DSP IUS anomaly

Philip Chien (kc4yer@amsat.org)
Sun, 11 Apr 1999 20:42:46 -0400

The Air Force launched a DSP satellite on Friday on a Titan IV launch
vehicle.  It uses an Interial Upper Stage.

There was some anomaly and DSP is now in an incorrect orbit.  From the
sketchy information available (Air Force says satellite has separated from
IUS and that the first stage of the IUS burned nominally, only three
objects in orbit have been tracked from this launch) it appears that the
first stage of the IUS burned but for some reason the first and second
stage never separated.

                 Satellite Catalog Action Report

Designator   CatNo Common Name               Source LaunchDate
------------ ----- ------------------------- ------ ----------
1999-017A    25669 USA 142                   US     1999/04/09
1999-017B    25670 TITAN 4 R/B               US     1999/04/09
1999-017C    25671 IUS (1)                   US     1999/04/09

note that there are only three objects from this launch, the IUS (2) stage
is missing.

The elements for DSP and the IUS are unavailable from OIG.  But I would
suspect that an orbit of 400 x 19,000 n.m. with a 28.5 degree inclination
and injection point half a world away from the Cape would be roughly

I strongly doubt the DSP has enough propellant to raise itself to geo
altitude.  That was only possible with TDRS-A because of the excess
propellant onboard.

What's interesting to speculate about is the possibility of putting DSP in
to a compromise orbit.  If it can handle the radiation environment there
would be an additional higher resolution DSP available providing
supplementary coverage.

In any case expect small delays to Titan launches since the upcoming
launches don't use the IUS.  But almost certainly a delay to the STS-93
AXAF mission.

Philip Chien, KC4YER
Earth News
world (in)famous writer, science fiction fan, ham radio operator,
all-around nice guy, etc.