Re: MARS HYBRID DESIGN II (First Draft)

[Steve VanDevender <stevev@efn.org>]

 > = Well, if the only important thing is the component of the
 > = thrust along the velocity vector, it can clearly be aligned
 > = the other way to oppose the velocity vector.  This pushes
 > = against the direction of travel, dropping the sail down the
 > = gravity well, causing it to speed up the whole time.  A
 > = solar sail, contrary to popular belief, can travel sunward
 > = just as easily as it can travel anti-sunward.

I wasn't saying that you couldn't move towards a star while using a
solar sail; lowering your orbit is completely possible and the article
is correct.  I was saying that you couldn't use the sail to produce
greater acceleration towards the star than you would get by just falling
towards the star.  You can slow yourself down in your orbit by angling
the sail to produce thrust opposite your direction of motion, but the
limit case is when you have stopped all transverse motion in your orbit.
At that point you are simply in free fall to the star.