POLAR PI Telecon Agenda August 27, 2004
POLAR TELECON:
PIs will be telephoned at their usual numbers
Other participants may call in at: 1-800-988-0215, password POLAR TELECON
(Leader: John Sigwarth)
Agenda
1. Operations:
Load shed anomaly
Eclipse Season Operations
Next sun-angle maneuver
2. Next Senior Review
Solicit team opinion regarding whether we should go for another 2 years operations
Discuss approach to the Senior Review proposal
Polar Science Team Meeting at AGU
3. E/PO Update
The web site for the final agenda will be:
http://pwg.gsfc.nasa.gov/polar/telecons/2004Aug27/
Tentative CY04 Science Discussions
[Errors/omissions/preferences to: john.b.sigwarth@nasa.gov
Sep 2004: MDI
Oct 2004: CAMMICE
Nov 2004: VIS
Dec 2004: no telecon due to AGU meeting
Jan 2005: EFI
Feb 2005: TIMAS
May 2005: CEPPAD
June 2005: TIDE
July 2005: PIXIE
Sep 2005: UVI
Future Polar Telecons (tentative dates)
Friday, September 30, 2004
Friday, October 29, 2004
Friday, November 19, 2004
Most of the PI teams are on the final year of their 3-year grant. New
proposals will be accepted for new grants to be issued for these PI
teams. In order to assure continuity of funding, please be prepared to
send 1) final reports and 2) proposal for new grants at least 2 months prior to
the end of your grant. For those PI teams on contracts, please submit 1)
the annual report and 2) a proposal to continue funding under the existing
contract at least 2 months prior to the end of your current contract end
date. Early next week, John Sigwarth will telephone all of the PIs to
discuss the status of their current grant or contract, level of effort, and
expected funding levels.
A load shed event occurred on 29 July 2004 (DOY 211) when the spacecraft was about 5 hours from Perigee and 4 hours before Apogee.
FOT experienced a negative acquisition during a DOY 211, 2120 GMT pass at DSS-46 (Canberra). Station troubleshooting yielded negative results. The FOT tried switching to DSS-34 with no results. Four attempts were made to turn on the transmitter in Comm. Mode 5 (normal communications mode with transmitter #1 and Solid State Power Amplifier [SSPA] #1). Predicts were checked and found to be correct. At the next pass (DOY 212, 0210 GMT, DSS-66 [Madrid]) the FOT again experienced a negative acquisition. After two more attempts to acquire in comm. mode 5, the FOT placed the S/C in Comm. Mode 10 (transmitter #2 and SSPA #2) and received garbled telemetry. The FOT next attempted to reset GTM #2 using the normal procedure, which triggers an on-board macro to perform the reset. This failed and the FOT used manual commands to reset the GTM and began receiving good telemetry. It was then found that the S/C was had entered safe mode and shed all non-essential loads. The load shed flag indicated an under voltage condition. This load shed event can only occur if the voltage on all three batteries drops below the threshold limit of 21.0V.
The load shed event caused all of the instruments to be turned off with the survival heaters enabled.
Analysis of the data indicates a possible single event upset (SEU) or bulk charging event in either the Power Supply Electronics (PSE) or Command Decoder Unit (CDU). Telemetry shows that the battery voltages never dropped to the load shed threshold. Telemetry also indicates no power problems with the primary transmitter/SSPA string. It was found that the S/C on-board macros were disabled by the load shed flag, thus the failure of the normal acquisition sequence for the primary string (the commands for the secondary string were via ground command instead of executing an on-board macro).
Analysis will continue to further isolate the cause of the load shed event. Preliminary analysis indicates possible relations to solar weather. This Figure shows that the magnetic storm caused >2 MeV electron fluxes at geosynchronous orbit to reach a new 20-year high on July 29th, 2004 of 8.0E+4 cm-2-s-1-sr-1. This new high is nearly a factor of 3 more intense than the previous high observed by GOES on September 3rd, 1987, 2.8E+4 cm-2-s-1-sr-1. Also HEO3 observed high dose rates per orbit with particularly hard high energy spectra.
In addition to the high radiation environment, there is also an issue of wear on the aging PSE or CDU that make either component more susceptible to SEUs. Last year the Mode Controller in the PSE was switched to the redundant side due to a failure.
The FOT began bringing instruments on-line on Monday, 8/2/2004 (DOY 215). By Saturday evening, 8/7 (DOY 220), all instruments were completely up and running: This was a great achievement and our thanks to the whole team for their superb efforts. I know that we all tend to deal with just one or two people over in the FOT, but so you know the people who performed so valiantly: Joyce Ross, John Wainwright, Bob Gardiner, Andre Jenning, Aurora Labador, Chris VanDyke, Mike Machado, Mark Carder, and Steve Odendahl
The Fall eclipse season began August 26, 2004 and will go through September 14, 2004. The longest eclipses are 124 minutes. Eclipses longer than ~ 90 minutes cause deep discharges of the spacecraft batteries. Consequently, power is being conserved during this 3-week period.
Under normal operating conditions, the spacecraft load sheds if the battery voltage drops below 19.2 V. In previous Fall eclipse seasons, the load shed was disabled and power was conserved by powering down all or some of most instruments. The Polar spacecraft can continue to operate on battery voltages as low as 18.4 V. This fall in addition, spacecraft contact schedules during this time period will be impacted by the return and recovery operations for the Genesis program. This has led to contact gaps in excess of 18 hours. Consequently the load shed WILL REMAIN ENABLED for spacecraft safety.
For this eclipse season the operations plan is:
Aug 25:
Aug 26: HIT Power off (
Aug 27: TIDE HV off (
Sep 1: TIMAS HV off
(
Sep 2: CEPPAD Power
off (
Sep 9: TIDE HV on (
TIMAS HV on (as soon as TIDE is finished)
Sep 10: CEPPAD Power
on (
HIT Power on (as soon as CEPPAD is finished)
Sep 13: Backup
contact for CEPPAD Power on (
Sep 14: Backup contact
for HIT Power on (
Sep 14 & 15: VIS HV ramp up
Contingency (to be executed as needed for power management during season)
TIMAS HV off
CEPPAD off
HYDRA HV off
As noted above, due to the
lengthy periods between contact times, we have decided to not disable load shed
as was done in previous years. This has meant that we have had to be more
conservative with the power management plan than we had hoped. We would like to
thank the PIs for their willingness to support this effort. We have created a
two stage operation plan in the hope of minimizing the inconvenience to the
instrument teams. During the initial eclipse season, only
If you have any concerns about this operating procedure, please contact Nicky Fox (nicola.fox@jhuapl.edu) as soon as possible.
Sun Angle Maneuver and Plan
The next Polar spacecraft
maneuver is planned for
The 2005 Senior Review
It is time to begin plans for the upcoming Senior Review process. The first item to clarify is whether we, as a team, feel that we should attempt to secure another 2 years operations funds for Polar. At present, we are scheduled for another full year of operations through September 2005. At that time our funding will be reduced to allow for data processing and analysis only. When we submitted our Senior Review proposal in 2003, it was thought that we would only have enough fuel remaining to allow us to safely operate the spacecraft until September 2005. However, upon further detailed analysis, we now estimate that we would be able to continue through December 2007. In short, we know that we have the necessary spacecraft resources but we need to ensure that we have the support from each of the teams.
In order to make the proposal thrust different from previous years, one suggestion has been to stress “System Science” i.e. we are no longer trying to show what we can do as an individual mission, but more how we are crucial to the Sun-Earth system studies as a whole. We want to look for synergy with Cluster and other geospace missions, and also try to bring in studies involving solar missions – can we pursue something with reconnection in the magnetosphere and in the corona for example? We also need to ensure that our science goals are clearly identified within the Research Focus Areas from the OSS Strategic Plan
Polar will make high-altitude measurements of the auroral acceleration region in collaboration with the THEMIS ground-based component – which will be deployed and tested in 2005. This will fully utilize the high bit-rate telemetry mode for in-situ measurements of the field-aligned currents together with the comprehensive northern hemisphere network of ground stations observing the ionospheric currents and auroral structures.
In addition, Polar will
collaborate with the FAST spacecraft in order to make simultaneous high and low
altitude observations of the auroral acceleration region with the UVI and
- need to get an update of the FAST orbit
- produce plot with both Polar and FAST orbit trajectories together to highlight collaborative campaign
- add THEMIS ground station locations to plot
Long-term Radiation Belts Statistics (expand current knowledge to
include the declining phase of the Solar Cycle).
It is known that the radiation belts behave differently during the
declining phase of a solar cycle. In early 2005 and continuing through
2007, the Polar orbit will be ideally situated to cross through all zones of
the radiation belts again through this declining phase of the solar cycle and
continuing down to solar minimum. The long baseline of Polar measurements
will be an invaluable resource for radiation belt modelers for the next half
decade.
- need to look into the availability of SAMPEX data for this period. If they are still taking data and actively using them, we should look at collaborative studies. If not, we should show that we have a crucial dataset that fills the gap left by SAMPEX
Revisiting the cusp with high temporal resolution
Polar in conjunction with Cluster can be used to resolve spatial-temporal
ambiguities in the cusp. With Polar in its high bit rate telemetry mode
for in-situ measurements details of the cusp not accessible before will now be
observed. We will study wave structures in the cusp, which would not be
possible without the high bit-rate data mode.
A suggestion was that Polar could get a second look with higher temporal resolution at the high-energy particles in the cusp, as the origin of these high-energy particles has been the subject of considerable controversy. Is this possible as only EFI, MFE and Hydra can take advantage of the increased data rate? Is the energy range of Hydra suitable to do this analysis? If CEPPAD or CAMMICE are required then we cannot claim the high data rate will give us anything that we have not had before. However we can be do collaborative studies of the cusp with Cluster.
Other suggestions for candidate science topics
- End to end energetic particle studies
- Inputs to Earth climate
- Configuration of magnetospheric system
- Conjugacy of Cluster in the northern hemisphere with Polar in the south – in particular conjugate reconnection during northward IMF periods
Structure the accomplishments section against what we proposed last time. (This should also help us to identify where we can go next)
· Exploring Interhemispherical Asymmetries: Quantify the fundamental magnetosphere-ionosphere coupling processes influenced and controlled by interhemispherical asymmetries.
Also need to include information on how many other people use Polar data – how many SR&T, TR&T and GI grants use Polar data
Next Polar Science Team Meeting
There has been a suggestion to have a small focused meeting during one evening at the AGU meeting. This would be a similar format to the one held prior to the 2003 Senior Review. This will be an idea-swapping meeting. A small proposal team would be formed, with members appropriate to the new science topics. This team would meet in January for an intensive writing workshop.
This small gathering at AGU would be in place of the full-up team meeting, which will be scheduled for Spring 2005.
The meeting is tentatively planned for Monday evening at AGU (Tuesday SPA dinner, Wednesday banquet, and Thursday agency night)
The Best of Polar DVD is in the final stages of production, with the animations, visuals, narrative, and on-camera interviews all complete. A number of PI teams have been assisting with this effort and we appreciate any help that you have given to the team.
The working title is “Earth's Dynamic Space: Solar Terrestrial Physics & NASA's Polar Mission". Any suggestions for a more catchy title are very welcome
The Polar DVD will be included in next year’s Sun Earth Day package and also distributed at the NASA teacher workshop throughout next summer. We are very pleased to have been invited to join this effort which will result in us reaching over a hundred thousand students of all ages.
