keithl (12/30/82)
Solar sails are romantic, but they aren't too compatable with a trip from
the shuttle to L5. The problem is air friction; at 300 Km altitude, for
example, the "wind" resistance is around 200 micro-newtons per meter squared
(at orbital velocity), while the peak sail force is around 8 uN/m2. To get to
sufficient altitude that the sail will work, an IUS is needed; why not just
use the IUS to get there, and avoid the weight of the sail?
Other problems include radiation damage to instrumentation from the long
exposure to the Van Allen belt, collisions between the sail and orbital debris,
and large gravitational gradients.
Sails are more suited to long haul interplanetary missions, where more
velocity change is needed and the vacuum is better.
Keith Lofstrom
uucp: {ucbvax,decvax,chico,pur-ee,cbosg,ihnss}!teklabs!tekcad!keithl
CSnet: keithl@tek
ARPAnet:keithl.tek@rand-relay