All,

Note: Angle at descending after apogee sun precession maneuver: 3.970 deg

I have looked at the orbit 639 ATS,

IBEX_2024_053_o0639a_v001.scr,


and I approve.

The only constraint violations in

IBEX_2024_053_o0639a_v001.ccvr


are from the removal of the

ACT_SetSpinPulseProtectEnable Enable


commands (2); the violations are expected.

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

IBEX_2024_053_o0639a_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_053_o0639a_v001.oef,


and as verified with ibex_orbit.

There are three star tracker outages.  The first starts before we descend in orbit 638 arc B and runs for 2+ days.  The second starts 1+ days before apogee and runs for 3 days.  The third starts 6 hours before 15 Re descending and runs for 7.5 hours.  Some despinning may be required due to these outages.

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

IBEX_Orbit639_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 sun precession maneuver at perigee of orbit 638 leaves us pointing in safe directions for the orbit 639 arc A ascending and descending sequences:

ibex_rotate -o -r +334.986 -d -10.376 -w ibex-sun -t 2024/02:23:08:33:09

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. +335.774 Decl. -10.107 (ibex-sun)

 error is     R.A.   +0.788 Decl.  +0.269

 for a total  0.821 deg


ibex_rotate -o -r +334.986 -d -10.376 -w ibex-sun -t 2024/02:27:10:29:00

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. +339.744 Decl.  -8.516 (ibex-sun)

 error is     R.A.   +4.758 Decl.  +1.860

 for a total  5.048 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 +339.815 -d -8.487 -w ibex-sun -t 2024/02:27:12:17:08

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

 points axis  +1.000000,+0.000000,+0.000000

 towards ECI  +0.928305,-0.341274,-0.147585

 which is     R.A. +339.815 Decl.  -8.487

 missing      R.A. +339.815 Decl.  -8.487 (ibex-sun)

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

 for a total  0.000 deg


ibex_rotate -o -r +339.815 -d -8.487 -w ibex-sun -t 2024/02:27:13:47:14

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

 points axis  +1.000000,+0.000000,+0.000000

 towards ECI  +0.928305,-0.341274,-0.147585

 which is     R.A. +339.815 Decl.  -8.487

 missing      R.A. +339.873 Decl.  -8.463 (ibex-sun)

 error is     R.A.   +0.058 Decl.  +0.024

 for a total  0.063 deg


ibex_rotate -o -r +339.815 -d -8.487 -w ibex-sun -t 2024/03:02:14:02:26

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

 points axis  +1.000000,+0.000000,+0.000000

 towards ECI  +0.928305,-0.341274,-0.147585

 which is     R.A. +339.815 Decl.  -8.487

 missing      R.A. +343.527 Decl.  -6.991 (ibex-sun)

 error is     R.A.   +3.712 Decl.  +1.496

 for a total  3.970 deg


The inertial precession maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 640 apogee:

ibex_rotate -o -u 0.959973,-0.252847,-0.120501 -w ibex-sun -t 2024/03:02:17:42:25

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

 points axis  +1.000000,+0.000000,+0.000000

 towards ECI  +0.959973,-0.252847,-0.120501

 which is     R.A. +345.244 Decl.  -6.921

 missing      R.A. +343.663 Decl.  -6.942 (ibex-sun)

 error is     R.A.   +1.581 Decl.  +0.021

 for a total  1.569 deg


ibex_rotate -o -u 0.959973,-0.252847,-0.120501 -w ibex-sun -t 2024-03-07T14:50:10.088Z

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

 points axis  +1.000000,+0.000000,+0.000000

 towards ECI  +0.959973,-0.252847,-0.120501

 which is     R.A. +345.244 Decl.  -6.921

 missing      R.A. +348.309 Decl.  -5.001 (ibex-sun)

 error is     R.A.   +3.065 Decl.  +1.920

 for a total  3.603 deg


Lo Normal mode for the entire orbit.

There is no overlap with orbit 638 commands by manual inspection or by checking at

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

Command Approval Checklist is attached.

Ken

On Thu, Feb 8, 2024 at 1:25 PM Perry, Timothy E [US] (SP) <Timothy.Perry@ngc.com> wrote:

All, 

   Attached are the planning files for Orbit #639. Please respond to this thread with comments and approvals. Approvals are required by COB 12 February 2024.

 

Please note the following: 

 

1.        No Battery Balancing

Eclipse Flag True: 2024/03/03 01:00:00

Eclipse Flag False: 2024/03/03 02:30:00

 

2.        Command Load Constraint Violation Report (CCVR) 

IBEX_2024_053_o0639a_v001.ccvr

# Input files:         1

#   IBEX_2024_053_o0639a_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 2024/02/23 06:39:01 UTC

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

             transition to science mode at 2024/02/27 13:17:14 UTC

 

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

OTHER MESSAGES

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

NO MESSAGES.

 

 

Timothy E.Perry

CRS IBEX OCO-2

Mission Operations

timothy.perry@ngc.com

Office (703) 406-5976

IBEX MOC (703)404-7470

Cell (301) 606-1430