POLAR Telecon Agenda for July 27, 2007
Agenda:
0. Upcoming Polar Telecon
1. New Polar Team Member
2. Operations
3. Polar SWT Meeting
4. Polar Mission Status
5. Polar-THEMIS coordination
6. Resident Archives
7. MFE Data Processing Status
8. PIXIE Science Report
0. Upcoming Polar
Telecon
Friday July 27, 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: 1-800-988-9524
Password: Polar Telecon
(Leader: John
Sigwarth)
The web site for the final agenda will be:
http://pwg.gsfc.nasa.gov/polar/telecons/2007Jul27/
Future Polar Telecons
Next telecon: Friday August 31, 2007
Future Telecon Science Discussion Schedule
[Errors/omissions/preferences to: nicola.fox@jhuapl.edu]
August 2007: PIXIE
September 2007: UVI
October 2007: MDI
November 2007:
CAMMICE
December 2007: VIS
January 2008: TIMAS
March 2008: EFI
April 2008: MFE
May 2008: CEPPAD
June 2008: TIDE
1. New Polar Team Member
Introducing James Daniel Sigwarth, born April 19th 2007
2. Operations
If you have any concerns about Polar operations, please
contact Nicky Fox (nicola.fox@jhuapl.edu)
Upcoming Polar Sun Angle maneuver
Previous estimates of Polar fuel used a bookkeeping method
that calculated cumulative thruster time-on and nominal fuel flow rates to
determine the fuel used and the fuel remaining in the tanks. However, there exists additional information
on the status of fuel in the Polar tanks in the form of pressure and
temperature. The fuel remaining can be
estimated from these values by using the ideal gas law (PV=nkT). Revised analysis using these pressures and
temperatures indicates that Polar may have ~14.8 kg ± 7.9 kg remaining in the
system (see the figures on Polar fuel
remaining). Approximately 6.8 kg of
fuel are required to achieve a 180° flip.
Consequently, it is likely that enough fuel remains to perform 2 flips
of 180°.
The first of these two flips will occur August 21-22, 2007.
A detailed operations plan will be distributed shortly. The final flip is planned for February, 2008
High Sun Angle Low Power Issues
For operations at orbit normal, four low power seasons are anticipated per year. Two of these are due to the eclipse seasons and two of these are due to high sun angle periods. The spring eclipse season is typically benign; the fall eclipse season is of primary concern due to the longer maximum eclipses. The fall eclipse season this year is from 8/2/07 - 9/04/07. The high sun angle periods are in the May/November time frames. Shedding loads during low power seasons are dependent on the solar array/battery capacity which is affected by maximum eclipse duration/sun angle. Depending on the predicted maximum depth of discharge, loads are shed to avoid falling below the voltage protection limits. Under-voltage protection can be disabled instead of shedding loads, but the project has never elected to proceed with that risk during low power seasons. Polar maneuvers are typically performed during the eclipse season, meaning instruments are off or in low power mode already.
It has been a long
time since Polar experienced a low power season due to high sun angle (1998). Unfortunately, due to solar array degradation
over the years, Polar no longer has the power output that it did in 1998 and
must resort to shedding loads to remain power positive and prevent the battery
temperatures from going past the point of no return on the cold side. In May, Polar experienced the latest high sun
angle low power season. Real time
contacts were reduced to the minimum required for data recovery. PWI, CAMMICE/HIT, TIDE, and TIMAS were
powered off to achieve a power positive condition. Polar returned to normal operation Monday June
4.
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
3. Polar SWT Meeting
Based on inputs from the science teams we have decided to
delay the Science Working Team meeting until mid-September. Please look at your
calendars and be ready to suggest suitable dates
Please send ideas for agenda items to Nicky
(nicola.fox@jhuapl.edu)
4. Polar Mission
Status
Dick Fisher at NASA/HQ has authorized
the requested extension to the Polar mission in order to support the THEMIS
tail science campaign in early 2008. This will be the last extension to
Polar.
We have been given
the following explicit instructions:
1) Operations of the
Polar spacecraft may close down prior to the end of the
THEMIS tail science
campaign on April 15, 2008.
2) End of operations
includes the passivation of the spacecraft, the closeout of the ground
operations activities, etc.
3) The instrument
teams need to complete their data processing activities.
4) Seek the advice
of the THEMIS PI and Project Scientist on which Polar instruments to emphasize
during this final phase of the Polar mission.
Adjust the instrument team budgets accordingly.
5) These instrument
teams need to continue to provide 'quick look' information observed by their
instruments to the THEMIS project during the remainder of Polar mission.
Congratulations on
the continued success and accomplishments of the Polar mission.
5. Polar-THEMIS coordination
As we reported above, the Polar mission has been granted an
extension to April 2008 by NASA/HQ. In
this extension the Polar Project has been directed to support the THEMIS
mission to the maximum extent possible.
Since our most recent Polar maneuver returned the spacecraft to orbit
normal, Polar is again collecting auroral images for approximately 12 hours out
of each 18.5 hour orbital period and the Polar apogee is high over the South
Pole and will remain in that region for the next year.
Some of the ideas for THEMIS-Polar coordinated science were
discussed at the January Polar telecon. These ideas included a magnetopause
campaign and an auroral acceleration campaign with THEMIS ground-based and
in-situ tail observations and Polar in-situ observations of the acceleration
region. If Polar can operate through April of 2008, it will be in position to
support the main magnetotail science of THEMIS.
6. Resident Archives.
Please note:
The call for resident archive maintenance (i.e. the
follow-on funding for your resident archive) is in the current ROSES FY2007
solicitation, appendix B9, section 1.3.
The notice of intent is due September 12, 2007 and the proposals are due
November 15, 2007. The Polar funding
will be running out by the time these proposals are selected so propose to this
call for maintenance of your resident archives beyond the end of the Polar
mission.
Keep in mind that a
Resident Archive grant will not support additional processing or reprocessing
of data. Also note that NASA/HQ is preparing an amendment to B.9 that
should be on NSPIRES in July or early August.
As we discussed at the telecon in March, we need to return
to the issue of finalizing the resident archive plans and their implementation.
The Polar Science Team had agreed previously on the following Guiding
Principles to aid in the development of the Polar resident archive environment:
1. The resident
archives are to be distributed at the PI institutions or their designated
locations where the expertise in handling the specific data resides.
2. The resident
archives should provide the highest available resolution (spatial and
temporal).
3. The resident
archives should be designed for minimal human support.
4. The data in the
resident archive should be available to a requestor without human intervention.
5. The archive should
provide for virtual observatories dynamic access to the full data set.
6. Every site should allow plots of the data, either
previously made or made on demand.
7. Every archive should
allow ASCII downloads of low and high resolution data for re-plotting by the
requestor.
8. Positional and
attitude information for the Polar spacecraft should be provided at one or more
sites.
9. Every site should
provide direct links with brief descriptions of every other Polar site.
10. Documented
procedures for producing scientifically useful data from the Polar instruments
will be made available and will be a fundamental element of the resident
archives.
In this telecon we will review the UVI resident archive
status report. At the next telecon CEPPAD
and CAMMICE teams will be asked to provide similar reports.
These status reports should cover: What products need to be
made available to the community [images, survey plots, custom plots, analysis
software, documentation, etc.]? What is
the best method to provide these products?
Do we need to poll the broader community for input?
7. MFE Data Processing Status
MFE Status Report
