[meteorite-list] Curiosity Rover Samples Active Linear Dune on Mars
https://www.jpl.nasa.gov/news/news.php?feature=6835 NASA Rover Samples Active Linear Dune on Mars Jet Propulsion Laboratory May 4, 2017 As it drives uphill from a band of rippled sand dunes, NASA's Curiosity Mars rover is toting a fistful of dark sand for onboard analysis that will complete the rover's investigation of those dunes. >From early February to early April, the rover examined four sites near a linear dune for comparison with what it found in late 2015 and early 2016 during its investigation of crescent-shaped dunes. This two-phase campaign is the first close-up study of active dunes anywhere other than Earth. Among the questions this Martian dune campaign is addressing is how winds shape dunes that are relatively close together, on the same side of the same mountain, into different patterns. Others include whether Martian winds sort grains of sand in ways that affect the distribution of mineral compositions, which would have implications for studies of Martian sandstones. "At these linear dunes, the wind regime is more complicated than at the crescent dunes we studied earlier," said Mathieu Lapotre of Caltech, in Pasadena, California, who helped lead the Curiosity science team's planning for the dune campaign. "There seems to be more contribution from the wind coming down the slope of the mountain here compared with the crescent dunes farther north." The linear dunes lie uphill and about a mile (about 1.6 kilometers) south from the crescent dunes. Both study locations are part of a dark-sand swath called the Bagnold Dunes, which stretches several miles in length. This dune field lines the northwestern flank of Mount Sharp, the layered mountain that Curiosity is climbing. "There was another key difference between the first and second phases of our dune campaign, besides the shape of the dunes," Lapotre said. "We were at the crescent dunes during the low-wind season of the Martian year and at the linear dunes during the high-wind season. We got to see a lot more movement of grains and ripples at the linear dunes." To assess wind strength and direction, the rover team now uses change-detection pairs of images taken at different times to check for movement of sand grains. The wind-sensing capability of the Curiosity's Rover Environmental Monitoring Station (REMS) is no longer available, though that instrument still returns other Mars-weather data daily, such as temperatures, humidity and pressure. Two of the six wind sensors on the rover's mast were found to be inoperable upon landing on Mars in 2012. The remainder provided wind information throughout the rover's prime mission and first two-year extended mission. A sample of sand that Curiosity scooped up from a linear dune is in the sample-handling device at the end of the rover's arm. One portion has been analyzed in the Sample Analysis at Mars (SAM) instrument inside the rover. The science team plans to deliver additional sample portions to SAM and to the rover's Chemistry and Mineralogy (CheMin) instrument. One factor in choosing to drive farther uphill before finishing analysis of the scooped sand is the status of Curiosity's rock-sampling drill, which has not been used on a rock since a problem with the drill feed mechanism appeared five months ago. Engineers are assessing how the use of vibration to deliver samples may affect the drill feed mechanism, which is used to move the drill bit forward and backwards. In addition, high winds at the linear-dunes location were complicating the process of pouring sample material into the entry ports for the laboratory instruments. "A balky brake appears to be affecting drill feed mechanism performance," said Curiosity Deputy Project Manager Steven Lee, of NASA's Jet Propulsion Laboratory, Pasadena, California. "In some cases, vibration has been observed to change feed effectiveness, so we're proceeding cautiously until we better understand the behavior. In the meantime, the engineering team is developing several methods to improve feed reliability." Curiosity landed near Mount Sharp in August 2012. It reached the base of the mountain in 2014 after successfully finding evidence on the surrounding plains that ancient Martian lakes offered conditions that would have been favorable for microbes if Mars has ever hosted life. Rock layers forming the base of Mount Sharp accumulated as sediment within ancient lakes billions of years ago. On Mount Sharp, Curiosity is investigating how and when the ancient habitable conditions known from the mission's earlier findings evolved into drier conditions that were less favorable for life. For more information about Curiosity, visit: http://mars.jpl.nasa.gov/msl News Media Contact Guy Webster / Andrew Good Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6278 / 818-393-2433 guy.webs...@jpl.nasa.gov / andrew.c.g...@jpl.nasa.gov Robert Perkins Caltech, Pasadena, Calif. 626-395-1862 / 6626-658-1053
[meteorite-list] Initial Results from the Close Approach of Asteroid 2014 JO25
https://cneos.jpl.nasa.gov/news/news196.html Initial Results from the Close Approach of Asteroid 2014 JO25 Center for NEO Studies (CNEOS) May 5, 2017 A relatively large asteroid called 2014 JO25 approached within 4.6 lunar distances (within 1.1 million miles or 1.8 million kilometers) of the Earth on April 19, 2017. This was the closest approach by an asteroid at least 600 meters in size since 4179 Toutatis, a 3 mile (5 kilometer) sized asteroid, approached within four lunar distances in September 2004. The close approach provided an outstanding opportunity to study the physical properties of the asteroid, and the images obtained by ground-based radars are comparable in resolution to those that could be obtained by a spacecraft flyby. 2014 JO25 was discovered by Al Grauer of the Catalina Sky Survey (CSS) near Tucson, Arizona in May 2014. The Catalina Sky Survey is a project of NASA's Near-Earth Object [NEO] Observations Program in collaboration with the University of Arizona. Figure 1: Part of the Catalina Sky Survey, this 1.52-meter Cassegrain telescope was used to discover 2014 JO25 in May 2014. The observatory is located just north of Tucson, Arizona in the Santa Catalina Mountains. Figure 1: Part of the Catalina Sky Survey, this 1.52-meter Cassegrain telescope was used to discover 2014 JO25 in May 2014. The observatory is located just north of Tucson, Arizona in the Santa Catalina Mountains. Shortly after its discovery Jet Propulsion Laboratory (JPL) astronomer Joe Masiero, a member of the NEOWISE science team, used observations made by the NEOWISE spacecraft in 2014 to estimate 2014 JO25's size as roughly 650 meters (2000 feet), and its optical albedo as 0.25. Albedo is the proportion of incident sunlight that a body reflects back into space. For comparison, the Moon has an albedo of 0.12, meaning that it reflects only 12% of the sunlight that reaches it. Based on initial estimates 2014 JO25's surface would be twice as reflective as the Moon's, fairly bright for an asteroid. Until the recent close pass, the asteroid's spectral class, rotation period, and pole direction were unknown. This close approach provided an opportunity for very detailed radar and optical observations, which allowed astronomers to better determine the characteristics of this unique object. But precision astrometry - measurements of the asteroid's position in space relative to stars in the background sky - was needed first to determine a more precise orbit, crucial for the radar observations. So in September 2016 Joe Masiero made a special effort to obtain more astrometric observations of 2014 JO25, which was distant at the time, and therefore very faint. He had to use the very large Gemini South 8.2-meter telescope on Cerro Pachon, Chile to make these measurements. These observations significantly reduced the orbital uncertainties for the asteroid. Using the more accurate orbit, Peter Veres of the Center for NEO Studies (CNEOS) at JPL looked through archival Pan-STARRS images taken in 2011, before the object was known to exist. These astrometric measurements were crucial for reducing the pointing uncertainties for this close pass in April 2017 and enabled the successful radar observations. Your browser does not support the video tag. You can the video instead. Figure 2: This animation shows the orbit of 2014 JO25 about the Sun. The orbit is inclined ~25 degrees with respect to the ecliptic; perihelion at 0.24 AU and aphelion at 3.9 AU [for reference Jupiter orbits the Sun at 5.2 AU]. The orbit of 2014 JO25 seems to resemble that of an Encke-like comet. For a high resolution version, download the video for external display. (NASA/JPL) Radar observations were performed at the National Science Foundation's Arecibo Observatory equipped with the NASA planetary radar system by a team led by Patrick Taylor of Arecibo Observatory between April 15-21, and at NASA's Goldstone Solar System Radar by a team led by Lance Benner of JPL from April 16-21. These dates cover the actual closest approach time at 08:24 EDT on April 19, and due to the proximity of the asteroid, the observations produced hundreds of radar images with resolutions of 7.5 meters/pixel from both observatories and a smaller number of images at 3.75 meter/pixel resolution at Goldstone. Figure 3: This sequence of images was obtained by NASA's 70-meter antenna at Goldstone near Barstow, California, on 18 April 2017 - the day before 2014 JO25's closest approach. The double-lobed asteroid safely passed by the Earth at a distance of 1.8 million kilometers (or ~4.6 times the average distance from Earth to the Moon (NASA/JPL). Figure 3: This sequence of images was obtained by NASA's 70-meter antenna at Goldstone near Barstow, California, on 18 April 2017 - the day before 2014 JO25's closest approach. The double-lobed asteroid safely passed by the Earth at a distance of 1.8 million kilometers (or ~4.6 times the
[meteorite-list] Dawn Journal - April 29, 2017
https://dawnblog.jpl.nasa.gov/2016/04/29/dawn-journal-april-29-2/ Dawn Journal by Dr. Marc Rayman April 29, 2017 Dear Glutdawnous Readers, The distant dwarf planet that Dawn is circling is full of mystery and yet growing ever more familiar. Ceres, which only last year was hardly more than a fuzzy blob against the stars, is now a richly detailed world, and our portrait grows more elaborate every day. Having greatly surpassed all of its original objectives, the reliable explorer is gathering still more data from its unique vantage point. Everyone who hungers for new knowledge about the cosmos or for bold adventures far from Earth can share in the sumptuous feast Dawn has been serving. One of the major objectives of the mission was to photograph 80 percent of Ceres' vast landscape with a resolution of 660 feet (200 meters) per pixel. That would provide 150 times the clarity of the powerful Hubble Space Telescope. Dawn has now photographed 99.8 percent with a resolution of 120 feet (35 meters) per pixel. [Haulani Crater in Enhanced Color] This image of Haulani Crater uses color pictures Dawn acquired during its third mapping orbit at an altitude of 915 miles (1,470 kilometers). We saw the crater from the same altitude in black and white here. This false color picture highlights differences in composition or other properties that your eye would not be able to detect. In this color scheme, blue is associated with geologically young material, consistent with the description of the black and white image as showing a young crater. It is easy to see that the surrounding region was affected by the formation of the crater. (The last picture below shows the area around another crater that was altered by an impact.) Also note the variation in terrain within the crater, including a prominent ridge in the center. The crater is 21 miles (34 kilometers) in diameter. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA This example of Dawn's extraordinary productivity may appear to be the limit of what it could achieve. After all, the spaceship is orbiting at an altitude of only 240 miles (385 kilometers), closer to the ground than the International Space Station is to Earth, and it will never go lower for more pictures. But it is already doing more. Since April 11, instead of photographing the scenery directly beneath it, Dawn has been aiming its camera to the left and forward as it orbits and Ceres rotates. By May 25, it will have mapped most of the globe from that angle. Then it will start all over once more, looking instead to the right and forward from May 27 through July 10. The different perspectives on the terrain make stereo views, which scientists can combine to bring out the full three dimensionality of the alien world. Dawn already accomplished this in its third mapping orbit from four times its current altitude, but now that it is seeing the sights from so much lower, the new topographical map will be even more accurate. [Oxo Crater at LAMO] Dawn captured this view of Oxo Crater on Jan. 16 from an altitude of 240 miles (385 kilometers). Although it is a modest six miles (10 kilometers) across, it is a particularly interesting crater. This is the only location (so far) on Ceres where Dawn has clearly detected water. Oxo is the second brightest area on Ceres. Only Occator Crater is brighter. Oxo also displays a uniquely large 'slump' in its rim, where a mass of material has dropped below the surface. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Dawn is also earning extra credit on its assignment to measure the energy of gamma rays and neutrons. We have discussed before how the gamma ray and neutron detector (GRaND) can reveal the atomic composition down to about a yard (meter) underground, and last month we saw initial findings about the distribution of hydrogen. However, Ceres' nuclear glow is very faint. Scientists already have three times as much GRaND data from this low altitude as they had required, and both spectrometers in the instrument will continue to collect data. In effect, Dawn is achieving a longer exposure, making its nuclear picture of Ceres brighter and sharper. In December we explained how using the radio signal to track the probe's movements allows scientists to chart the gravity field and thereby learn about the interior of Ceres, revealing regions of higher and lower density. Once again, Dawn performed even better than expected and achieved the mission's planned accuracy in the third mapping orbit. Because the strength of the dwarf planet's gravitational tug depends on the distance, even finer measurements of how it varies from location to location are possible in this final orbit. Thanks to the continued smooth operation of the mission, scientists now have a gravitational map fully twice as accurate as they had anticipated. With additional measurements, they may be able to squeeze out a little more detail, perhaps
[meteorite-list] Special Mars HiRISE event at the Lunar and Planetary Lab
Dear Meteorite-List Friends, I have a special meteorite "parent-body" posting that might be of interest to collectors of Martian meteorites especially: Come celebrate incredible images of the Martian surface from *NASA's HiRISE* mission on *Thursday, May 11 from 6-8pm* at the University of Arizona's *Lunar and Planetary Laboratory (LPL) Kuiper Building in Tucson, Arizona*! The University of Arizona Press cordially invites you to join us in celebrating the release of _/Mars: Pristine Beauty of the Red /__/Planet/_, the most outstanding and uniquely curated selection of Mars orbital images ever assembled in one volume. Enjoy remarks from College of Science Dean Joaquin Ruiz, LPL Director (and meteoriticist) Tim Swindle, HiRISE Principal investigator Alfred McEwen, Deputy PI Candice Hansen-Koharcheck & Outreach Coordinator Ari Espinoza. What better way to envision the variety of settings and terrains from which Martian meteorites were ejected? We hope to see you all there! Best regards, Dolores Hill -- Dolores H. Hill Sr. Research Specialist Lunar & Planetary Laboratory Kuiper Space Sciences Bldg. #92 The University of Arizona 1629 E. University Blvd. Tucson, AZ 85721 http://www.lpl.arizona.edu/ OSIRIS-REx Asteroid Sample Return Mission Communication & Public Engagement Team Lead OSIRIS-REx Ambassadors program Co-lead OSIRIS-REx Target Asteroids! citizen science program Co-coordinator Target NEOs! observing program of the Astronomical League Association of Lunar & Planetary Observers - Meteorite Section http://osiris-rex.lpl.arizona.edu/ http://osiris-rex.lpl.arizona.edu/?q=target_asteroids http://www.astroleague.org/files/u3/NEO_HomePage.pdf __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] AD - No Reserve Auctions Ending On Highest Rated Lunar Ever
Dear List Members, Although I have cut back on the number of no reserve auctions, I still have a few ending this evening and tomorrow night so please take a look if you get a chance. There are six specimens of the worlds highest rated lunar meteorite up for consideration and bidding. I am in the process of loading up my store in anticipation of transitioning to fixed pricing on the little amount of material that is still left. Link to all auctions: http://www.ebay.com/sch/merchant/ancientechoesartifacts NWA 5000 Specimens Ending At Auction This Evening - NO RESERVE! Legendary NWA 5000 Lunar Meteorite Moon Rock .970 grams - NEARLY A GRAM - NO RESERVE!! http://r.ebay.com/EW7lc0 Legendary NWA 5000 Lunar Meteorite Moon Rock .554 grams - NO RESERVE!! http://r.ebay.com/w5kSB1 Legendary NWA 5000 Lunar Meteorite Moon Rock .470 grams - NO RESERVE!! http://r.ebay.com/pTMAHP Legendary NWA 5000 Lunar Meteorite Moon Rock 1.0 grams Pure Dust!! http://r.ebay.com/ywrIha NWA 5000 Specimens Ending At Auction Tomorrow Night - NO RESERVE! Legendary NWA 5000 Lunar Meteorite Moon Rock .788 grams - NO RESERVE!!! http://r.ebay.com/yYNjzx Legendary NWA 5000 Lunar Meteorite Moon Rock .656 grams - NO RESERVE!!! http://r.ebay.com/IO98CB Legendary NWA 5000 Lunar Meteorite Moon Rock .510 grams - NO RESERVE!!! http://r.ebay.com/gISILj Legendary NWA 5000 Lunar Meteorite Moon Rock 1.0 grams Pure Dust!! http://r.ebay.com/p4M9eC Thank you for looking and if your bidding, good luck, Adam __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteorite Picture of the Day
Today's Meteorite Picture of the Day: NWA xxx Contributed by: Darryl Pitt http://www.tucsonmeteorites.com/mpodmain.asp?DD=05/09/2017 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
