A Nasa spacecraft that will hurtle past Pluto on Tuesday at more than 45,000 kilometres per hour has revealed the dwarf planet to be larger than scientists thought. 
 
 Fresh measurements from New Horizons, the first spacecraft to reach Pluto on the outer edge of the solar system, show that it is 2,370 kilometres across, roughly two-thirds the size of Earth’s moon. 
 
 
 
 Alan Stern, the lead scientist on the $700m (£450m) mission, said the increased dimensions meant Pluto must hold more ice and less rock beneath its surface than researchers had expected. Pluto has been hard to measure with any accuracy from Earth because it is so far away, and its atmosphere creates mirages that can fool ground-based telescopes. 
 
 Other instruments onboard New Horizons confirmed that Pluto’s north pole bears an icy cap. The latest measurements beamed to Earth from the probe picked up chemical signatures of methane and nitrogen ice in the polar cap. 
 
 
 
 One early image received from New Horizons last week showed Pluto as an orangey globe bearing a large bright spot shaped like a heart. More recent images have revealed cliffs, craters and chasms larger than the Grand Canyon. 
 
 “The science we’ve already made is mouth-watering,” said Stern. “The Pluto system is enchanting in its strangeness and its alien beauty.” 
 
 
 
 New Horizons will perform its historic flyby at 12.49pm BST on Tuesday. But scientists must wait until 2am BST on Wednesday for the probe to make contact with Earth and confirm it has survived the encounter. 
 
 The most dangerous hazards for New Horizons are dust particles trapped in orbit around Pluto after being dislodged from its moons by meteorite impacts. A strike from a dust particle the size of a grain of rice could destroy the spacecraft, but the risk of such a disaster is low, at around one in 10,000. 
 
 
 
 The New Horizons spacecraft has spent more than nine years on its 4.8bn kilometre journey to Pluto, the last world in the solar system to be visited by a spacecraft. On board are seven sophisticated instruments and the ashes of Clyde Tombaugh, the astronomer who discovered Pluto in 1930. 
 
 
 
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 When the probe blasted off in January 2006, Pluto was the ninth planet in the solar system. Seven months later, astronomers at the International Astronomical Union voted to downgrade the icy body to a dwarf planet, because it does not dominate its region of space in the way the other major planets do. 
 
 
 
 The spacecraft will take scores of photographs as it speeds past Pluto and its five known moons, Charon, Hydra, Nix, STyx and Kerberos. The images will give the first close-up view of the mountains and valleys of the unknown world, and its tenuous atmosphere seen as the sun rises and sets behind it. Instruments on New Horizons might even find evidence that it snows on the tiny world. 
 
 
 
 Nasa officials expect the first images from the flyby to be released on Wednesday night. The snapshots from onboard cameras will capture details up to 100 metres across, a vast improvement on those taken on approach, which pick out features about 15 kilometres across. 
 
 But scientists are in for a long wait to learn everything New Horizons sees. The probe will collect so much information as it passes Pluto that it will take 16 months to send it all back to Earth. 
 
 
 
 The mission marks the end of the US space agency’s bid to explore every planet in the solar system, starting with Venus in 1962. Tuesday’s flyby coincides with the 50th anniversary of the first ever fly-by of Mars by the Mariner 4 probe. ||||| Image copyright NASA/JHU-APL/SWRI Image caption Pluto (R) and Charon (L) are the key targets for observation during the flyby 
 
 Nasa's New Horizons spacecraft has begun the most intense period of its encounter with Pluto. 
 
 The probe is set to hurtle past the dwarf world on Tuesday, grabbing a mass of pictures and other science data. 
 
 Controllers got a last health status report, before the robotic craft turned its antenna away from the Earth to concentrate on its target. 
 
 Only when New Horizons has its trove of images safely in its onboard memory will it call home again. 
 
 This is not expected to happen until just after midnight (GMT) into Wednesday. 
 
 It means there will be a long, anxious wait for everyone connected with the mission, as they hold out for a signal that will be coming from almost five billion km away. 
 
 New Horizons' flyby of 2,370km-wide Pluto is a key moment in the history of space exploration. 
 
 Its successful execution will complete the initial reconnaissance of the "classical" nine planets in our Solar System. 
 
 It will mark the fact that every body in that system - from Mercury through to Pluto - will have been visited at least once by a space probe. 
 
 Image copyright NASA Image caption The robotic probe turns its antenna away from Earth during the flyby 
 
 New Horizons has been returning a steady stream of information on approach to the dwarf world in recent days, but this will be as nothing compared to the huge number of observations it plans to acquire when passing just 12,500km from the surface. 
 
 This is timed to occur at 11:50 GMT (12:50 BST). 
 
 The probe will investigate not only Pluto but also its five moons: Charon, Styx, Nix, Kerberos and Hydra. 
 
 To achieve that, it must perform a furious set of manoeuvres as it points every which way in the sky to get the images and other types of data it needs. 
 
 "I can't wait to get into the data and really start making sense of it. Right now, we're just standing under the waterfall and enjoying it," New Horizons' principal investigator, Alan Stern, told BBC News. 
 
 Just getting the probe in position to make the flyby has been a monumental feat. 
 
 Because the observations are all run on an automated command sequence, New Horizons must fly a perfect path past Pluto, and with perfect timing - otherwise its cameras will shoot empty sky where the dwarf or its moons are expected to be. 
 
 This has necessitated aiming New Horizons at a "keyhole" in space just 100km by 150km (60miles by 90 miles), and arriving at that location within a set margin of 100 seconds. 
 
 All this has been achieved after a multi-billion-km flight across the Solar System lasting nine and a half years. 
 
 The mission team will not celebrate until New Horizons contacts Earth again, which should happen at 00:53 GMT Wednesday (01:53 BST). 
 
 This communication will contain only engineering information on the status of the probe, but controllers should be able to tell very quickly whether the flyby sequence worked properly or not. 
 
 The first high-resolution pictures from the pass should be downlinked later on Wednesday. 
 
 There is a very small possibility that New Horizons could be lost as it flies through the Pluto system. 
 
 Any stray icy debris would be lethal if it collides with the spacecraft at its 14km/s velocity (31,000mph). 
 
 As an insurance policy, the mission team therefore downlinked one last set of data from all seven of the probe's instruments on Monday. 
 
 This included a final full-frame picture of Pluto before the approaching dwarf filled the entire field of view. This image is expected to be released by Nasa on its website at the moment of closest approach on Tuesday. 
 
 Media caption Prof Alan Stern says Pluto is "a little larger than anticipated" 
 
 On Monday, the New Horizons team announced a new, more precise measurement of Pluto's diameter at 2,370km. The probe sees the girth of Charon to be very similar to earlier estimates, at 1,208km. 
 
 Nix is estimated to be about 35km across, and Hydra about 45km in diameter. Kerberos and Hydra are a lot smaller, but New Horizons has not yet been able to make a good determination of their size. This will come from the flyby data. 
 
 Image copyright NASA Image caption How Pluto and its biggest moon, Charon, compare in size to the Earth 
 
 The BBC will be screening a special Sky At Night programme called Pluto Revealed on Monday 20 July, which will recap all the big moments from the New Horizons flyby. 
 
 Follow Jonathan on Twitter. ||||| Ahead of Tuesday's historic flyby, NASA's New Horizons spacecraft has already delivered data that 'is a gift for the ages.' Among the discoveries: Pluto is bigger than previously thought. 
 
 Will Macy's become the next store to drop the Ivanka Trump brand? 
 
 On the eve of NASA's historic flyby of Pluto, scientists and tourists at the Lowell Observatory in Flagstaff, Arizona are excited about the images and discoveries the New Horizons' spacecraft will beam back to Earth. 
 
 NASA's New Horizons mission to the Pluto-Charon system has yet to mark its finest hours – a historic flyby that makes its closest approach to the binary planet and its moons Tuesday morning. 
 
 But even as the spacecraft puts the wraps on its final approach, data New Horizons has delivered within the past 48 hours "is a gift for the ages," says Alan Stern, a planetary scientist at the Southwest Research Institute in Boulder, Colo., and the mission's principal investigator. 
 
 The craft's approach is revealing "tremendous diversity between the two planets in the system and their moons," he said. "We're already seeing complex and nuanced surfaces that tell us of history for these two bodies that is probably beyond our wildest dreams." 
 
 In short, "the Pluto system is enchanting in its strangeness and alien beauty," Dr. Stern said during a briefing Monday. 
 
 How alien? 
 
 It's as though "we're on the bridge of the Enterprise approaching some alien planet around Alpha Centauri 3 or whatever it is," said Paul Schenk, a planetary geologist at the Lunar and Planetary Institute in Houston and a member of the New Horizons science team. "It's like someone painted it for a 'Star Trek' episode." 
 
 Even seemingly mundane measurements, such as a new, more-accurate determination of Pluto's size – now pegged at 1,473 miles across, at the high end of estimates that have ranged from 1,429 miles to around 1,491 miles – carry import. 
 
 The new size, combined with long-established, precise measurements of Pluto's mass, yields a dwarf planet a bit less dense than previously estimated. That means its interior contains more ice, versus rock, than previously estimated. This change has implications – yet to be worked out – for the process that formed the binary-planet system as well as for the chemistry of the disk of dust, gas, and ice that encircled the sun and provided the building blocks for the planets ad their moons, Stern explained. 
 
 Bragging rights also come into play. 
 
 "The new measurement unambiguously settles the debate about the largest object in the Kuiper Belt," Stern said, referring to a region of the solar system extending more than 2 billion miles beyond Neptune. By some estimates, the region hosts trillions of comets as well as several hundred thousand objects larger than 60 miles across. It's also the region that gave birth to Pluto and the object that would collide with it to form Charon. Another Kuiper Belt inhabitant, Eris, had previously laid claim to the "largest" label at 1,445 miles across. 
 
 A larger Pluto also means that the lower layer of the atmosphere is shallower than previously thought, which will affect models that try to shed light on the atmosphere's structure and behavior. 
 
 Another early result involves nitrogen escaping from Pluto's tenuous atmosphere. New Horizons' instruments began to pick up the great escape five days ago, when the craft supposedly was too far away to see it, Stern said. It could mean that the nitrogen is fleeing the planet at a higher rate than models have suggested or that the mechanism responsible for triggering the loss is different than researchers have anticipated. 
 
 In addition, incoming data show that a hypothesized polar cap on Pluto is in fact an ice cap consisting of nitrogen and methane ices. 
 
 New Horizons also is revealing features on Pluto that are generating speculation, pending more detail from measurements taken at the closest approach. 
 
 For instance, images of Pluto released over the weekend show a surface that in many places hosted vast expanses of small, tightly packed dimple-like formations. 
 
 The features appear to be similar to those on Neptune's moon Triton, Dr. Schenk said. Triton – itself thought to be a Kuiper Belt object that Neptune captured – hosts a surface "that looks like a boiling pot of porridge, with cells of material popping up. They create a cellular pattern that looks like the skin of a cantaloupe." 
 
 There, researchers suspect that relatively buoyant rock or ice has risen from deeper in the crust to build the array of hills and depressions – similar in principle to salt domes that rise through surrounding rock to form low hills in southern Louisiana or southeastern Texas. 
 
 The science team hopes to get a closer look at some of these dimpled regions in images New Horizons takes during its closest approach Tuesday morning. 
 
 In addition, images so far show a relatively smooth surface over much of Pluto, suggesting that the surface could be relatively young, Schenk said. 
 
 Again, he cites Triton as a possible analog. The relative smoothness of much of Triton's surface suggests that it's less than 100 million years old. "On Triton, everything is very young," Schenk said. 
 
 It speaks to Triton as a captured Kuiper Belt object whose orbit around Neptune initially would have been elliptical, but over time became circular. The change in orbit would have heated Triton significantly, allowing fresh material to well up from depth and repave the surface, erasing any evidence of impact craters that would have accumulated over time. 
 
 On Pluto, "we're not seeing any large craters that would pop out and say: There's a big basin here," he says. "So we're beginning to think that maybe that it's a very young surface." 
 
 The source of internal heating required to provide material for repaving Pluto is unclear, Schenk acknowledges. Perhaps heat left over from the impact that formed Charon remained intense enough long enough to provide sources of fresh material for resurfacing Pluto. 
 
 "We still don't know," he says. "But we'll find that out." 
 
 [Correction: This article has been updated to correct the new measurements of Pluto's diameter.] ||||| NASA’s New Horizons spacecraft will fly within 8,000 miles of Pluto on Tuesday and reveal the last world in the solar system—or at least the last of the planets that most of us learned about in school. Until now, Pluto’s face has remained hidden because it's so far away. To really see it as more than a blurry blob, we needed to go there. (Learn more about the historic mission to Pluto on the National Geographic Channel.) 
 
 But getting to the icy world is no easy feat. By the time New Horizons reaches Pluto at 7:50 a.m. EDT Tuesday, it will have traveled roughly 3 billion miles for a single, fleeting chance to fly past the dwarf planet. 
 
 Launched in 2006, New Horizons is the fastest spacecraft to ever leave Earth. It crossed the orbit of Jupiter the next year and has been traveling nearly a million miles a day —but it still took 9.5 years for the spacecraft to reach Pluto and its moons. 
 
 View Images On Saturday, New Horizons got one of its last looks at this side of Pluto, which faces its moon Charon. Captured from a distance of 2.5 million miles from Pluto, the photo shows mysterious geometric features above the equator, along with sinewy dark splotches. Photograph by NASA/JHUAPL/SWRI 
 
 In fact, New Horizons is going so fast—more than 30,000 miles per hour—that the spacecraft will pass by Pluto in just three minutes. 
 
 The entire close encounter lasts for hours, though, with New Horizons making hundreds of observations of Pluto and its five bizarre moons . The first of the highest-resolution images will be released Wednesday afternoon, and the rest of the data will trickle in over the next 16 months. 
 
 While waiting for the flyby at New Horizons mission headquarters, space writer Nadia Drake answers some of the biggest questions about Tuesday's event. 
 
 1. Why a flyby? Why not slow down or orbit Pluto? 
 
 Simply put, slowing down and orbiting Pluto is nearly impossible if you want to get there in a reasonable amount of time. The planet’s gravity is so weak that a spacecraft pulling into orbit would need to be going really slowly. For New Horizons to slow down enough, it would have to carry enough fuel to fire its brakes and reverse all its forward momentum—that’s about as much fuel as was used to launch the spacecraft and get it zooming along in the first place. Launching all that propellent, plus the spacecraft, is pretty much impossible . (Read about chasing Pluto's shadow ). 
 
 WATCH: NASA's New Horizons spacecraft will fly by Pluto on July 14, after traveling three billion miles from Earth in roughly 9.5 years. Video by Johns Hopkins University Applied Physics Laboratory 
 
 2. We see amazing shots of faraway galaxies, so why haven't we ever gotten a good picture of Pluto? 
 
 Though they’re far away, those distant, glittering galaxies are really big and bright, which is why telescopes like Hubble can see them. But Pluto is too small and dim for even our sharpest Earth-based eyes to get a good look at: It's only about two-thirds as wide as Earth’s moon. Even dwarf planet Ceres, which lives much closer to Earth, is too small to be anything but a blurry blob in Hubble pictures. (Learn more about Pluto's first close-up ). 
 
 3. What's the biggest thing that could go wrong? 
 
 It could be disastrous for the spacecraft to run into a dust particle as it flies through the Pluto system. Because the spacecraft is going so fast, colliding with something the size of a rice pellet could be catastrophic. So, the team has spent the last few weeks intensively surveying the system for anything that might be shedding dust and debris in the spacecraft’s path, and so far have found nothing to be concerned about. (Learn what happened when the spacecraft went silent ). 
 
 4. What will the pictures of Pluto look like? 
 
 The images coming back from New Horizons are already by far the best ever taken of the dwarf planet, even though the latest image, on July 12, was taken from about a million miles away. Tuesday’s encounter will produce close-up, detailed images of Pluto and Charon, plus some images of the smaller moons. (Also see " Three Possible Plutos "). 
 
 On the side of Pluto that the spacecraft will be able to see, features as small as the lakes in New York City’s Central Park will be visible. But that’s not all: After New Horizons zooms by Pluto, it will swivel around and take a look at the planet’s south pole, which we haven’t seen yet. (Check out the weirdest feature I'd like to see on Pluto ). Facing away from the sun, that pole is in the dark, except for the soft glow of sunlight reflected off Charon. In other words, New Horizons will give us a glimpse of Pluto’s wintry pole, in Charon's moonlight. (Also see: " Proposed Names for Pluto System's Features Include Kirk and Spock "). 
 
 5. How long does it take to send a photo of Pluto to Earth? 
 
 Radio signals traveling at the speed of light take 4.5 hours to travel between Pluto and Earth. So, data received from New Horizons will have been on the road for about as long as it takes to drive between San Francisco and Santa Barbara. Because of that, it will take about 16 months for all of New Horizons’ flyby data to make it to Earth—meaning that new discoveries will be trickling in through the end of 2016. (See the first color image of Pluto from New Horizons ). 
 
 View Images The New Horizons spacecraft, illustrated here flying past Pluto, traveled about 3 billion miles to visit the dwarf planet and its five known moons. Illustration by Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI) 
 
 6. What are we going to learn about Pluto? 
 
 New Horizons will take a good, detailed look at Pluto and its large moon Charon (in fact, Charon is so large it forms a binary system with Pluto). Scientists are curious about Pluto’s terrains and composition, whether there’s evidence for geologic activity, and what the planet’s thin, nitrogen atmosphere is doing. They’ll also be looking for clues to how the Pluto system formed and evolved—and many of those clues might lie in the features of the four small moons Nix, Hydra, Kerberos, and Styx . (Check out Pluto's possible polar cap ). 
 
 7. What will New Horizons do after it passes Pluto? How long can it keep going? 
 
 After New Horizons passes Pluto, it will continue sailing on into the Kuiper Belt, which is a vast, icy debris ring outside the orbit of Neptune. If NASA approves it, New Horizons will sail past and study another icy world within the next five years. The spacecraft carries enough fuel for that encounter (it’ll use the propellent to adjust its course), and will still be able to send data back to Earth, even though that body is nearly a billion miles farther out. Ultimately, it will continue heading out of the solar system, much as NASA’s Voyager I and II spacecraft are doing. (Learn more about New Horizon's Mission ). 
 
 8. Is this our only chance, or will any other spacecraft be going to Pluto? 
 
 There are no plans at this point to send another spacecraft to Pluto, but it sure would be nice to learn even more about that enigmatic little world and its cousins on the fringe of the observable solar system. 
 
 9. Is it carrying a message for aliens? 
 
 Not yet. There is a project, called the One Earth Message, that aims to upload a digital message to the spacecraft once it’s done collecting data and sending it all to Earth. That could be years from now, if New Horizons flies by another body in the Kuiper Belt. The message would be something like a new version of the Voyager Golden Record , which carried the sights and sounds of Planet Earth into the cosmos aboard the Voyager I and II spacecraft. 
 
 10. What did New Horizons do during the nine years it took to get to Pluto? 
 
 It spent a lot of that time hibernating, but did occasionally wake up for system tests. And, of course, it woke up to take a look at Jupiter as it flew by the giant planet in 2007. No sense missing out on that view! Later, when it crossed Neptune’s orbit in 2014, New Horizons woke up again to snap a picture of the icy blue giant—but Neptune was so far away it looked like a faint dot. (Learn about the spacecraft first awakening after a multi-year nap ). ||||| NASA/JPL-Caltech If all went according to plan, NASA's New Horizons spacecraft made history Tuesday morning after snagging the world's first close-up look at Pluto. 
 
 But completing the Solar System's planetary family portrait is just a small part of the spacecraft's journey — it's already explored Jupiter and is now destined to probe a mysterious zone of icy objects called the Kuiper Belt. 
 
 In fact, mission leader and planetary scientist Alan Stern says New Horizons may have decades' worth of exploration left in it, thanks to its long-lived nuclear power source. 
 
 Pre-Pluto homework 
 
 Before its personal rendezvous with Pluto, New Horizons swung by Jupiter for a gravitational speed boost. This shaved almost 4 years off its travel time, to a total of 9 1/2 years. 
 
 New Horizons did a little science while it was in the Jovian neighborhood, too. For example, its cameras caught the Tvashtar volcano exploding on Jupiter's third-largest moon, Io. It also made about 700 other observations, giving New Horizons the opportunity to test its suite of seven scientific instruments. 
 
 Now, about 8 years later, New Horizons is completing what's arguably the most popular leg of its trip — zooming past Pluto and its moons, of which there are at least five. 
 
 A first look at the icy dwarf planet 
 
 The busiest part of New Horizon's flyby past Pluto and its largest moon, Charon, began about 12 hours before its closest approach, and is slated to last about 12 hours afterward. 
 
 New Horizons passed within 7,600 miles of Pluto's surface for about 30 minutes. During that time it took what will be the best-ever pictures of Pluto, which should resolve surface features as small as 80 feet across. 
 
 But the flyby wasn't just about taking breathtaking close-ups. Scientific instruments also recorded ultraviolet emissions emanating from Pluto's atmosphere — measurements that will help assemble the best maps of Pluto and Charon we may see in our lifetimes. Other devices on New Horizons studied the composition of the dwarf planet's crust, measured variations in its surface temperatures, sifted for space dust, and snapped images of Pluto's moons. 
 
 New Horizons photo of Pluto. Monica Manalo 
 
 After the spacecraft passed by, it turned around to examine Pluto and Charon's dark sides. That's the best way to detect atmospheric haze, search for rings of debris, and identify whether their surfaces are smooth or rough. 
 
 New Horizons also got a good look at Earth and the Sun as they set and rose through Pluto's atmosphere. While this happened, the spacecraft scanned for radio waves from Earth-based transmitters to profile the composition, structure, and temperature profile of Pluto's atmosphere in incredible detail. 
 
 Next stop, the Kuiper Belt... 
 
 An artist's concept of a Kuiper Belt Object. NASA, ESA, and G. Bacon (STScI) If all went well with the planned flyby, New Horizons will soon begin the next major leg of its journey: chasing down a Kuiper Belt object (KBO) that measures at least 30 miles in diameter. 
 
 New Horizons has at least three KBOs it can reach, given it's current path through space and limited on-board fuel supply. Their names aren't very exciting: PT1, PT2, and PT3 (where PT means "potential target"). 
 
 Sometime this August, according to SpaceflightNow.com, NASA will pick the KBO it likes the most, then fire New Horizons's thrusters to steer it in that direction. The trip will take at least 2 years. 
 
 New Horizons might be able to study more than one KBO. And each time it does, the spacecraft will scrutinize the icy object in the same way it did Pluto and Charon: map the surface, measure temperatures, scout for moons, and search for traces of atmosphere. 
 
 ...And beyond 
 
 After scrutinizing a KBO or two, New Horizons will escape the sun's influence and never again return to our Solar System. 
 
 "It could go for another 20 years," Stern said during a NASA press conference on Tuesday. Around that time, the nuclear power source on board New Horizons will become too weak to supply energy for taking measurements and communicating with Earth. 
 
 This all assumes, of course, that we don't lose the spacecraft anywhere along the way. 
 
 The flyby was the riskiest part of the mission, and its success is still uncertain; right now, there's still a 1-in-10,000 chance debris around Pluto thwarted the mission. We'll have to wait until Tuesday night before NASA can say whether or not the maneuver went off without a hitch. 
 
 Yet during Tuesday morning's press briefing, Stern seemed upbeat. He noted that you could fly hundreds of New Horizons and they'd likely all survive. 
 
 One way or another, the mission has already made history. Whether in one piece or a shower of spacecraft parts, we've reached the last unexplored world in our Solar System. And that's something not even the International Astronomical Union can take away. ||||| This artist's rendering shows NASA's New Horizons spacecraft during its flyby of Pluto and its moons on July 14, 2015. The spacecraft awoke from its final hibernation period on Dec. 6, 2014 in preparation for the epic Pluto encounter at the edge of the solar system. 
 
 LAUREL, Md. — Pluto, get ready for your close-up: A NASA spacecraft has roused itself from the final slumber of its nine-year trek to the edge of the solar system, setting the stage for the first close encounter with Pluto next year. 
 
 The New Horizons spacecraft, currently located 2.9 billion miles (4.6 billion kilometers) from Earth, had been in hibernation since August — with most of its systems turned off to reduce wear. But late Saturday (Dec. 6), mission scientists received a confirmation signal from New Horizons at the probe's Mission Operations Center here at the Johns Hopkins Applied Physics Laboratory. The probe is now wide awake for its 2015 flyby of Pluto. 
 
 At the time of its wakeup call, New Horizons was just over 162 million miles (261 million km) from Pluto. About 20 people gathered in a conference room here at APL to await the signal from New Horizons. [Photos from NASA's New Horizons Pluto Probe] 
 
 NASA's New Horizon Pluto flyby mission operations manager Alice Bowman and operations team Karl Whittenburg watch screens for signals confirming that the New Horizons probe awoke from hibernation on Dec. 6, 2014. The New Horizons mission is managed from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. Credit: NASA 
 
 First word from the probe arrived at about 9:30 p.m. EST on Saturday (Dec. 6) — generating a burst of happy applause from the attendees, including Alan Stern, New Horizon's principle investigator, and Jim Green, NASA's director of planetary sciences. 
 
 At 9:52 p.m. EST (0252 GMT), mission managers confirmed that New Horizons was awake, with all systems functioning normally. The wakeup sets the stage for the probe's flyby of Pluto on July 14, 2015. 
 
 "This is the turning of a page. This is changing from a mission in cruise to a mission at its destination," said Stern, of the Southwest Research Institute in Boulder, Colorado. Stern popped a champagne bottle and offered a toast to the mission following the signal confirmation. 
 
 New Horizons even got a wakeup song to mark the occasion: the tune "Where My Heart Will Take Me" by English tenor Russell Watson. The song, which included a special greeting from Watson for New Horizons, was played in the mission operations center after the confirmation signal was received. You can hear Watson's New Horizons wakeup song here. 
 
 This photo of Pluto (center) and its largest moon Charon was captured by NASA's New Horizons spacecraft in July 2014 and released on Aug. 7. New Horizons took this image and others from a range of 267 million to 262 million miles (429 million to 422 million kilometers). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute 
 
 English tenor Russell Watson recorded a special version of his song "Where My Heart Will Take Me" to help wake up NASA's New Horizons spacecraft on Dec. 6, 2014 ahead of the probe's 2015 Pluto flyby. Credit: NASA 
 
 New Horizons will begin its Pluto science campaign in January, and will make its closest approach to Pluto in July. It will explore the outer-most and most-populated region of the solar system, the Kuiper belt, which is full of rocky, icy objects that have remained largely unchanged since the formation of the solar system. 
 
 "This is the place that this spacecraft was built to operate, and these are the operations that this team has waited a decade to actually go and execute," Stern said. "So it's game time." 
 
 NASA launched the New Horizons mission in 2006 on a $700 million mission to be the first spacecraft ever to see Pluto and its five moons up close. The piano-size spacecraft is powered by a nuclear power source and has traveled nearly 3 billion miles (4.8 billion km) to reach Pluto in a mere nine years, making it the fastest space probe ever launched). It has spent two-thirds of its journey in a hibernation state that has both prolonged the life of the instruments and reduced staff costs on the ground. 
 
 While New Horizons has gone through 18 hibernation periods, sleeping for about 1,873 days in all, this is the last one before it begins taking data on the Pluto system. 
 
 For 20 weeks of its flyby of Pluto, New Horizons will provide better photos of Pluto and its moons than those taken by the Hubble Space Telescope, Stern said. In analogy, if the spacecraft were flying over a city it would be able to count the individual buildings on the ground. New Horizons may also identify as-yet-unknown moons or rings around Pluto. 
 
 At the wake-up event, Stern handed out small, 2-inch-long pencils — whittled down from extensive use. 
 
 "This is the metaphor for persistence," Stern said, holding up the pencil stub. "Since this mission went through so many ups and downs — the way the exploration of Pluto did — I thought this was an appropriate thing to give away. It's very simple, but it's meaningful." 
 
 Follow Calla Cofield @callacofield.Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com. 
 
 Pluto, the most famous dwarf planet in our solar system, underwent a well-publicized (and somewhat controversial) reclassification that took away its title as the ninth and most distant planet from the sun. So, how well do you know this fascinating world? Start the Quiz 0 of 10 questions complete ||||| Countdown to discovery! Not since Voyager 2’s flyby of Neptune in 1989 have we flung a probe into the frozen outskirts of the Solar System. Speeding along at 30,800 miles per hour New Horizons will pierce the Pluto system like a smartly aimed arrow. 
 
 Edging within 7,800 miles of its surface at 7:49 a.m. EDT, the spacecraft’s long-range telescopic camera will resolve features as small as 230 feet (70 meters). Fourteen minutes later, it will zip within 17,930 miles of Charon as well as image Pluto’s four smaller satellites — Hydra, Styx, Nix and Kerberos. 
 
 After zooming past, the craft will turn to photograph Pluto eclipsing the Sun as it looks for the faint glow of rings or dust sheets illuminated by backlight. At the same time, sunlight reflecting off Charon will faintly illuminate Pluto’s backside. What could be more romantic than Charonshine? 
 
 Six other science instruments will build thermal maps of the Pluto-Charon pair, measure the composition of the surface and atmosphere and observe Pluto’s interaction with the solar wind. All of this will happen autopilot. It has to. There’s just no time to send a change instructions because of the nearly 9-hour lag in round-trip communications between Earth and probe. 
 
 Want to go along for the ride? Download and install NASA’s interactive app Eyes on Pluto and then click the launch button on the website. You’ll be shown several options including a live view and preview. Click preview and sit back to watch the next few days of the mission unfold before your eyes. 
 
 Like me, you’ve probably wondered how daylight on Pluto compares to that on Earth. From 3 billion miles away, the Sun’s too small to see as a disk with the naked eye but still wildly bright. With NASA’s Pluto Time, select your city on an interactive map and get the time of day when the two are equal. For my city, daylight on Pluto equals the gentle light of early evening twilight six minutes after sunset. An ideal time for walking, but step lightly. In Pluto’s gentle gravity, you only weigh 1/15 as much as on Earth. 
 
 New Horizons is the first mission to the Kuiper Belt, a gigantic zone of icy bodies and mysterious small objects orbiting beyond Neptune. This region also is known as the “third” zone of our solar system, beyond the inner rocky planets and outer gas giants. Pluto is its most famous member, though not necessarily the largest. Eris, first observed in 2003, is nearly identical in size. It’s estimated there are hundreds of thousands of icy asteroids larger than 61 miles (100 km) across along with a trillion comets in the Belt, which begins at 30 a.u. (30 times Earth’s distance from the Sun) and reaches to 55 a.u. 
 
 Below you’ll find a schedule of events in Eastern Time. (Subtract one hour for Central, 2 hours for Mountain and 3 hours for Pacific). Keep in mind the probe will be busy shooting photos and gathering data during the flyby, so we’ll have to wait until Wednesday July 15 to see the the detailed close ups of Pluto and its moons. Even then, New Horizons’ recorders will be so jammed with data and images, it’ll take months to beam it all back to Earth. 
 
 Fasten your seat belts — we’re in for an exciting ride. 
 
 We’ll be reporting on results and sharing photos from the flyby here at Universe Today, but you’ll also want to check out NASA’s live coverage on NASA TV, its website and social media. 
 
 Monday, July 13 
 
 10:30 a.m. to noon – Media briefing on mission status and what to expect broadcast live on NASA TV 
 
 Tuesday, July 14 
 
 7:30 to 8 a.m. – Arrival at Pluto! Countdown program on NASA TV 
 
 At approximately 7:49 a.m., New Horizons is scheduled to be as close as the spacecraft will get to Pluto, approximately 7,800 miles (12,500 km) above the surface, after a journey of more than 9 years and 3 billion miles. For much of the day, New Horizons will be out of communication with mission control as it gathers data about Pluto and its moons. 
 
 The moment of closest approach will be marked during a live NASA TV broadcast that includes a countdown and discussion of what’s expected next as New Horizons makes its way past Pluto and potentially dangerous debris. 
 
 8 to 9 a.m. – Media briefing, image release on NASA TV 
 
 Wednesday, July 15 
 
 3 to 4 p.m. – Media Briefing: Seeing Pluto in a New Light; live on NASA TV and release of close-up images of Pluto’s surface and moons, along with initial science team reactions. 
 
 We’ll have the latest Pluto photos for you, but you can also check these excellent sites: 
 
 * Long Range Reconnaissance Imager (LORRI) archive 
 
 * Pluto Photojournal 
 
 * New Horizons science photo gallery 
 
 Need more Pluto? Spend a few minutes watching this excellent New York Times mission documentary. 
 
 Related 
 
 By Bob King - 
 
 I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. I also write a daily astronomy blog called Astro Bob. Check out my forthcoming book "Night Sky with the Naked Eye", a guide to the wonders of the night using only your eyes. Available on Amazon and BN. 
 
 Charon, Clyde Tombaugh, flyby, kuiper belt, NASA, New Horizons, Pluto ||||| NASA's New Horizons spacecraft is four weeks away from its flyby of Pluto, with just 20 million miles to go. This diagram shows the current position of New Horizons, along with its path so far (in green) and the road ahead (in red). 
 
 NASA's New Horizons spacecraft is less than one month away from its flyby of Pluto and in great shape for what promises to be a truly epic encounter with the dwarf planet. 
 
 New Horizons, the first spacecraft ever sent to investigate Pluto, has been traveling for nine long years and has just 20 million miles (32 million kilometers) to go before it makes a historic flyby of the dwarf planet. During its close encounter with Pluto, New Horizons will fly within 7,750 miles (12,500 km) of the dwarf planet and capture the first-ever close-up views of the icy world. [See the latest photos of Pluto from New Horizons] 
 
 "This is getting really exciting," Cathy Olkin, New Horizons' deputy project scientist, said in a video update today (June 16). 
 
 New Horizons has been tracking Pluto with its instruments and snapping ever-sharper views of the dwarf planet. Last week, NASA unveiled images of the four "faces of Pluto" — views of the different surface features on the dwarf planet as it rotated over the course of four days. 
 
 These images of Pluto from the Long Range Reconnaissance Imager on NASA's New Horizons spacecraft show views of the dwarf planet as it rotates, revealing details about the dimensions of its dark surface patches. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute 
 
 "We've always known Pluto had dark areas, but now, we're starting to see how large they are, where they're exactly located, what shape they take — and it's very fascinating to see this level of detail," Olkin said. 
 
 This week, New Horizons will begin taking infrared photographs of Pluto and its largest moon, Charon, to help map their surface geology and temperature. The probe will also begin taking daily color images that record Pluto's full rotational phase. It will also continue taking measurements with its Long Range Reconnaissance Imager, nicknamed LORRI. 
 
 New Horizons' Pluto flyby will also mark the first time a spacecraft has explored the icy Kuiper Belt, where Pluto resides, and the probe's mission won't stop once it zips by Pluto. 
 
 Chris Hersman, a New Horizons mission systems engineer, said that if the probe's power supply remains healthy, its mission could continue through the outer edge of the solar system for quite some time. 
 
 "There are a lot of interesting interactions between the heliosphere and what's beyond that, so we'd like to get there — and it looks like we can make it until the mid-2030s at least," Hersman said. (The heliosphere is the magnetic bubble containing our solar system, solar wind and the entire solar magnetic field.) 
 
 NASA's New Horizons mission update today was the first in a series of weekly updates — held each Tuesday this month — leading up to the Pluto flyby on July 14. Starting July 7, NASA and the New Horizons team will begin providing daily updates on the mission's progress. 
 
 To see NASA's complete schedule of New Horizons updates leading up to the Pluto flyby, visit: 
 
 http://www.nasa.gov/press-release/nasa-announces-television-coverage-media-activities-for-pluto-flyby. 
 
 Email Sarah Lewin at slewin@space.com or follow her @SarahExplains. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.
– This is one of the biggest days in the exploration of our solar system since Voyager 2 approached Neptune in 1989—and there may not be a day like it again. According to NASA's calculations, its New Horizons spacecraft flew by Pluto at 31,000mph at 7:49am EDT today; confirmation of that will come tonight, some 13 hours later, reports the AP. The confirmation will mark the completion of NASA's tour of the "classical nine" planets, reports the AP, which notes that Pluto was considered a full-fledged planet instead of a dwarf one when the probe began its journey in 2006. Some things to know about the historic flyby, which comes 50 years to the day after the first successful flyby of Mars: New Horizons will have to capture a vast amount of data in a short time. The probe will be pushed to its limits as it pivots to capture photos and information on Pluto and its moons Charon, Styx, Nix, Kerberos, and Hydra during the flyby. "I can't wait to get into the data and really start making sense of it. Right now, we're just standing under the waterfall and enjoying it," principal New Horizons scientist Alan Stern tells the BBC. We don't know whether it was a success. The probe is far too busy to "phone home," the AP notes, but it's expected to send a confirmation signal at around 9pm tonight. The eagerly awaited first photos from the flyby should be released tomorrow night, the Guardian reports, though it will take 16 months to send all the data from the flyby back to Earth. We've already learned a lot of new things about Pluto. "The science we've already made is mouth-watering," says Stern. "The Pluto system is enchanting in its strangeness and its alien beauty." Among NASA's findings in recent days: Pluto's North Pole has an icy cap and the planet's diameter is 1,597 miles across, not 1,471 miles as previously thought. The finding suggests the planet contains a lot more ice and a lot less rock than thought, the Christian Science Monitor reports. There are still a lot of mysteries to be solved. Scientists hope the first close-up look at Pluto's surface will explain features like heart- and doughnut-shaped features recently spotted for the first time. LiveScience notes that new information from Pluto could help explain how our own planet formed and how life began. "There's a feeling among scientists that Pluto probably will tell us what the early solar system looked like and it's now locked in deep freeze and maybe it will tell us what we once were, a long time ago," the director of the Deep Space Communication Complex tells Reuters. The Australian facility will be first to receive new information from the spacecraft. New Horizons isn't done. New Horizons will keep traveling into the Kuiper Belt debris field and beyond after it passes Pluto, National Geographic notes, and it may have more research to do if NASA approves funding. (The astronomer who first spotted Pluto in 1930 is the spacecraft's only passenger.)