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Samstag, 26. Dezember 2015 - 20:15 Uhr

Raumfahrt - NEW HORIZONS bei Pluto - Update-19

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New Horizons Returns First, Best Images of Pluto

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The Mountainous Shoreline of Sputnik Planum: In this highest-resolution image from NASA’s New Horizons spacecraft, great blocks of Pluto’s water-ice crust appear jammed together in the informally named al-Idrisi mountains. "The mountains bordering Sputnik Planum are absolutely stunning at this resolution," said New Horizons science team member John Spencer of the Southwest Research Institute. "The new details revealed here, particularly the crumpled ridges in the rubbly material surrounding several of the mountains, reinforce our earlier impression that the mountains are huge ice blocks that have been jostled and tumbled and somehow transported to their present locations."
Credits: NASA/JHUAPL/SwRI
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NASA’s New Horizons spacecraft has sent back the first in a series of the sharpest views of Pluto it obtained during its July flyby – and the best close-ups of Pluto that humans may see for decades.
Each week the piano-sized New Horizons spacecraft transmits data stored on its digital recorders from its flight through the Pluto system on July 14. These latest pictures are part of a sequence taken near New Horizons’ closest approach to Pluto, with resolutions of about 250-280 feet (77-85 meters) per pixel – revealing features less than half the size of a city block on Pluto’s diverse surface.  In these new images, New Horizons captured a wide variety of cratered, mountainous and glacial terrains. 
“These close-up images, showing the diversity of terrain on Pluto, demonstrate the power of our robotic planetary explorers to return intriguing data to scientists back here on planet Earth,” said John Grunsfeld, former astronaut and associate administrator for NASA’s Science Mission Directorate. “New Horizons thrilled us during the July flyby with the first close images of Pluto, and as the spacecraft transmits the treasure trove of images in its onboard memory back to us, we continue to be amazed by what we see."
These latest images form a strip 50 miles (80 kilometers) wide on a world 3 billion miles away. The pictures trend from Pluto’s jagged horizon about 500 miles (800 kilometers) northwest of the informally named Sputnik Planum, across the al-Idrisi mountains, over the shoreline of Sputnik, and across its icy plains. (To view the strip in the highest resolution possible, click here and zoom in.)
 “These new images give us a breathtaking, super-high resolution window into Pluto’s geology,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Nothing of this quality was available for Venus or Mars until decades after their first flybys; yet at Pluto we’re there already – down among the craters, mountains and ice fields – less than five months after flyby! The science we can do with these images is simply unbelievable."
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Layered Craters and Icy Plains: This highest-resolution image from NASA’s New Horizons spacecraft reveals new details of Pluto’s rugged, icy cratered plains, including layering in the interior walls of many craters. "Impact craters are nature's drill rigs, and the new, highest-resolution pictures of the bigger craters seem to show that Pluto's icy crust, at least in places, is distinctly layered,” said William McKinnon, deputy lead of the New Horizons Geology, Geophysics and Imaging team, from Washington University in St. Louis. "Looking into Pluto’s depths is looking back into geologic time, which will help us piece together Pluto's geological history.”
Credits: NASA/JHUAPL/SwRI
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Pluto’s ‘Badlands’: This highest-resolution image from NASA’s New Horizons spacecraft shows how erosion and faulting have sculpted this portion of Pluto’s icy crust into rugged badlands topography.
Credits: NASA/JHUAPL/SwRI
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The images above were captured with the telescopic Long Range Reconnaissance Imager (LORRI) aboard New Horizons, about 15 minutes before New Horizons’ closest approach to Pluto – from a range of just 10,000 miles (17,000 kilometers). They were obtained with an unusual observing mode; instead of working in the usual “point and shoot,” LORRI snapped pictures every three seconds while the Ralph/Multispectral Visual Imaging Camera (MVIC) aboard New Horizons was scanning the surface. This mode requires unusually short exposures to avoid blurring the images.
These new images are six times better than the resolution of the global Pluto map New Horizons obtained, and five times better than the best images of Pluto’s cousin Triton, Neptune’s large moon, obtained by Voyager 2 in 1989.
Mission scientists expect more imagery from this set over the next several days, showing even more terrain at this highest resolution.
Quelle: NASA
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Update: 10.11.2015
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Pluto’s Close-up, Now in Color

This enhanced color mosaic combines some of the sharpest views of Pluto that NASA’s New Horizons spacecraft obtained during its July 14 flyby. The pictures are part of a sequence taken near New Horizons’ closest approach to Pluto, with resolutions of about 250-280 feet (77-85 meters) per pixel – revealing features smaller than half a city block on Pluto’s surface. Lower resolution color data (at about 2,066 feet, or 630 meters, per pixel) were added to create this new image.
The images form a strip 50 miles (80 kilometers) wide, trending (top to bottom) from the edge of “badlands” northwest of the informally named Sputnik Planum, across the al-Idrisi mountains, onto the shoreline of Pluto’s “heart” feature, and just into its icy plains. They combine pictures from the telescopic Long Range Reconnaissance Imager (LORRI) taken approximately 15 minutes before New Horizons’ closest approach to Pluto, with  – from a range of only 10,000 miles (17,000 kilometers) – with color data (in near-infrared, red and blue) gathered by the Ralph/Multispectral Visible Imaging Camera (MVIC) 25 minutes before the LORRI pictures.
The wide variety of cratered, mountainous and glacial terrains seen here gives scientists and the public alike a breathtaking, super-high-resolution color window into Pluto’s geology.
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Zooming in on Pluto’s Pattern of Pits

On July 14 the telescopic camera on NASA’s New Horizons spacecraft took the highest resolution images ever obtained of the intricate pattern of “pits” across a section of Pluto’s prominent heart-shaped region, informally named Tombaugh Regio. Mission scientists believe these mysterious indentations may form through a combination of ice fracturing and evaporation. The scarcity of overlying impact craters in this area also leads scientists to conclude that these pits – typically hundreds of yards across and tens of yards deep – formed relatively recently. Their alignment provides clues about the ice flow and the exchange of nitrogen and other volatile materials between the surface and the atmosphere.
The image is part of a sequence taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft passed within 9,550 miles (15,400 kilometers) of Pluto’s surface, just 13 minutes before the time of closest approach. The small box on the global view shows the section of the region imaged in the southeast corner of the giant ice sheet informally named Sputnik Planum. The magnified view is 50-by-50 miles (80-by-80 kilometers) across. The large ring-like structure near the bottom right of the magnified view -- and the smaller one near the bottom left -- may be remnant craters. The upper-left quadrant of the image shows the border between the relatively smooth Sputnik Planum ice sheet and the pitted area, with a series of hills forming slightly inside this unusual “shoreline.”
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On July 14 the telescopic camera on NASA’s New Horizons spacecraft took the highest resolution images ever obtained of the intricate pattern of “pits” across a section of Pluto’s prominent heart-shaped region, informally named Tombaugh Regio. The image is part of a sequence taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft passed within 9,550 miles (15,400 kilometers) of Pluto’s surface, just 13 minutes before the time of closest approach.
Quelle: NASA
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Update: 17.12.2015
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New Findings from NASA’s New Horizons Shape Understanding of Pluto and its Moons

 
“We’re much less than halfway through transmitting data about the Pluto system to Earth, but a wide variety of new scientific results are already emerging” -  Alan Stern, New Horizons principal investigator
Five months after NASA’s New Horizons spacecraft flew past Pluto to take the first images and measurements of this icy world and its system of satellites, knowledge about this distant system continues to unfold.
New Horizons science team members are highlighting the latest findings from the Pluto flyby at this week’s American Geophysical Union (AGU) fall meeting in San Francisco. Among the highlights are insights into Pluto’s geology and composition, as well as new details about the unexpected haze in Pluto’s atmosphere and its interaction with the solar wind.
“We’re much less than halfway through transmitting data about the Pluto system to Earth, but a wide variety of new scientific results are already emerging,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado.
Geological evidence has been found for widespread past and present glacial activity, including the formation of networks of eroded valleys, some of which are “hanging valleys,” much like those in Yellowstone National Park, Wyoming. “Pluto has greatly exceeded our expectations in diversity of landforms and processes — processes that continue to the present,” said Alan Howard of the University of Virginia, Charlottesville, a scientific collaborator with the New Horizons’ Geology, Geophysics and Imaging team.
Key to understanding activity on Pluto is the role of the deep layer of solid nitrogen and other volatile ices that fill the left side of Pluto’s ‘heart’—a vast, 620-mile (1,000-kilometer) -wide basin, informally named Sputnik Planum. New numerical models of thermal convection within this ice layer not only explain the numerous polygonal ice features seen on Sputnik Planum’s surface, but indicate this layer may be up to a few miles thick. Evaporation of this nitrogen and condensation on higher surrounding terrain leads to glacial flow back toward the basin; additional numerical models of nitrogen ice flow show how Pluto’s landscape has been and is still being transformed.
“Pluto has greatly exceeded our expectations in diversity of landforms and processes — processes that continue to the present,” - Alan Howard, University of Virginia, Charlottesville
In the last few months, New Horizons has also returned a multitude of color and phase-angle data on the remarkable atmospheric haze that surrounds Pluto, rising hundreds of miles or kilometers above the surface. In addition to assessing its optical properties, the science team is examining several important questions about Pluto’s extensive haze: where it originates, why it forms layers, and how it varies spatially around Pluto.
“Like almost everything on Pluto, the haze is much more complicated than we thought,” said Andy Cheng, New Horizons co-investigator with the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland. “But with the excellent New Horizons data currently in hand, we soon expect to have a much better understanding.”
New Horizons has also found new and more stringent limits for an atmosphere on Pluto’s largest moon, Charon. Moreover, scientists studying infrared spectral observations of Charon from the LEISA instrument aboard New Horizons are reporting evidence that ammonia (NH3) absorption occurs at a low level across a large portion of Charon's surface, not just the high local concentrations that had been previously detected in a few locations. One of those, the informally named Organa Crater, had been noted as being especially rich in NH3. It’s not yet known what controls the distribution of Charon’s NH3, or if it comes from Charon’s interior or an external source.
New Horizons scientists are also presenting findings about how Pluto and its moons interact with the solar wind, a constant stream of particles and plasma that flows from the sun and is still traveling at 900,000 miles per hour (1.4 million kilometers per hour) at Pluto. Pluto’s outflowing atmosphere provides a source of neutral atoms that can exchange electrons with the solar wind’s positively charged atoms of oxygen (O), carbon (C), and nitrogen (N). Observations from the Earth-orbiting Chandra X-ray Observatory during closest approach contributed to scientists’ understanding of the processes at work. Team members searched for X-ray emissions near Pluto to help determine the rate at which Pluto’s atmosphere is being lost to space, in much the same way X-ray emissions are used to characterize the outflow of material from comets.
Zigzagging across Pluto
This high-resolution swath of Pluto (right) sweeps over the cratered plains at the west of the New Horizons’ encounter hemisphere and across numerous prominent faults, skimming the eastern margin of the dark, forbidding region informally known as Cthulhu Regio, and finally passing over the mysterious, possibly cryovolcanic edifice Wright Mons, before reaching the terminator or day-night line. Among the many notable details shown are the overlapping and infilling relationships between units of the relatively smooth, bright volatile ices from Sputnik Planum (at the edge of the mosaic) and the dark edge or “shore” of Cthulhu. The pictures in this mosaic were taken by the Long-Range Reconnaissance Imager (LORRI) in “ride-along” mode with the LEISA spectrometer, which accounts for the ‘zigzag’ or step pattern. Taken shortly before New Horizons’ July 14 closest approach to Pluto, details as small as 500 yards (500 meters) can be seen. NOTE: Click on the image and ZOOM IN for optimal viewing.
Quelle: NASA
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Update: 26.12.2015
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Pluto through a Stained Glass Window: a Movie from the Edge of Our Solar System
Today’s post is written by Alex Parker, a research scientist at the Southwest Research Institute in Boulder, Colorado, working on NASA’s New Horizons mission.
As New Horizons flew by Pluto, it recorded spectacular images of the icy world’s surface using the LORRI and MVIC cameras. It recorded the plasma and dust environments with the PEPSSI, SWAP, and SDC instruments. But one instrument, designed to measure the composition of Pluto and Charon’s surfaces, did something you might not expect: it recorded the first movies from the edge of our solar system.
Recorded with a 256 x 256 pixel camera at under two frames per second, they are not exactly HDTV. However, they are movies. And they are in color. Sort of.
The instrument is LEISA, New Horizons’ infrared imaging spectrometer. It is an extremely clever instrument; it takes 2-D images just like a normal camera, but it takes them through a linearly-varying filter. One side of the camera can only see light of one specific wavelength of infrared light (light that has longer wavelengths than can be seen by our eyes), and each row of pixels can see a subtly different wavelength.
This linear filter allows light with wavelengths as short as 1.25 microns (a micron is one millionth of a meter; human eyes can perceive light with wavelengths as short as 0.39 microns to long as 0.7 microns) to fall on one side of the image sensor, and smoothly changes to allow light with wavelengths as long as 2.5 microns to fall on the far side of image sensor. This wavelength range was selected because many ices and other materials that exist on the surface of Pluto that have spectral features in this wavelength range that can uniquely identify them, like a fingerprint. We use this instrument to map the distribution of these ices and other materials across Pluto and its moons. A second linear filter to one side of the imager is designed to provide a finer measurement of the spectrum in a region of particular interest between wavelengths of 2.1 to 2.25 microns.
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Figure 1: A simplified schematic of the how the LEISA instrument works. As the scene (in this case, Pluto) moves by along the scan direction, the imager records many frames of video in sequence, imaging each part of Pluto though each segment of the linear filter and building up a spectral map of the entire object. Credits: NASA/JHUAPL/SwRI/Alex Parker
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The effect is much like looking through a stained glass window designed for infrared eyes. By scanning this image sensor with its linear filter across a scene and quickly recording many images during the scan (like a movie), LEISA builds up a two-dimensional map of the scene in front of the camera with a measurement of the infrared spectrum (the brightness versus wavelength) at every location in the image. It makes this complex measurement with exactly zero moving parts — highly reliable for deep-space operations.
The side-effect of collecting this scientifically-important data set, capable of measuring the composition of every location on the surface of Pluto and Charon that is imaged, is that LEISA collected low frame rate infrared color movies of Pluto and Charon as seen by New Horizons during its flyby.
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Pluto Through Stained Glass: A Movie from the Edge of the Solar System. This colorful movie drifting across Pluto by was recorded by New Horizons’ LEISA infrared imaging spectrometer during the July 14 closest approach. The movie has been sped up approximately 17 times from its raw frame rate, and the infrared colors that LEISA sees have been translated into visual colors. Credits: NASA/JHUAPL/SwRI/Alex Parker
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The animation shown here is one such movie collected by New Horizons during its flyby of Pluto. Each pixel is colored to show the relative wavelength of light that each pixel was allowed to see by LEISA’s linear filter. However, since LEISA sees in infrared light, the colors LEISA can see have been re-mapped for this video onto the human visual spectrum — the rainbow. The video has been sped up from its raw frame rate to show the motion smoothly.
In this animation, Pluto drifts by outside the spacecraft as New Horizons scans LEISA across the surface. As Pluto slides beneath the camera, you can see it nod back and forth from the top of the frame to the bottom — these changes in direction are due to New Horizons thrusters firing during the recording of the movie.
This is what you would have actually seen if you were on board the New Horizons spacecraft on July 14, looking out at Pluto through a stained glass window with infrared eyes.
The composition of Pluto makes itself apparent in the animation. Dark bands top-to-bottom correspond to absorption by specific chemicals on the surface of Pluto; many of the bands visible in this view are due to absorption from solid methane ice. However, as some terrains slide by, you can see that they do not become dark under those bands like other terrains; in these areas, the chemical responsible for that absorption is absent.
The discovery of water ice on Pluto was made using the data in this movie. The discovery of ammonia ice within the informally-named Organa crater was made using data from a similar movie of Charon. The New Horizons composition team is busy analyzing these and other movies taken by the LEISA instrument in order to further understand what the surface of Pluto and Charon are made of and how they might be changing with time.
But please — just take a moment and imagine you were on board our little robotic emissary to the farthest worlds ever explored, watching Pluto come into view through a colorful window on the side of the spacecraft. Sure, it might not be in HD, but I promise that you’ve never seen anything like this before!
Quelle: NASA

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