[Isocops] Fwd: STF for Orbits 0129-30

fair-play at comcast.net fair-play at comcast.net
Thu Jun 16 12:36:22 EDT 2011


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.edu 
Sent: Thursday, June 16, 2011 12:17:03 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 Decl. +22.680 
missing 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 
towards ECI +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 pointing vector and distribute to the 
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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