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T O P I C R E V I E W

Robert Pearlman

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.

Robert Pearlman

Atlas V rolls out to pad with New Horizons

The Atlas V rocket with NASA's New Horizons spacecraft was rolled out of the Vertical Integration Facility this morning to its launch pad on Complex 41 at the Cape Canaveral Air Force Station in Florida. Liftoff is scheduled for 1:24 p.m. EST Tuesday, January 17.

New Horizons will be the fastest spacecraft ever launched, reaching lunar orbit distance in just nine hours and passing Jupiter 13 months later. It will reach Pluto in 2015.

Credit: collectSPACE.com/Robert Z. Pearlman

Robert Pearlman

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.

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.

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?

DChudwin

NASA release

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.

Robert Pearlman

NASA release

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.

Robert Pearlman

JHU/APL release

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."

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.

Robert Pearlman

JHU/APL release

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.

Robert Pearlman

JHU/APL release

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.

"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!"

Robert Pearlman

NASA release

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."

Robert Pearlman

NASA release

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.

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."

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.

Robert Pearlman

NASA release

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.

Robert Pearlman

Johns Hopkins Applied Physics Laboratory release

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.

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."

Robert Pearlman

JHU Applied Physics Laboratory release

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.