With attachment.

Carol Weaver

University of New Hampshire

503.902.8492

From: Carol Weaver <Carol.Weaver@unh.edu>
Date: Wednesday, 2021-September-8 at 10:01
To: Perry, Timothy E [US] (SP) <Timothy.Perry@ngc.com>, Chubin, Eric [US] (SP) <Eric.Chubin@ngc.com>, David Heirtzler <David.Heirtzler@unh.edu>, ADS-IBEX@l3harris.com <ADS-IBEX@l3harris.com>, IBEXOPS@gmail.com <IBEXOPS@gmail.com>, isocops@lists.sr.unh.edu <isocops@lists.sr.unh.edu>, fair-play@comcast.net <fair-play@comcast.net>, kwfairchild@gmail.com <kwfairchild@gmail.com>, Kenneth Fairchild <Ken.Fairchild@unh.edu>, angoldconsulting@earthlink.net <angoldconsulting@earthlink.net>, Paul.Janzen@mso.umt.edu <Paul.Janzen@mso.umt.edu>, Tyler, Ryan S [US] (SP) <Ryan.Tyler@ngc.com>, Wesley, Sheral R [US] (SP) <Sheral.Wesley@ngc.com>, Wynn, Reese [US] (SP) <Reese.Wynn@ngc.com>
Subject: Re: IBEX Orbit #541 ATS Approval (14 - 23 Sept, 2021)

Hi all,

The 541 ATS is already on board and this is a retroactive approval before its execution. The one issue found in the ATS has been fixed in the uploaded commands.

The angle at Orbit 542 apogee after the perigee sun precession maneuver is 4.528 degrees.

I have looked at the orbit 0541 ATS file, IBEX_2021_257_o0541a_v001.scr and I approve.

The constraint violations in IBEX_2021_257_o0541a_v001.ccvr are from the removal of the ACT_SetSpinPulseProtectEnable Enable commands and adding the commanding tracks for the end of the Hi background test. The violations are acceptable.

The PL commands in IBEX_2021_257_o0541a_v001.scr match those in the STF, IBEX_2021_257_o0541a_v002.stf, aside from the fixed command in the ATS.

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_2021_257_o0541a_v001.oef and as verified with ibex_orbit.

There are 2 star tracker outages this orbit. First outage lasts for 2 days and 2:08:37 hours and ends 8:41:44 hours before the apogee maneuver. The second star track outage lasts for 1:38:47 hours directly during the perigee maneuver.

The ground station command sequences are correct and the timing and bit rates match those in the contacts file, IBEX_Orbit541_Contacts.txt for all contacts (5).

No Battery Balancing this orbit

The Inertial maneuver at perigee of orbit 0540 left us pointing in safe directions for the orbit 0541 arc A ascending and descending sequences:

ibex_rotate -o -u -0.9817,0.178104,0.067406 -w ibex-sun -t 2021/09:14:17:28:18

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.981700,+0.178104,+0.067406

which is R.A. +169.717 Decl. +3.865

missing R.A. +172.500 Decl. +3.218 (ibex-sun)

error is R.A. +2.783 Decl. +0.647

for a total 2.852 deg

ibex_rotate -o -u -0.9817,0.178104,0.067406 -w ibex-sun -t 2021/09:18:22:12:22

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.981700,+0.178104,+0.067406

which is R.A. +169.717 Decl. +3.865

missing R.A. +176.161 Decl. +1.678 (ibex-sun)

error is R.A. +6.444 Decl. +2.187

for a total 6.798 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 -0.993233,0.110145,0.036836 -w ibex-sun -t 2021/09:18:23:55:29

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.993233,+0.110145,+0.036836

which is R.A. +173.672 Decl. +2.111

missing R.A. +176.226 Decl. +1.651 (ibex-sun)

error is R.A. +2.554 Decl. +0.460

for a total 2.594 deg

ibex_rotate -o -u -0.993233,0.110145,0.036836 -w ibex-sun -t 2021/09:19:01:30:36

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.993233,+0.110145,+0.036836

which is R.A. +173.672 Decl. +2.111

missing R.A. +176.286 Decl. +1.626 (ibex-sun)

error is R.A. +2.614 Decl. +0.485

for a total 2.657 deg

ibex_rotate -o -u -0.993233,0.110145,0.036836 -w ibex-sun -t 2021/09:22:19:16:28

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.993233,+0.110145,+0.036836

which is R.A. +173.672 Decl. +2.111

missing R.A. +179.754 Decl. +0.121 (ibex-sun)

error is R.A. +6.082 Decl. +1.990

for a total 6.398 deg

The Sun precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 0542 apogee:

ibex_rotate -o -r +179.897 -d +0.052 -w ibex-sun -t 2021/09:22:23:00:41

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.999998,+0.001798,+0.000908

which is R.A. +179.897 Decl. +0.052

missing R.A. +179.897 Decl. +0.052 (ibex-sun)

error is R.A. +0.000 Decl. +0.000

for a total 0.000 deg

ibex_rotate -o -r +179.897 -d +0.052 -w ibex-sun -t 2021-09-27T17:10:45

Quaternion +0.000000,+0.000000,+0.000000,+0.000000

points axis +1.000000,+0.000000,+0.000000

towards ECI -0.999998,+0.001798,+0.000908

which is R.A. +179.897 Decl. +0.052

missing R.A. +184.054 Decl. -1.743 (ibex-sun)

error is R.A. +4.157 Decl. +1.795

for a total 4.528 deg

There is no overlap with orbit 0540 commands.

Command Approval Checklist is attached.

Carol

Carol Weaver

University of New Hampshire

503.902.8492

From: Perry, Timothy E [US] (SP) <Timothy.Perry@ngc.com>
Date: Friday, 2021-September-3 at 13:29
To: Carol Weaver <carol.weaver@unh.edu>, Chubin, Eric [US] (SP) <Eric.Chubin@ngc.com>, David Heirtzler <David.Heirtzler@unh.edu>, ADS-IBEX@l3harris.com <ADS-IBEX@l3harris.com>, IBEXOPS@gmail.com <IBEXOPS@gmail.com>, isocops@lists.sr.unh.edu <isocops@lists.sr.unh.edu>, fair-play@comcast.net <fair-play@comcast.net>, kwfairchild@gmail.com <kwfairchild@gmail.com>, Kenneth Fairchild <Ken.Fairchild@unh.edu>, angoldconsulting@earthlink.net <angoldconsulting@earthlink.net>, Paul.Janzen@mso.umt.edu <Paul.Janzen@mso.umt.edu>, Perry, Timothy E [US] (SP) <Timothy.Perry@ngc.com>, Tyler, Ryan S [US] (SP) <Ryan.Tyler@ngc.com>, Wesley, Sheral R [US] (SP) <Sheral.Wesley@ngc.com>, Wynn, Reese [US] (SP) <Reese.Wynn@ngc.com>
Subject: IBEX Orbit #541 ATS Approval (14 - 23 Sept, 2021)

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All,

Attached are the planning files for Orbit #541. Please respond to this thread with comments and approvals.

Approvals are required by COB 04 Sept 2021

Please note the following:

Perigee Sun Maneuver - 2021/09:22:22:45:41

No Battery Balancing this orbit

Command Load Constraint Violation Report (CCVR)

The 2 IBX-CLC-006 soft violations are acceptable. The reason is that I added a contact for the end of Hi background test.

IBEX,USHI02,ADD,09/22/21,265,16:30:00,09/22/21,265,17:30:00,LAHO 64K IBEX-2 Orbit# 540 Tracking/End Hi Background Test Contact 16re Desc

IBEX,AUWA01,ADD,09/22/21,265,19:30:00,09/22/21,265,20:30:00,LAHO 160K IBEX-2 Orbit# 541 SSR_Dump/Tracking Contact 15re Desc

IBEX_2021_257_o0541a_v001.ccvr

# Input files: 1

# IBEX_2021_257_o0541a_v001.scr

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

HARD CONSTRAINT VIOLATIONS

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

NO VIOLATIONS.

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

SOFT CONSTRAINT VIOLATIONS

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

IBX-CLC-006: Planned transmission at 2021/09/22 16:28:00 UTC - 2021/09/22

17:32:00 UTC is followed by one or more additional transmissions

which, when combined, exceed the maximum transmission time of 5400

seconds within a 18000-second window (total planned transmission

time this window is 7680.000 seconds)

IBX-CLC-006: Planned transmission at 2021/09/22 19:28:00 UTC - 2021/09/22

20:32:00 UTC is preceded by one or more additional transmissions

which, when combined, exceed the maximum transmission time of 5400

seconds within a 18000-second window (total planned transmission

time this window is 7680.000 seconds)

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

transition to science mode at 2021/09/14 14:43:12 UTC

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

transition to science mode at 2021/09/19 01:00:36 UTC

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

OTHER MESSAGES

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

NO MESSAGES.

Timothy E.Perry

CRS IBEX OCO-2

Mission Operations

timothy.perry@ngc.com

Office (703) 406-5976

Cell (301) 606-1430