[Isocops] Upcoming Star Tracker Outages

[Reno, Michelle]

Hello,
 
We have entered the season of long star tracker outages. These orbits require substantial despinning. 
Summary of Star Tracker Outages through o115 is below.  

 

These predictions are conservative - they use the 100% valid mark as the start/stop threshold. The ACS system produces valid quaternions using the measured data down to 22% valid, a combination of measurements and a static rate measured after the re-pointing maneuver until 18% valid, and the static rate below 18% valid.

 

For example - using the 100% valid mark places all of orbit 109 in an outage. Using the 25% valid mark shows a period of 3 days in the middle of the orbit that are not in an outage. %valid report through orbit 115 is attached. 

 

Orbit 109 & 113 have outages at perigee. For these orbits we will perform sun-pointing maneuvers, which will result in slightly non-standard pointing for orbits 110 & 114.

 

Orbit

Earth/

Start Time
(100% valid)

End Time
(100% valid)

Approx.
Dur

Start Alt

End Alt

Moon

(Re)

(Re)

105

M

12/15/10 04:49:50

12/18/10 20:40:14

3d 16h

46a

10d

106

M

12/19/10 19:53:46

12/21/10 07:47:21

1d 22h

22a

41a

108

E

01/03/10 19:41:15

01/04/10 13:43:27

18h

14a

29a

109

E/M

01/11/10 16:19:47

-

8d 21h

11a

-

110

-

01/20/10 13:25:25

-

36a

111

E

01/26/10 17:00:00

01/30/10 14:46:21

3d 22h

12a

46d

112

E

02/03/11 04:38:43

02/07/11 23:30:12

4d 12h

14a

43d

113

E/M

02/11/11 01:44:05

-

13d

18a

-

114

-

02/24/11 01:27:51

-

39d

115

E

02/27/11 02:18:09

03/04/11 16:23:11

5d 14h

29a

27d

 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chelle Reno
Austin Mission Consulting
(210) 478-7337 (c)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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