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From: dietz@SLB-DOLL.CSNET (Paul Dietz)
Newsgroups: net.space
Subject: Beamed Power
Message-ID: <8512101754.AA19045@s1-b.arpa>
Date: Mon, 9-Dec-85 18:36:23 EST
Article-I.D.: s1-b.8512101754.AA19045
Posted: Mon Dec  9 18:36:23 1985
Date-Received: Thu, 12-Dec-85 04:42:32 EST
Sender: bloom@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 21

AWST (Dec. 9, page 18) reports that SDIO is claiming "incredible
progress" in developing free-electron lasers at Livermore.  The
laser is large (100 meters long) but tunable and highly efficient
(the article does not state the efficiency, but I've seen figures
of 50% elsewhere).  Recent tests in Hawaii have used automatic
compensation for atmospheric turbulence to focus a low power
laser on a missile in flight.  The intention is to use this
technology to direct a free electron laser beam to orbiting mirrors.
According to the article, competing technologies, excimer and
chemical lasers, are being deemphasized (I suppose because these
would be less efficient, more massive and space based).

While the utility of free-electron lasers for BMD is debatable,
and the actual results obtained at Livermore unknown, FEL's
are an ideal technology for more peaceful beamed power
applications, such as powering electric engines in OTV's, supplying
power to a lunar colony (or colonies) during the lunar night, or
beaming power back from powersats.  It is conceivable that we
can use a ground-based FEL to deliver a continuous beam of light
orders of magnitude more powerful than sunlight anywhere in
cislunar space.