All,

Note: Angle at orbit 639 apogee after perigee sun precession maneuver: 5.114 deg

I have looked at the orbit 638 ATS,

IBEX_2024_044_o0638a_v001.scr,

and I approve.

The only constraint violations in

IBEX_2024_044_o0638a_v001.ccvr

are from the removal of the

ACT_SetSpinPulseProtectEnable Enable

commands (2) and the proximity of two contacts; the violations are expected.

The PL commands in the v001 ATS match those in the v002 STF,

IBEX_2024_044_o0638a_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_2024_044_o0638a_v001.oef,

and as verified with ibex_orbit.

There is one star tracker outage. The outage starts about 10 1/2 hours before 15 Re descending and runs for 1+ days. 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_Orbit638_Contacts.txt,

for all contacts (3).

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

The inertial precession maneuver at perigee of orbit 637 leaves us pointing in safe directions for the orbit 638 arc A ascending and descending sequences:

ibex_rotate -o -u 0.820389,-0.520575,-0.236567 -w ibex-sun -t 2024/02:14:00:23:36

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.820389,-0.520575,-0.236567

which is R.A. +327.603 Decl. -13.684

missing R.A. +326.758 Decl. -13.388 (ibex-sun)

error is R.A. +0.845 Decl. +0.296

for a total 0.873 deg

ibex_rotate -o -u 0.820389,-0.520575,-0.236567 -w ibex-sun -t 2024/02:17:17:45:46

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.820389,-0.520575,-0.236567

which is R.A. +327.603 Decl. -13.684

missing R.A. +330.490 Decl. -12.039 (ibex-sun)

error is R.A. +2.887 Decl. +1.645

for a total 3.260 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 0.865296,-0.456219,-0.207673 -w ibex-sun -t 2024/02:17:19:28:54

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.865296,-0.456219,-0.207673

which is R.A. +332.200 Decl. -11.986

missing R.A. +330.559 Decl. -12.013 (ibex-sun)

error is R.A. +1.641 Decl. +0.027

for a total 1.605 deg

ibex_rotate -o -u 0.865296,-0.456219,-0.207673 -w ibex-sun -t 2024/02:17:21:04:00

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.865296,-0.456219,-0.207673

which is R.A. +332.200 Decl. -11.986

missing R.A. +330.623 Decl. -11.989 (ibex-sun)

error is R.A. +1.577 Decl. +0.003

for a total 1.543 deg

ibex_rotate -o -u 0.865296,-0.456219,-0.207673 -w ibex-sun -t 2024/02:22:10:28:50

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.865296,-0.456219,-0.207673

which is R.A. +332.200 Decl. -11.986

missing R.A. +334.882 Decl. -10.411 (ibex-sun)

error is R.A. +2.682 Decl. +1.575

for a total 3.066 deg

The sun precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 639 apogee:

ibex_rotate -o -r +334.986 -d -10.376 -w ibex-sun -t 2024/02:22:13:11:08

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.891385,-0.415925,-0.180107

which is R.A. +334.986 Decl. -10.376

missing R.A. +334.986 Decl. -10.376 (ibex-sun)

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

for a total 0.000 deg

ibex_rotate -o -r +334.986 -d -10.376 -w ibex-sun -t 2024-02-27T12:02:06.441Z

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

points axis +1.000000,+0.000000,+0.000000

towards ECI +0.891385,-0.415925,-0.180107

which is R.A. +334.986 Decl. -10.376

missing R.A. +339.805 Decl. -8.491 (ibex-sun)

error is R.A. +4.819 Decl. +1.885

for a total 5.114 deg

Lo Normal mode for the entire orbit.

There is no overlap with orbit 637 commands by manual inspection or by checking at

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

Command Approval Checklist is attached.

Ken

On Wed, Jan 31, 2024 at 2:53 PM Perry, Timothy E [US] (SP) <Timothy.Perry@ngc.com> wrote:

All,

   Attached are the planning files for Orbit #638. Please respond to this thread with comments and approvals. Approvals are required by COB 03 February 2024.

Please note the following:

1.        Battery Balancing

Eclipse Flag True: 2024/02/22 18:00:00

Eclipse Flag False: 2024/02/22 19:30:00

2.        Command Load Constraint Violation Report (CCVR)

IBEX_2024_044_o0638a_v001.ccvr

# Input files:         1

#   IBEX_2024_044_o0638a_v001.scr

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

HARD CONSTRAINT VIOLATIONS

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

NO VIOLATIONS.

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

SOFT CONSTRAINT VIOLATIONS

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

IBX-CLC-006: Planned transmission at 2024/02/22 20:58:00 UTC - 2024/02/22

             22:02:00 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 5880.000 seconds)

IBX-CLC-006: Planned transmission at 2024/02/23 02:28:00 UTC - 2024/02/23

             03:32:00 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 5880.000 seconds)

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

             transition to science mode at 2024/02/13 22:32:00 UTC

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

             transition to science mode at 2024/02/17 20:34:00 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