Wednesday, May 21, 2014

USA 224 recovered, USA 186 still drifting, and looking for GPS IIF-6 20 minutes after launch

For various reasons, I am a bit late in keeping the reader up to what is happening to the KH-11 Keyhole/CRYSTAL system of optical reconnaissance satellites.

USA 186 (2005-042A), the secondary West plane KH-11, is still in a non sun-synchronous orbit and hence still drifting westwards. It is drifting for over half a year now. The difference in RAAN with USA 245, the primary West plane KH-11, is now over 20 degrees (21.8 degrees on May 19th). I am very curious as to when the drifting will stop, if ever. If it continues to drift for many weeks to come, we should contemplate whether perhaps the satellite is "dead", i.e. has lost manoeuverability. Problem is that NW European observers temporarily have lost visibility of the satellite, due to the current short nights. Tracking all comes down now to observers in the US and southern Europe.

Meanwhile, Russell Eberst in Scotland recovered USA 224 (2011-002A), the primary East plane KH-11, on May 9th. It is in a 260 x 1006 km orbit, which means it has slightly lowered its apogee. Before the winter blackout it was in a 258 x 1023 km orbit. The difference in RAAN with USA 245, the primary West plane KH-11, is now 48.5 degrees.

My own first observation of USA 224 was in the night of May 16-17. The image below shows it crossing through Corona borealis:

click image to enlarge

USA 161 (2001-044A), the secondary East plane KH-11, has still not emerged out of the winter blackout. Meanwhile, USA 129 (1996-072A) has gone missing since April 24 (see a previous post). There is a good chance it has been de-orbitted.

The current KH-11 constellation now looks like this (where the current orbital configuration of USA 161, in red, is uncertain, and USA 129 left out as it is no longer in its old orbit, and presumed de-orbitted):

click images to enlarge

In the early morning of May 17 (evening of May 16 in the US) and after a one day delay due to bad weather, a new GPS satellite, GPS II-F6 was launched from Cape Canaveral on a Delta IV rocket. It would pass over the Netherlands some 20 minutes after launch, still ascending and still attached to the 2nd stage. A number of search orbit had been published, but it looks like none of these was very accurate. I visually observed a bright UNID near 00:24:00 UT (May 17) moving just a few degrees to the 'right' of Altair on a trajectory parallel to the predicted ones but some 20 degrees cross-track in a southern direction. It was already descending over the roof when I picked it up, so I had no time to snap a picture alas. It did not match any known object so I am quite confident it was GPS II F-6 on its way to orbit. It was bright, about mag +1 to 0.

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