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View Full Version : Dawn mission and Ion drive



cr1t
2007-Sep-17, 10:05 AM
Hi

I was reading this article today
http://www.jpl.nasa.gov/news/features.cfm?feature=1468

The article makes it sound like the Ion drive accelarates the ship from rest, is this true? I would have thought that the ship would start off with the velocity that it has when it separates with the Delta2 rocket.

antoniseb
2007-Sep-17, 02:20 PM
I don't read it that it starts from rest. I do read that it has an initial velocity, and that the ion engine adds to that velocity.

Keep in mind, however, that the actual velocity that the probe will have is highly dependent on how much gravitational potential energy it gains as it climbs out of the Sun's potential well. So the actual velocity will be going down as it accelerates.