Five year old unknown observation identified?

Ted Molczan (molczan@fox.nstn.ca)
Tue, 14 May 1996 23:26:52 -0400

I believe that I may have identified two Dec 1990 observations by
Russell Eberst as the rocket body from the classified satellite,
USA 40.

USA 40 was deployed into a 300 km, 57 deg orbit by STS 28, in=20
Aug 1989. I discovered it about 10 days after deployment, in a=20
454 km, 57 deg orbit. It remained in this orbit until mid Nov 1989,
when it apparently manoeuvred and disappeared. A few weeks later,
NORAD catalogued 89061D, the rocket body used to make the initial
manoeuvre to what is widely believed to be a Molniya orbit.

On 11 Dec 1990, Russell made two observations of an unknown flashing
object (10 s flash period) during a single pass. He suggested that I =
investigate, because he suspected it was in a near 57 deg orbit.=20
Naturally, we wondered whether or not the unknown was connected with=20
the USA 40 mission. I fit a circular orbit to the observations, which =
yielded a near 57 deg, 450 km orbit. The fit was not very good, and=20
there was reason to suspect that the orbit was fairly eccentric. If the =
object was related to USA 40, and assuming its RAAN had completed one=20
"lap" around the Earth, its apogee had to be at least 6,400 km. Knowing
that the object would be difficult to recover, I did not pursue it
further.

Several months ago, I came across Jonathan McDowell's listing of
classified U.S. orbital debris data submitted to the U.N. I was=20
surprised to see a long list of fragments from what had to have been=20
USA 40's rocket. All of the pieces were in 57 deg orbits, typically
532 km x 8135 km. I reasoned that this information could help identify
Russell's unknown, or at least determine whether or not it could
have come from that mission.

I carried out my analysis with the aid of Paul Hirose's ELCOR, orbit
improvement program. Russell's data is presented below in Elcor orbit.
His 1950 epoch coordinates have been precessed to 2000.0 as required
by Elcor.

Obs 1
1990 dec 11 1659:48.88 55.9486 -3.1386 43 2.65182 49.39690 1
Obs 2
1990 dec 11 1700:43.42 55.9486 -3.1386 43 3.63117 28.77976 1

I restricted the correction to the eccentricity, argument of perigee,=20
RAAN, and the mean anomaly. I forced a 57 deg inclination and mean=20
motion of 7.83135, consistent with the U.N. listing. The starting=20
eccentricity of 0.3549 was also based on the U.N. data. The result was:

USA 40 r ?       2.0  0.0  0.0  6.9
1 20344U 89061  D 90345.70820463  .00000000  00000-0  00000-0 0    01
2 20344  57.0000 244.7429 3574038 106.3696 353.6502  7.83135000    01

Further analysis was carried out to determine the relationship between
the unknown object's orbit, and USA 40's last known orbit:

USA 40          10.0  3.0  0.0  5.0
1 20167U 89061  B 89317.24535400  .00016407  00000-0  39372-3 0    09
2 20167  57.0247 349.9838 0074022  66.2735 294.5013 15.37995556    00

To determine whether or not the object could be related to USA 40, I=20
found the earliest date after USA 40 disappeared that the two objects=20
were co-planar. The last reported obs of USA 40 was by Curtis Haase, at=20
day 89319.48. Russell's unknown was coplanar with USA 40's orbit at day
89319.83, only hours after Curtis' observation, when both objects
would have had a RAAN of 338.95 deg. A few days later, we discovered
that USA 40 was missing.

Also, I precessed the unknown's argument of perigee back to 89319.83,
and found that it would have been about 265 deg. That is a very=20
reasonable value for a Molniya payload, especially an SDS (Satellite
Data System), which is widely believed to be USA 40's identity. SDS
relays KH-11 data over the north pole to western-based ground-stations.

A few days before it disappeared, USA 40 was detected to have made
a manoeuvre, which increased its eccentricity, resulting in an
approximately 402 km x 503 km orbit, with the argument of perigee
at about 66 deg. At day 89319.83 it would have been at about
71 deg, which means the apogee would have been at about 251 deg.
Elcor determined that the unknown was in a 505 km x 8161 km orbit.
Both objects' argument of perigee and eccentricity, suggest that=20
USA 40's rocket was fired at its apogee, which became its rocket's=20
perigee.

The unknown's near-perigee region will be in morning visibility
in October 1996, and in evening in December 1996. Recovering it
would be difficult, but I believe it is possible.

bye for now