RE: starship-design: Go Starwisps

["L. Parker" <lparker@cacaphony.net>]

Kelly,

I have always had a big problem with shielding requirements on 
interstellar flights. It doesn't even require extraordinary 
densities, at near relativistic speeds the IMPACT density per 
unit time at the front of the ship is going to be generating 
enough radiation to fry a small planet. At Starwisp velocities, 
there will be some degradation of performance, but we only need 
about 0.96 c for realistic missions. The probe doesn't care about 
time dilation. The  sail material is thin enough that most particles 
would pass right through without even noticing it. Because of the 
wavelength of the propelling laser (or sunlight), it could look like 
swiss cheese and still be functioning with 99 percent efficiency.

This brings up an interesting point, the bow wave of radiation given 
off by a starship travelling at near relativistic speeds should be 
detectable for a LONG ways. Since we have observed no such effects a 
few conclusions are possible:

1)	There are no nearby star travelling civilizations (possible)
2)	There are no star travelling civilizations (unlikely)
3)	Star travelling civilizations don't travel at near relativistic 
	velocities
4)	There is no life out there...

Lee Parker

"Never underestimate the joy people derive from hearing something they 
already know."

-- Enrico Fermi (1901-1954)



You don't need to send a probe on an interstellar flight to check out the
engines, and we have a fair idea of what radiation is in interstellar space.
 A bigger concern whould be what material is in interstellar space.  If as
one theory suggests, theirs traces of lots of lose carbon molecules in deep
space.  Runing into them at near light speeds could be real hard on a ship.
 It would also shread a starwhisp or micro wave sail very quickly.

Probably we'ld have to assume the worst and build in counter measures.  Like
per blast a area of interstellar space with the big maser area and see what
glowed, and launch a dust cloude ahead of the ship to blast a path clear.

Kelly