next up previous
Next: USA 86/116 comments Up: Tracking classified satellites Previous: May 12 Titan

USA 86/116 search and identification.

After Rainer Kracht's re-discovery of KH 11-8, I searched for USA 86/USA 116.

KH 11-8
1 19625U 88 99  A 96100.00000000  .00004977  00000-0  56091-4 0    08
2 19625  97.9452 163.0822 0536195 346.5294 214.0067 14.74317898    07
88-99A has been calculated by Pierre Neirinck
1 19625U 88 99 A  96101.1156201   .00006553  00000-0  72091-4 0    00
2 19625  97.9310 164.1532 0539919 343.4394 014.6661 14.74337435    00
USA 116 search  15.0  3.0  0.0  4.6
1 23727U 95 65  A 95236.04494499  .00000200  00000-0  20565-5 0    00
2 23727  97.9150 349.1432 0536000 145.4015 214.5983 14.75389450    00

My USA 116 search orbit is based on the fact (?) that it was launched when USA 86 orbit was over Vandenberg, and its perigee at about lat.10N ! So, if it is an operational replacement, chances are it follows the pattern detected by Pierre Neirinck:

Soon after an apogee raise by KH 11-8 (to MM=3D14.75) USA 86 trailed KH 11-8 by 165 minutes. Then, USA 86 was raised to MM=3D14.76, so that it started catching up on KH 11-8. When the separation dropped to 115 minutes, USA 86 was raised (decreased its MM by 0.02) to start reclaiming the 165 minute gap. Next time KH 11-8 MM is decreased by 0.02. This cycle takes about 3 months, and is followed by a 0.02 increase etc ...., until it is time for another major reboost.

The observation on 4/4 by Rainer Kracht agrees with a major reboost at about 8 am UT, since it was about 5 minutes early w.r.t. the new elsets. I found nothing else within +- 5 minutes to explain this observation.

I observed an object that seemed to match the expected appearance, track and time of USA 86 or USA 116. I measured two positions, RA 20.66 decl+43.7 at 21:57:31.8 UT and RA 21.53 decl.+46.05 at 21:57:54.3 UT (2000.0) The first declination may be mis-identified by 0.5 degrees. As a check I also clocked the culmination speed between Lyra and Cygnus : 1.73 seconds / degree. I reported this orbit to match the track:

USA 116 obs?
1 23728U 95 66  A 96101.83503417  .00006400  00000-0  70000-4 0    00
2 23728  97.9000 214.0000 0540000 118.0000 247.6927 14.75300000    00

I missed the second pass because of too many clouds in the wrong place. The track is approximately at 415 km altitude, 64 degrees N and 29 degrees E. Later analysis shows the angular speed of culmination to be only 1.94 seconds/degree, and a track to match my obs., but as close to these elsets as possible, would have to be around 375 km, at 27.5 degrees E.

If this were to be the object later determined to be in the "23728" orbits below, and moved between Apr.10.9 and Apr.13.8 from MM=14.73 into that orbit by a single in-plane Hohmann apogee kick, it would have passed near the estimated place observed. This assumes that the orbit was "synchronized" with KH 11-8 at the time.

23728 passed about 61 minutes earlier. This is about 0.62 revolutions. The MM decrease required to move in position for an orbit change within about 3 days is 0.20, so MM must have been at least 14.74. Such an orbit would also need a few degrees lower RAAN, and/or a larger inclination than the 23728 orbit. A close approximation is given below. It is a fairly typical KH 11 orbit, but its RAAN is about 5 degrees lower than I would expect from USA 86, if still in orbit.

USA 116 -18
1 23728U 95 66  A 96103.46300000  .00000235  00000-0  15727-4 0   184
2 23728  97.9000 213.8000 0540000  98.4493 270.9000 14.76077690   189

This orbit would come close to the apogee of 23728 below, on Apr.13 20:53, where a correction of 38 m/s along-track would bring it into this higher orbit. However, the cross-track correction to change incl/RAAN would be several hundred m/s !? My Elcor "solutions" do not appear correct, so I will have to modify this conclusion.

Singular observation Apr.10: (In pelcor.exe format)

23728 Apr.10
1996 APR 10 2157:31.79 59.2237  18.2286   44 20.660   43.70 1.0
23728 Apr.10
1996 APR 10 2157:54.29 59.2237  18.2286   44 21.530   46.05 1.0

Some preliminary results are:

1. It is possible for my first Apr.10 observation to be of an object in a typical KH 11 orbit.

2. An orbit, with the same apogee height as the 23728 orbit, and reaching its apogee on Apr.13 at 20:53 UT - which is when 23728 reached its apogee - is also possible.

3. However, an orbit matching my observation is about 4 degrees west of the 23728 orbit, which would need a very large cross- track impulse to obtain.

4. An orbit matching my observation is also about 4 degrees west of the estimated 22251 orbit, if it wasn't maneuvred more than KH 11-8 during our winter.

5. My current speculation is that USA 86 is the object now tracked. The object observed on Apr.10 was USA 116, at 400 km altitude 29 E, 64 N at 21:58 UT.

All other observations I have made/heard of match the following orbits :

USA 116?
1 23728U 95 66  A 96123.00000000  .00000235  00000-0  15727-4 0    08
2 23728  97.7808 234.8982 0426478  37.5018  67.9382 14.54448452    00
USA 116?
1 23728U 95 66  A 96118.02730750  .00000605  00000-0  00000-0 0    01
2 23728  97.7228 230.0957 0435638  53.8374 310.1157 14.54447880    07



next up previous
Next: USA 86/116 comments Up: Tracking classified satellites Previous: May 12 Titan



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