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Re: MARS HYBRID DESIGN II (First Draft)



L. Parker writes:
 > I am not going to get into the math, but you CAN tack a solar sail to sail
 > towards the sun, so what is the problem with using TC? You might have to
 > have the Pathfinder tack around TC several times in a decreasing spiral, but
 > it should be possible to decelerate with JUST the energy from TC.

No, please, get into the math.  The only way I know of to get a solar
sail to move towards a star is to let it fall in the star's gravity.
The thrust from a solar sail _always_ has an outwards component, never
inwards.  You can direct the sideways component to do things like drop
your orbit to a lower radius, but you can't accelerate towards the star
any faster than you would accelerate by falling.

Of course, having the outwards component is what you want if you're
trying to brake.  I think in practical terms, though, you can't build a
sail big enough to decelerate from relatvistic speeds, and you can't
spiral in towards the star unless you get below the star's escape
velocity.