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Re: (meteorobs) satellite baseball
Hello Steve,
> I was wondering, with all the satellites and God knows what else
> orbiting the Earth right now and especially with the recent collision of
> Mir, is there any documentation on the chances that a satellite could,
> or has been struck by a meteor?
>
> It seems that there is a pretty good
> chance that this could happen, especially when you think about how many
> satellites are out there. Isn't it like several hundred satellites, or
> some such number?
even though the number of satellites orbiting Earth is increasing, the
danger from meteoroid streams is still very low. Just remember, the number
densitites of the Geminids, Perseids and Quadrantids at their maximum are
something like a few ten to hundred particles per 10^9 km^3 (as derived
from visual meteor observations). That is, in a cube with an edge length
of 1000 km x 1000 km x 1000 km, you have just a handful of particles in
the densest parts of these streams intersecting the Earth orbit.
Still, at times of meteor storms this may become a more serious problem.
You probably know that the launch of the space shuttle in August 1993
was delayed since it was feared, that an intense outburst of the Perseids
could become a real threat. After the outburst we knew, that the activity
was much too low. Then we have the Leonids. In the storm component the
number density is that high, that the danger for sattelites is not
neglectible anymore. I once read a newspaper article, that ensurance
companies for satellites have much to do in these days, as the owners
really fear the loss of satellites.
Essentially you have no chance to protect yourself up there. I read that
the satellites are oriented that way, that the most sensitive parts are
turned away from the arriving meteoroids and 'shielded' by the
satellite itself. However, if the particle is only large enough, it will
destroy anything on it's way due to it's enormous encounter velocity.
So you can only hope, that your satellite is just 'behind Earth' when
we are travelling through the densest part of the Leonid stream.
Another very real thread is human made space debris. It is not just old
satellites and boosters which became more numerous with times. In the
early days, rockets were destroyed when not needed anymore, and these
explosions produced thousands and millions of pieces tumbling around Earth
at many different orbits. I heard at some time, that certain orbits are
already crowded today.
Finally, as was already mentioned by Wayne, there was the first 'satellite
victim' about a year ago. So far as I remember from the stroy written in
S&T, a piece of space debris hit a solar panel of a satellite. It did not
just destoy, but completely evaporate the panel...
Sirko
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