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29.04.2015
New Horizons Sees Features on Pluto
At a press conference on Wednesday astronomers working on the New Horizons space probe revealed new images that show surface features on Pluto for the first time!
The probe was just over 100 million kilometers from Pluto when the images were taken on April 12–18 (the Earth is 150 million km from the Sun, for comparison). Hubble images taken over the years have shown the diminutive world has darker and lighter patches on its surface, and these images match that.
In fact, these images are now at higher resolution than Hubble can produce! And they'll be getting better every day ...
Pluto looks lumpy in the animation, but that’s certainly an illusion; darker spots near the edge make it look like Pluto has chunks taken out of it. It’s expected that Pluto will be quite round; its gravity should compress it enough for it to be mostly spherical. I wonder if it’ll be oblate (slightly flattened) due to tides from its moon Charon. We’ll know pretty soon.
Charon can be seen in the animation as well, orbiting Pluto once every six days or so. Actually, it’s about ¼ the diameter of Pluto, and massive enough that it pulls on its parent pretty hard, hard enough that it’s more correct to say they both orbit their common barycenter, their center of mass.
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The raw images form the probe are combined and processed mathematically to sharpen them.
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I’ll note these images have been deconvolved; that means they’ve been sharpened using techniques that help bring them into better focus. The raw images look like blurs, but by combining them and using these techniques, the surface features can be detected.
The rotation axis of Pluto is labeled in the animation. Pluto’s spin is tilted compared with its orbit, so the probe is coming into the system nearly “face-on”. Interestingly, as NH Principal Investigator Alan Stern points out, there’s a bright spot on Pluto at the lower right, right at the pole. Is that some sort of ice cap? Maybe. It’s too soon to tell, but in a few months we’ll know better once New Horizons can see features better, and analyze their composition.
Pluto is tiny, just 2,370 km across—our own Moon is far larger (3,470 km). That’s why it still appears so small to New Horizons. The probe is closing in on Pluto rapidly, though, moving at about 14 km/sec. Right now, New Horizons is about 90 million kilometers from Pluto, and 4.7 billion km from Earth. It takes the radio signals from the probe nearly 4.5 hours to get here!
Closest approach occurs at noon UTC on July 14. Even in early June Pluto will only be a little over 10 pixels across, and 100 pixels four days before the encounter. Things will happen rapidly starting then. Pluto flies through the system in only a few hours, and it’ll take months to send all the data back to Earth. Bandwidth is limited when you’re that far from home.
I'll note that the raw images off the probe are being posted online, too. I suggest checking in on them every day or two, and watch them get better and better as time goes on, and New Horizons approaches Pluto.
I’m very excited about this mission. If they’re getting detail like this now, imagine what we’ll see in July!
Quelle: BadAstronomy
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Update: 2.05.2015
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New Horizon's Best Images of Pluto Yet Reveal Terrain and Possible Polar Ice Cap
New Horizons LORRI Optical Navigation Campaign 3, showing a full orbit of the dwarf planet’s moon Charon around Pluto, as well as a full rotation of Pluto itself. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
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NASA’s nuclear-powered New Horizons spacecraft has turned Pluto from an astronomy object with just a pinpoint of light into a planetary body with surface features and a possible polar ice cap. For the first time, images from the Johns Hopkins Applied Physics Laboratory spacecraft, built near Baltimore, Md., are revealing bright and dark regions on the surface of faraway Pluto—the primary target of the New Horizons close flyby in mid-July.
“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, Colo.
“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,” Stern said.
According to NASA, the images were captured in early- to mid-April from within 70 million miles (113 million km) of Pluto using the telescopic Long Range Reconnaissance Imager (LORRI) camera on the spacecraft.
A technique called image deconvolution was used to sharpen the raw, unprocessed images beamed back to Earth, the space agency said.
New Horizons scientists interpreted the data to reveal how 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, said NASA.
Images from the spacecraft will dramatically improve as New Horizons speeds closer to its July rendezvous with Pluto, says NASA. The overall mission cost is about $700 million.
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, Md.
The science team believes the spacecraft’s instruments will reveal the composition of rocks even on the sides of craters. Pluto’s surface temperature is estimated to be -380 Fahrenheit, with a basic composition of nitrogen, methane, and carbon monoxide ice.
The National Academy of Sciences believes the New Horizons data will be important to understanding the earliest building blocks of the Solar System, as well as the planetary discs of debris around new stars spotted by the Hubble Space Telescope.
The new images mark the first time that the 1,054-lb spacecraft has returned images of Pluto exceeding the resolution that can be obtained by Hubble.
New Horizons, one of the most beautiful of all planetary spacecraft ever flown, has a 200-watt radioisotope thermoelectric generator (RTG) but uses only 28 watts to run its science instruments.
The instruments are the most compact high performance science devices ever flown on the first reconnaissance of a body in the Solar System, according to the Southwest Research Institute (SwRI) in San Antonio, Texas.
Instrument highlights include:
-LORRI: Developed by SwRI, the Long Range Reconnaissance Imager uses an 20.83-cm aperture telescope to return surface resolutions of about 25 meters. The instrument should reveal features the size of a basketball court.
-Ralph: The visible/infrared imaging spectrometer is to obtain 0.5 km monochromatic images and 1.5 km resolution color imagery and composition data with 7 km resolution. It was developed by Ball Aerospace, SwRI and the Goddard Space Flight Center to search for unknown moons or ring systems aiding navigation toward or away from them.
The main color and infrared camera suite on New Horizons is named after Ralph Kramden of the 1950s television series “The Honeymooners.” It is collocated on the spacecraft with his TV wife Alice.
-Alice: The Ultraviolet Imaging Spectrometer will obtain data on atmospheric composition. Developed by SwRI it is nearly identical to one flying on the European Rosetta comet mission.
-Swap: The SwRI solar wind instrument will measure when Pluto’s tenuous atmosphere begins to interact with the solar wind and characterize the rate which pluto is losing its atmosphere.
-Pepssi: The APL energetic particle detector will also help characterize Pluto’s atmosphere.
-Rex: The APL/Stanford University radio science instrument will use the spacecraft’s 83-inch diameter to obtain atmospheric data and terrain temperatures.
-SDC: The Student Dust Counter, managed by Univ. of Colorado students, has already provided years of educational space instrument experience to students. It will continue to do this for years into the future.
Quelle: AS
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Update: 7.05.2015
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Pluto-bound craft hunts for hazardous moons
Unknown satellites pose danger to New Horizons mission as it journeys to the edge of the Solar System.
On 11 May, a telescope aboard a NASA craft will turn and stare at Pluto — like a space-robot equivalent of a sailor watching for shoals that could take out his vessel.
As the New Horizons craft hurtles towards its 14 July rendezvous with Pluto, mission scientists are preparing to guide it through what could be a dangerous dusty realm. It will skim the orbit of the dwarf planet’s largest moon, Charon, at more than 48,000 kilometres per hour. At that speed, hitting a dust particle the size of a rice grain could be fatal.
To minimize the risk of hitting debris from Charon or another, unknown moon, scientists will conduct seven 45-minute observation sessions between 11 May and 1 July. If they find a potential hazard, the team can change the spacecraft’s course. That would mean forgoing some science observations, but it could also mean the difference between life and death for the first spacecraft ever to visit Pluto.
Mission leaders calculate that the chance of a dust particle knocking out New Horizons is just 1 in 10,000. The only way to avoid the hazard completely would be to stay away from Pluto altogether, says Marc Buie, a mission co-investigator at the Southwest Research Institute in Boulder, Colorado.
New Horizons, now roughly 90 million kilometres from Pluto, is giving humans their best-ever view of the dwarf planet. The spacecraft carries the Long Range Reconnaissance Imager, a giant zoom lens with a 20.8-centimetre aperture. During the hazard observations, the instrument will scan the space around Pluto and its five known moons, looking for objects as small as a few kilometres across.
The mission is almost certain to discover new moons in the process. The Hubble Space Telescope found two during its hazard searches before the Pluto mission: Kerberos, which measures 14–40 kilometres across, in 2011, and the smaller Styx in 2012. “I wouldn’t be at all surprised if there were more,” says Cathy Olkin, a New Horizons deputy project scientist at the Southwest Research Institute.
Charon, which is roughly the same width as Texas, is thought to have formed during a giant impact early in Pluto’s history. The other four known moons are much smaller and may be debris spit out during the same collision. “The architectural details of this system are fascinating,” says William McKinnon, a planetary scientist at Washington University in St. Louis, Missouri. “It’s like a miniature planetary system.”
New-found moons might appear in any of a number of places around Pluto, says Buie. There is, for example, a pocket that nestles inside the orbit of Charon that is gravitationally stable enough for a moon to survive there for millions of years. But planetary scientists do not have a plausible explanation for how a moon might have appeared there to begin with, Buie says.
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Another place that could have small moons is outside the orbit of Hydra, Pluto’s outermost known moon. Buie hopes to find an exotic arrangement: moons sharing the same orbit. Any such discovery would rewrite the origin story of the Pluto–Charon system, he says.
As New Horizons gets closer to Pluto, it may even spot rings of dust around the dwarf planet. These could form when meteorites hit the small moons, kicking up dust that drifts away from the moons’ low-gravity environments and into orbit around Pluto.
It is this streaming dust that poses the biggest danger to New Horizons. Mission scientists have been modelling where they think the dust from Pluto’s moons might flow, and will do so again after the upcoming hazard searches.
If mission planners do spot something dangerous, they can divert New Horizons onto one of three alternative routes (see ‘Perilous path’). One option would leave the spacecraft on its current course but rotate it so that its antenna acts as a shield against incoming debris. Another possibility would send the craft diving much closer to Pluto, inside the orbit of Charon — assuming that there is no extra moon there. A third would nudge the spacecraft slightly farther away from Pluto.
The last chance to divert to one of these courses comes on 4 July. Choosing any of them would burn some of the fuel that engineers need to steer the spacecraft when it departs Pluto for a planned visit to a second icy world in the outer Solar System’s Kuiper belt.
Even so, mission planners have a backup for this backup. They will command New Horizons to radio a little of its crucial data back to Earth in the two days before its Pluto encounter — just in case something takes the spacecraft out.
Quelle: nature
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Update: 13.05.2015
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All 5 of Pluto's Known Moons Spied by NASA Probe (Photo)
NASA's New Horizons spacecraft captured these views of Pluto and its moons on April 25, 2015.
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NASA's New Horizons spacecraft has snapped its first-ever family portrait of the Pluto system, capturing the dwarf planet and all five of its known moons.
New Horizons, which is speeding toward a historic flyby of Pluto on July 14, took a series of images from April 25 through May 1 using its Long Range Reconnaissance Imager (LORRI) camera. The shots mark the first time New Horizons has managed to resolve the extremely faint Pluto moons Kerberos and Styx, mission team members said.
"Detecting these tiny moons from a distance of more than 55 million miles [88.5 million kilometers] is amazing, and a credit to the team that built our LORRI long-range camera and [mission team member] John Spencer’s team of moon and ring hunters," New Horizons principal investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado, said in a statement.
Pluto's five known satellites are Charon, Hydra, Nix, Kerberos and Styx. At 648 miles (1,043 km) in diameter, Charon is nearly half as wide as Pluto itself, but the other four moons are minuscule. Kerberos and Styx, for example, are thought to be just 4 to 13 miles (7 to 21 km) and 6 to 20 miles (10 to 32 km) wide, respectively.
The four tiny moons are visible individually in the new images, while Charon melds with Pluto in a much brighter blur at the center of the other satellites' orbits. New Horizons scientists processed the original LORRI photos extensively to reduce the Pluto-Charon glare and reveal the faint small moons.
Kerberos and Styx were first spotted in 2011 and 2012, respectively, by New Horizons team members using NASA's Hubble Space Telescope. The spacecraft is poised to begin a moon search of its own in the coming days, as part of an effort to identify hazards that could complicate New Horizons' July 14 Pluto flyby.
"New Horizons is now on the threshold of discovery," Spencer, who's also based at the Southwest Research Institute in Boulder, said in the same statement. "If the spacecraft observes any additional moons as we get closer to Pluto, they will be worlds that no one has seen before."
The $700 million New Horizons mission launched in January 2006 to conduct the first up-close reconnaissance of Pluto and its moons. Pluto has remained mysterious since its 1930 discovery because it is relatively small and lies so far from the sun; even the best Hubble images show the dwarf planet as a blur of pixels.
But New Horizons will bring Pluto into focus: On July 14, the probe will zoom within just 7,800 miles (12,500 km) of the dwarf planet's frigid surface.
Quelle: SC
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Update: 16.05.2015
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NASA Pluto Probe Begins Search for New Moons, Rings
A NASA spacecraft speeding toward Pluto is casting a wary eye on the dwarf planet system, looking for anything that could trip it up in the home stretch of its historic mission.
NASA's New Horizons probe, which is set to perform the first-ever flyby of Pluto on July 14, has begun hunting for possible rings and undiscovered moons, in an effort to identify potential hazards near the dwarf planet. The campaign began Monday (May 11) and involves roughly weekly observations with the spacecraft's long-range camera through July 1, mission team members said.
"You know how Curiosity had its 'seven minutes of terror?'" said New Horizons principal investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado, referring to the NASA Mars rover's harrowing "sky crane" landing in August 2012. "Well, we call this 'seven weeks of suspense.'"
Small debris, big impact
New Horizons was the speediest spacecraft ever launched when it blasted off in January 2006, and it's now rocketing along at a healthy 32,570 mph (52,416 km/h) relative to the sun — so fast that a collision with a piece of debris just a few millimeters wide could prove fatal, even though the probe is protected by a Kevlar "bulletproof vest."
So the hazard-hunting team is on the lookout for any regions on or around New Horizons' path that may harbor such debris. That explains why the researchers are concerned about undiscovered moons.
"New moons might be shedding dust into the system, into a place where we can encounter it," said New Horizons science team member John Spencer, also of SwRI, who is leading the hazard search. The odds of actually slamming into a newfound moon are extremely small, he added.
Pluto is known to have five moons: Charon, Nix, Hydra, Kerberos and Styx. Charon, the innermost moon, was first spotted in 1978; at 648 miles (1,043 kilometers) in diameter, it's nearly half as wide as Pluto itself. The other four satellites are all tiny, and were discovered by NASA's Hubble Space Telescope between 2005 and 2012.
Spencer said he wouldn't be surprised if New Horizons did indeed add some more names to this list.
"We know quite a lot of places where moons could be stable in the system," Spencer.
Quelle: SC
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Update: 28.05.2015
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New Spacecraft Photos Hint at a Rich and Complex Pluto
Three new observations captured on May 8th, 10th and 12th by NASA's New Horizons probe of the dwarf planet Pluto. At flyby in July, the resolution of these images will be 5,000 times this resolution.
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As NASA’s New Horizons spacecraft blasts closer to Pluto at a pace of 750,000 miles per day, increasingly detailed images are beginning to come our way.
In the latest series of images beamed back to Earth from the mission’s Long-Range Reconnaissance Imager (LORRI) instrument, a complex small world is beginning to reveal itself — vast, dark regions are coming into focus. Now we are in a new regime of Plutonian discovery; these pixelated views are the highest resolution photos we have ever seen of the dwarf planet.
“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 in a news release today (Wednesday). “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,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colo. “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.”
In less than 2 months New Horizons will make its Pluto close encounter and as these gradually-sharpening images are showing us, it seems likely that Pluto will be a rich and complex place.
“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,” added Hal Weaver, New Horizons project scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md.
These latest photos are derived through a method known as “image deconvolution”, which allows us to see the broad differences in surface morphology. These changes in surface albedo likely real features, revealing the (possible) bright polar ice caps and vast regions that appear to absorb more light. However, some of the image processing can generate spurious details that will disappear in later observations.Could these regions be vast dune fields? Or could they be complex canyons intersecting large, ancient craters and extinct volcanoes? For now, those details are out of reach of New Horizons’ resolving capabilities, but it’s hard not to imagine what magnificent features await New Horizons as it prepares to shoot past Pluto and its system of moons in July.
Quelle: D-News
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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.
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.
"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," said 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.
Following a January 2006 launch, New Horizons is currently about 2.95 billion miles from home; the spacecraft is healthy and all systems are operating normally.
APL designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. 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.
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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.
Quelle: NASA
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So Far, All Clear: New Horizons Team Completes First Search for Pluto System Hazards
NASA’s New Horizons team has analyzed the first set of hazard-search images of the Pluto system taken by the spacecraft itself – and so far, all looks clear for the spacecraft’s safe passage
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This image shows the results of the New Horizons team’s first search for potentially hazardous material around Pluto, conducted May 11-12, 2015, from a range of 47 million miles (76 million kilometers). The image combines 48 10-second exposures, taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI), to offer the most sensitive view yet of the Pluto system. The left panel is a combination of the original images before any processing. The combined glare of Pluto and its large moon Charon in the center of the field, along with the thousands of background stars, overwhelm any faint moons or rings that might pose a threat to the New Horizons spacecraft. The central panel is the same image after extensive processing to remove Pluto and Charon’s glare and most of the background stars, revealing Pluto’s four small moons -- Styx, Nix, Kerberos and Hydra -- as points of light. The right panel overlays the orbits and locations of all five moons, including Charon. Remaining unlabeled spots and blemishes in the processed image are imperfectly removed stars, including variable stars which appear as bright or dark dots. The faint grid pattern is an artifact of the image processing. Celestial north is up in these images.
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The observations were made May 11-12 from a range of 47 million miles (76 million kilometers) using the telescopic Long Range Reconnaissance Imager (LORRI) on New Horizons. For these observations, LORRI was instructed to take 144 10-second exposures, designed to allow a highly sensitive search for faint satellites, rings or dust sheets in the system. The mission team is looking carefully for any indications of dust or debris that might threaten New Horizons before the spacecraft’s flight through the Pluto system on July 14; a particle as small as a grain of rice could be fatal.
The observations, downlinked to Earth May 12-15 and processed and analyzed May 12-18, detected Pluto and all five of its known moons, but no rings, new moons, or hazards of any kind. The New Horizons hazard detection team, led by John Spencer of the Southwest Research Institute in Boulder, Colorado, determined that small satellites with about half the brightness of Pluto’s faintest known moon, Styx, could have been detected at this range. Any undiscovered moons outside the orbit of Pluto’s largest and closest moon, Charon, are thus likely smaller than 3-10 miles (5-15 kilometers) in diameter. If any undiscovered rings are present around Pluto outside Charon’s orbit, they must be very faint or narrow – less than 1,000 miles wide or reflecting less than one 5-millionth of the incoming sunlight.
The next hazard-search images will be taken May 29-30, and should have about twice the sensitivity of the first batch. The team expects to complete a thorough analysis of the data and report on its results by June 12. The New Horizons team has until July 4 to divert the spacecraft to one of three alternate routes if any dangers are found.
New Horizons is nearly 2.95 billion miles from home, speeding toward Pluto and its moons at just under 750,000 miles per day. The spacecraft is healthy and all systems are operating normally.
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. Southwest Research Institute, San Antonio and Boulder, Colorado, 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.
Quelle: NASA
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