RE: U.S. lifts veil on spy satellite launch
Ted Molczan (molczan@fox.nstn.ca)
Thu, 19 Dec 1996 18:22:45 -0500
John Pike posted the following:
> WASHINGTON (Reuter) - A supersecretive Pentagon arm
>Wednesday lifted the veil for the first time on the scheduled
>launch of a U.S. spy satellite in what it called a major step
>toward greater openness. But the payload and its mission remain
>classified.
Not for long, if some of us can help it!
> The launch period opens at 11:30 A.M. EST and extends until
>1:00 P.M. EST.
This equals 16:30 to 18:00 UTC on 20 Dec 96.
Interestingly, on 4 Dec, John Pike posted
information from "usually reliable sources" that
the period would run from 16:30 to 19:00 UTC,
for an 18 Dec 96 launch. I wonder why the period
now ends one hour earlier?
One possibility is that either John Pike's
or Reuter's information is incorrect.
Another possibility is that the period is
closing earlier because of the precession
of the desired orbital plane. But for a
LEO orbit, at say Lacrosse 2's inclination
of 68 deg, the launch window would move
earlier at only about 15 min/day, not
enough to justify shrinking the launch
period by 1 hour over 2 days.
I have been predicting for some time that
the payload is a KeyHole, destined for the
western Keyhole plane, which would require
a launch at about 18:00 UTC. My best estimate
is that the launch would occur no earlier
than about 18:07 +/- about 2 min. It would
not surprise me to see them launch quite
a few minutes later than that. That would place
the parking orbit a little bit west of the final
destination, but because the parking orbit
is somewhat lower than the final orbit, it
would drift gradually eastward. It would
not be long before the orbit reached the
desired plane, at which point it would be
altered to its final dimensions, stopping
the drift.
So a Keyhole launch would appear to be almost
ruled out by the launch period published by Reuters,
but comfortably within John Pike's 4 Dec launch
period, so we need to find out which one is
correct.
By coincidence, a Lacrosse launch into a plane
180 deg from Lacrosse 2 would have to liftoff at
about 18:07 UTC - same as for the Keyhole payload.
One way to distinguish between a Keyhole
and a Lacrosse launch is by the azimuth. A
Keyhole would head into azimuth approx 193 deg;
a Lacrosse, about 156 deg.
Ted Molczan