Orbital Lasers & SDI June 12, 1997
If a nuclear attack were launched on America, it could
involve hundreds of missiles carrying thousands of warheads, each
travelling at up to 4 miles (6.4km) a second towards targets they
would reach within 30 minutes of launch. To protect themselves, the
US have therefor developed their Strategic Defense Initiative (SDI) or
'Star Wars' programme.
A major part of this programme is to develop lasers that
will shoot down enemy missiles within five minutes of launch. If it
was left any later that this, then the defence system becomes much
more difficult because the missile releases up to ten seperate
warheads and many decoys, greatly increasing the number of targets
that have to be hit. Lets face it, any laser in existant is hardly
rapid fire such as in the movies,
this is real life.
Lasers destroy their targets by directing onto them an
intense beam of energy which travels at the speed of light - 186,000
miles (300,000km) a second.
The simplest method of destruction is to focus a beam of
infrared radiation on a missile so that it burns a hole in the rocket
casing, causing fuel to escape so stopping the missile from reaching
orbit. Or the beam could disrupt the rocket's electronic guidance
system.
The US are developing (maybe developed by now, anyone
know so?) a chemical laser in which hydrogen and fluorine react
together to form hydrogen fluoride, which is a corrosive gas or liquid
which can be made to release a powerful burst of infrared radiation.
The laser is focused and aimed by prisms and mirrors.
A chemical laser of sufficient power (at least 25
megawatts) could destroy a missile almost 2000 miles away. (3200km).
The lasers would attack their targets from battle
stations in space ... a few hundred miles above the Earth. However
... a total of about 100 stations would really be needed to give the
US the possibility of complete protection, and getting that many in
space, as you know, would simply dwarf any previous space project.
Just the hydrogen fluoride needed to fuel the lasers
would weigh about 2000 tons!!! Think of the costs for that kind of
payload ... how would such a project be funded?
A possible alternative to that, might be to base the
lasers on land. The difficulty then though is that the atmosphere
would disperse the laser beam, making it impossible to focus on the
missile's skin. Putting the lasers on top of high mountains would
reduce distortion ... obviously because their would be less atmosphere
to penetrate. Advanced optical
techniques designed to counteract the dispersive effect of the
atmosphere may also help.
Even so, no more than a tenth of the power of the laser
could be expected to reach the target, which means that the lasers
fired from Earth would need to be very powerful indeed! They would
probably need to have the power of around 400! megawatts each ... the
same electricity consumption of a medium-sized city, and 1000 times
more powerful than any laser known to exist today! Darth Vader eat
your heart out.
Mirrors would have to keep the lasers locked onto the
missile for several seconds before it would be destroyed. Even if
this were achieved .. the enemy could probably still defeat the laser
by putting a heat shield around the missile .. or by making it spin so
that the beam could not be focused on the same spot long enough to
burn a hole.
The Star Wars programme has also been developing lasers
which produce X-rays rather than a beam of light. These X-rays are
produced in a single pulse rather than a continuous beam (a pulse
laser). The source of the X-rays is a small nuclear explosion. When
the pulse of X-rays hits the enemy missile ... they are absorbed by
its skin, vaporising it and blowing the missile apart. Great.
Because X-rays are rapidly
absorbed by the atmosphere, they would also have to be fired from
space, when both laser ... and the missile it was attacking .. had
risen above the atmosphere .. at least 50 miles (80km) above the
Earth.
The 'idea' is not to station the lasers permanently in
space, but to launch them only when satellite observations show that
an enemy attack is already under way. The X-ray lasers would be
launched from submarines, and would then be quickly boosted into orbit
... where they would be aimed and fired accordingly and automatically.
Note: Lasers are 25 year old technology. Now mounted on
the Military Satilites are Microwave cannons wieghing less than 150
lbs. These are instantaneous and fry everything to a cinder in
seconds. Even these are likely old technology now and are being
replaced with weapons even Buck Rogers would be envious
of.......Col.
by Richard G. Gall
mib@cyborg.force9.net