On 9/29/2011 8:44 AM, Onno Meyer wrote:
regarding the comments by Anthony and Hal, I was assuming a Hohmann transfer orbit with a hefty murphy factor for low trust engines and another fudge factor to reduce the timeframe a bit. The goal is to get the asteroid into Earth orbit, or perhaps L5 or an orbit around the sun very similar to that of Earth.
Actually getting stuff into orbit is tough.
Earth to Ceres is a minimum of 17 kps, while Earth to Pluto (as a stand-in for a generic comet) is 22 kps. Call it 15 mps, then.
What are you using for hohmann transfer orbit solving? A hohmann transfer orbit from 1 AU to 2.76 AU is 11.2 kps, not 17 kps, and from 1 AU to 39.3 AU is 15.5 KPS (and takes 45 years), not 22, so your method is either wrong or including calculations of other costs. If you've got enough thrust to take advantage of the Oberth effect, which you probably don't, you can cut that down sizeably, as most of the delta-V is for circularizing your orbit at 1 AU.
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