[Isocops] [Isocdev] Orbit 82 STF questions

[Nathan Schwadron]

Note that isocops is the right list to use here .. 

On Jun 8, 2010, at 7:05 PM, Mark Tapley wrote:

> All,
> 	OK, finally got time to look carefully over the Orbit 82 STF 
> and .oef files, and I have a couple of questions. I'm looking at:
> 
> /home/gbc/IBEX/work/ops/hvscistf/IBEX_2010_170_05_02_v001.stf
> 

That one is right .. 

> and
> 
> /home/gbc/IBEX/work/ops/hvscistf/IBEX_orbit_events.oef
> 

I believe that is right .. Roland/Geoff?


> 1) Are these the correct files to look at?
> 
> 
> 	In the .stf file, I see:
> 
> ## 2010-06-20T12:12:48Z MOON+6.5-Entry(+6.499998)          78.88277954 (RE)
> ## 2010-06-21T09:28:14Z MOON+0-Center(-0.000019)           82.78838326 (RE)
> ## 2010-06-22T03:49:45Z MOON+6.5-Exit(+6.499976)           82.55686787 (RE)
> 

I don't know what that is. Goeff?

> 2) What do those lines signify?
> 
> 
> 	In the .oef file, I see:
> 
> 2010-06-25T21:13:26.190Z,StarTrackerOutageStart,orbit:82,dueTo:overlap
> ...
> 2010-06-27T10:53:04.828Z,RepointingTargetVector,vtsX:-0.09713517962079862,orbit:83,vtsZ:0.3961860371665777,vtsY:0.9130177330338543
> 2010-06-28T05:16:46.190Z,StarTrackerOutageStop,orbit:83,dueTo:overlap
> 
> 	I think this implies a Repointing maneuver during a star 
> tracker outage, and is in fact a symptom of the o83 Sun-Pointing 
> problem we have been looking forward to.
> 
> 3) Is this correct?
> 
> 

Yes, that seems correct to me. 

> 
> 	In the .stf, I see:
> 
> 2010-06-20T12:12:48.000Z||CEU_LO_PMT_LVL       300
> 2010-06-20T12:12:50.000Z||CEU_LO_IF_STAR_ADJ     0
> #010-06-21T09:28:14.000Z centered; range 78.9 (Re)
> 2010-06-22T03:49:43.000Z||CEU_LO_IF_STAR_ADJ   250
> 2010-06-22T03:49:45.000Z||CEU_LO_PMT_LVL       800
> 
> 	But the .oef says:
> 
> 2010-06-20T06:32:23.102Z,MoonInLoFovStart,orbit:82
> 2010-06-22T07:42:40.626Z,MoonInLoFovStop,orbit:82
> 
> 	I'm curious why the times don't correspond exactly. It looks 
> like the PMT level goes down some 6 hours after the moon blanks it, 
> and comes back up 4 hours before it can work.
> 
> 4) Is this correct?
> 
> 
> 	When I put the vector from the repointing maneuver on 
> 2010-06-18T18:20:08.616Z (per the .oef, this vector is: 
> (0.031071571318898306,0.916920484258135,0.3978584962063797) ) into 
> ibex-rotate, it gives the following sun angles on the following dates:
> 
> 2010-06-19T05:01:18.121Z	+0.529
> 2010-06-26T06:31:05.880Z	+6.231
> 
> implying we are at good sun pointings at the beginning and end of the 
> orbit, so I should not worry about that (even with a 1 degree margin 
> for error).
> 
> 5) Did I do that correctly?
> 
> 
> 
> 	Pending resolution of these questions, I'll approve the .stf. 
> If needed, I think I can approve immediately, since it does sot look 
> like any of these pose a threat to the spacecraft, but I'd like to 
> understand the above things first if I can.
> 
> 
> -- 
> 						- Mark     210-379-4635
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