From: email@example.com (Henry Spencer)
Subject: Re: Endeavour Class Missions
Date: Sun, 12 Sep 1999 15:27:01 GMT
In article <firstname.lastname@example.org>,
Frank Crary <email@example.com> wrote:
>>Seems to me that either the Earth-Moon or Sun-Earth Lagrange points
>>would be a better place to start a Mars mission then LEO...
>If you plug in some numbers, you will see that the total delta v
>is higher if you stop along the way...
Only if you insert into your interplanetary trajectory direct from the
high orbit. If you do insertion using a close Earth flyby, you recover
almost all of the losses; indeed, you may actually show a gain, because
you can do the insertion at a lower altitude than a LEO assembly base
could safely maintain. The only losses are whatever delta-V you need to
go from your assembly orbit to the Earth flyby, plus a similar amount
earlier to inject into the assembly orbit. With a good choice of assembly
orbit -- say, a halo orbit around the Earth-Sun L1 point -- those delta-Vs
can be very small.
The good old days | Henry Spencer firstname.lastname@example.org
weren't. | (aka email@example.com)