From: jdnicoll@prism.ccs.uwo.ca (James Davis Nicoll)
Subject: Re: Wreaking a habitat (was Re: Wrecking a Planet
Organization: University of Western Ontario, London
Date: Mon, 11 Jan 1993 19:49:03 GMT


	Let's suppose an Unruly Lot of O'Neilers, feeling safe in their
billion tonne structure (Complete with windows made of spendidium, the
miracle material of the 21st Century and mighty engines capable of an
impressive 0.01 m/s**2 acceleration), have irked the Powers That Be, who
have ordered the reduction of the O'Neil colony. Let us further suppose 
that the PTB also have an unsightly  surplus of spiffy nuclear weapons and
have decreed the latter problem to be dealt with dealing with the former 
problem. How might one use nukes to pacify the ULO?

	Just detonating a nuke in the vicinity of the ULO probably won't
work efficiently, unless it is a direct hit, given the lack of phenomina
like shock waves due to the deporable lack  of a propagating medium. EMR
has the disadvantage following the inverse-square law, so intensity drops
off rather rapidly with range. One possible solution is to transform the 
energy of the nuclear pacification device to a more useful form and this 
is  how *I* might do it.

	For folks unfamiliar with the Orion program, in the early stages
of the American nuclear weapons program, it was noted that structures
in the close vicinity of ground zero were not always evaporated in the
fireball, but occasionally were found transported some distance away. 
If memory serves, people (Including but not restricted to Taylor and
Dyson) decided that what was happening was that surface  material on  
the transported objects was ablating and  the expanding gasses propelled
the objects away from  ground zero before they could entirely evaporate.
They then designed a propulsion  system which exploited this effect, which
for several reasons never got built. This effect can be used offensively
as follows:

	Take a 500 mt pacification device. Clad it in a large quantity
of graphite coated projectiles (About 100 t, say), each about 1 kg. Get
the device within 100,000 km of the ULO and detonate it. Let us suppose
that 99% of the energy is wasted, and only 1% ends up as Ek of the
projectiles. Let us  suppose that 1/2  the mass of the projectiles
is evaporated. That leaves 100,000 0.5 kg objects with ~2.1 x 10**16 J
total Ek. That's ~2.1x10**11 J each, (About 50 t equivalent) which means
the projectiles could be moving at ~900 km/s. This would be visible to  the 
ULO, who immediatly attempt to dodge the incoming swarm. In the 111 seconds
they have until impact, the ULO can change the future position of their home 
by 62 meters. If the ULO is a billion tonnes, 1/1000 the density of water,
and a sphere, its diameter would be ~12,400 meters, or about 200 times 
as wide as the maximum distance it can jink in 111 seconds. I don't think
the 100,000 projectiles need terminal guidance, if the PTB nuclear weapons
designers can produce a device that projects  the swarm in a narrow cone
(Which is why I assume most of the energy is wasted). That's 1 projectile
every 2400 square meters, which is what, about 60 m apart?

	If the swarm is only moving at 70 km/s (The velocity the plug 
capping an underground nuclear test in the 1960s was clocked at), the
ULOs have 1430 seconds, and can jink up to 10.2 km, in which case the
swarm is aiming at a circle with about 3 times the area of the ULO
home, so only 1/3 of the projectiles may hit, so case 2 has projectiles
hitting every 100 meters or so...

	Anyone know how large a hole a 0.5 kg object moving at 900 km/s
(Case one) or 70 km/s (Case two) will blow? I suspect 100K or 33K craters
that size will be rather inconveniant...


							James Nicoll

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