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  • richardmitnick 4:11 pm on September 26, 2017 Permalink | Reply
    Tags: , , Buried treasures in the asteroid belt, , , NASA Dawn   

    From DLR: “Buried treasures in the asteroid belt” 

    DLR Bloc

    German Aerospace Center

    26 September 2017

    Contacts
    Elke Heinemann
    German Aerospace Center (DLR)
    Corporate Communications
    Tel.: +49 2203 601-2867
    Fax: +49 2203 601-3249

    Prof.Dr. Ralf Jaumann
    German Aerospace Center (DLR)
    Institute of Planetary Research, Planetary Geology
    Tel.: +49 30 67055-400
    Fax: +49 30 67055-402

    Ulrich Köhler
    Deutsches Zentrum für Luft- und Raumfahrt (DLR) – German Aerospace Center
    Tel.: +49 30 67055-215
    Fax: +49 30 67055-402

    1

    Ten years of the Dawn mission
    Buried treasures in the asteroid belt – German camera on the Dawn space probe is providing fundamental information on the formation of planets from Vesta and Ceres

    NASA/Dawn Spacecraft

    __________________________________________________________________
    The Dawn spacecraft set off on en route to Vesta and Ceres, the two most massive objects in the main asteroid belt, on 27 September 2007.

    The investigation of these two large bodies, which offer valuable information about the earliest period of the Solar System, is of fundamental importance to understanding the origin and evolution of Earth.

    DLR is responsible for evaluating the images, processing the stereo-image data into global maps, and generating digital terrain models from which the topography of the two bodies can be derived.

    __________________________________________________________________

    Ten years ago, NASA’s Dawn space probe embarked on a mission destined to become one of the most exciting and scientifically productive in the history of the unmanned exploration of the Solar System. Dawn has explored two of the largest bodies in the asteroid belt: the asteroid Vesta and the dwarf planet Ceres. On board is a German camera system – the ‘framing camera’. The camera was specially developed for this mission by the Max Planck Institute for Solar System Research, the DLR Institute of Planetary Research and the Institute of Computer and Network Engineering at the Technical University of Braunschweig. DLR is responsible for evaluating the images, processing the stereo-image data into global maps, and generating digital terrain models from which the topography of the two bodies can be derived with a precision of a few metres.

    Dawn is the first space probe that has been put into orbit around two different celestial bodies in the Solar System. Target 1: Vesta, an asteroid with a diameter of around 500 kilometres; Target 2: the dwarf planet Ceres, with a diameter of almost 1000 kilometres and the largest body in the asteroid belt. And although the expectations of the mission were met and exceeded a long time ago, Dawn’s fuel reserves will allow the probe to continue investigating Ceres until at least mid-2019. Both targets, Vesta and Ceres, have astounded the approximately 50 scientists in the team – which includes several DLR researchers – with an abundance of surprising and significant discoveries, providing insight into the early Solar System.

    The one-ton research probe was launched into space from Cape Canaveral in the United States on 27 September 2007. At first, things progressed at a comparatively leisurely pace. This was because Dawn was accelerated out of Earth’s orbit with an ion thruster. Unlike a conventional rocket engine, which uses a chemical combustion process to generate thrust, an ion thruster ionises inert gas using electrical energy. The charged xenon ions can then be concentrated using a magnetic field and expelled in a targeted way. The generated acceleration is weak, but the thrust can be sustained for months or years.

    The three engines on board Dawn have a thrust of 90 millinewtons – about as strong as a sheet of paper falling to the floor. But when applied over a long period, the thrust builds up to a speed comparable to that of a conventional rocket engine. The probe has some of those on board as well, in the form of small steering nozzles that are used for course correction, but primarily for slowing the probe down into its orbits around Vesta and Ceres. About 425 kilograms of xenon was initially stowed on board for the ion thrusters – much less mass than would have been needed with conventional fuel. The energy for starting the ionisation reaction with the inert gas is provided by two large solar panels with a span of almost 20 metres.

    In the times of the ‘sky police’

    Like the European comet chaser Rosetta, Dawn initially increased its momentum in the inner Solar System until its two identical cameras laid eyes on its first target – the asteroid Vesta – four years later.

    ESA/Rosetta spacecraft

    The expectations were great, as there was still much to learn about these minor planets. Vesta was the fourth asteroid to be discovered, by Heinrich Olbers, a doctor and astronomer from Bremen, in 1807. In those days, astronomers were looking for a planet that they suspected was in the 500 million kilometre-wide gap between the orbits of Mars and Jupiter. At the beginning of the 19th century astronomers Franz Xaver von Zach and Johann Hieronymus Schroeter founded the Himmelspolizey (‘sky police’), an international research collaboration, specifically to look for this ‘gap filler’. A total of 24 European observatories were each given a quadrant of the ecliptic – the orbital band of the planets – for a sky survey.

    The search was successful in 1801, when Giuseppe Piazzi at the Palermo Astronomical Observatory discovered a large body somewhat by chance. It was given the name Ceres. But it soon became clear that the orbital gap was not just home to one planet, but dozens – today we know that hundreds of thousands of rocky objects circle the Sun in orbits similar to those of the planets. Due to its gravitational pull, Jupiter, the most massive planet and ‘guardian’ of the inner Solar System, prevented the formation of a planet from these bodies, which range in size from a few dozen metres to several hundred kilometres.

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    Towering 22 kilometres, almost three times the height of Mount Everest, a still-unnamed mountain rises in the centre of a 450 kilometre-wide impact basin at the south pole of the asteroid Vesta. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Until Dawn’s arrival at Vesta, the only image we had of this asteroid was a few pixels in diameter, taken by the Hubble Space Telescope. In addition to this, spectral measurements were available that indicated the reflective properties of the surface in visible light and the near infrared. Surprisingly, the information on its composition obtained from the spectral measurements resembled that of several meteorites in collections on Earth, leading to the deduction that material had been ejected from Vesta during collisions with other asteroids, and that a tiny fraction of this material had landed on Earth as meteorites. Confirmation of this by spectral measurements taken in the direct vicinity of Vesta would mean that we had samples of the asteroid in our laboratories. This would be enormously important reference material because asteroids are in essence ‘impeded’ planets, and the early period of planetary formation can largely be reconstructed from them.

    Cameras revealing a ‘new world’

    And so it was: The spectra of Vesta recorded by Dawn confirmed that the howardites, eucrites and diogenites – the exotic-sounding names for the meteorites found on Earth – come from Vesta and its fragments, known as Vestoids. Today, we even know with a degree of certainty which region on Vesta they come from. The two cameras on board Dawn showed a structure unlike any discovered on other celestial bodies. With a diameter of around 500 kilometres, Vesta initially formed as a spherical body as it reached what is known in geophysics as ‘isostatic equilibrium’. But a large part of Vesta was ‘missing’ at its south pole, torn away in two gigantic collisions. Among the evidence for this is a 450 kilometre-wide circular rim surrounding a basin-shaped, eight kilometre-deep depression. In the centre is a huge mountain, which formed as a result of the rebound of the rocky crust reacting elastically under high-impact energies. It is a 22 kilometre-high massif, almost three times the height of Mount Everest!

    3
    Measurements with the spectrometers on the Dawn probe confirm that the howardite, eucrite and diogenite types of meteorite come from the asteroid Vesta. In the laboratory, analyses with polarised light can now be used to precisely determine the mineral content. Credit: NASA/University of Tennessee

    A minor planet made of rock and iron

    The Dawn probe orbited its first target for over a year. The team of scientists was overwhelmed by the variety of complex geological and tectonic features. Vesta is located close to the inner edge of the Main Asteroid Belt. In the first few million years of the early Solar System, very high temperatures reigned in that region, where the planetary embryos – planetesimals – first formed and quickly grew into large bodies. Volatile matter, such as water and gases, could not be integrated into the planetesimals and instead were driven to the outskirts of the rotating disc of dust and gas. Vesta also had to be a body that is comparable with the four terrestrial planets of the inner Solar System, with little water in its interior, but rock and metal instead. The meteorites from Vesta also contain these elements. Vesta is evidently the miniature version of a ‘real’ major planet – with a core of iron and nickel, a mantel of heavy silicate rocks, rich in magnesium and iron, and finally a lighter crust. It is even possible that volcanic eruptions once occurred on Vesta as can be deduced from several darker areas on the surface.

    4
    According to Dawn’s recordings, the largest body in the Main Asteroid Belt could be constructed as follows: A core dominated by hydrated silicates, above it a thick mantle of water ice with silicate components and on the exterior a crust made up of light rocks and frozen volatile components, mainly water ice. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    A salty dwarf of ice and rock

    Delighted by the treasures unearthed at Vesta, mission scientists directed the space probe towards its second target, the dwarf planet Ceres, in September 2012. Located almost on the outer edge of the Main Asteroid Belt, researchers were expecting a very different type of ‘minor body’, Ceres being the largest and most massive body in this region, after all. Its size and spherical shape were the main reasons why the International Astronomical Union bumped the asteroid to ‘dwarf planet’ in 2006. During its journey, the probe crossed an invisible divide, known by scientists as the ‘frost line’. Beyond this hypothetical line in the protoplanetary disc of gas and dust, temperatures were low enough for gases to condense into solid icy grains and become part of the material resources of the bodies forming there. However, not much was known about Ceres either. The best telescopes only resolved enough to make very rough regional structures recognisable. From the mass and orbit of the dwarf planet, it could be concluded that a considerable proportion of Ceres must consist of ice.

    5
    At the centre of the 90 kilometre-wide impact structure Occator is the largest occurrence of the strange white deposits on Ceres. These are principally carbonates, salts and carbonic acid. The blue false colours also indicate the existence of bright deposits associated with sulphuric salts, popularly known as plaster. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    The slow approach to Ceres in early 2015 was a hard test of patience for the team. As the image resolution finally enabled the identification of details in the large craters, there was something of a surprise: Very bright, almost snow-white, spots could be seen in some places. What were they? Ceres does not even reflect one tenth of the incident sunlight, so its surface is much darker than Vesta’s, and the scientists had not expected bare ice on the surface. The riddle could not be solved during the initial mapping orbit at 13,000 kilometres, which was still too far away. More patience was required, until the probe dropped to its two lower orbits as close as 375 kilometres from the surface and was able to capture higher-resolution images as well as – most importantly – more detailed spectral data.

    The result was spectacular. The white areas appeared to consist of salty deposits, such as soda (sodium carbonate), magnesium sulphate and even ammonia-containing clay minerals, in addition to other sulphuric salts and chlorides. This means that there must be a process that partially melts the water ice clearly existing in Ceres’ interior, and enriches it with mineral salts. It is forced up to the surface as brine, where the salty solution freezes immediately and the water evaporates. The heat required for this might come from the decay of radioactive elements in the dwarf planet’s interior, but this question has yet to be conclusively answered. It is also generally accepted today that so-called cryovolcanic processes must have occurred on Ceres in the geologically recent past. This is a form of volcanism in which warm, hydrothermal mineral water with dissolved salts – instead of scorching molten rock – are pushed up to the surface. Salt crusts are left after the water has evaporated. The Herschel space telescope discovered water vapour around Ceres in 2014.

    Its low overall density of barely two grams per cubic centimetre is also a strong indicator that Ceres must have a high proportion of water (up to a quarter of its mass). And, like Vesta, Ceres could have a differentiated interior, to a certain degree, with its iron-rich rock components, probably pure metals at its core, surrounded by a mantle of ice and surrounded by a crust of water ice and light, partially hydrated ‘dry’ (clay) minerals with a proportion of ammonia. As the bright deposits are generally located in craters, it is also conceivable that energy for hydrothermal processes taking place beneath the surface arises from the impacts that formed these craters.

    6
    Ahuna Mons on Ceres, with crater-free (therefore geologically young) slopes, rises some 5000 metres above the surroundings, which are otherwise pockmarked by craters. Is it a cryovolcano that spews out ice as well as lava? Researchers think it is possible. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    But there is yet another scientific and aesthetic controversy: The most unusual landscape feature on Ceres is a mountain that, at first glance, is reminiscent of potash-mining slag heaps. Ahuna Mons has a base diameter of 20 kilometres and rises an impressive five kilometres above its surroundings. Ceres has its own Mont Blanc, albeit with very even slopes and gullies that are thought to have formed from the slippage of silicates and carbonates. In general, Ahuna Mons is similar to volcanic domes on Earth. So, is it a cryovolcano – a construct of ice, salt, carbonates and hydrated minerals that get the necessary upward thrust from heat and density differences in order to rise up and form a mountain? It appears so. Presumably, the ice in the mountain evaporated long ago, so only dry minerals are left. However, there is no other mountain like it on Ceres.

    7
    The crater Haulani is about 34 kilometres in diameter, about the size of the Nördlinger Ries in the Swabian Alb. It does not seem to be very old yet, because the edge is still sharp. The blue tones in the contrast-enhanced image are also indicative of this. Landslides show that erosion has begun its setting work. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Exciting finale at perihelion

    Dawn continues to orbit the dwarf planet. This could be the case for years to come. The orbit around this body, with its homogeneous mass distribution and barely any fluctuations in its gravitational field as a result, can be kept stable with almost no fuel. The probe should ‘live’ until 2019. This is when Ceres reaches perihelion, its closest distance to the Sun along its orbit. There is reason to hope that, with the increase in solar radiation at that point, some of the ice in the dwarf planet’s crust will sublimate and even that active cryovolcanism might be observed. This would be the final highlight of a mission rich in discoveries.

    See the full article here .

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    DLR Center

    DLR is the national aeronautics and space research centre of the Federal Republic of Germany. Its extensive research and development work in aeronautics, space, energy, transport and security is integrated into national and international cooperative ventures. In addition to its own research, as Germany’s space agency, DLR has been given responsibility by the federal government for the planning and implementation of the German space programme. DLR is also the umbrella organisation for the nation’s largest project management agency.

    DLR has approximately 8000 employees at 16 locations in Germany: Cologne (headquarters), Augsburg, Berlin, Bonn, Braunschweig, Bremen, Goettingen, Hamburg, Juelich, Lampoldshausen, Neustrelitz, Oberpfaffenhofen, Stade, Stuttgart, Trauen, and Weilheim. DLR also has offices in Brussels, Paris, Tokyo and Washington D.C.

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  • richardmitnick 3:13 pm on July 11, 2017 Permalink | Reply
    Tags: , , , , , Cornelia crater, , , Haulani Crater, Marcia crater, NASA Dawn, Terrain Clues to Ice in the Outer System, The human expansion into the Solar System will demand our being able to identify sources of water, Vesta   

    From Centauri Dreams: “Terrain Clues to Ice in the Outer System” 

    Centauri Dreams

    July 11, 2017
    Paul Gilster

    The human expansion into the Solar System will demand our being able to identify sources of water, a skill we’re honing as explorations continue. On Mars, for example, the study of so-called ‘pitted craters’ has been used as evidence that the low latitude regions of the planet, considered its driest, nonetheless have a layer of underlying ice. The Dawn spacecraft discovered similar pitted terrain on Vesta, as you can see in the image below.

    NASA/Dawn Spacecraft

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    These enhanced-color views from NASA’s Dawn mission show an unusual “pitted terrain” on the floors of the craters named Marcia (left) and Cornelia (right) on the giant asteroid Vesta. The views show that the physical properties or composition of the material in which these pits form is different from crater to crater. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/JHUAPL.

    Vesta’s Marcia crater contains the largest number of pits on the asteroid. The 70-kilometer feature is also one of the youngest craters found there. So what accounts for this kind of terrain? Perhaps the water that formed the pits came from Vesta itself. Another possibility: Low-speed collisions with carbon-rich meteorites could have deposited hydrated materials on the surface, to be released in the heat of subsequent high-speed collisions within the asteroid belt. An explosive degassing into space could explain such pothole-like depressions.

    But Dawn wasn’t through when it left Vesta, and what it has found at Ceres is proving invaluable at understanding what appears to be a common marker of volatile-rich material. In new work from Hanna Sizemore [Geophysical Reseach Letters] (Planetary Science Institute) and colleagues, we learn that Ceres is home to the same kind of pitted terrain. As Sizemore notes:

    “Now, we’ve found this same type of morphological feature on Ceres, and the evidence suggests that ice in the Cerean subsurface dominated the formation of pits there. Finding this type of feature on three different bodies suggests that similar pits might be found on other asteroids we will explore in the future, and that pitted materials may mark the best places to look for ice on those asteroids.”

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    Haulani Crater, Ceres, showing abundant pitted materials on the crater floor. Similar pitted materials have previously been identified on Mars and Vesta, and are associated with rapid volatile release following impact. Their discovery on Ceres indicates pitted materials may be a common morphological indicator of volatile-rich materials in the asteroid belt. Haulani Crater is 34 km in diameter. Color indicates topography. Credit: NASA/MPS/PSI/Thomas Platz.

    Sizemore’s team studied the formation of pitted craters on Ceres through numerical models that explored the role of water ice and other volatiles. The morphological similarities between the Ceres features and what has been found on Mars and Vesta are striking. With water ice evidently significant in pit development on two asteroids and a planet, similar terrains will be of clear interest for future missions in terms of in situ resource utilization.

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    Pitted terrain on Mars as seen by HiRISE aboard the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona.

    Centauri Dreams


    See the full article here .

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    Tracking Research into Deep Space Exploration

    Alpha Centauri and other nearby stars seem impossible destinations not just for manned missions but even for robotic probes like Cassini or Galileo. Nonetheless, serious work on propulsion, communications, long-life electronics and spacecraft autonomy continues at NASA, ESA and many other venues, some in academia, some in private industry. The goal of reaching the stars is a distant one and the work remains low-key, but fascinating ideas continue to emerge. This site will track current research. I’ll also throw in the occasional musing about the literary and cultural implications of interstellar flight. Ultimately, the challenge may be as much philosophical as technological: to reassert the value of the long haul in a time of jittery short-term thinking.

     
  • richardmitnick 5:08 pm on February 17, 2017 Permalink | Reply
    Tags: , NASA Dawn, , Organics at Ceres   

    From JPL-Caltech: “Dawn Discovers Evidence for Organic Material on Ceres” 

    NASA JPL Banner

    JPL-Caltech

    Feb. 16, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, CA
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This enhanced color composite image, made with data from the framing camera aboard NASA’s Dawn spacecraft, shows the area around Ernutet Crater. The bright red portions appear redder with respect to the rest of Ceres. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    NASA’s Dawn mission has found evidence for organic material on Ceres, a dwarf planet and the largest body in the main asteroid belt between Mars and Jupiter.

    NASA/Dawn Spacecraft
    NASA/Dawn Spacecraft

    Scientists using the spacecraft’s visible and infrared mapping spectrometer (VIR) detected the material in and around a northern-hemisphere crater called Ernutet. Organic molecules are interesting to scientists because they are necessary, though not sufficient, components of life on Earth.

    The discovery adds to the growing list of bodies in the solar system where organics have been found. Organic compounds have been found in certain meteorites as well as inferred from telescopic observations of several asteroids. Ceres shares many commonalities with meteorites rich in water and organics — in particular, a meteorite group called carbonaceous chondrites. This discovery further strengthens the connection between Ceres, these meteorites and their parent bodies.

    “This is the first clear detection of organic molecules from orbit on a main belt body,” said Maria Cristina De Sanctis, lead author of the study, based at the National Institute of Astrophysics, Rome. The discovery is reported in the journal Science.

    Data presented in the Science paper support the idea that the organic materials are native to Ceres. The carbonates and clays previously identified on Ceres provide evidence for chemical activity in the presence of water and heat. This raises the possibility that the organics were similarly processed in a warm water-rich environment.

    Significance of organics

    The organics discovery adds to Ceres’ attributes associated with ingredients and conditions for life in the distant past. Previous studies have found hydrated minerals, carbonates, water ice, and ammoniated clays that must have been altered by water. Salts and sodium carbonate, such as those found in the bright areas of Occator Crater, are also thought to have been carried to the surface by liquid.

    “This discovery adds to our understanding of the possible origins of water and organics on Earth,” said Julie Castillo-Rogez, Dawn project scientist based at NASA’s Jet Propulsion Laboratory in Pasadena, California.

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    his enhanced color composite image from Dawn’s visible and infrared mapping spectrometer shows the area around Ernutet Crater on Ceres. The instrument detected the evidence of organic materials in this area, as reported in a 2017 study in the journal Science. In this view, areas that appear pink with respect to the background appear to be rich in organics, and green areas are where organic material appears to be less abundant.Light with a wavelength of 2000 nanometers is shown in blue, 3400 nanometers is shown in green and 1700 nanometers is shown in red. Credits: NASA/JPL-Caltech/UCLA/ASI/INAF

    Where are the organics?

    The VIR instrument was able to detect and map the locations of this material because of its special signature in near-infrared light.

    The organic materials on Ceres are mainly located in an area covering approximately 400 square miles (about 1,000 square kilometers). The signature of organics is very clear on the floor of Ernutet Crater, on its southern rim and in an area just outside the crater to the southwest. Another large area with well-defined signatures is found across the northwest part of the crater rim and ejecta. There are other smaller organic-rich areas several miles (kilometers) west and east of the crater. Organics also were found in a very small area in Inamahari Crater, about 250 miles (400 kilometers) away from Ernutet.

    In enhanced visible color images from Dawn’s framing camera, the organic material is associated with areas that appear redder with respect to the rest of Ceres. The distinct nature of these regions stands out even in low-resolution image data from the visible and infrared mapping spectrometer.

    “We’re still working on understanding the geological context for these materials,” said study co-author Carle Pieters, professor of geological sciences at Brown University, Providence, Rhode Island.

    Next steps for Dawn

    Having completed nearly two years of observations in orbit at Ceres, Dawn is now in a highly elliptical orbit at Ceres, going from an altitude of 4,670 miles (7,520 kilometers) up to almost 5,810 miles (9,350 kilometers). On Feb. 23, it will make its way to a new altitude of around 12,400 miles (20,000 kilometers), about the height of GPS satellites above Earth, and to a different orbital plane. This will put Dawn in a position to study Ceres in a new geometry. In late spring, Dawn will view Ceres with the sun directly behind the spacecraft, such that Ceres will appear brighter than before, and perhaps reveal more clues about its nature.

    The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://www.nasa.gov/dawn

    http://dawn.jpl.nasa.gov

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 12:04 pm on August 31, 2016 Permalink | Reply
    Tags: , , , NASA Dawn,   

    From JPL-Caltech: “Dawn Sets Course for Higher Orbit” 

    NASA JPL Banner

    JPL-Caltech

    August 31, 2016
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This artist concept shows NASA’s Dawn spacecraft above dwarf planet Ceres, as seen in images from the mission. NASA/JPL-Caltech

    After studying Ceres for more than eight months from its low-altitude science orbit, NASA’s Dawn spacecraft will move higher up for different views of the dwarf planet.

    Dawn has delivered a wealth of images and other data from its current perch at 240 miles (385 kilometers) above Ceres’ surface, which is closer to the dwarf planet than the International Space Station is to Earth. Now, the mission team is pivoting to consider science questions that can be examined from higher up.

    After Dawn completed its prime mission on June 30, having surpassed all of its scientific objectives at Vesta and at Ceres, NASA extended the mission to perform new studies of Ceres. One of the factors limiting Dawn’s lifetime is the amount of hydrazine, the propellant needed to orient the spacecraft to observe Ceres and communicate with Earth. By going to a higher orbit at Ceres, Dawn will use the remaining hydrazine more sparingly, because it won’t have to work as hard to counter Ceres’ gravitational pull.

    “Most spacecraft wouldn’t be able to change their orbital altitude so easily. But thanks to Dawn’s uniquely capable ion propulsion system, we can maneuver the ship to get the greatest scientific return from the mission,” said Marc Rayman, chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory, Pasadena, California.

    On Sept. 2, Dawn will begin spiraling upward to about 910 miles (1,460 kilometers) from Ceres. The altitude will be close to where Dawn was a year ago, but the orientation of the spacecraft’s orbit — specifically, the angle between the orbit plane and the sun — will be different this time, so the spacecraft will have a different view of the surface.

    The mission team is continuing to develop the extended mission itinerary and will submit a full plan to NASA next month.

    Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://dawn.jpl.nasa.gov

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 8:01 am on November 21, 2015 Permalink | Reply
    Tags: , , NASA Dawn   

    From JPL-Caltech: “First Complete Look at Ceres’ Poles” 

    JPL-Caltech

    1

    Researchers from NASA’s Dawn mission have composed the first comprehensive views of the north (left) and south pole regions (right) of dwarf planet Ceres, using images obtained by the Dawn spacecraft.

    NASA Dawn Spacescraft
    Dawn

    The images were taken between Aug. 17 and Oct. 23, 2015, from an altitude of 915 miles (1,470 kilometers).

    The region around the south pole appears black in this view because this area has been in shade ever since Dawn’s arrival on March 6, 2015, and is therefore not visible.

    At the north polar region, craters Jarovit, Ghanan and Asari are visible, as well as the mountain Ysolo Mons. Near the south pole, craters Attis and Zadeni can be seen.

    Detailed maps of the polar regions allow researchers to study the craters in this area and compare them to those covering other parts of Ceres. Variations in shape and complexity can point to different surface compositions. In addition, the bottoms of some craters located close to the poles receive no sunlight throughout Ceres’ orbit around the sun. Scientists want to investigate whether surface ice can be found there.

    Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK, Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. For a complete list of acknowledgments, see http://dawn.jpl.nasa.gov/mission.

    For more information about the Dawn mission, visit http://dawn.jpl.nasa.gov.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 3:47 am on February 26, 2015 Permalink | Reply
    Tags: , , NASA Dawn, ,   

    From The Conversation : “NASA missions may re-elevate Pluto and Ceres from dwarf planets to full-on planet status” 

    Conversation
    The Conversation

    February 25 2015
    David A Weintraub, Professor of Astronomy at Vanderbilt University

    1
    Two views of Ceres acquired by NASA’s Dawn spacecraft ten hours apart on Feb. 12, 2015, from a distance of about 52,000 miles as the dwarf planet rotated. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Ceres is the largest object in the asteroid belt, and NASA’s Dawn spacecraft will arrive at this dwarf planet on March 6, 2015.

    2

    NASA Dawn Spacescraft
    Dawn


    Pluto is the largest object in the Kuiper belt, and NASA’s New Horizons spacecraft will arrive at this dwarf planet on July 15, 2015.

    2
    Kuiper Belt

    NASA New Horizons spacecraft
    New Horizons

    These two events will make 2015 an exciting year for solar system exploration and discovery. But there is much more to this story than mere science. I expect 2015 will be the year when general consensus, built upon our new knowledge of these two objects, will return Pluto and add Ceres to our family of solar system planets.

    The efforts of a very small clique of Pluto-haters within the International Astronomical Union (IAU) plutoed Pluto in 2006. Of the approximately 10,000 internationally registered members of the IAU in 2006, only 237 voted in favor of the resolution redefining Pluto as a “dwarf planet” while 157 voted against; the other 9,500 members were not present at the closing session of the IAU General Assembly in Prague at which the vote to demote Pluto was taken. Yet Pluto’s official planetary status was snatched away.

    Ceres and Pluto are both spheroidal objects, like Mercury, Earth, Jupiter and Saturn. That’s part of the agreed upon definition of a planet. They both orbit a star, the Sun, like Venus, Mars, Uranus and Neptune. That’s also part of the widely accepted definition of a planet.

    Unlike the larger planets, however, Ceres, like Pluto, according to the IAU definition, “has not cleared the neighborhood around its orbit.” The asteroid belt is, apparently, Ceres’ neighborhood while the Kuiper Belt is Pluto’s neighborhood – though no definition of a planet’s neighborhood exists, and no agreed upon understanding of what “clearing the neighborhood” yet exists. Furthermore, no broad-based agreement exists as to why “clearing the neighborhood” need be a requirement in order for an object to be considered a planet.

    Some planetary astronomers would argue that were the Earth placed in the Kuiper Belt, it would not be able to clear its neighborhood and thus would not be considered, by the IAU definition, a planet; apparently location matters. Here a planet, there not a planet. I’d argue that location shouldn’t matter; instead, the intrinsic properties of the objects themselves should matter more. And so we are led back to Ceres and Pluto.

    Never before visited by human spacecraft, Ceres and Pluto, as we will soon bear witness, are both evolving, changing worlds. Yesterday, Ceres and Pluto were strangers, distant, barely known runt members of our solar system. By the end of this calendar year, however, we will have showered both objects with our passion and our attention, we will have welcomed them both into our embrace. And we almost certainly will once again call both of them planets.

    Ceres, temporarily a planet

    Ceres was discovered on New Year’s Day in 1801, by Italian astronomer Giuseppe Piazzi, a member of an international team of astronomers dubbed the Celestial Police, who were searching for a supposedly missing planet in between the orbits of Mars and Jupiter. When discovered, Ceres was immediately recognized as a planet, the eighth one known at the time (neither Neptune nor Pluto had been discovered yet).

    But within a few years, other objects in the asteroid belt were discovered and Ceres no longer seemed to stand out as far from the crowd. In 1802, the great astronomer [Sir Frederick] William Herschel suggested that Ceres and Pallas and any other smaller solar system objects should be called asteroids – meaning star-like. In telescope images, they were so tiny that they looked point-like, like stars, rather than disk-like, like planets. And so, more than a century before Pluto was discovered, Ceres was plutoed.

    3
    Animation of rotating Ceres, made from a series of images taken by NASA’s Dawn spacecraft on February 4, 2015, at a distance of about 90,000 miles from the planet.

    With increasing knowledge and familiarity, we’ll no longer be able to identify meaningful criteria to keep these good planets down.

    These two events will make 2015 an exciting year for solar system exploration and discovery. But there is much more to this story than mere science. I expect 2015 will be the year when general consensus, built upon our new knowledge of these two objects, will return Pluto and add Ceres to our family of solar system planets.

    The efforts of a very small clique of Pluto-haters within the International Astronomical Union (IAU) plutoed Pluto in 2006. Of the approximately 10,000 internationally registered members of the IAU in 2006, only 237 voted in favor of the resolution redefining Pluto as a “dwarf planet” while 157 voted against; the other 9,500 members were not present at the closing session of the IAU General Assembly in Prague at which the vote to demote Pluto was taken. Yet Pluto’s official planetary status was snatched away.

    Ceres and Pluto are both spheroidal objects, like Mercury, Earth, Jupiter and Saturn. That’s part of the agreed upon definition of a planet. They both orbit a star, the Sun, like Venus, Mars, Uranus and Neptune. That’s also part of the widely accepted definition of a planet.

    Unlike the larger planets, however, Ceres, like Pluto, according to the IAU definition, “has not cleared the neighborhood around its orbit.” The asteroid belt is, apparently, Ceres’ neighborhood while the Kuiper Belt is Pluto’s neighborhood – though no definition of a planet’s neighborhood exists, and no agreed upon understanding of what “clearing the neighborhood” yet exists. Furthermore, no broad-based agreement exists as to why “clearing the neighborhood” need be a requirement in order for an object to be considered a planet.

    Some planetary astronomers would argue that were the Earth placed in the Kuiper Belt, it would not be able to clear its neighborhood and thus would not be considered, by the IAU definition, a planet; apparently location matters. Here a planet, there not a planet. I’d argue that location shouldn’t matter; instead, the intrinsic properties of the objects themselves should matter more. And so we are led back to Ceres and Pluto.

    Never before visited by human spacecraft, Ceres and Pluto, as we will soon bear witness, are both evolving, changing worlds. Yesterday, Ceres and Pluto were strangers, distant, barely known runt members of our solar system. By the end of this calendar year, however, we will have showered both objects with our passion and our attention, we will have welcomed them both into our embrace. And we almost certainly will once again call both of them planets.

    Ceres, temporarily a planet

    Ceres was discovered on New Year’s Day in 1801, by Italian astronomer Giuseppe Piazzi, a member of an international team of astronomers dubbed the Celestial Police, who were searching for a supposedly missing planet in between the orbits of Mars and Jupiter. When discovered, Ceres was immediately recognized as a planet, the eighth one known at the time (neither Neptune nor Pluto had been discovered yet).

    But within a few years, other objects in the asteroid belt were discovered and Ceres no longer seemed to stand out as far from the crowd. In 1802, the great astronomer [Sir Frederick] William Herschel suggested that Ceres and Pallas and any other smaller solar system objects should be called asteroids – meaning star-like. In telescope images, they were so tiny that they looked point-like, like stars, rather than disk-like, like planets. And so, more than a century before Pluto was discovered, Ceres was plutoed.

    6
    Animation of rotating Ceres, made from a series of images taken by NASA’s Dawn spacecraft on February 4, 2015, at a distance of about 90,000 miles from the planet. NASA

    But Ceres does still stand out. It’s the largest asteroid, by far, nearly 1,000 kilometers across (twice as large in diameter as Vesta, the second largest asteroid), though not perfectly spherical in shape.

    As happened inside Earth and other planets, planetary scientists think that long ago, the denser material in Ceres separated from the lighter material and sank to form a core.

    Astronomers think Ceres is rich in water – as much as one-third of Ceres might be water – and may have a thin atmosphere. Bright, white spots on its surface might even be large frozen lakes. Ceres may, in fact, have as much fresh water as Earth, have Earth-like polar caps, and might even have a sub-surface liquid ocean layer, like Jupiter’s moon Europa and Saturn’s moon Enceladus.

    Beginning this month, we’ll start to learn more about these tantalizing possibilities. With our increasing knowledge of and familiarity with Ceres, we will no longer be able to identify meaningful criteria that will allow us to continue to classify Ceres as not-a-planet. Ceres will continue to be a small planet, but in 2015 we will come to understand that dwarf planets are planets, too.

    Pluto’s short planetary reign

    Pluto also has an unusual orbit, as it crosses Neptune’s orbit, though it does so in such a way that it can never collide with Neptune.

    Pluto’s modern-day troubles began in 1992, when astronomers David Jewitt and Jane Luu discovered the first objects in the region of the solar system now known as the Kuiper Belt. Whereas the asteroid belt where Ceres resides is made mostly of house- and mountain-sized rocks that orbit the Sun in between the orbits of Mars and Jupiter, the Kuiper Belt is made mostly of house- and mountain-sized chunks of ice that orbit the Sun beyond the orbit of Neptune. Pluto, as it turns out, is one of the biggest objects in the Kuiper Belt.

    So what is Pluto?

    7
    Image of Pluto and its moon Charon, taken by NASA’s New Horizons spacecraft on January 25, 2015, from a distance of 125 million miles. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

    Pluto is the last unexplored planet in our solar system. And the Kuiper Belt may contain hundreds of other planetary worlds like Pluto. These may be the most numerous worlds in the solar system; they may contain, together, the most total surface area of all the solid-surfaced planets.

    8
    Pluto and its five moons – as seen from the Hubble Space Telescope in July, 2012. NASA, ESA, and M. Showalter (SETI Institute)

    NASA Hubble Telescope
    Hubble

    Pluto has one large moon, Charon, and at least four small moons: Nix, Hydra, Kerberos and Styx. It has an atmosphere that expands and contracts as Pluto warms and cools during its 248 year orbit around the Sun. The surface is likely rich in water ice, enriched with methane and nitrogen and carbon monoxide frosts; these ices might contain complex organic molecules.

    The New Horizons mission is poised to answer some of our myriad questions about Pluto. How did it form? What is the atmosphere made of? What is the surface like? Does Pluto have a magnetic field? What are the moons like? Does Pluto have a subsurface ocean? Is the surface of Pluto’s moon Charon pure water ice?

    Pluto has guarded its secrets for four and half billion years. But in a few months, a few intrepid humans will pull back the curtain on Pluto and say “Hello, Pluto, we’re here.” And Pluto will begin to share her secrets with us. When she does, as with Ceres, our familiarity with Pluto will help us recognize that Pluto is, was, and has always been a planet, albeit a small one.

    We only get to visit Ceres and Pluto for the very first time, once. This year. March 6 and July 15. In your lifetime. In this incredible year of the dwarf planet. Get ready to party. Ceres and Pluto are coming home.

    See the full article here.

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    The Conversation US launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
    Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.
    Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

     
  • richardmitnick 8:43 am on January 30, 2015 Permalink | Reply
    Tags: , , , NASA Dawn   

    From Space.com- “Vesta: Facts About the Brightest Asteroid” 

    space-dot-com logo

    SPACE.com

    January 29, 2015
    Nola Redd

    1
    Vesta with comparative asteroids

    Vesta is the second most massive body in the asteroid belt, surpassed only by Ceres, which is classified as a dwarf planet. The brightest asteroid in the sky, Vesta is occasionally visible from Earth with the naked eye. It is the first asteroid to be visited by a spacecraft. The Dawn mission orbited Vesta in 2011, providing new insights into this rocky world.

    NASA Dawn Spacecraft
    NASA/Dawn

    Celestial Police

    In 1596, while determining the elliptical shape of planetary orbits, Johannes Kepler came to believe that a planet should exist in the gap between Mars and Jupiter. Mathematical calculations by Johann Daniel Titius and Johann Elert Bode in 1772 — later known as the Titus-Bode law — seemed to support this prediction. In August 1798, a group known as the Celestial Police formed to search for this missing planet. Among these was German astronomer Heinrich Olbers. Olbers discovered the second known asteroid, Pallas. In a letter to a fellow astronomer, he put forth the first theory of asteroid origin. He wrote, “Could it be that Ceres and Pallas are just a pair of fragments … of a once greater planet which at one time occupied its proper place between Mars and Jupiter?”

    Olbers reasoned that the fragments of such a planet would intersect at the point of the explosion, and again in the orbit directly opposite. He observed these two areas nightly, and on March 29, 1807, discovered Vesta, becoming the first person to discover two asteroids. After measuring several nights’ worth of observations, Olbers sent his calculations to mathematician Carl Friedrich Gauss, who remarkably computed the orbit of Pallas in only 10 hours. As such, he was given the honor of naming the new body. He chose the name Vesta, goddess of the hearth, and sister to Ceres.

    See the full article here.

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  • richardmitnick 3:08 pm on January 28, 2015 Permalink | Reply
    Tags: , , NASA Dawn   

    From Space.com: “NASA Finds Mysterious Bright Spot on Dwarf Planet Ceres: What Is It?” 

    space-dot-com logo

    SPACE.com

    January 23, 2015
    Calla Cofield

    1
    A mysterious white spot can be seen in the newest images from NASA’s Dawn space telescope, which is rapidly approaching the dwarf planet.
    Credit:NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

    A strange, flickering white blotch found on the dwarf planet Ceres by a NASA spacecraft has scientists scratching their heads.

    The white spot on Ceres in a series of new photos taken on Jan. 13 by NASA’s Dawn spacecraft, which is rapidly approaching the round dwarf planet in the asteroid belt between the orbits of Mars and Jupiter. But when the initial photo release on Monday (Jan. 19), the Dawn scientists gave no indication of what the white dot might be.

    NASA Dawn Spacecraft
    Dawn

    a
    Asteroid Belt
    The inner Solar System, from the Sun to Jupiter. Also includes the asteroid belt (the white donut-shaped cloud), the Hildas (the orange “triangle” just inside the orbit of Jupiter), the Jupiter trojans (green), and the near-Earth asteroids. The group that leads Jupiter are called the “Greeks” and the trailing group are called the “Trojans” (Murray and Dermott, Solar System Dynamics, pg. 107).

    “Yes, we can confirm that it is something on Ceres that reflects more sunlight, but what that is remains a mystery,” Marc Rayman, mission director and chief engineer for the Dawn mission, told Space.com in an email.

    The new images show areas of light and dark on the face of Ceres, which indicate surface features like craters. But at the moment, none of the specific features can be resolved, including the white spot.

    “We do not know what the white spot is, but it’s certainly intriguing,” Rayman said. “In fact, it makes you want to send a spacecraft there to find out, and of course that is exactly what we are doing! So as Dawn brings Ceres into sharper focus, we will be able to see with exquisite detail what [the white spot] is.”

    Ceres is a unique object in our solar system. It is the largest object in the asteroid belt and is classified as an asteroid. It is simultaneously classified as a dwarf planet, and at 590 miles across (950 kilometers, or about the size of Texas), Ceres is the smallest known dwarf planet in the solar system.

    The $466 million Dawn spacecraft is set to enter into orbit around Ceres on March 6. Dawn left Earth in 2007 and in the summer of 2011, it made a year-long pit stop at the asteroid Vesta, the second largest object in the asteroid belt.

    While Vesta shared many properties with our solar system’s inner planets, scientists with the Dawn mission suspect that Ceres has more in common with the outer most planets. 25 percent of Ceres’ mass is thought to be composed of water, which would mean the space rock contains even more fresh water than Earth. Scientists have observed water vapor plumes erupting off the surface of Ceres, which may erupt from volcano-like ice geysers.

    The mysterious white spot captured by the Dawn probe is one more curious feature of this already intriguing object.

    See the full article here.

    NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Dawn mission for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. The University of California at Los Angeles (UCLA) is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Virginia, designed and built the spacecraft. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research, Gottingen, Germany, with significant contributions by German Aerospace Center (DLR), Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL. The Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

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  • richardmitnick 4:17 pm on January 22, 2015 Permalink | Reply
    Tags: , , NASA Dawn   

    From NASA Dawn: “Gullies on Vesta Suggest Past Water-Mobilized Flows” 

    NASA Dawn

    NASA Dawn Spacescraft
    Dawn
    January 21, 2015
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This image shows Cornelia Crater on the large asteroid Vesta. On the right is an inset image showing an example of curved gullies, indicated by the short white arrows, and a fan-shaped deposit, indicated by long white arrows. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    Protoplanet Vesta, visited by NASA’s Dawn spacecraft from 2011 to 2013, was once thought to be completely dry, incapable of retaining water because of the low temperatures and pressures at its surface. However, a new study shows evidence that Vesta may have had short-lived flows of water-mobilized material on its surface, based on data from Dawn.

    3
    As NASA’s Dawn spacecraft takes off for its next destination, this mosaic synthesizes some of the best views the spacecraft had of the giant asteroid Vesta. Dawn studied Vesta from July 2011 to September 2012. The towering mountain at the south pole — more than twice the height of Mount Everest — is visible at the bottom of the image. The set of three craters known as the “snowman” can be seen at the top left.

    “Nobody expected to find evidence of water on Vesta. The surface is very cold and there is no atmosphere, so any water on the surface evaporates,” said Jennifer Scully, postgraduate researcher at the University of California, Los Angeles. “However, Vesta is proving to be a very interesting and complex planetary body.”

    The study has broad implications for planetary science.

    “These results, and many others from the Dawn mission, show that Vesta is home to many processes that were previously thought to be exclusive to planets,” said UCLA’s Christopher Russell, principal investigator for the Dawn mission. “We look forward to uncovering even more insights and mysteries when Dawn studies Ceres.”

    Dawn is currently in the spotlight because it is approaching dwarf planet Ceres, the largest object in the main asteroid belt between Mars and Jupiter. It will be captured into orbit around Ceres on March 6. Yet data from Dawn’s exploration of Vesta continue to capture the interest of the scientific community.

    5
    The Dawn spacecraft observed Ceres for an hour on Jan. 13, 2015, from a distance of 238,000 miles (383,000 kilometers). A little more than half of its surface was observed at a resolution of 27 pixels. This animated GIF shows bright and dark features.

    Scully and colleagues, publishing in the journal Earth and Planetary Science Letters, identified a small number of young craters on Vesta with curved gullies and fan-shaped (“lobate”) deposits.

    “We’re not suggesting that there was a river-like flow of water. We’re suggesting a process similar to debris flows, where a small amount of water mobilizes the sandy and rocky particles into a flow,” Scully said.

    The curved gullies are significantly different from those formed by the flow of purely dry material, scientists said. “These features on Vesta share many characteristics with those formed by debris flows on Earth and Mars,” Scully said.

    The gullies are fairly narrow, on average about 100 feet (30 meters) wide. The average length of the gullies is a little over half a mile (900 meters). Cornelia Crater, with a width of 9 miles (15 kilometers), contains some of the best examples of the curved gullies and fan-shaped deposits.

    The leading theory to explain the source of the curved gullies is that Vesta has small, localized patches of ice in its subsurface. No one knows the origin of this ice, but one possibility is that ice-rich bodies, such as comets, left part of their ice deep in the subsurface following impact. A later impact would form a crater and heat up some of the ice patches, releasing water onto the walls of the crater.

    “If present today, the ice would be buried too deeply to be detected by any of Dawn’s instruments,” Scully said. “However, the craters with curved gullies are associated with pitted terrain, which has been independently suggested as evidence for loss of volatile gases from Vesta.” Also, evidence from Dawn’s visible and infrared mapping spectrometer and gamma ray and neutron detector indicates that there is hydrated material within some rocks on Vesta’s surface, suggesting that Vesta is not entirely dry.

    It appears the water mobilized sandy and rocky particles to flow down the crater walls, carving out the gullies and leaving behind the fan-shaped deposits after evaporation. The craters with curvy gullies appear to be less than a few hundred million years old, which is still young compared to Vesta’s age of 4.6 billion years.

    Laboratory experiments performed at NASA’s Jet Propulsion Laboratory, Pasadena, California, indicate that there could be enough time for curved gullies to form on Vesta before all of the water evaporated. “The sandy and rocky particles in the flow help to slow the rate of evaporation,” Scully said.

    The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA’s Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science.

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    NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Dawn mission for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. The University of California at Los Angeles (UCLA) is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Virginia, designed and built the spacecraft. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research, Gottingen, Germany, with significant contributions by German Aerospace Center (DLR), Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL. The Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 5:16 am on December 30, 2014 Permalink | Reply
    Tags: , , , , NASA Dawn   

    From JPL: “Dawn Spacecraft Begins Approach to Dwarf Planet Ceres” 

    NASA

    NASA

    December 29, 2014
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    Elizabeth.Landau@jpl.nasa.gov

    Dawn has entered its approach phase toward Ceres
    The spacecraft will arrive at Ceres on March 6, 2015

    NASA’s Dawn spacecraft has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft. Dawn launched in 2007 and is scheduled to enter Ceres orbit in March 2015.

    c
    NASA’s Hubble Space Telescope color image of Ceres, the largest object in the asteroid belt. Astronomers optimized spatial resolution to about 18 km per pixel, enhancing the contrast in these images to bring out features on Ceres’ surface, that are both brighter and darker than the average which absorbs 91% of sunlight falling on it. (Original description by NASA) (Earth Distance: 1.64 AU and Angular diameter: 0.798″)

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Huble

    NASA Dawn Spacecraft
    NASA Dawn schematic
    NASA/Dawn

    Dawn recently emerged from solar conjunction, in which the spacecraft is on the opposite side of the sun, limiting communication with antennas on Earth. Now that Dawn can reliably communicate with Earth again, mission controllers have programmed the maneuvers necessary for the next stage of the rendezvous, which they label the Ceres approach phase. Dawn is currently 400,000 miles (640,000 kilometers) from Ceres, approaching it at around 450 miles per hour (725 kilometers per hour).

    The spacecraft’s arrival at Ceres will mark the first time that a spacecraft has ever orbited two solar system targets. Dawn previously explored the protoplanet Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.

    “Ceres is almost a complete mystery to us,” said Christopher Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles. “Ceres, unlike Vesta, has no meteorites linked to it to help reveal its secrets. All we can predict with confidence is that we will be surprised.”

    The two planetary bodies are thought to be different in a few important ways. Ceres may have formed later than Vesta, and with a cooler interior. Current evidence suggests that Vesta only retained a small amount of water because it formed earlier, when radioactive material was more abundant, which would have produced more heat. Ceres, in contrast, has a thick ice mantle and may even have an ocean beneath its icy crust.

    Ceres, with an average diameter of 590 miles (950 kilometers), is also the largest body in the asteroid belt, the strip of solar system real estate between Mars and Jupiter. By comparison, Vesta has an average diameter of 326 miles (525 kilometers), and is the second most massive body in the belt.

    The spacecraft uses ion propulsion to traverse space far more efficiently than if it used chemical propulsion. In an ion propulsion engine, an electrical charge is applied to xenon gas, and charged metal grids accelerate the xenon particles out of the thruster. These particles push back on the thruster as they exit, creating a reaction force that propels the spacecraft. Dawn has now completed five years of accumulated thrust time, far more than any other spacecraft.

    “Orbiting both Vesta and Ceres would be truly impossible with conventional propulsion. Thanks to ion propulsion, we’re about to make history as the first spaceship ever to orbit two unexplored alien worlds,” said Marc Rayman, Dawn’s chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory in Pasadena, California.

    The next couple of months promise continually improving views of Ceres, prior to Dawn’s arrival. By the end of January, the spacecraft’s images and other data will be the best ever taken of the dwarf planet.

    The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA’s Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science.

    More information about Dawn:

    http://dawn.jpl.nasa.gov

    See the full article here.

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    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
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