Brandon Cope sez:
}but at a 100* km range, a 0.001 degree error would result
}in a miss by 1.75 meters.
Well, when you have a camera in orbit capable of resolving 10cm
objects on the surface, it's easy enough to correct fire.
Mark sez:
}SDI MIRCL(Midrange InfraRed Chemical Laser) tests
}in the early 80's. Even at a range of < 20 miles, there was
}significant beam diffusion and energy loss. In addition to
}airborne crud (dust, pollen, bugs, ultra-light pilots, etc.)
Don't forget the private and commercial pilots! :-)
(not to mention grav belt nutz! :-)
}which block and scatter the beam, there is the problem of the
}clear atmosphere itself. Under the stimulation of a high-energy
}laser, the air in the path of the beam heats to an energized
}plasma state, which then presents the same sort of problems as
}airborne particles. The main problem is defocusing of the beam
}(the assumption being that a large enough power source can pump
}a laser beam of such high energy that any energy loss in transit
}will still leave enough punch to toast the target at the other
}end). Current ground-based laser research is attempting to
}overcome this beam diffusion by using computer-controlled
}variable geometry mirrors. As the beam is diffused in the
}atmosphere, that beam scatter is automatically measured by the
}computer and the mirrors geometry is modified to correct for the
}diffusion. Success so far has been only moderate, according to
}de-classified documents on the research.
Now, these tests are made with today's laser technology. That
being lasers which go from infrared to ultraviolet. The
atmosphere of the earth is notably transparent in the visible
range and becomes more optically thick the farther out you get
from that range (which is one of the reasons why we evolved to
see in what you and I call the 'visible' range.)
However, Traveller TL 13+ lasers are X-rays. I do not know
exactly how transparent the atmosphere is in that range, but I
would say that if the human body is transparent to X-rays, the
atmosphere dang well outta be too. Thus, much less energy will
be lost to the atmosphere than in IR to UV lasers. Less energy
loss, the less the atmosphere will heat, therefore less beam
diffraction.
Also, when we are dealing with beams of ***250 MEGAwatts*** I
still think yer gonna give somebody an AWFUL sunburn... Even
*with* Sunblock 50 million! :-) Heck! Even the beam scattering
from a 250MW laser on the ground is gonna be lethal. Think about
it: A 250MW laser would *REALLY* light up a room... You wear
goggles to protect your eyes from lasers of less than half a
watt. And a 0.095milliwatt laser can damage your eye if you
stare at it. You miss by a few meters and nobody will notice.
}(Tom Clancy covers this subject a fair amount, in layman's
}terms, in his novel _A_Cardinal_in_the_Kremlin_.)
Good book! Got the man's autograph at a diamond convention he
addressed. (diamond coated mirrors in that book)
Scott "Laser Jock" Kellogg