Brian Vastag, of the Washington Post, reports in Destination asteroid: NASA probe arrives at ancient ‘mini moon’ that a NASA probe, named Dawn, has arrived in orbit around Vesta, after a four year flight.
Three hundred fifty miles wide and heavily cratered, Vesta formed some 4.5 billion years ago, when the sun was still young. By probing its secrets, scientists hope to catch a glimpse of how the planets, including Earth, formed out of a swirling disk of gas and dust. ...
Unlike most smaller asteroids — thought to be nearly uniform lumps of rock — Vesta is a “mini moon,” Russell said, made up of three layers: an iron core, a rocky mantle and an upper crust. Early in Vesta’s existence, Russell said, lava welled up from its interior and cooled to form a crust of volcanic rock.
http://www.washingtonpost.com/...
“Vesta is unique among the large asteroids,” said Richard Binzel, professor of planetary sciences at the Massachusetts Institute of Technology. “It’s the only one covered with a volcanic surface.” ...
The second-most-massive asteroid in the solar system, Vesta circles the sun in the asteroid belt between Mars and Jupiter. Had Jupiter’s massive gravity not interfered, the millions of space rocks in the asteroid belt might have coalesced into another planet, scientists say. ...
Unlike rocket-powered craft sent to Mars, Jupiter and other planets, Dawn is driven by a weak-but-steady ion engine. Powered by solar panels, Dawn’s engines zap a gas, xenon, with an electrical charge. As the charged gas shoots out a nozzle, it imparts a gentle push — equivalent to the weight of a sheet of paper sitting on your hand, said Mark Rayman, chief engineer for Dawn at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. ...
Sipping just milligrams of xenon a day, the super-efficient engines leave Dawn with enough fuel to push itself toward a second asteroid. If all goes well, next summer the 65-foot-wide craft will depart Vesta and head toward the largest asteroid in the solar system, Ceres, with arrival scheduled for 2015. Ceres intrigues scientists because it apparently holds a huge reservoir of water, Russell said.
If successful, in getting to Ceres, this will be the first time, an spacecraft has orbited two celestial objects, other than earth, as far as we know.
I’m glad we've funded all of these space missions. It is sad to think much of this kind of science funding may be cut in these budget meetings, instead, of returning military spending, and taxation to Clinton era levels.
But, there may be a small glimmer of hope on the horizon for supporters of space exploration. I've read that China and India are getting ready to take up where we are leaving off.
Who knows. If we're cooperative, supportive, and pay all of our bills on time, maybe they will name an asteroid after us, in appreciation for doing the initial research and development work for space exploration?