[Isocops] [Isocdev] Fwd: High resolution (oxygen mode) test during lunarviewing

[Reno, Michelle]

Hey Mark,
 
The sunpointing vector will unfortunately not put us on the RepointingTargetVector in the OEF. That target vector is used only for the inertial repointing maneuvers done by the star trackers. The sun pointing maneuvers are done by the course sun sensor and do not accept target vectors - they just point at the sun when you send the ACS_SUN command and enable thrusters.
 
We will begin pointing at the sun (plus slop for ACS deadband) at 
 
06/26/10 20:50:36 Maneuver Start time
 
Please re-verify our pointing at the DESC commands using this info.
 
Thanks,
Chelle
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chelle Reno
Austin Mission Consulting
106 E. 6th St. Ste. 939
Austin, TX  78701
(512) 704-3394 (o)
(210) 478-7337 (c)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

________________________________

From: isocdev-bounces at lists.sr.unh.edu on behalf of Mark Tapley
Sent: Wed 6/9/2010 2:34 PM
To: Nathan Schwadron
Cc: isocops at lists.sr.unh.edu; isocdev at lists.sr.unh.edu
Subject: Re: [Isocdev] Fwd: High resolution (oxygen mode) test during lunarviewing



Nathan,
        Sorry, just dug back to this message now. Looks like Greg
responded with syntax, timing, etc.

        The sun-pointing maneuver is between 10 and 15 Re, not 3 Re.

        If the sun-pointing maneuver puts us directly on the pointing
vector given in the .oef,

2010-06-27T10:53:04.828Z,RepointingTargetVector,vtsX:-0.09713517962079862,orbit:83,vtsZ:0.3961860371665777,vtsY:0.9130177330338543


        then ibex_rotate shows sun angles as follows:

2010-07-01T14:00:00.000Z        +4.000
2010-07-01T24:00:00.000Z        +4.395
2010-07-03T15:00:00.000Z        +5.916

        No problem, even if we add in a 1 degree deadband error.
        If the sun-pointing maneuver points us directly at the sun,
then ibex_rotate shows:

2010-07-01T14:00:00.000Z        4.575 deg
2010-07-01T24:00:00.000Z        4.970 deg
2010-07-03T15:00:00.000Z        6.491 deg

        Still OK, but worst-case 1 degree deadband is now dicey
(total 7.491 degrees from sun). But considering this is worst-case, I
think we are OK.



>Hey Mark
>
>It looks like you are digging into the IBEX ops and starting to
>understand our chaos. Well done!
>
>Could you please verify the stuff below (Manuever times and sun
>pointing at the end of the message).
>
>Also, I need to find out if the syntax is correct for the message I
>sent to Greg ..
>

--
                                                - Mark     210-379-4635
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