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From: dcn@ihuxl.UUCP (Dave Newkirk)
Newsgroups: net.space
Subject: Re: cheap interstellar probes
Message-ID: <1572@ihuxl.UUCP>
Date: Tue, 28-May-85 08:49:40 EDT
Article-I.D.: ihuxl.1572
Posted: Tue May 28 08:49:40 1985
Date-Received: Thu, 30-May-85 02:27:14 EDT
References: <1946@mordor.UUCP>
Organization: AT&T Bell Laboratories
Lines: 19

> From: redford%avoid.DEC@decwrl.ARPA  (John Redford)
> 
> Hmmm, what could we do to make a cheap interstellar probe?  The parameters
> proposed were that the probe has to report back within a hundred years 
> from a star no more than 20 light years away.  That seems a long way away.
...
> John Redford
> DEC-Hudson

A cheaper way might be a simple ion drive.  A mix of solar and nuclear power
to provide electricity, and a cheap fuel source that can be ionized.
It's not a big thrust, but it can be maintained for long periods, building
up impressive speeds.

I also think you gave up too soon on the laser-driven light sails.
For more ideas on this, see Robert Forward's new book "Dragonfly".
Remember, solar energy is cheap and plentiful in the inner solar system.
-- 
				Dave Newkirk, ihnp4!ihuxl!dcn