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From: dietz@SLB-DOLL.CSNET (Paul Dietz)
Newsgroups: net.space
Subject: REAL Star Wars...
Message-ID: <8511300112.AA08255@s1-b.arpa>
Date: Fri, 29-Nov-85 18:31:39 EST
Article-I.D.: s1-b.8511300112.AA08255
Posted: Fri Nov 29 18:31:39 1985
Date-Received: Sat, 30-Nov-85 07:07:56 EST
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Organization: The ARPA Internet
Lines: 37

While thinking about Star Wars and possible Soviet countermeasures, I
thought back to Niven & Pournelle's latest book ("Footfall").




To battle the invading aliens, the good guys built an Orion-style pulse
rocket.  The US was working on this in the early sixties but dropped it
when the Atmospheric Test Ban Treaty was signed.  The idea is well
known: a massive spacecraft is propelled by exploding shaped nuclear
charges under it.  The charges send streams of high velocity material
(polyethylene, say) against a massive steel pusher plate/radiation
shield.  One launch uses tens of bombs and puts thousands of
tons in orbit.

There's nothing high tech about this.  If we could do it in the early
sixties the Russians could probably do it today.  They have lots of
bombs and lots of steel, and the technology is more like shipbuilding
than rocketry.

Orion's justification was as a space battleship.  What a ship!  By
turning its pusher plate against oncoming warheads it could withstand
a one megaton blast 500 feet away.  It could use its own propulsion
charges as weapons.  It has plenty of mass budget for shielding against
lasers, particle beams, rocks, or whatever, and for its own offensive
weaponry.  An Orion-type ship pitted against an SDI-type defense would
be like a cat amongst the pidgeons.  The only way to counter it
is build your own.

Orion-style ships could lift armored reentry vehicles and scads of
decoys into space.  Even worse, such a ship could be lifted into
a retrograde orbit where it could scatter large quantities of gravel.
An effective ploy would be to scatter 1000 tonnes of 1 milligram
tungsten particles (say) in retrograde equatorial orbits out to several
earth radii.  Any satellite intersecting this disk would be hit within
several months.  Near-earth space could be seeded much more heavily,
rendering the shuttle useless.