Re: starship-design: solar sail

[KellySt@aol.com]

> In discussions of solar/laser sail systems, the question 
> of braking at destination seems to be a problem which 
> hasn't been resolved. It has occurred to me that perhaps 
> the sail can be physically reshaped to permit some 
> braking, without having to turn the ship around.===

Boy did we discus this.  This was a major issue.  If you had major maser /
laser stations at each end a sail could go fast as hell.  But decelerating it
was about impossible.  Your periscope like light path turn out not to work.
Forward in his Roche world series suggested you drop a mirror sail that
reflects the beam back as the mirror is blasted away (REAL! impractical).  I
suggested something like your periscope deal with microwaves, but reflected
backwards off a plasma mirror.  The plasma is lost but the beam is refleacted
back in a way that could decel the ship.. I think.

My Fuel/Sail ideas a good compramise.  The fusion fuel you'll need to
decelerate into the target system is spun out into filiments and wolven out
intoa huge microwave sail.  You boost out with the sail.  Decel later with the
fusion fuel (you collect in the sail during the flight).  Boost back with fuel
mined in system, and use a small sail to decel into Sol.  You could get up to
40% of light speed that way.

Kelly