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From: dbb@aicchi.UUCP (Burch)
Newsgroups: net.space
Subject: Re: Re: Interstellar probes
Message-ID: <483@aicchi.UUCP>
Date: Sun, 2-Jun-85 08:53:42 EDT
Article-I.D.: aicchi.483
Posted: Sun Jun  2 08:53:42 1985
Date-Received: Tue, 4-Jun-85 05:32:29 EDT
References: <1957@mordor.UUCP> <5632@utzoo.UUCP>
Organization: Analysts International Corp; Chicago Branch
Lines: 15

As for how to slow a probe at target when you are using "solar" sails as
propulsion: In a DOD report, Robert L. Forward proposed using a light sail
that is in to segments, a large outer ring and a small inner circle. When
departing, the two segments are used as a single sail. When decelerating, the
large outer ring is dropped, and the spacecraft with small sail attached
turns around. You then (Well, you actually start years before) turn on your
earth based LASERs. The large outer ring acts as a mirror, and reflects
the light from earth onto the probe's sail. Needless to say, the reflector
sail departs the probe at a healthy acceleration, but they are both so far
from earth that the subtended angle will not change much over the course of the
deceleration program. As a sind note, the light reaching the small sail would
be extremely redshifted...

-Ben Burch
AIC