[Isocops] Fwd: Orbit 130 STF v002

[Mark Tapley]

IsoCops,
	OK, I fooled with pointing for this load. All estimates below 
assume we actually get what we ask for, which we now think won't be 
the case; however, the 0.8 degree deadband is still OK in all cases 
(Max. sun angle would be 7.511 degrees, but actually the deadband 
error will generally be perpendicular to the sun angle).

If we do the pointing vector I suggest for the repoint maneuver,

+0.0542216, +0.918386, +0.391954

We will be pointing in a safe direction between now (June 17) and the 
Descending macros for the first observing leg of

IBEX_2011_172_o0130a_v001.stf

[tapley at ena ~]$ ibex_rotate -o -u 0.0542216,0.918386,0.391954 -w 
ibex-sun -t 2011-06-17T10:36:00.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  +0.054222,+0.918386,+0.391954
  which is     R.A.  +86.621 Decl. +23.076
  missing      R.A.  +85.494 Decl. +23.344 (ibex-sun)
  error is     R.A.   +1.128 Decl.  +0.268
  for a total  1.070 deg
[tapley at ena ~]$ ibex_rotate -o -u 0.0542216,0.918386,0.391954 -w 
ibex-sun -t 2011-06-25T13:27:10.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  +0.054222,+0.918386,+0.391954
  which is     R.A.  +86.621 Decl. +23.076
  missing      R.A.  +93.918 Decl. +23.366 (ibex-sun)
  error is     R.A.   +7.297 Decl.  +0.290
  for a total  6.711 deg


If we do another repoint using the included pointing vector at 
apogee, we will point in a safe direction at the time of the 
maneuver, and at the succeeding ascending and descending passes

tapley at ena ~]$ ibex_rotate -o -u -0.030163,0.921876,0.386309 -w 
ibex-sun -t 2011-06-25T15:01:00.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.030163,+0.921876,+0.386309
  which is     R.A.  +91.874 Decl. +22.725
  missing      R.A.  +93.986 Decl. +23.364 (ibex-sun)
  error is     R.A.   +2.112 Decl.  +0.639
  for a total  2.046 deg
[tapley at ena ~]$ ibex_rotate -o -u -0.030163,0.921876,0.386309 -w 
ibex-sun -t 2011-06-25T16:46:04.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.030163,+0.921876,+0.386309
  which is     R.A.  +91.874 Decl. +22.725
  missing      R.A.  +94.063 Decl. +23.361 (ibex-sun)
  error is     R.A.   +2.189 Decl.  +0.636
  for a total  2.112 deg
[tapley at ena ~]$ ibex_rotate -o -u -0.030163,0.921876,0.386309 -w 
ibex-sun -t 2011-06-29T23:14:08.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.030163,+0.921876,+0.386309
  which is     R.A.  +91.874 Decl. +22.725
  missing      R.A.  +98.417 Decl. +23.196 (ibex-sun)
  error is     R.A.   +6.543 Decl.  +0.471
  for a total  6.042 deg

Finally, if we repoint using the final repointing vector for perigee, 
we will point in a safe direction at the time of the maneuver and up 
to the succeeding Apogee.

[tapley at ena ~]$ ibex_rotate -o -u -0.104294,0.9175090,0.383796 -w 
ibex-sun -t 2011-06-30T05:50:38.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.104294,+0.917509,+0.383796
  which is     R.A.  +96.485 Decl. +22.569
  missing      R.A.  +98.679 Decl. +23.192 (ibex-sun)
  error is     R.A.   +2.194 Decl.  +0.623
  for a total  2.115 deg
[tapley at ena ~]$ ibex_rotate -o -u -0.104294,0.9175090,0.383796 -w 
ibex-sun -t 2011-07-04T23:50:07.000Z
Quaternion    +0.000000,+0.000000,+0.000000,+0.000000
  points axis  +1.000000,+0.000000,+0.000000
  towards ECI  -0.104294,+0.917509,+0.383796
  which is     R.A.  +96.485 Decl. +22.569
  missing      R.A. +103.676 Decl. +22.815 (ibex-sun)
  error is     R.A.   +7.191 Decl.  +0.246
  for a total  6.639 deg




>Date: Thu, 16 Jun 2011 21:03:43 +0000 (UTC)
>From: fair-play at comcast.net
>Subject: Orbit 130 STF v002
>X-Originating-IP: [76.119.123.55]
>To: Chelle Reno <mreno at swri.edu>, Nathan Schwadron <nschwadron at mac.com>,
>         Sheral Wesley <wesley.sheral at orbital.com>,
>         Tim Perry <Perry.Tim at orbital.com>,
>         Roland Vanderspek <roland at space.mit.edu>,
>         Mark Tapley <mark.tapley at swri.org>
>Cc: Ken Fairchild <fair-play at comcast.net>
>
>All,
>
>I put the following file on the SFTP site:
>
>IBEX_2011_172_o0130a_v002.stf
>
>Ken


-- 
						- Mark     210-379-4635
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