[Isocops] IBEX Orbit #493 ATS Approval ( 4 - 13 July 2020 ) - v001 approval

Thu Jun 11 00:10:07 EDT 2020

All,

I have looked at the orbit 493 ATS files,

IBEX_2020_185_o0493a_BUS_v001.scr

and

IBEX_2020_185_o0493a_INST_v001.scr,

and I approve.

The only constraint violations in

IBEX_2020_185_o0493a_BUS_v001.ccvr

and

IBEX_2020_185_o0493a_INST_v001.ccvr

are from the removal of the

ACT_SetSpinPulseProtectEnable Enable

commands (2); the violations are expected.

The PL commands in

IBEX_2020_185_o0493a_INST_v001.scr

match those in the v002 STF,

IBEX_2020_185_o0493a_v002.stf.

Ascending and descending command sequences are consistent with each other, 15 Re ascending, the apogee maneuver time and 15 Re descending as determined from the OEF,

IBEX_2020_185_o0493a_BUS_v001.oef,

and as verified with ibex_orbit.

There are two star tracker outages.   The first starts about 2 hours before orbit 492 perigee and ends about 15 hours after 15 Re ascending.  The second starts 4- hours before perigee and runs for about 9 hours.  Sone despinning may be required due to the first outage.

The ground station command sequences are correct and the timing and bit rates match those in the contacts file,

IBEX_Orbit493_Contacts.txt,

for all contacts (4).

We are not doing battery cell balancing this orbit; we'll do it again in the next orbit.

The sun precession maneuver at perigee of orbit 492 left us pointing in safe directions for the orbit 493 arc A ascending and descending sequences:

ibex_rotate -o -r +102.699 -d +22.935 -w ibex-sun -t 2020/07:04:03:46:43
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.202451,+0.898420,+0.389687
which is R.A. +102.699 Decl. +22.935
missing R.A. +103.405 Decl. +22.843 (ibex-sun)
error is R.A. +0.706 Decl. +0.092
for a total 0.657 deg

ibex_rotate -o -r +102.699 -d +22.935 -w ibex-sun -t 2020/07:07:19:17:11
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.202451,+0.898420,+0.389687
which is R.A. +102.699 Decl. +22.935
missing R.A. +107.156 Decl. +22.503 (ibex-sun)
error is R.A. +4.457 Decl. +0.432
for a total 4.134 deg

The inertial precession maneuver at apogee leaves us pointing in safe directions at the time of the maneuver and for arc B ascending and descending sequences:

ibex_rotate -o -u -0.241295,0.894339,0.376742 -w ibex-sun -t 2020/07:07:21:00:19
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.241295,+0.894339,+0.376742
which is R.A. +105.099 Decl. +22.132
missing R.A. +107.231 Decl. +22.496 (ibex-sun)
error is R.A. +2.132 Decl. +0.364
for a total 2.006 deg

ibex_rotate -o -u -0.241295,0.894339,0.376742 -w ibex-sun -t 2020/07:07:22:35:25
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.241295,+0.894339,+0.376742
which is R.A. +105.099 Decl. +22.132
missing R.A. +107.301 Decl. +22.490 (ibex-sun)
error is R.A. +2.202 Decl. +0.358
for a total 2.068 deg

ibex_rotate -o -u -0.241295,0.894339,0.376742 -w ibex-sun -t 2020/07:12:11:49:06
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.241295,+0.894339,+0.376742
which is R.A. +105.099 Decl. +22.132
missing R.A. +111.999 Decl. +21.912 (ibex-sun)
error is R.A. +6.900 Decl. +0.220
for a total 6.400 deg

The inertial precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 494 apogee:

ibex_rotate -o -u -0.316162,0.873961,0.369098 -w ibex-sun -t 2020/07:12:15:18:53
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.316162,+0.873961,+0.369098
which is R.A. +109.888 Decl. +21.660
missing R.A. +112.139 Decl. +21.886 (ibex-sun)
error is R.A. +2.251 Decl. +0.226
for a total 2.103 deg

ibex_rotate -o -u -0.316162,0.873961,0.369098 -w ibex-sun -t 2020-07-17T13:21:12.559Z
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.316162,+0.873961,+0.369098
which is R.A. +109.888 Decl. +21.660
missing R.A. +117.058 Decl. +21.121 (ibex-sun)
error is R.A. +7.170 Decl. +0.539
for a total 6.697 deg

Lo Background mode for the entire orbit.

There is no overlap with orbit 492 commands by manual inspection or by checking at

http://ibex.unh.edu/cgi-bin/ats.cgi. 

Command Approval Checklist is attached.

Ken

> On June 8, 2020 at 4:32 PM "Perry, Timothy E [US] (IS)" <Timothy.Perry at ngc.com> wrote:
> 
> 
>     All,
> 
>        Attached are the planning files for Orbit #493
> 
>     Please respond to this thread with comments and approvals.  
> 
>     Approvals are required by 14:00 on 10 June 2020
> 
>      
> 
>     Please note the following:
> 
>        1. I generated 3 separate ATS files BUS, INST and a complete file. The BUS and INST will be the files to be uplinked. The complete ATS, I used as a sanity check to see how the commands lined up. Since we are in a new phase of ATS generation. IF you have any ideas of doing this differently, let me know.
> 
>          
> 
>        1. The 3 ATS files have been changed to word  files and encrypted. I will send out another email with the password. The files that have been transferred via MFT have not been encrypted and are still text files.  
> 
>          
> 
>        1. I moved the 2 House Keeping commands from the INST ATS to the BUS ATS. I commented out the 2 commands in the INST ATS. If for some reason we were unable to uplink the INST Commands for this orbit, we would have been in the wrong spacecraft state for executing the maneuver commands.
> 
>      
> 
>        1. Note the CEU Lo Science Mode is set to BACKGROUND
> 
>          
> 
>        1. No Battery Balancing this orbit
> 
>      
> 
>        1. Command Load Constraint Violation Report (CCVR)
> 
>     IBEX_2020_185_o0493a_v001.ccvr
> 
>          
> 
>         ==========================
> 
>         HARD CONSTRAINT VIOLATIONS
> 
>         ==========================
> 
>         NO VIOLATIONS.
> 
>          
> 
>         ==========================
> 
>         SOFT CONSTRAINT VIOLATIONS
> 
>         ==========================
> 
>         IBX-CLC-016: No command to enable spin pulse protection was found after
> 
>                      transition to science mode at 2020/07/04 01:30:36 UTC
> 
>         IBX-CLC-016: No command to enable spin pulse protection was found after
> 
>                      transition to science mode at 2020/07/07 22:05:25 UTC
> 
>          
> 
>         ==============
> 
>         OTHER MESSAGES
> 
>         ==============
> 
>         NO MESSAGES.
> 
>          
> 
>      
> 
>      
> 
>      
> 
>      
> 
>     Timothy E.Perry
> 
>     CRS IBEX OCO-2
> 
>     Mission Operations
> 
>     timothy.perry at ngc.com
> 
>     Office (703) 406-5976
> 
>     Cell (301) 606-1430
> 
>      
> 
>     [cid:image001.png at 01D542D6.6047A400]
> 
>      
> 
>      
> 

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