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Posts Tagged ‘dawn spacecraft’

Asteroid’s Troughs Suggest Stunted Planet

September 28, 2012 1 comment

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Enormous troughs that reach across the asteroid Vesta may actually be stretch marks that hint of a complexity beyond most asteroids. Scientists have been trying to determine the origin of these unusual troughs since their discovery just last year. Now, a new analysis supports the notion that the troughs are faults that formed when a fellow asteroid smacked into Vesta’s south pole. The research reinforces the claim that Vesta has a layered interior, a quality normally reserved for larger bodies, such as planets and large moons.

Asteroid surface deformities are typically straightforward cracks formed by crashes with other asteroids. Instead, an extensive system of troughs encircles Vesta, the second most massive asteroid in the solar system, about one-seventh as wide as the Moon. The biggest of those troughs, named Divalia Fossa, surpasses the size of the Grand Canyon by spanning 465 kilometers (289 miles) long, 22 km (13.6 mi) wide and 5 km (3 mi) deep.

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Dawn Suggests Special Delivery Of Hydrated Material To Vesta

September 27, 2012 Leave a comment

The mechanism by which water is incorporated into the terrestrial planets is a matter of extensive debate for planetary scientists. Now, observations of Vesta by NASA’s Dawn mission suggest that hydrous materials were delivered to the giant asteroid mainly through a build-up of small particles during an epoch when the Solar System was rich in dust. This is a radically different process from the way in which hydrous materials are deposited on the moon and may have implications for the formation of terrestrial planets, including the delivery of the water that forms Earth’s oceans.

Maria Cristina De Sanctis, of the Institute of Astrophysics and Space Planetology in Rome, said, ‘Vesta’s surface shows distinct areas enriched with hydrated materials. These regions are not dependent on solar illumination or temperature, as we find in the case of the Moon. The uneven distribution is unexpected and indicates ancient processes that differ from those believed to be responsible for delivering water to other airless bodies, like the Moon.’

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=387&Itemid=1

Dawn Mission Discovers Hydrogen On Giant Asteroid Vesta

September 24, 2012 Leave a comment

The first measurements of the elemental composition of the surface of the giant asteroid Vesta indicate that hydrogen was brought to the body by impactors, research by a team led by Planetary Science Institute Senior Scientist Thomas H. Prettyman has shown.

Using data collected by the NASA Dawn mission’s spacecraft’s gamma ray and neutron detector instrument – GRaND – as it circled the giant asteroid, researchers also confirmed the elemental composition of the surface of Vesta matches meteorites found on Earth believed to have originated from Vesta.

The highest concentrations of hydrogen were found in equatorial regions, where water ice is not stable. The lowest amounts were found within the giant, south-polar Rheasilvia impact basin.

Full Story: http://www.psi.edu/news/press-releases

Dawn Sees Hydrated Minerals On Giant Asteroid

September 24, 2012 Leave a comment

View of Cornelia crater on the giant asteroid Vesta shows an example of “pitted terrain,” Image credit: NASA/JPL Caltech /UCLA/MPS /DLR
/IDA /JHUAPL

NASA’s Dawn spacecraft has revealed that the giant asteroid Vesta has its own version of ring around the collar. Two new papers based on observations from the low-altitude mapping orbit of the Dawn mission show that volatile, or easily evaporated materials, have colored Vesta’s surface in a broad swath around its equator.

Pothole-like features mark some of the asteroid’s surface where the volatiles, likely water, released from hydrated minerals boiled off. While Dawn did not find actual water ice at Vesta, there are signs of hydrated minerals delivered by meteorites and dust evident in the giant asteroid’s chemistry and geology. The findings appear today in the journal Science.

Vesta is the second most massive member of the main asteroid belt. The orbit at which these data were obtained averaged about 130 miles (210 kilometers) above the surface. Dawn left Vesta earlier this month, on Sept. 4 PDT (Sept. 5 EDT), and is now on its way to its second target, the dwarf planet Ceres.

Full Story:http://www.jpl.nasa.gov/news/news.php?release=2012-297
Also: http://www.nasa.gov/mission_pages/dawn/news/dawn20120920.html

Vesta In Dawn’s Rear View Mirror

September 11, 2012 Leave a comment

Image credit: NASA /JPL – Caltech /UCAL /MPS /DLR /IDA

NASA’s Dawn mission is releasing two parting views of the giant asteroid Vesta, using images that were among the last taken by the spacecraft as it departed its companion for the last year.

The first set of images is a color-coded relief map of Vesta’s northern hemisphere, from the pole to the equator. It incorporates images taken just as Dawn began to creep over the high northern latitudes, which were dark when Dawn arrived in July 2011. The other image is a black-and-white mosaic that shows a full view of the giant asteroid, created by synthesizing some of Dawn’s best images.

“Dawn has peeled back the veil on some of the mysteries surrounding Vesta, but we’re still working hard on more analysis,” said Christopher Russell, Dawn’s principal investigator at UCLA. “So while Vesta is now out of sight, it will not be out of mind.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-284

Dawn Has Departed The Giant Asteroid Vesta

September 6, 2012 Leave a comment

Image credit: NASA/JPL Caltech/UCLA/MP /DLR/IDA

Mission controllers received confirmation today that NASA’s Dawn spacecraft has escaped from the gentle gravitational grip of the giant asteroid Vesta. Dawn is now officially on its way to its second destination, the dwarf planet Ceres.

Dawn departed from Vesta at about 11:26 p.m. PDT on Sept. 4 (2:26 a.m. EDT on Sept. 5). Communications from the spacecraft via NASA’s Deep Space Network confirmed the departure and that the spacecraft is now traveling toward Ceres.

“As we respectfully say goodbye to Vesta and reflect on the amazing discoveries over the past year, we eagerly look forward to the next phase of our adventure at Ceres, where even more exciting discoveries await,” said Robert Mase, Dawn project manager, based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-277

NASA’s Dawn Prepares For Trek Toward Dwarf Planet

August 31, 2012 Leave a comment

This image of NASA’s Dawn spacecraft and the giant asteroid Vesta is an artist’s concept. Image credit: NASA/JPL-Caltech

NASA’s Dawn spacecraft is on track to become the first probe to orbit and study two distant solar system destinations, to help scientists answer questions about the formation of our solar system. The spacecraft is scheduled to leave the giant asteroid Vesta on Sept. 4 PDT (Sept. 5 EDT) to start its two-and-a-half-year journey to the dwarf planet Ceres.

Dawn began its 3-billion-mile (5-billion kilometer) odyssey to explore the two most massive objects in the main asteroid belt in 2007. Dawn arrived at Vesta in July 2011 and will reach Ceres in early 2015.

To make its escape from Vesta, the spacecraft will spiral away as gently as it arrived, using a special, hyper-efficient system called ion propulsion. Dawn’s ion propulsion system uses electricity to ionize xenon to generate thrust. The 12-inch-wide ion thrusters provide less power than conventional engines, but can maintain thrust for months at a time.

Full Story: http://www.nasa.gov/mission_pages/dawn/news/dawn20120830.html