POLAR Telecon Agenda for January 26, 2007

  

Agenda:

 

0. Upcoming Polar Telecon

1. Polar Extended Mission

2. Polar-THEMIS Science Coordination

3. Operations

4. Polar SWT Meeting

5. MFE Data Processing Status

6. MFE Science Report

 

0.  Upcoming Polar Telecon

 

Friday January 26, 2007

4 pm ET, 3 pm CT, 2 pm MT, 1 pm PT

PIs and their designated representatives will be telephoned at their usual numbers.

Other participants may call in at:

1-888-469-1668, Password POLAR TELECON

(Leader: John Sigwarth)

 

The web site for the final agenda will be:

http://pwg.gsfc.nasa.gov/polar/telecons/2007Jan26/

 

Future Polar Telecons

Next telecon: Friday February 23, 2007

Future Telecon Science Discussion Schedule

 

[Errors/omissions/preferences to: nicola.fox@jhuapl.edu]

 

February 2007:  CEPPAD

March 2007:  TIDE

April 2007:  PIXIE

May 2007:  UVI

June 2007:  MDI

July 2007:  CAMMICE

August 2007:  VIS

September 2007: TIMAS

October 2007: EFI

November 2007: Hydra

December 2007:  MFE

 

1. Polar Extended Mission Approval

 

We are delighted to report that NASA/HQ has approved our request for a final 6-month extension of the Polar mission.  In a message from Chuck Holmes, we were informed that NASA/HQ has approved our request to extend the Polar mission operations to the end of September 2007.  We have been given a small amount of additional funding for the operation of the instruments and for bare-bones operation of the spacecraft.  We have been directed that the primary science objective for Polar will shift to complementing the commissioning and early science operations of THEMIS and that we continue to provide processed data for the benefit of the THEMIS investigators.

 

The combined thrust from the small amount of remaining fuel and from the inert gas in the tanks will be expended in the final maneuver sequence scheduled for Feb 26-March 2.  The maneuver will aim for rotating the spin axis to orbit normal, but will likely fall well short.  The planned maneuver is designed to keep the EFI antennas out of the spacecraft shadow and increase the available auroral viewing time.  This will extend the working life of Polar to September.  After this, the spacecraft battery radiators will be in sunlight, causing the batteries to overheat and to fail after an unknown amount of time.

 

Note that this is the final extension of the Polar mission and the operations of the spacecraft are to be terminated at the end of this extension period.

 

We are extremely grateful to NASA/HQ for approving this final extension.

 

2. Discussion of Polar-THEMIS Science Coordination

 

Chris Russell will lead a discussion on proposed ideas for coordinated Polar and THEMIS science.  The material for this discussion can be found at:

 

http://www-ssc.igpp.ucla.edu/polar/Telecon_2007.html

 

3. Operations

 

If you have any concerns about Polar operations, please contact Nicky Fox (nicola.fox@jhuapl.edu)

 

Sun Angle maneuver

 

The Polar team successfully executed Attitude Adjust Maneuver #10 on January 9, 2007. The commands to start the maneuver were on time at 15:00:02z and the FOT verified 488 pulses. The spin rate after the maneuver was within range but still fluctuating around 9.99 RPM. It appears that the entire maneuver was conducted with fuel with no signs of using the inert gas yet.

 

Upcoming Polar maneuvers

 

The next Polar maneuver is currently scheduled for February 26 - March 2. The Polar operations team is meeting weekly to discuss this attitude adjustment. It is planned that we will attempt to orient the spacecraft as close to orbit normal as possible expending the remaining fuel and inert gas in the tanks.  The possible range of sun angles is illustrated in the accompanying sun angle figure.  It is estimated that the remaining thrust is equivalent to ~ 2 kg of fuel.  If this estimate is correct, the spin axis will be approximately 15 degrees from orbit normal.  This orientation will keep the EFI antenna out of the spacecraft shadow until August and allow 10 hours of imaging centered on perigee.  The remaining 8 hours of the orbit will be used for science mode 2 operations.

 

GTM-like Upsets

 

1. On 12/17/06 (DOY 351) between 11:29:59-12:15:32 UT, the Polar spacecraft experienced an upset that can best be described as a GTM upset that affected serial telemetry from only 3 instruments: HYDRA, TIMAS, and MFE. The exact time cannot be determined due to a gap in the data. During the 1630 support with station D46, telemetry indicated that the HYDRA write protect flag was enabled, TIMAS HV off, and MFE flipper in an undefined position with magnetic vector data not updating. Normally, the HYDRA write protect flag is enabled; TIMAS HV is on, MFE flipper is in the left position with azimuth and elevation telemetry updating. During the next support with station D46, the FOT sent commands to return instruments to nominal operations.

 

2. On 01/26/07 (DOY 026) between 00:30:00-05:07:00 UT, the Polar spacecraft experienced an upset that can best be described as a GTM upset that affected telemetry from only 2 instruments: HYDRA, and TIDE. The exact time of the anomaly is still under investigation. A mode change in the SCT load at 05:07 likely recovered the telemetry. Configuration monitor violations near the beginning (05:52:36 UT) of the 0545 support with station D24, indicated that the HYDRA write protect flag was enabled and TIDE was upset.

TIMAS and CEPPAD telemetry appear to be nominal. The MFE flipper remains in an undefined position from the last upset on 12/17/06. However, MFE magnetic vector data (Bxyz for Az/El data) is updating. During the support with station D46 from 1420-1545, the FOT sent commands to recover the TIDE instrument.  Below is a summary of events:

 

025/00:30:00-026/05:07:00   GTM type upset affecting HYDRA, TIDE

026/14:30:34            TIDE HV_OFF

026/14:31:44            TIDE Reset

026/14:57:28            Loaded TIDE patches

 

TIDE HV_RAMP and HYDRA commanding will continue on Monday DOY 029 at ~15:20 UT (DOY 026 remaining support is downlink only).

 

A corrupted data stream as well as impacts to the instrument serial telemetry has accompanied GTM upsets in the past. Upsets are corrected by executing the GTM recovery procedure that includes sending a mode change command. Previous instrument only upsets have been re-classified as probable GTM upsets. This was the twenty-second upset to occur since November 10, 2003 (all on GTM-2) and the twenty- sixth since launch (including GTM-1).

 

GTM upset history:

 

         GTM-1 Upset Events

o       -May 6, 1998 (DOY 126, 08:15:27)

o       -September 30, 1998 (DOY 273, 14:00:05)

o       -October 22, 1998 (DOY 295, 21:48:50)

o       -September 22, 2000 (DOY 266, 01:26:44)

 

         GTM Switch March 27, 2001 (DOY 086, 22:00)

 

         GTM-2 Upset Events

o       -November 10, 2003 (DOY 314, 18:26:38)

o       -November 17, 2003 (DOY 321, 15:13:36)

o       -November 24, 2003 (DOY 328, 16:38:08)

o       -December 6, 2003 (DOY 340, 21:44:27)

o       -December 18, 2003 (DOY 352, 09:37:02)

o       -February 12, 2004 (DOY 043, 03:04:52)

o       -March 3, 2004 (DOY 063, 20:14:33)

o       -April 3, 2004 (DOY 094, 09:04:59)

o       -July 29, 2004 (DOY 211, 20:51:19)

o       -August 27, 2004 (DOY 240, 14:06:55)

o       -November 13, 2004 (DOY 318, 18:37:34)

o       -January 4, 2005 (DOY 004, 03:05:43)

o       -January 21, 2005 (DOY 021, 04:00:58)

o       -February 23, 2005 (DOY 054, 21:01:53)

o       -May 21, 2005 (DOY 141, 09:04:54)

o       -June 3, 2005 (DOY 154, 07:57:08)

o       -June 12, 2005 (DOY 165, 22:14:31)

o       -July 31, 2005 (DOY 212, 17:40:46)

o       -September 12, 2005 (DOY 255, 16:28:13)

o       -April 18, 2006 (DOY 108, 20:11:13)

o       -December 17, 2006 (DOY 351, 11:29:59-12:15:32)

o       -January 26, 2007 (DOY 026, 00:30:00-05:07:00)

 

  Other GTM upsets have been preceded by significant solar activity in the days or weeks leading up to a GTM anomaly. The GTM is restored by commanding to a given telemetry mode. An Anomaly Review Team report was released on April 22, 2004 to close out the anomaly. A Standard Operating Procedure (SOP) has been generated specifically for the FOT identification and recovery of a GTM upset to streamline the recovery process.

 

 

 

Unattended Weekends

 

The 12 hour shifts during the weekdays are still being covered as usual and the MOC staff has a pager to cover emergencies on the weekend.

MOC staff pager: 301-224-0386

 

Mike Machado should be contacted by cell phone for instrument emergencies.

Mike's cell phone: 443-694-4317

 

4. Polar SWT Meeting

 

Date for your calendar – April 3-4, 2007. Please send ideas for agenda items to Nicky (nicola.fox@jhuapl.edu)

 

5. MFE Data Processing Status

 

MFE Status Report

 

6.  The MFE Science Report

 

http://www-ssc.igpp.ucla.edu/polar/Telecon_2007.html