dietz@SLB-DOLL.CSNET (Paul Dietz) (11/30/85)
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.henry@utzoo.UUCP (Henry Spencer) (12/01/85)
> ...Orion's justification was as a space battleship...
No, its original justification was as a heavy launch vehicle, and a
spaceship capable of exploring the whole solar system quickly and cheaply.
(Sample: a large manned Mars expedition tentatively planned for 1965.)
That's why a lot of very good people put a lot of effort into the early
stages. The switch to military justifications came towards the end, when
Orion was visibly dying as a result of high-level policy decisions in favor
of chemical rockets and against nuclear propulsion.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henrydietz@SLB-DOLL.CSNET (Paul Dietz) (12/02/85)
>> ...Orion's justification was as a space battleship... >No, its original justification was as a heavy launch vehicle, and a >spaceship capable of exploring the whole solar system quickly and cheaply. Quite right. DOD took over only after the civilians decided to go with chemical propellants (I just reread the relevant chapter of Dyson's book). What really killed Orion, I suspect, is the fallout problem.
jr@bbncc5.UUCP (John Robinson) (12/03/85)
In article <8511300112.AA08255@s1-b.arpa> dietz@SLB-DOLL.CSNET (Paul Dietz) writes: ... >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. Sounds kinda' like Saturn, no (except for the retrograde orbit)? Could the rings be the last vestiges of a civilization that burned itself up (or froze (or moved closer to the sun)) gigayears ago? Might be a good SciFi theme. (Maybe current Saturn formation theories aren't going far enough :-) /jr
henry@utzoo.UUCP (Henry Spencer) (12/03/85)
> ...What really killed Orion, I suspect, is the fallout problem. ...
That's not what killed it at the time, although it would prevent restarting
it now. Its originators were aware of the issue. At a time when nuclear
tests in the atmosphere were routine, the extra fallout from a moderate level
of Orion testing and use would have been minor. With fallout-production rates
much reduced nowadays, it would be less acceptable. The Test-Ban Treaty did
administer the coup de grace to Orion, since the two were incompatible without
further negotiation (which is provided for in the treaty, by the way), but the
project was already nearly dead for lack of support.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry