[Isocops] EXT :Re: IBEX Orbit #650 ATS Approval (June 02 - 10, 2024)

[Tyler, Ryan S [US] (SP)]

Well, there definitely isn’t an eclipse there, since the sun and Earth vectors are close to 90 deg apart at that time. So I have no idea what that constraint check is reacting to.

Looking at other cases where this constraint tripped I can see that the math is a bit wonky. A ~70 minute eclipse (they type where we typically set the long eclipse flag and everything is fine) gets reported at having 0 W-min left (i.e., battery fully depleted). That goes up a bit for eclipses that are a bit shorter.

Even the recent penumbral sliver of an eclipse, where the spacecraft still saw 98% of the sunlight so the battery never came close to discharging at all, got flagged by this constraint as having the battery go down to 2700 W-min.

So when this constraint shows the battery going down to 3700 W-min, a smaller discharge than that penumbral eclipse, I think it’s safe to say that the constraint violation is meaningless.

From: Ken Fairchild <kwfairchild at gmail.com>
Sent: Monday, May 20, 2024 4:02 PM
To: Perry, Timothy E [US] (SP) <Timothy.Perry at ngc.com>
Cc: carol.weaver at unh.edu; Chubin, Eric [US] (SP) <Eric.Chubin at ngc.com>; David.Heirtzler at unh.edu; ADS-IBEX at l3harris.com; IBEXOPS at gmail.com; isocops at lists.sr.unh.edu; Ken.Fairchild at unh.edu; angoldconsulting at earthlink.net; Paul.Janzen at mso.umt.edu; Tyler, Ryan S [US] (SP) <Ryan.Tyler at ngc.com>; Wesley, Sheral R [US] (SP) <Sheral.Wesley at ngc.com>; Wynn, Reese [US] (SP) <Reese.Wynn at ngc.com>; Ken Fairchild <kwfairchild at gmail.com>
Subject: EXT :Re: IBEX Orbit #650 ATS Approval (June 02 - 10, 2024)

Tim,

That's a weird constraint violation.  I looked at last month's forecast OEFs and both versions of this month's OEF.  The outage times on 06-01 all track pretty closely and end shortly after 23:00 on the 1st.  I checked the FDG outage report and the outage times there also track well with those in the OEFs.  Perhaps Ryan can use his fancy tool to see if there's something going on that would explain this violation?

Ken

On Mon, May 20, 2024 at 12:22 PM Perry, Timothy E [US] (SP) <Timothy.Perry at ngc.com<mailto:Timothy.Perry at ngc.com>> wrote:

All,

   Attached are the planning files for Orbit #650. Please respond to this thread with comments and approvals. Approvals for the Orbit 650 ATS are required by 1700 , 23 May 2024.





Please note the following:



1.        Battery Balancing

Eclipse Flag True: 2024/06/10 21:00:00

Eclipse Flag False: 2024/06/10 22:30:00



2.        Command Load Constraint Violation Report (CCVR)

IBEX_2024_153_o0650a_v001.ccvr

# Input files:         1

#   IBEX_2024_153_o0650a_v001.scr



==========================

HARD CONSTRAINT VIOLATIONS

==========================

NO VIOLATIONS.



==========================

        SOFT CONSTRAINT VIOLATION

==========================



I saw this violation IBX-CLC-015. I looked for any small eclipses or close transmitter times. We never drop to zero. I can’t explain why this is flagging other than maybe an MPS miscalculation.



IBX-CLC-015: Battery charge falls below minimum from 2024/06/02 04:43:00 UTC -

             2024/06/02 14:04:00 UTC. Lowest charge level is 3736.960000

             watt-minutes during this interval.

IBX-CLC-016: No command to enable spin pulse protection was found after

             transition to science mode at 2024/06/02 07:01:28 UTC

IBX-CLC-016: No command to enable spin pulse protection was found after

             transition to science mode at 2024/06/06 00:17:58 UTC



==============

OTHER MESSAGES

==============

NO MESSAGES.








Timothy E.Perry
CRS IBEX OCO-2
Mission Operations
timothy.perry at ngc.com<mailto:timothy.perry at ngc.com>
Office (703) 406-5976
IBEX MOC (703)404-7470
Cell (301) 606-1430

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