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Operational EORSATs

Cosmos 2326 is still operational. The screen snapshots below shows Mean Motion values from elsets.

You can see many cycles of decreasing MM, with intervals of about 12 days and amplitude of about 0.0015. This is very different from the normal operation of the KeyHoles and the Russian photo-reconnaissance spacecraft, that increase their MM by about a hundred times this amplitude by atmospheric drag over periods of nine days to many months, and then reclaim that by single (or double) rocket impulses.

The smooth decreases seem to indicate a continuous low-thrust orbit correction system - but there are lots of data points between and during these periods. They could indicate inaccurate orbital elements, or a correction system that is working by small impulses - not always exact. The integrated effect of these fluctuations would never place the satellite more than 150 km from the position of an ideal object, moving at a constant rate in in a perfect circle ! (I have not verified this estimate by looking at accurate predictions yet.)

Figure 3: Mean motion for Cosmos 2326 as a function of time

Cosmos 2313 is operational, in the same orbital plane as 2326 (and 2293).

Figure 4: Mean motion for Cosmos 2313 as a function of time

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