[Isocops] [Ibex-soc] IBEX Orbit# 87 ATS (27 July - 4 Aug 10)

[Mark Tapley]

At 11:46 -0400 7/15/10, Ibex Mission Operations wrote:
>Please review the ATS for Orbit# 87
>I have included the battery balancing commands
>
>Approval/comments for the ATS are needed by COB Friday, 16 July 10
>The ATS will be uploaded during one of the Orbit# 85  perigee 
>contacts listed below in UTC
>IBEX,USAK01,ADD,07/19/10,200,11:00:00,07/19/10,200,12:10:00,,LAHO 
>160K IBEX Orbit# 85 SSR_Dump/Tracking
>IBEX,USHI01,ADD,07/20/10,201,07:30:00,07/20/10,201,08:05:00,,LAHO 2K 
>IBEX Orbit# 85 Tracking Contact


Sheral,
	looked over the attached files. One interesting thing caught 
my eye. The  short .oef file, IBEX_2010_Orbit87_v001.oef, says:

2010-07-27T02:00:00.000Z,StarTrackerOutageStart,orbit:86,dueTo:overlap
2010-07-27T07:16:33.245Z,Perigee,orbit:86
2010-07-27T07:31:48.185Z,StarTrackerOutageStart,orbit:86,dueTo:moon
2010-07-27T07:41:44.932Z,StarTrackerOutageStop,orbit:86,dueTo:overlap
2010-07-27T10:39:28.379Z,StarTrackerOutageStop,orbit:86,dueTo:moon


but the Forecast .oef file, IBEX_2010_Forecast_15July10-23Oct10_v001.oef, says:

2010-07-26T02:25:23.395Z,StarTrackerOutageStart,orbit:86,dueTo:overlap
2010-07-26T21:40:10.652Z,15RECrossing,direction:desc,orbit:86
2010-07-27T01:39:55.832Z,10RECrossing,direction:desc,orbit:86,oMode:0
2010-07-27T07:16:33.245Z,Perigee,orbit:86
2010-07-27T07:35:19.913Z,StarTrackerOutageStop,orbit:86,dueTo:overlap

With the short file claiming the outage lasts a lot longer, up to 
10:39:28. This is interesting because according to the o0086 ATF, the 
repointing maneuver starts in between the two times (but not much, 
almost to the end of even the later prediction):

   @ACT_SetThrustEnable ENABLE $TIME=2010/07:27:10:38:22
   @ACT_SetThrustEnable DISABLE $TIME=2010/07:27:10:53:22

******

How are the star tracker outage times calculated differently between 
the two files?

******

Ken reports that the instrument commands match the STF, good.

Ascending and Descending commands match up with 15 Re times, good.

Ground contact times match the transmitter on times, good.

According to ibex_rotate, sun angles at the time of the inertial 
maneuver, at the next Ascending 15 Re crossing, and at the next 
descending 15 Re crossing are all good (1.01, 0.435, and 6.228 
degrees respectively):

[tapley at ena ~]$ ibex_rotate -o -u 
-0.6709580708861025,0.6801661773297624,0.2952782388348625 -w ibex-sun 
-t 2010/08:03:17:20:27
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.670958,+0.680166,+0.295278
  which is     R.A. +134.610 Decl. +17.174
  missing      R.A. +133.593 Decl. +17.418 (ibex-sun)
  error is     R.A.   +1.017 Decl.  +0.244
  for a total  1.001 deg
[tapley at ena ~]$ ibex_rotate -o -u 
-0.6709580708861025,0.6801661773297624,0.2952782388348625 -w ibex-sun 
-t 2010-08-04T08:22:39.899Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.670958,+0.680166,+0.295278
  which is     R.A. +134.610 Decl. +17.174
  missing      R.A. +134.172 Decl. +17.292 (ibex-sun)
  error is     R.A.   +0.438 Decl.  +0.118
  for a total  0.435 deg
[tapley at ena ~]$ ibex_rotate -o -u 
-0.6709580708861025,0.6801661773297624,0.2952782388348625 -w ibex-sun 
-t 2010-08-11T06:12:31.549Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.670958,+0.680166,+0.295278
  which is     R.A. +134.610 Decl. +17.174
  missing      R.A. +140.798 Decl. +15.307 (ibex-sun)
  error is     R.A.   +6.189 Decl.  +1.867
  for a total  6.228 deg
[tapley at ena ~]$


Pending being convinced that star tracker outage times are OK, I'll approve.
-- 
						- Mark     210-379-4635
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