Re: How many satellites are in geosynchronous orbit by now?

In message <Ir58H4.JKJ@xxxxxxxxxxxxx>, Henry Spencer <henry@xxxxxxxxxxxxx> writes 
(Stuffie is normally in my killfile, but every now and then it's worth
a brief rebuttal anyway...)


A simple way to invalidate the original statement at issue is to
consider all of the objects that have been radar tracked at distances
far greater than GSO.


This stops looking so simple when you consider the resources that are
needed to track them.  There have been a *few* quite impressive feats of
spacecraft tracking, notably when it was possible to use Arecibo and
Goldstone in combination.  Those facilities are not available for routine
spacecraft tracking, or even mildly unusual spacecraft tracking, and
Arecibo in particular can point at only quite limited areas of the sky.

Note that when Contour was silent after its departure burn, its pieces
were found optically, not by radar.

As it happens, this is a subject I've been professionally involved in, in
a small way.  Optical tracking is the method of choice for high-altitude
objects, because radar works poorly at such distances and the resources
needed to make it work halfway well are not routinely available for
spacecraft tracking.

OTOH, the SOHO spacecraft was found by radar when it was "lost" in 1998 <http://science.nasa.gov/newhome/headlines/ast28jul98_1.htm>
I'm not sure how bright an object that size would be at the L1 position, quite apart from the fact that it's always in daylight! But that was anything but routine, of course.
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