Wednesday 14 September 2011

USA 161 new orbit finally established

The saga earlier covered here and here is finally coming to an end: it seems that the KH-12 keyhole USA 161 now no longer is escaping our detection.

The reboost on August 24 has provided our observer's and analysts corps with quite a challenge. After initial failures to recover it, the satellite was detected by several observers (including me) for a number of times in the early days of September. But in each case it was subsequently lost again and each new preliminary orbit solution put forward seemed to be wrong (see the two posts linked above in the introduction). Analysts were in despair, and observers confused.

Then Ted finally found a solution which seemed to agree with all observations and asked observers to search according to this search orbit early this week. Following this, Scott Tilley in the USA indeed recovered the object in a position much as predicted by Ted's solution, with Russell Eberst in Scotland following suit.

The now established orbit is quite different from the earlier search orbits. Instead of the perigee having  been raised, it turns out that it has been lowered, with the perigee 40 km lower and apogee 120 km lowered.

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