[Isocops] IBEX Orbit# 117 Star Tracker Post Burn Contact 23 Mar 11 @ 1455 UTC - Sun Angles look good.
Mark Tapley
mtapley at swri.edu
Wed Mar 23 15:00:06 EDT 2011
All,
OK, done. The angles come out much better than I expected.
According to ibex-rotate using the quaternions Sheral supplied, our
pointing now and at completion of the Descending macros
(2011/03:27:02:37:18 according to IBEX_2011_079_00_00_v003.txt) are
both safe. Sun angle now is 3.708 degrees, and at completion of
descending it will be 7.062 degrees, well within the 7.25 degree
limit we previously have been working to.
Double-checking with the unit vector (vs. the quaternion)
gives the same answer to 3 decimal places.
I think the next contact is not needed, since we should be at
safe sun angles through descending.
[tapley at ena ~]$ ibex_rotate -o -z
-0.39015700,0.58665600,-0.40660400,0.58162300 -w ibex-sun -t
2011-03-23T14:49:46.000Z
Quaternion -0.390157,+0.586656,-0.406604,+0.581623
points axis +0.000000,+0.000000,+1.000000
towards ECI +0.999704,-0.023225,+0.007224
which is R.A. +358.669 Decl. +0.414
missing R.A. +2.331 Decl. +0.994 (ibex-sun)
error is R.A. +356.338 Decl. +0.580
for a total 3.708 deg
[tapley at ena ~]$ ibex_rotate -o -z
-0.39015700,0.58665600,-0.40660400,0.58162300 -w ibex-sun -t
2011/03:27:02:37:18
Quaternion -0.390157,+0.586656,-0.406604,+0.581623
points axis +0.000000,+0.000000,+1.000000
towards ECI +0.999704,-0.023225,+0.007224
which is R.A. +358.669 Decl. +0.414
missing R.A. +5.468 Decl. +2.335 (ibex-sun)
error is R.A. +353.202 Decl. +1.921
for a total 7.062 deg
[tapley at ena ~]$ ibex_rotate -o -u 0.999704,-0.023225,0.007224 -w
ibex-sun -t 2011/03:27:02:37:18
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI +0.999704,-0.023225,+0.007224
which is R.A. +358.669 Decl. +0.414
missing R.A. +5.468 Decl. +2.335 (ibex-sun)
error is R.A. +353.202 Decl. +1.921
for a total 7.062 deg
At 13:29 -0500 3/23/11, Reno, Michelle wrote:
>Did you get confirmation from Mark that the contact is not needed?
>He needs to analyze the off-sun pointing at the time of payload
>DESCENDING to make sure we do not need to send up a new set of
>commands.
>
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Chelle Reno
>Austin Mission Consulting
>(210) 478-7337 (c)
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>From: isocops-bounces at lists.sr.unh.edu on behalf of Ibex Mission Operations
>Sent: Wed 3/23/2011 1:14 PM
>To: Bret Hautamaki; IBEX-FDG; IBEXOPS/ORB; ISOC at New Hampshire;
>John Cavallo; Tapley, Mark; Robert Lockwood; Roland Vanderspek; Ryan
>Tyler; Sheral Wesley; Thomas Regiec; Tim Perry; Walker Cross
>Subject: [Isocops] IBEX Orbit# 117 Star Tracker Post Burn Contact 23
>Mar 11 @ 1455 UTC
>
>Guys,
> The star tracker post burn contact was nominal for command/telemetry
>The static Z rate was set to 0.418 according to CAR# 377
>The full Goat Herder will be sent out tonight
>The contact scheduled for 24 Mar 11 @ 2030 UTC will be canceled
>
>--
>Sheral R. Wesley
>SPVR., Satellite Operations
>IBEX Mission OPS
>(304) 279-6678
--
- Mark 210-379-4635
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