Dawn spacecraft spirals down to lowest orbit

Dec 13, 2011
This artist's concept shows NASA's Dawn spacecraft orbiting the giant asteroid Vesta. The depiction of Vesta is based on images obtained by Dawn's framing cameras. Image credit: NASA/JPL-Caltech

(PhysOrg.com) -- NASA's Dawn spacecraft successfully maneuvered into its closest orbit around the giant asteroid Vesta today, beginning a new phase of science observations. The spacecraft is now circling Vesta at an altitude averaging about 130 miles (210 kilometers) in the phase of the mission known as low altitude mapping orbit.

"Dawn has performed some complicated and beautiful choreography in order to reach this lowest orbit," said Marc Rayman, Dawn chief engineer and mission manager based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are in an excellent position to learn much more about the secrets of Vesta's surface and interior."

Launched in 2007, Dawn has been in orbit around Vesta, the second most massive object in the asteroid belt between Mars and Jupiter, since July 15. The team plans to acquire data in the low orbit for at least 10 weeks.

Dawn's framing camera and visible and instruments will image portions of the surface at greater resolution than obtained at higher altitudes. But the primary goal of the low orbit is to collect data for the gamma ray and (GRaND) and the gravity experiment. GRaND will be looking for the by-products of cosmic rays reflected off Vesta to reveal the identities of many kinds of atoms in the surface of Vesta. The instrument is most effective at this low altitude.

Close proximity to Vesta also enables ultrasensitive measurements of its gravitational field. These measurements will tell scientists about the way masses are arranged in the giant asteroid's interior.

"Dawn's visit to Vesta has been eye-opening so far, showing us troughs and peaks that telescopes only hinted at," said Christopher Russell, Dawn's principal investigator, based at UCLA. "It whets the appetite for a day when can see the wonders of asteroids for themselves."

After the science collection is complete at the low altitude mapping orbit, Dawn will spiral out and conduct another science campaign at the high altitude mapping orbit altitude (420 miles, or 680 kilometers), when the sun will have risen higher in the northern regions. Dawn plans to leave Vesta in July 2012 and arrive at its second destination, the dwarf planet Ceres, in February 2015.

Explore further: Video gives astronaut's-eye view inside NASA's Orion spacecraft

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User comments : 4

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Nanobanano
2.5 / 5 (2) Dec 13, 2011
They'll end up with a better map of Vesta than we have for anything else in the solar system.
GSwift7
5 / 5 (3) Dec 13, 2011
Dawn plans to leave Vesta in July 2012 and arrive at its second destination, the dwarf planet Ceres, in February 2015.


The average American taxpayer doesn't even have a clue this mission is happening. The technical achievement of getting there and now doing the things they are doing is beyond comprehension of 99% of people. There's a reason that the majority of the attempts by other countries to do similar missions have failed.

Heck, my parents didn't even know the Mars Science Lab had launched already. Most people in the US think that the Shuttle program was all NASA did, and that Obama shut NASA down. People don't have a clue generally.
ACW
5 / 5 (2) Dec 13, 2011
I am very interested to see what we learn from this mission. Ceres should also prove to be illuminating.
Another interesting mission is New Horizons
GSwift7
5 / 5 (3) Dec 13, 2011
New Horizons is cool, but MSL is the king of missions in the near future. The technology being tested to get MSL on the ground, or something very similar, will be needed to get people there. If MSL succeeds, it'll be a big step towards a human trip. In order to get people onto Mars, you need the ability to get a very heavy load down to the surface. Nobody has ever tried that on Mars before, and it's a whole different engineering problem than trying to do it on the Moon or Earth. It's actually easier to do it on the Moon or Earth than it is on Mars. Mars has a nasty combination of relatively high gravity and just enough atmosphere to cause problems, but not enough atmosphere to be much of a help slowing down. I'm very interested in seeing the proof of concept of the skycrane method and the new heat shield. Once again, it's a big engineering milestone that nobody will know anything about.

Nobody else would/could even attempt it.

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