Thu, 07 Dec 95 09:33:00 -0600

Lutz Schindler inquired:

LS>is there anybody out there, who can tell me something
LS>about the Japanese EGP satellite ?

LS>What is the job of this sat and was is the reason for
LS>the very fast flash effect.

EGP is an "Experimental Geodetic Payload."  It was the first
satellite launched by Japan's new H-1 launch vehicle back in 1986.  It
is a passive retroreflector target, i.e. it doesn't do anything but
reflect laser beams shot at it for geodetic measurements. To accomplish
that mission it is a very heavy satellite placed in a very high orbit
(900+ miles) so that its drag coefficient is infinitessimal and it is
very precisely predictable.  Then the big secret of its flashes is that
it's a big mirror ball about 3 meters in diameter.  It's a sphere
covered with mirrors that flash as it rotates in the sunlight. That
makes it one of the most fun satellites to watch, as far as I'm