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USA 86/116 comments

Ted Molczan

Rainer Kracht issued the following elset:

from observations 1996 April 13.97 - 17.96

USA 86/116
1 23728U 92 83  A 96107.98244861  .00002318  00000-0  15640-3 0    05
2 23728  97.7471 220.8325 0425208  85.0128 275.7025 14.54440137    07

The mean motion seems to have stabilized over several days of obs, so I decided to do some preliminary analysis to try to gain some insights into this unusual orbit, and perhaps find a clue to the object's identity. What follows is highly speculative, given that the orbital elements have not completely settled down.

It is an interesting orbit. Its RAAN and argument of perigee are in very nearly the standard relation to 88099A, so I suspect it is USA 116, not USA 86. Normally, a KH-11 repeats its groundtrack almost exactly after 4 days (59 revs). This orbit repeats every two days (29 revs). I wonder whether or not this is a temporary orbit, to facilitate observing an area of special interest. Two such areas could be Lebanon and the Koreas. I do not have a convenient groundtrack program. Someone might want to run some plots, to see what areas this orbit overflies.

I have long believed that the KH-11s did not need to go into station-keeping orbits because the two satellite constellation was deployed in a manner that already ensured frequent groundtrack repetition, and also due to its excellent slant-range resolution, as evidenced by the images in the books Deep Black and America's Secret Eyes in Space. On the other hand, there may well be situations, such as unusually cloudy weather, that lead to a requirement for more frequent overflights of a specific area. (Mid-northern latitude areas suffer a significant winter cloudy season, as most mid-northern satellite observers can attest.)

The orbit is quite a bit off its normal sun-synch precession, yet it is almost exactly the standard RAAN separation from 88099A. Assuming it is USA 116, then it could not have been in the present orbit for very long, and yet remain so close to the standard RAAN into which it was launched late last year.

The main difference between the object's orbit and a standard KH-11 orbit is its perigee height, which is about 150 km higher than normal. By itself, this feature suggests USA 86 as the identity, because it would be an orbit that would greatly reduce drag, thus conserving orbital maintenance propellant, while maintaining a close to normal orbit. A similar adjustment was made to 84122A's orbit, about 8 months after 88099A had taken its place as the primary spacecraft in the "early" KH-11 orbital plane. The main difference from the object being tracked now was that the apogee had been permitted to decay to below 800 km.

Of course the perigee-raising may simply be the manoeuvre chosen to effect a temporary 2 day station- keeping orbit.

It will be interesting to see what develops after the orbit is known more precisely. Also, we need to see how it manoeuvres in orbit over many weeks or months.

next up previous
Next: USA 86/116 speculations Up: Tracking classified satellites Previous: USA 86/116 search

Bart de Pontieu
Fri May 24 11:30:41 MET DST 1996