[Isocops] IBEX Orbit# 471 ATS Approval (17 Dec - 27 Dec 19) - v001 approval

KEN FAIRCHILD fair-play at comcast.net
Sat Dec 7 10:44:29 EST 2019


All,

Note: Angle at orbit 471 arc B descending after the apogee sun precession maneuver: 4.247 deg

I have looked at the orbit 471 ATS,

IBEX_2019_351_o0471a_v001.scr,

and I approve.

The only constraint violations in

IBEX_2019_351_o0471a_v001.ccvr

are from the removal of the

ACT_SetSpinPulseProtectEnable Enable

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

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

IBEX_2019_351_o0471a_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_2019_351_o0471a_v001.oef,

and as verified with ibex_orbit.

There is one star tracker outage.  The outage starts 2- days after 15 Re ascending and runs for 3+ 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_Orbit471_Contacts.txt,

for all contacts (5).

We are not doing battery cell balancing this orbit - there is an eclipse near perigee.

The inertial maneuver at perigee of orbit 470 left us pointing in safe directions for the orbit 471 arc A ascending and descending sequences:

ibex_rotate -o -u -0.069298,-0.911205,-0.406083 -w ibex-sun -t 2019/12:17:19:31:14
Quaternion. +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.069298,-0.911205,-0.406083
which is R.A. +265.651 Decl. -23.959
missing R.A. +264.897 Decl. -23.375 (ibex-sun)
error is R.A. +0.754 Decl. +0.584
for a total 0.905 deg

ibex_rotate -o -u -0.069298,-0.911205,-0.406083 -w ibex-sun -t 2019/12:21:22:49:36
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.069298,-0.911205,-0.406083
which is R.A. +265.651 Decl. -23.959
missing R.A. +269.429 Decl. -23.430 (ibex-sun)
error is R.A. +3.778 Decl. +0.529
for a total 3.500 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 +269.511 -d -23.429 -w ibex-sun -t 2019/12:22:00:37:44
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.007831,-0.917520,-0.397612
which is R.A. +269.511 Decl. -23.429
missing R.A. +269.511 Decl. -23.429 (ibex-sun)
error is R.A. +0.000 Decl. +0.000
for a total 0.000 deg

ibex_rotate -o -r +269.511 -d -23.429 -w ibex-sun -t 2019/12:22:02:07:50
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.007831,-0.917520,-0.397612
which is R.A. +269.511 Decl. -23.429
missing R.A. +269.579 Decl. -23.428 (ibex-sun)
error is R.A. +0.068 Decl. +0.001
for a total 0.062 deg

ibex_rotate -o -r +269.511 -d -23.429 -w ibex-sun -t 2019/12:26:04:39:19
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI -0.007831,-0.917520,-0.397612
which is R.A. +269.511 Decl. -23.429
missing R.A. +274.138 Decl. -23.363 (ibex-sun)
error is R.A. +4.627 Decl. +0.066
for a total 4.247 deg

The inertial maneuver at perigee leaves us pointing in safe directions at the time of the maneuver and at orbit 472 apogee:

ibex_rotate -o -u 0.09429,-0.909322,-0.405269 -w ibex-sun -t 2019/12:26:07:46:03
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI +0.094290,-0.909322,-0.405269
which is R.A. +275.920 Decl. -23.908
missing R.A. +274.291 Decl. -23.365 (ibex-sun)
error is R.A. +1.629 Decl. +0.543
for a total 1.588 deg

ibex_rotate -o -u 0.09429,-0.909322,-0.405269 -w ibex-sun -t 2019-12-31T05:39:55.908Z
Quaternion +0.000000,+0.000000,+0.000000,+0.000000
points axis +1.000000,+0.000000,+0.000000
towards ECI +0.094290,-0.909322,-0.405269
which is R.A. +275.920 Decl. -23.908
missing R.A. +279.746 Decl. -23.127 (ibex-sun)
error is R.A. +3.826 Decl. +0.781
for a total 3.594 deg

No Lo O-mode.

There is no overlap with orbit 470 commands by manual inspection or by checking at

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

Command Approval Checklist is attached.

Ken


> On December 5, 2019 at 4:13 PM "Wesley, Sheral R [US] (IS)" <Sheral.Wesley at ngc.com> wrote:
> 
> 
>     All,
> 
>     I have attached the planning files for Orbit# 471
> 
>     Please respond to this email thread with your comments and approvals.
> 
>     Approvals are required by COB 6 Dec 19
> 
>      
> 
>     Please note the following:
> 
>     1.       Moderate Eclipse
> 
>     # ORBIT$ 471 PERIGEE: Eclipse  Commands
> 
>     # 2019-12-26T12:47:44.059Z,PenumbraEntry,orbit:471
> 
>     # 2019-12-26T12:47:44.059Z,EclipseEntry,moderate:true,long:false,orbit:471 
> 
>     # 2019-12-26T14:06:34.424Z,PenumbraExit,orbit:471
> 
>     # 2019-12-26T14:06:34.424Z,EclipseExit,moderate:true,long:false,orbit:471
> 
>     SetLongEclipseFlag TRUE $TIME=2019/12:26:10:45:00
> 
>     SetLongEclipseFlag FALSE $TIME=2019/12:26:14:10:00
> 
>      
> 
>     2.       Command Load Constraint Violation Report
> 
>     IBEX_2019_351_o0471a_v001.scr
> 
>      
> 
>     ==========================
> 
>     HARD CONSTRAINT VIOLATIONS
> 
>     ==========================
> 
>     NO VIOLATIONS.
> 
>      
> 
>     ==========================
> 
>     SOFT CONSTRAINT VIOLATIONS
> 
>     ==========================
> 
>     IBX-CLC-006: Planned transmission at 2019/12/17 16:58:00 UTC - 2019/12/17
> 
>                  18:02:00 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 7680.000 seconds)
> 
>     IBX-CLC-006: Planned transmission at 2019/12/17 19:58:00 UTC - 2019/12/17
> 
>                  21:02:00 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)
> 
>                                                    
> 
>     *             SSR_Dump/Tracking Contact  17 Dec 19 @1658z - 1802z
> 
>     *             IBEX Hi- BAckground TEst   17 Dec 19 @1958z - 2102z 
> 
>     IBX-CLC-015: Battery charge falls below minimum from 2019/12/26 13:41:44 UTC -
> 
>                  2019/12/26 15:04:34 UTC. Lowest charge level is 6353.767108
> 
>                  watt-minutes during this interval.
> 
>     *   ORBIT# 471 PERIGEE: Eclipse  Commands
> 
>     # 2019-12-26T12:47:44.059Z,PenumbraEntry,orbit:471
> 
>     # 2019-12-26T12:47:44.059Z,EclipseEntry,moderate:true,long:false,orbit:471 
> 
>     # 2019-12-26T14:06:34.424Z,PenumbraExit,orbit:471
> 
>     # 2019-12-26T14:06:34.424Z,EclipseExit,moderate:true,long:false,orbit:471
> 
>     SetLongEclipseFlag TRUE $TIME=2019/12:26:10:45:00
> 
>     SetLongEclipseFlag FALSE $TIME=2019/12:26:14:10:00                                    
> 
>                                                      
> 
>     IBX-CLC-016: No command to enable spin pulse protection was found after
> 
>                  transition to science mode at 2019/12/17 16:59:35 UTC
> 
>     IBX-CLC-016: No command to enable spin pulse protection was found after
> 
>                  transition to science mode at 2019/12/22 01:37:50 UTC
> 
>      
> 
>     ==============
> 
>     OTHER MESSAGES
> 
>     ==============
> 
>     NO MESSAGES.
> 
>      
> 
>      
> 
>     Thanks,
> 
>      
> 
>     Sheral  R. Wesley
> 
>     Principal Engr. Satellite Systems
> 
>     ICESat-2 Mission OPS Lead
> 
>     IBEX , OCO2 Mission OPS
> 
>     CRS/CYGNUS Mission Planning
> 
>     Northrop Grumman Innovation Systems
> 
>     Bldg. 2   Room 1337
> 
>     Cell (202) 236-0802
> 
>      
> 
>      
> 


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