Martin Posted October 23, 2010 Share Posted October 23, 2010 (edited) I am intrigued by the Dawn mission to Vesta and Ceres---the two largest in the asteroid belt. Ceres is now rated "dwarf planet", diameter ~1000 km, estimated large amount of underground water. Dawn uses solar-powered Xenon ion drive. Dawn and Vesta are now both roughly the same distance from the sun (about 2 AU) and "running neck and neck" at roughly the same speed around 20 km/second. Vesta is slowly overtaking and Dawn is thrusting to speed up, so that it can exactly match speeds. It is now about 0.1 AU from Vesta. Ion propulsion is very gradual. It will take 9 to 10 months before Dawn is in orbit around Vesta. The first "science orbit" will be August 2011. Dawn will stay in useful orbit around Vesta for 9 or 10 months (in the general vicinity for roughly one year but not all that time in "science orbit"). In May 2012 the plan is for it to turn on thrust, spiral out from Vesta and go spend some time studying Ceres. If all goes well it will be orbit Ceres for about 5 months (February-July 2015.) Here's a map of the Dawn journey: http://neo.jpl.nasa.gov/orbits/fulltraj.jpg Simulated view of Sun, Earth, and Venus as seen from the spacecraft's perspective http://neo.jpl.nasa.gov/orbits/fullview3.jpg General overview: http://dawn.jpl.nasa.gov/mission/dawn_fact_sheet.pdf Current status report: http://dawn.jpl.nasa.gov/mission/status.asp More simulated views, if anyone is interested: http://dawn.jpl.nasa.gov/mission/live_shots.asp http://en.wikipedia.org/wiki/Ceres_(dwarf_planet) ~1000 km diameter http://en.wikipedia.org/wiki/4_Vesta (average diameter ~530 km) Edited October 23, 2010 by Martin 1 Link to comment Share on other sites More sharing options...
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