[Ibex-maneuver-engineering] [Isocops] Fwd: STF for Orbits 0129-30
Mark Tapley
mtapley at swri.edu
Thu Jun 16 13:49:32 EDT 2011
Got it. Talked to Nathan about that, and I think I understand. When
antennas are available might play into it as well. Anyway, when we
get the final ATS, I'm hoping we have less than 23 hours off at
apogee.
At 16:36 +0000 6/16/11, fair-play at comcast.net wrote:
>Mark,
>
>The reason for the long period out of science mode at apogee in
>orbit 130 is because we normally use the OEF to determine the actual
>maneuver time and, based on that, determine when we can transition
>back to HV. There was no usable forecast OEF available for these
>orbits so we transition at the end of the window. We could manually
>adjust the times if necessary (or go through the forecast
>STF/forecast OEF generation process).
>
>Ken
>
>----- Original Message -----
>From: "Mark Tapley" <mtapley at swri.edu>
>To: "IBEX Operator" <ibexops at lists.sr.unh.edu>,
>isocops at lists.sr.unh.edu, IBEXOPS at gmail.com, "wesley sheral"
><wesley.sheral at orbital.com>, "perry tim" <perry.tim at orbital.com>,
>ibexops at orbital.com
>Cc: ibex-maneuver-engineering at lists.sr.unh.eduSent: 2:17:03 PM
>Subject: [Isocops] Fwd: STF for Orbits 0129-30
>
>All,
> Ken's edited .stf files for Orbits 129 and 130,
>IBEX_2011_163_o0129a_v001.stf and IBEX_2011_172_o0130a_v001.stf for
>have appeared.
> Orbit 129's pointing vector,
>
>0.042788,0.92168,0.385584
>
> is appropriate and safe for any time from now (June 16, 1423
>UTC) until sometime after the Descending macros prior to the Orbit
>130 apogee maneuver at 2011-06-25T14:01:00.000Z.
>
>
>[tapley at ena ~]$ ibex_rotate -o -u 0.042788,0.92168,0.385584 -w
>ibex-sun -t 2011-06-16T14:23:08.000Z
>Quaternion +0.000000,+0.000000,+0.000000,+0.000000
> points axis +1.000000,+0.000000,+0.000000
> towards ECI +0.042788,+0.921680,+0.385584
> which is R.A. +87.342 Dec l. +22.6 R.A. +84.613 Decl.
>+23.322 (ibex-sun)
> error is R.A. +2.729 Decl. +0.642
> for a total 2.593 deg
>[tapley at ena ~]$ ibex_rotate -o -u 0.042788,0.92168,0.385584 -w
>ibex-sun -t 2011-06-22T02:33:09.000Z
>Quaternion +0.000000,+0.000000,+0.000000,+0.000000
> points axis +1.000000,+0.000000,+0.000000
> towards ECI +0.042788,+0.921680,+0.385584
> which is R.A. +87.342 Decl. +22.680
> missing R.A. +90.219 Decl. +23.450 (ibex-sun)
> error is R.A. +2.877 Decl. +0.770
> for a total 2.757 deg
>[tapley at ena ~]$ ibex_rotate -o -u 0.042788,0.92168,0.385584 -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< I
> +0.042788,+0.921680,+0.385584
> which is R.A. +87.342 Decl. +22.680
> missing R.A. +93.918 Decl. +23.366 (ibex-sun)
> error is R.A. +6.576 Decl. +0.686
> for a total 6.090 deg
>
> In each case, Sun is appx. 0.7 deg north of the target
>vector, so the resulting actually achieved vector for a normal weekly
>repoint would be on the ecliptic. However, for the first maneuver
>after the Delta-V, if we are coming from our Delta-V pointing vector
>at ~RA 59, Dec 43, we need to think about a different offset unless
>we want to do a two-part slew, going first to ~RA 80, Dec 22.6 first
>and then to the target vector, RA 87, Dec 22.6 .
>
> To preserve the procedure intact (after talking with Chelle)
>I'll generate a new offset poi nting ve e
>ibex-maneuver-engineering at lists.sr.unh.edu list for confirmation.
>
> Ascent and descent macro times in 130a make sense wrt 15 Re
>times as given in PreADV2_MAC_Slides.pdf. However I note we are out
>of HV for 23 hours around apogee, which seems long.
>
> Moon-in-FOV setback commands appear in the STF; I have not
>checked lunar predictions from .oef.
>
> I think the ATS needs an updated target vector (see above).
>
>--
> - Mark 210-379-4635
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