[Isocops] Revised .STF for earlier Descending macros this orbit

[Mark Tapley]

All,
	I have posted to the SFTP site (datainfo.orbital-lsg.com) the 
following file:

/IBEX/moc/Soc-Moc/stf/IBEX_2010_177_17_44_v006.stf

A plain-text version of the same file is attached (with an .stf extension)

Changes from v004:
Many comments, explaining that we moved DESCENDING macros earlier to 
avoid a 7.6 degree sun off-pointing condition.

The last 6 actual commands each had 7 hours subtracted from their 
execute times, so that they now span 07:48 to 08:11 on July 3. This 
produces a sun-point angle of < 7.4 degrees (7.380 degrees) according 
to ibex_rotate at the conclusion of the DESCENDING macros.


Version v005 (also on the SFTP site) contains all commands, 
un-commented-out. That file is for reference only; use only version 
v006 to create the new DESCENDING macros!


At 11:33 -0400 6/29/10, Roland Vanderspek wrote:
>It'd be interesting to know what happened, why the original 
>descending commands were off.  Any ideas?

The original set of commands assumed that the sun-point would be 
accurate to within 1 degree. As described in the comments, the 
quaternion sent out in the goat herder indicates that that was not 
achieved - the actual angle was more like 1.433 degrees. The effect 
was that the sun-point angle at the end of the orbit was 7.647 
degrees, which turns out to be too close for comfort to the design 
margin.

It might be interesting to go back and check previous sun-pointing 
maneuvers to see whether they also came up 1.4 or so degrees short, 
rather than 1.0 degrees.

Thanks to Chelle for kicking me off to go double-check the orbit-end pointing!
-- 
						- Mark     210-379-4635
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Large Asteroids headed toward planets
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