All,

Note: Angle at orbit 518 arc B descending after the apogee sun precession maneuver: 4.101 deg

Angle at Orbit 519 apogee after the perigee sun precession maneuver: 4.856 deg

I have looked at the orbit 518 ATS files,

'IBEX_2021_047_o0518a_INST_v001.scr', 'IBEX_2021_047_o0518a_BUS_v001.scr'

and I approve.

The only constraint violations in

IBEX_2021_047_o0518a_BUS_v001.ccvr

and

IBEX_2021_047_o0518a_INST_v001.ccvr

are from the removal of the

ACT_SetSpinPulseProtectEnable Enable

commands (2); the violations are expected.

The PL commands in

IBEX_2021_047_o0518a_INST_v001.scr

match those in the v002 STF,

IBEX_2021_047_o0518a_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_2021_047_o0518a_BUS_v001.oef

and as verified with ibex_orbit.

There is one star tracker outage. The outage starts 4 days before apogee and runs for ~17 hours. Some despinning may be required due to this outage.

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

IBEX_Orbit518_Contacts.txt,

for all contacts (3).

We are doing battery cell balancing this orbit and the balancing commands are correct and offset by enough time from other commands.

The inertial precession maneuver at perigee of orbit 517 left us pointing in safe directions for the orbit 518 arc A ascending and descending sequences:

ibex_rotate -o -u 0.855404,-0.471118,-0.215247 -w ibex-sun -t 2021/02:16:18:53:43

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.855404,-0.471118,-0.215247

which is R.A. +331.156 Decl. -12.430

missing R.A. +330.213 Decl. -12.174 (ibex-sun)

error is R.A. +0.943 Decl. +0.256

for a total 0.956 deg

ibex_rotate -o -u 0.855404,-0.471118,-0.215247 -w ibex-sun -t 2021/02:20:22:51:56

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.855404,-0.471118,-0.215247

which is R.A. +331.156 Decl. -12.430

missing R.A. +334.307 Decl. -10.630 (ibex-sun)

error is R.A. +3.151 Decl. +1.800

for a total 3.574 deg

The sun 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 -r +334.355 -d -10.611 -w ibex-sun -t 2021/02:21:00:05:22

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.886077,-0.425393,-0.184140

which is R.A. +334.355 Decl. -10.611

missing R.A. +334.355 Decl. -10.611 (ibex-sun)

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

for a total 0.000 deg

ibex_rotate -o -r +334.355 -d -10.611 -w ibex-sun -t 2021/02:21:01:37:00

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.886077,-0.425393,-0.184140

which is R.A. +334.355 Decl. -10.611

missing R.A. +334.414 Decl. -10.587 (ibex-sun)

error is R.A. +0.059 Decl. +0.024

for a total 0.063 deg

ibex_rotate -o -r +334.355 -d -10.611 -w ibex-sun -t 2021/02:25:04:56:56

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.886077,-0.425393,-0.184140

which is R.A. +334.355 Decl. -10.611

missing R.A. +338.233 Decl. -9.120 (ibex-sun)

error is R.A. +3.878 Decl. +1.491

for a total 4.101 deg

The sun precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 519 apogee:

ibex_rotate -o -r +338.390 -d -9.066 -w ibex-sun -t 2021/02:25:08:50:56

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.918098,-0.363686,-0.157572

which is R.A. +338.390 Decl. -9.066

missing R.A. +338.390 Decl. -9.066 (ibex-sun)

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

for a total 0.001 deg

ibex_rotate -o -r +338.390 -d -9.066 -w ibex-sun -t 2021-03-02T01:42:14

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.918098,-0.363686,-0.157572

which is R.A. +338.390 Decl. -9.066

missing R.A. +342.933 Decl. -7.235 (ibex-sun)

error is R.A. +4.543 Decl. +1.831

for a total 4.856 deg

Lo Normal mode for the entire orbit.

There is an overlap with orbit 517 commands with the last transmission and transition to science mode, but this is okay.

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: Wednesday, 2021-February-3 at 14:49
To: Weaver, Carol <Carol.Weaver@unh.edu>, Chubin, Eric [US] (SP) <Eric.Chubin@ngc.com>, Heirtzler, David <David.Heirtzler@unh.edu>, IBEX@applieddefense.info <IBEX@applieddefense.info>, 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>, angoldconsulting@earthlink.net <angoldconsulting@earthlink.net>, paul.janzen@umontana.edu <paul.janzen@umontana.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 #518 ATS Approval (16 - 25 Feb 21)

Caution - External Email

All,

Attached are the planning files for Orbit #518

Please respond to this thread with comments and approvals.

Approvals are required by COB on 06 February 2021

Please note the following:

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.

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.

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.

Apogee Sun Maneuver - 2021/02:20:23:50:22

Perigee Sun Maneuver - 2021/02:25:08:35:56

Battery Balancing this orbit

Begin 2021/02:25:13:00:00 – End 2021/02:25:14:30:00

# Orbit# 516 Reset Master Timer - 2021/02:07:16:45:00

Command Load Constraint Violation Report (CCVR)

IBEX_2021_047_o0518a_v001.ccvr

# Input files: 1

# IBEX_2021_047_o0518a_v001.scr

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

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 2021/02/16 15:45:27 UTC

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

transition to science mode at 2021/02/21 01:07:00 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