NASA's Dawn mission to the asteroids

[Rick]

Solar-powered ion drive asteroid probe set for launch

NASA has confirmed that the "Dawn" space probe to the asteroid belt will indeed launch on Saturday, ending speculation that the mission might be delayed.

After launching, Dawn will spend four years in transit to the asteroids, circling the Sun twice and gaining a "gravity assist" on the way by making a close approach to Mars.

In 2011, Dawn will go into orbit around Vesta, one of the larger rock-like asteroids in the Belt.

More: http://www.theregister.co.uk/2007/07/04/solar_powered_spaceship_is_go/

[Rick]

Dawn, NASA's mission to the asteroids, has been postponed again - this time until September. Mission managers had hoped to launch on Monday, but the final decision to delay was taken on Saturday.

More: http://www.theregister.co.uk/2007/07/09/dawn_postponed/

[Rick]

NASA's Dawn Collects a Bounty of Beauty from Vesta

A new video from NASA's Dawn spacecraft takes us on a flyover journey above the surface of the giant asteroid Vesta.

The data obtained by Dawn's framing camera, used to produce the visualizations, will help scientists determine the processes that formed Vesta's striking features. It will also help Dawn mission fans all over the world visualize this mysterious world, which is the second most massive object in the main asteroid belt.

The video, which shows Vesta as seen from Dawn's perspective, can be viewed at: http://www.jpl.nasa.gov/video/index.cfm?id=1020.

More: http://www.jpl.nasa.gov/news/news.cfm?release=2011-293

[Rick]

NASA Dawn Mission Reveals Secrets of Large Asteroid

NASA's Dawn spacecraft has provided researchers with the first orbital analysis of the giant asteroid Vesta, yielding new insights into its creation and kinship with terrestrial planets and Earth's moon.

Vesta now has been revealed as a special fossil of the early solar system with a more varied, diverse surface than originally thought. Scientists have confirmed a variety of ways in which Vesta more closely resembles a small planet or Earth's moon than another asteroid. Results appear in today's edition of the journal Science.

More: http://www.jpl.nasa.gov/news/news.cfm?release=2012-132

[mickw]

Virtual flyover movie -

http://apod.nasa.gov/apod/ap120514.html

[Rick]

Dawn Journal - June 30, 2012

Having successfully completed its orbital raising maneuvers to ascend to its second high-altitude mapping orbit (HAMO2), Dawn looks down from about 680 kilometers (420 miles). This is the same height from which it mapped Vesta at the end of September and October 2011. The lifeless rocky landscape has not changed since then, but its appearance to the spacecraft's sensors has. The first high-altitude mapping orbit (HAMO1) was conducted shortly after southern hemisphere summer began on Vesta, so the sun was well south of the equator. That left the high northern latitudes in the deep darkness of winter night. With its slower progression around the sun than Earth, seasons on Vesta last correspondingly longer. Thanks to Dawn's capability to linger in orbit, rather than simply conduct a brief reconnaissance as it speeds by on its way to its next destination, the probe now can examine the surface with different lighting.

More: http://dawn.jpl.nasa.gov/mission/journal_06_30_12.asp

[Rick]

Dawn has completed the final intensive phase of its extraordinary exploration of Vesta, and it has now begun its gradual departure. Propelled by its uniquely efficient ion propulsion system, the probe is spiraling ever higher, reversing the winding path it followed into orbit last year.

More: http://dawn.jpl.nasa.gov/mission/journal_07_25_12.asp

[Rick]

Dawn has Departed the Giant Asteroid Vesta

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.

More: http://www.jpl.nasa.gov/news/news.php?release=2012-277
and: http://dawn.jpl.nasa.gov/mission/journal_09_05_12.asp

[Rick]

Vesta in Dawn's Rear View Mirror

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.

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

[mickw]

Out between Mars and Jupiter lies a rubble of planets that never quite formed. Although the asteroids date to the birth of our solar system, our closest looks at them have been glimpses from spacecraft whizzing by en route to the glamorous outer solar system.

That changed last July, when NASA's Dawn probe slipped into orbit around Vesta, the asteroid belt's second most massive member.

More:   Vesta

[Rick]

Dawn Sees 'Young' Surface on Giant Asteroid

Like a Hollywood starlet constantly retouching her makeup, the giant asteroid Vesta is constantly stirring its outermost layer to present a young face. Data from NASA's Dawn mission show that a form of weathering that occurs on the moon and other airless bodies we've visited in the inner solar system does not alter Vesta's outermost layer in the same way. Carbon-rich asteroids have also been splattering dark material on Vesta's surface over a long span of the body's history. The results are described in two papers released today in the journal Nature.

"Dawn's data allow us to decipher how Vesta records fundamental processes that have also affected Earth and other solar system bodies," said Carol Raymond, Dawn deputy principal investigator at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "No object in our solar system is an island. Throughout solar system history, materials have exchanged and interacted."

More: http://www.jpl.nasa.gov/news/news.php?release=2012-342

[Rick]

Dawn Reality-Checks Telescope Studies of Asteroids

Tantalized by images from NASA's Hubble Space Telescope and ground-based data, scientists thought the giant asteroid Vesta deserved a closer look. They got a chance to do that in 2011 and 2012, when NASA's Dawn spacecraft orbited the giant asteroid, and they were able to check earlier conclusions. A new study involving Dawn's observations during that time period demonstrates how this relationship works with Hubble and ground-based telescopes to clarify our understanding of a solar system object.

"Since the vast majority of asteroids can only be studied remotely by ground-based and space-based facilities, confirming the accuracy of such observations using in-situ measurements is important to our exploration of the solar system," said Vishnu Reddy, the lead author of a paper published recently in the journal Icarus. Reddy is based at the Planetary Science Institute in Tucson, Ariz., and the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany.

In the paper, Reddy and other members of Dawn's framing camera team describe how up-close observations of Vesta have confirmed and provided new insights into more than 200 years of Earth-based observations.

More: http://www.jpl.nasa.gov/news/news.php?release=2013-293

[Rick]

It's Complicated: Dawn Spurs Rewrite of Vesta's Story

Just when scientists thought they had a tidy theory for how the giant asteroid Vesta formed, a new paper from NASA's Dawn mission suggests the history is more complicated.

If Vesta's formation had followed the script for the formation of rocky planets like our own, heat from the interior would have created distinct, separated layers of rock (generally, a core, mantle and crust). In that story, the mineral olivine should concentrate in the mantle.

However, as described in a paper in this week's issue of the journal Nature, that's not what Dawn's visible and infrared mapping spectrometer (VIR) instrument found. The observations of the huge craters in Vesta's southern hemisphere that exposed the lower crust and should have excavated the mantle did not find evidence of olivine there. Scientists instead found clear signatures of olivine in the surface material in the northern hemisphere.

More: http://www.jpl.nasa.gov/news/news.php?release=2013-321

[Rick]

NASA's Dawn Fills out its Ceres Dance Card

It's going to be a ball when NASA's Dawn spacecraft finally arrives at the dwarf planet Ceres, and mission managers have now inked in the schedule on Dawn's dance card.

Dawn has been cruising toward Ceres, the largest object in the main asteroid belt between Mars and Jupiter, since September 2012. That's when it departed from its first dance partner, Vesta.

Ceres presents an icy -- possibly watery -- counterpoint to the dry Vesta, where Dawn spent almost 14 months. Vesta and Ceres are two of the largest surviving protoplanets -- bodies that almost became planets -- and will give scientists clues about the planet-forming conditions at the dawn of our solar system.

When Dawn enters orbit around Ceres, it will be the first spacecraft to see a dwarf planet up-close and the first spacecraft to orbit two solar system destinations beyond Earth.

More: http://www.jpl.nasa.gov/news/news.php?release=2013-347
Also: http://dawn.jpl.nasa.gov/mission/journal_11_30_13.asp

[Rick]

An update on Dawn's mission to Ceres

Dawn draws ever closer to the mysterious Ceres, the largest body between the sun and Pluto not yet visited by a probe from Earth. The spacecraft is continuing to climb outward from the sun atop a blue-green beam of xenon ions from its uniquely efficient ion propulsion system. The constant, gentle thrust is reshaping its solar orbit so that by March 2015, it will arrive at the first dwarf planet ever discovered. Once in orbit, it will undertake an ambitious exploration of the exotic world of ice and rock that has been glimpsed only from afar for more than two centuries.

An important characteristic of this interplanetary expedition is that Dawn can linger at its destinations, conducting extensive observations. Since December, we have presented overviews of all the phases of the mission at Ceres save one. (In addition, questions posted by readers each month, occasionally combined with an answer, have helped elucidate some of the interesting features of the mission.) We have described how Dawn will approach its gargantuan new home (with an equatorial diameter of more than 600 miles, or 975 kilometers) and slip into orbit with the elegance of a celestial dancer. The spacecraft will unveil the previously unseen sights with its suite of sophisticated sensors from progressively lower altitude orbits, starting at 8,400 miles (13,500 kilometers), then from survey orbit at 2,730 miles (4,400 kilometers), and then from the misleadingly named high altitude mapping orbit (HAMO) only 910 miles (1,470 kilometers) away. To travel from one orbit to another, it will use its extraordinary ion propulsion system to spiral lower and lower and lower. This month, we look at the final phase of the long mission, as Dawn dives down to the low altitude mapping orbit (LAMO) at 230 miles (375 kilometers). We will also consider what future awaits our intrepid adventurer after it has accomplished the daring plans at Ceres.

More: http://dawnblog.jpl.nasa.gov/2014/08/31/dawn-journal-august-31/