spacecraft has taken its best image of four dark spots that continue to captivate.

Above: New Horizons' last look at Pluto's Charon-facing hemisphere reveals intriguing geologic details that are of keen interest to mission scientists. This image, taken early the morning of July 11, 2015, shows newly-resolved linear features above the equatorial region that intersect, suggestive of polygonal shapes. This image was captured when the spacecraft was 2.5 million miles (4 million kilometers) from Pluto. (NASA/JHUAPL/SWRI)

The spots appear on the side of Pluto that always faces its largest moon, Charon—the face that will be invisible to New Horizons when the spacecraft makes its close flyby the morning of July 14. New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, describes this image as "the last, best look that anyone will have of Pluto's far side for decades to come."

The spots are connected to a dark belt that circles Pluto's equatorial region. What continues to pique the interest of scientists is their similar size and even spacing. "It's weird that they're spaced so regularly," says New Horizons program scientist Curt Niebur at NASA Headquarters in Washington. Jeff Moore of NASA's Ames Research Center, Mountain View, California, is equally intrigued. "We can't tell whether they're plateaus or plains, or whether they're brightness variations on a completely smooth surface."

The large dark areas are now estimated to be 300 miles (480 kilometers) across, an area roughly the size of the state of Missouri. In comparison with earlier images, we now see that the dark areas are more complex than they initially appeared, while the boundaries between the dark and bright terrains are irregular and sharply defined.

In addition to solving the mystery of the spots, the New Horizons Geology, Geophysics and Imaging team is interested in identifying other surface features such as impact craters, formed when smaller objects struck the dwarf planet. Moore notes, "When we combine images like this of the far side with composition and color data the spacecraft has already acquired but not yet sent to Earth, we expect to be able to read the history of this face of Pluto."

When New Horizons makes its closest approach to Pluto in just three days, it will focus on the opposing or "encounter hemisphere" of the dwarf planet. On the morning of July 14, New Horizons will pass about 7,800 miles (12,500 kilometers) from the face with a large heart-shaped feature that's captured the imagination of people around the world.

posted 07-12-2015 09:27 PM               

Charon's Chasms and Craters

New Horizons' newest images reveal Pluto's largest moon Charon to be a world of chasms and craters. The most pronounced chasm, which lies in the southern hemisphere, is longer and miles deeper than Earth's Grand Canyon, according to William McKinnon, deputy lead scientist with New Horizon's Geology and Geophysics investigation team.

Above: Chasms, craters, and a dark north polar region are revealed in this image of Pluto's largest moon Charon taken by New Horizons on July 11, 2015. (NASA/JHUAPL/SWRI)

"This is the first clear evidence of faulting and surface disruption on Charon," says McKinnon, who is based at the Washington University in St. Louis. "New Horizons has transformed our view of this distant moon from a nearly featureless ball of ice to a world displaying all kinds of geologic activity."

The most prominent crater, which lies near the south pole of Charon in an image taken July 11 and radioed to Earth today, is about 60 miles (96.5 kilometers) across. The brightness of the rays of material blasted out of the crater suggest it formed relatively recently in geologic terms, during a collision with a small Kuiper Belt Object (KBO) some time in the last billion years.

The darkness of the crater's floor is especially intriguing, says McKinnon. One explanation is that the crater has exposed a different type of icy material than the more reflective ices that lie on the surface. Another possibility is that the ice in the crater floor is the same material as its surroundings but has a larger ice grain size, which reflects less sunlight. In this scenario, the impactor that gouged the crater melted the ice in the crater floor, which then refroze into larger grains.

Above: Chasms, craters, and a dark north polar region are revealed in this image of Pluto's largest moon Charon taken by New Horizons on July 11, 2015. The annotated version includes a diagram showing Charon's north pole, equator, and central meridian, with the features highlighted. (NASA/JHUAPL/SWRI)

A mysterious dark region near Charon's north pole stretches for 200 miles. More detailed images that New Horizons will take around the time of closest approach to the moon on July 14 may provide hints about the dark region's origin.

At 7:49 AM EDT on Tuesday, July 14 New Horizons will zip past Pluto at 30,800 miles per hour (49,600 kilometers per hour), with a suite of seven science instruments busily gathering data. The mission will complete the initial reconnaissance of the solar system with the first-ever look at the icy dwarf planet.

posted 07-12-2015 09:28 PM               

One Million Miles to Go; Pluto is More Intriguing than Ever

As NASA's unmanned New Horizons spacecraft speeds closer to a historic July 14 Pluto flyby, it's continuing to multi-task, producing images of an icy world that's growing more fascinating and complex every day.

Above: Pluto as seen from New Horizons on July 11, 2015. (NASA/JHUAPL/SWRI)

On July 11, 2015, New Horizons captured this image, which suggests some new features that are of keen interest to the Geology, Geophysics and Imaging (GGI) team now assembled at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland. For the first time on Pluto, this view reveals linear features that may be cliffs, as well as a circular feature that could be an impact crater. Just starting to rotate into view on the left side of the image is the bright heart-shaped feature that will be seen in more detail during New Horizons' closest approach.

The New Horizons spacecraft is now approaching a milestone — only one million miles to Pluto — which will occur at 11:23 p.m. EDT tonight, Sunday, July 12. It's approaching Pluto after a more than nine-year, three-billion mile journey. At 7:49 AM EDT on Tuesday, July 14 the unmanned spacecraft will zip past Pluto at 30,800 miles per hour (49,600 kilometers per hour), with a suite of seven science instruments busily gathering data. The mission will complete the initial reconnaissance of the solar system with the first-ever look at the icy dwarf planet.

Above: On July 11, 2015, New Horizons captured a world that is growing more fascinating by the day. For the first time on Pluto, this view reveals linear features that may be cliffs, as well as a circular feature that could be an impact crater. Rotating into view is the bright heart-shaped feature that will be seen in more detail during New Horizons' closest approach on July 14. The annotated version includes a diagram indicating Pluto's north pole, equator, and central meridian. (NASA/JHUAPL/SWRI)

posted 07-13-2015 08:39 PM               

How Big Is Pluto? New Horizons Settles Decades-Long Debate

NASA's New Horizons mission has answered one of the most basic questions about Pluto — its size.

Above: A portrait from the final approach. Pluto and Charon display striking color and brightness contrast in this composite image from July 11, showing high-resolution black-and-white LORRI images colorized with Ralph data collected from the last rotation of Pluto. Color data being returned by the spacecraft now will update these images, bringing color contrast. (NASA-JHUAPL-SWRI)

Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were used to make this determination. This result confirms what was already suspected: Pluto is larger than all other known solar system objects beyond the orbit of Neptune.

"The size of Pluto has been debated since its discovery in 1930. We are excited to finally lay this question to rest," said mission scientist Bill McKinnon, Washington University, St. Louis.

Pluto's newly estimated size means that its density is slightly lower than previously thought, and the fraction of ice in its interior is slightly higher. Also, the lowest layer of Pluto's atmosphere, called the troposphere, is shallower than previously believed.

Measuring Pluto's size has been a decades-long challenge due to complicating factors from its atmosphere. Its largest moon Charon lacks a substantial atmosphere, and its diameter was easier to determine using ground-based telescopes. New Horizons observations of Charon confirm previous estimates of 751 miles (1208 km) kilometers) across

LORRI has also zoomed in on two of Pluto's smaller moons, Nix and Hydra.

"We knew from the time we designed our flyby that we would only be able to study the small moons in detail for just a few days before closest approach," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado. "Now, deep inside Pluto's sphere of influence, that time has come."

Nix and Hydra were discovered using the Hubble Space Telescope in 2005. Even to Hubble, they appeared as points of light, and that's how they looked to New Horizons until the final week of its approach to Pluto. Now, the latest LORRI images show the two diminutive satellites not as pinpoints, but as moons seen well enough to measure their sizes. Nix is estimated to be about 20 miles (about 35 kilometers) across, while Hydra is roughly 30 miles (roughly 45 kilometers) across. These sizes lead mission scientists to conclude that their surfaces are quite bright, possibly due to the presence of ice.

What about Pluto's two smallest moons, Kerberos and Styx? Smaller and fainter than Nix and Hydra, they are harder to measure. Mission scientists should be able to determine their sizes with observations New Horizons will make during the flyby and will transmit to Earth at a later date.

posted 07-14-2015 06:50 AM               

New Horizons probe should have flown by Pluto by now (knock on wood)

By the time you read this, NASA's New Horizons spacecraft should be somewhere beyond Pluto, having completed a historic first flyby of the dwarf planet.

That is, if it survived the encounter.

Knock on wood.

The piano-sized probe, which was launched to the dwarf planet nine and a half years ago in 2006, was scheduled to make its closest approach to the dwarf planet at 7:49 a.m. EDT (1149 GMT) on Tuesday (July 14). Operating on its own, because New Horizons is traveling extremely fast — 30,800 mph (49,600 kph) — and it takes four hours and 25 minutes for a signal to stretch across the 3 billion miles (5 billion km) between Earth and Pluto, the spacecraft's fate won't be known until 8:53 p.m. EDT (0053 GMT) when its call home is expected to arrive.