Superbird A flashes

Rob Matson (
27 Sep 1996 12:41:12 -0800

                      Subject:                              Time:  11:44
  OFFICE MEMO         Superbird A flashes                   Date:  96/09/27

Aaron Brown wrote:

> Keep in mind that the earth is turning.  The earth's shadow may
> have been toward the moon at 0315 UT.  A geosynchronous satellite
> "turns with the earth" in some sense.  It may move into the earth's
> shadow even if it is nowhere near it in the sky a few hours before.

True.  However, Robert was indicating that Superbird A was going into shadow
shortly after the time the flashes were visible -- indeed, that the reason the
flashes were no longer visible was due to shadow entry.  But this is not the
case.  The flashes are only visible for a short time because the specular
geometry is changing.  The earth subtends less than 20 degrees from geosynch,
so the satellite would have to be less than 10 degrees from the moon (during
the eclipse) to go into shadow.  This doesn't happen until early in the
morning; the flashes were in the evening around 8pm local...  --Rob