[Isocops] Orbit 109/110 Sun Precession maneuver

Reno, Michelle mreno at swri.edu
Thu Jan 6 17:37:56 EST 2011

Hey folks,
I put together a detailed timeline for the upcoming sun precession maneuver. It includes a chart of when the star tracker outages occur wrt other things of interest (apogee, perigee, Lo entering O-mode, etc). Please note that there is only a line item per event of interest, so time duration is not visually represented. 
The special activities that need to be performed during/directly after the passes are included (Mark, Tim, Sheral these are for you). Hopefully we can use the HAW02 calibration pass to determine if we need to send the DESCENDING commands earlier. That will give us time to generate the new STF/ATS prior to the apogee pass (being rescheduled, updates on exact time will be sent out later).
Bonus: looks like there is a day in orbit 109 where we will not be in an outage.
Let me know if this is useful. I can produce something similar for the orbit 113/114 maneuver.
% valid FYI
Included are the start/stop of the outage per the 100, 75, 50 & 25% marks assessed by FDG. For planning we use 100% valid as the 'official' start/stop of the outage, 90% needed to set the static-Z rate after a sun precession maneuver, 50% needed to perform an inertial precession maneuver. 
On-orbit the Attitude Control System changes it's method of calculating the spin pulse by the % valid (configurable in each ATS): 
* 100- 85% quaternions only. 
* 85-18% quaternions + static-Z rate (a measured constant - the spin rate taken 15min after thrusters disabled each orbit)
* 18 - 0 - 23% static Z-rate only
* 23- 90% quaternions + static-Z rate 
* > 90% quaternions only
Chelle Reno
Austin Mission Consulting
(210) 478-7337 (c)
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