All,

Note: Angle at orbit 519 arc B descending after the apogee sun precession maneuver: 4.018 deg

I have looked at the orbit 519 ATS files,

IBEX_2021_056_o0519a_INST_v002.scr, IBEX_2021_056_o0519a_BUS_v001.scr

and I approve.

The only constraint violations in

IBEX_2021_056_o0519a_BUS_v001.ccvr

and

IBEX_2021_056_o0519a_INST_v001.ccvr

are from the removal of the

ACT_SetSpinPulseProtectEnable Enable

commands (2); the violations are expected.

The PL commands in

IBEX_2021_056_o0519a_INST_v002.scr

match those in the v002 STF,

IBEX_2021_056_o0519a_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_056_o0519a_BUS_v001.oef

and as verified with ibex_orbit.

There are two star tracker outages. The first outage overlaps with Orbit 518 and ends around 16Re ascending. The second outage begins two days before Apogee and runs for 3 days.

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

IBEX_Orbit519_Contacts.txt,

for all contacts (3) and reset master timer in Orbit 517.

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

The sun precession maneuver at perigee of orbit 518 left us pointing in safe directions for the orbit 519 arc A ascending and descending sequences:

ibex_rotate -o -r +338.390 -d -9.066 -w ibex-sun -t 2021/02:25:22:52:48

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. +338.976 Decl. -8.861 (ibex-sun)

error is R.A. +0.586 Decl. +0.205

for a total 0.614 deg

ibex_rotate -o -r +338.390 -d -9.066 -w ibex-sun -t 2021/03:02:00:43:01

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. +342.896 Decl. -7.251 (ibex-sun)

error is R.A. +4.506 Decl. +1.815

for a total 4.815 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 +342.942 -d -7.231 -w ibex-sun -t 2021/03:02:01:56:18

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.948405,-0.291007,-0.125870

which is R.A. +342.942 Decl. -7.231

missing R.A. +342.942 Decl. -7.231 (ibex-sun)

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

for a total 0.000 deg

ibex_rotate -o -r +342.942 -d -7.231 -w ibex-sun -t 2021/03:02:03:28:05

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.948405,-0.291007,-0.125870

which is R.A. +342.942 Decl. -7.231

missing R.A. +343.001 Decl. -7.206 (ibex-sun)

error is R.A. +0.059 Decl. +0.025

for a total 0.064 deg

ibex_rotate -o -r +342.942 -d -7.231 -w ibex-sun -t 2021/03:06:05:20:59

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.948405,-0.291007,-0.125870

which is R.A. +342.942 Decl. -7.231

missing R.A. +346.678 Decl. -5.692 (ibex-sun)

error is R.A. +3.736 Decl. +1.539

for a total 4.018 deg

The inertial precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 520 apogee:

ibex_rotate -o -u 0.974523,-0.201548,-0.098399 -w ibex-sun -t 2021/03:06:09:33:55

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.974523,-0.201548,-0.098399

which is R.A. +348.315 Decl. -5.647

missing R.A. +346.842 Decl. -5.632 (ibex-sun)

error is R.A. +1.473 Decl. +0.015

for a total 1.465 deg

ibex_rotate -o -u 0.974523,-0.201548,-0.098399 -w ibex-sun -t 2021-03-11T02:25:33

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.974523,-0.201548,-0.098399

which is R.A. +348.315 Decl. -5.647

missing R.A. +351.312 Decl. -3.732 (ibex-sun)

error is R.A. +2.997 Decl. +1.915

for a total 3.548 deg

Lo Normal mode for the entire orbit.

There is no overlap with orbit 518 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: Wednesday, 2021-February-10 at 16:21
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 #519 ATS Approval (25 Feb – 06 Mar 21)

Caution - External Email

All,

Attached are the planning files for Orbit #519

Please respond to this thread with comments and approvals.

Approvals are required by COB on 15 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 - 2021/03:02:01:41:18

Battery Balancing this orbit

Begin 2021/03:06:14:00:00– End 2021/03:06:15:30:00

# Orbit# 517 Reset Master Timer - 2021/02:16:16:15:00

Command Load Constraint Violation Report (CCVR)

IBEX_2021_056_o0519a_v001.ccvr

# Input files: 1

# IBEX_2021_056o0519a_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 2021/02/25 19:45:58 UTC

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

transition to science mode at 2021/03/02 02:58:05 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