POLAR PI NEWSLETTER - FEBRUARY 2004

POLAR TELECON: Friday 27 February 2004 4pm EST, 3pm CST, 2pm MST, 1pm PST

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

Other participants may call in at: +1-888-889-1956, password POLAR TELECON

(Leader: John Sigwarth)

 

The web site for the final agenda will be:

 

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

 

 

Preliminary Agenda

1. Budget Update and Planning for Future Funding
2. GTM Upsets
3. MFE Status
4. Sun Angle Maneuvers and Plan
5. E/PO updates
6. CAWSES Campaign March 29-April 2, April 19-23
7. Science Discussion: PIXIE

Tentative CY04 Science Discussions
[Errors/omissions/preferences to:  john.b.sigwarth@nasa.gov ]

Feb 2004:  PIXIE
Mar 2004:  SEPS
Apr 2004:  UVI
May 2004:  PWI/MDI
Jun 2004:  CAMMICE
Jul 2004:   VIS
Aug 2004:  EFI
Sep 2004:  TIMAS
Oct 2004:  HYDRA
Nov 2004:  MFE
Dec 2004:  CEPPAD
Jan 2005:  TIDE

 

Budget Update and Planning for Future Funding

 

The Presidentâs New Lunar/Mars initiatives are having major impacts on SEC. The MIDEX AO has been delayed at least one year. The MMS down selection and launch will be delayed. The Jupiter Polar Orbiter, Geospace Electrodynamics Connections, and Magnetospheric Constellation will be delayed beyond the time frame of the budget projection.

 

NASA had projected to terminate the investigations of four currently operating missions (including Polar) during the time period of the budget FY 2005-2009.  The FY 2005 President's budget, if approved, will force the termination of an additional six missions as early as FY 2006. The senior review is being used to determine which missions will be turned off with the lowest priority missions being turned off first.

 

The current budget exercise has Polar turning off in September, 2005, some science analysis in FY 2006.This is unchanged from the plan since the results of the Senior Review. There will be mini-reviews in March, 2004. The actual POP for the budget comes in April, 2004.

Other issues potentially impacting the Polar budget.

Consideration is being given to moving the next Senior Review to the summer of 2005. Given the fuel situation on Polar, the minimum end-of-life for Polar is December, 2005. The maximum end-of-life for Polar is around December 2007. See the discussion below on the Sun Angle Maneuvers and Plan.

 

We need ideas from the Polar PI teams on the scientific themes for Mission Life beyond September 2005. We need those by COB, Friday March 5.

 

 

Spacecraft Upsets

Another GTM anomaly occurred on February 12 at 043/03:04:52 UT while the spacecraft was out of contact. This was the sixth upset to occur since November 10, 2003 - all on GTM-2 - and the tenth since launch. TIMAS and TIDE suffered telemetry latchups, and the MFE ADC was reset. During the support at 17:10-18:20, the GTM anomaly was cleared; TIMAS was returned to operation; the MFE ADC was recovered but the flipper remained in an undetermined position; the HYDRA eeprom write-protect flag was cleared. TIDE was restored during the contact at 044/00:10-02:10.

 

The assumption is that radiation-produced SEUs or deep dielectric charging are producing the upsets, although no definite cause has been found as yet. The Anomaly Review Team is studying the system documentation in an effort to overcome these problems.

 

Note: an attempt was made to switch the PSE back to the original side on 12 Jan. The command was successfully received by the spacecraft, but failed to change the state of the Mode Controller. The command was sent a second time from the STOL procedure at 04/012/23:23:06. Again, the spacecraft acknowledged receipt of the command, but no change of state occurred. A separate Anomaly Review Team is also investigating this problem. The team was due to reconvene last week but the meeting was postponed to allow further analysis of the issues. It is hoped that the team will meet this week so that an update can be given at the telecon on February 27, 2003.

 

TIDE, TIMAS Response to GTM Upsets

TIDE and TIMAS, which share a common DPU architecture, both are safed automatically during the GTM anomalies, but are readily restored to full operation, albeit requiring real time passes for high voltage ramps. In at least one case of a fast recovery, though, TIDE came through an upset recovery running normally. After the anomaly review, it was hypothesized that TIDE and TIMAS are reacting to the interruption of the s/c clock signal, but during recovery from the most recent upset, this clock was not interrupted, and both instruments still had the same problem with being automatically safed. Everyone involved is seeking to determine a way to prevent this effect on TIDE and TIMAS.

 

Hydra HV Anomaly

After the recent GTM reset on 12/19, one of the Hydra electron detector bias supplies was automatically safed after recording a current overage, and behaved anomalously upon being ramped. It was therefore shut off while further analysis was carried out by Jerry Needell. On 1/9/2004 the anomalous Electron Bias Supply was turned back on and has been operating at it lowest energy setting since then. This allows the detectors to be used for monitoring some background count information. The subsequent GTM upsets have not caused any additional problems.

 

MFE Status from the MFE Team

This MFE flipper status flag was thrown into an indeterminate state by the GTM upset on 12 February, and was corrected on February 18. The flipper did not change position, only the flipper status telemetry was affected. The MFE data should not otherwise be in error, but software that uses this flipper status flag will have problems.

 

Science mode 2 magnetometer data reaches the ground via two paths. The UCLA data stream contains 20 Hz data and the Hydra data contains 54 Hz data. UCLAâs data stream passes through an underpowered microprocessor that can just handle the 20 Hz data when the flight spare is used but cannot completely keep up in the spacecraft environment. The MFE team can adjust which vectors will be dropped but they cannot prevent the occurrence of a few dropped vectors. They view this as an annoyance rather than a serious issue. Thus they propose just to tweak their in-flight software a little and continue to process these data and supply them to the community as usual. The MFE processing software has been revised now to handle the Science mode 2 fairly automatically, with a modicum of special handling. The only issue is what to do with the Hydra data.

 

The magnetometer data transmitted by Hydra are an important set of data. The 20 Hz data that UCLA obtains in Science mode 2 has the same as low frequency filter as our 8 Hz data stream in Science mode 1. The Hydra data stream has a higher corner frequency appropriate to the 108 Hz data from whence it was derived. Since this corner frequency was conservatively chosen, the data should have little aliasing even having been decimated by a factor of two to obtain the 54 Hz data. Forrest Mozer in fact was surprised at how smooth these data were. These data would be ideal for studying the magnetopause and tail current systems.

 

The MFE team proposes that Iowa send the 54 Hz data files to UCLA and they will despin these data and make them available to the community. The work in developing timing-tables etc. is equally applicable to the 54 Hz and 20 Hz data sets. Thus it is not much extra work.

 

Science Mode 2 Operations Plan

In General:

The default plan will provide for acquisition of images in Mode 1 during the ecliptic crossings of the POLAR orbit, for those portions of the orbit when the horizon sensor can see the Earth and the platform can be controlled. In-situ science in Mode 2 will be done throughout the remaining orbit period and at any time when imaging is impractical because of sun angle or maneuvers.  Each operations segment will have a minimum duration of 2 hours to satisfy the MFE requirement.

For sub-solar magnetopause science (local noon +/- 3 hrs):

The spacecraft will operate in Science Mode 2 at all times except for the prime imaging period for each orbit.  The prime imaging period is defined as follows:  In the 3 out of 4 orbits on average for which the southern auroral viewing is not optimal, the Mode 1 imaging period will begin 1-hour before horizon sensor loss of the Earth.  In the 1 out of 4 orbits on average for which the southern auroral viewing is optimal, the Mode 1 imaging period will begin when the horizon sensor acquires the Earth.  In both cases the total length of the Mode 1 period will be 2 hours to satisfy the MFE requirement.  The remaining time on each orbit (16.4 hours) will be dedicated to in-situ science with telemetry Mode 2.

Rationale:
This approach balances two imperatives from our Senior Review Proposal: 1) to place priority on in situ magnetopause science during the season when the spacecraft encounters the magnetopause frequently, and 2) to provide supporting context imaging for periods of magnetopause science, as well as periodic global monitoring of the dayside hemisphere airglow.

With this plan, of the possible 73.5 hours in the 4 orbits, 65.5 hours are in Mode 2 (in-situ) and 8 hours are in Mode 1.  That is, 89% of the available time is devoted to in-situ observations.  Of the Mode 1 time, only 5 hours are actual imaging time. This is ~7% of the total time. 

More importantly for the most interesting interval for the in-situ measurements near the dayside magnetopause from apogee at 9.55 RE into 6.2 RE, the highly valued observational time is approximately 6.17 hours per orbit or 24.7 hours in total for the 4 consecutive orbits.  Of these 24.7 hours, 19.7 hours are devoted to in-situ observations in Mode 2.  Consequently with this plan, 80% of the high priority time is devoted to in-situ observations.

In addition, for the 1 out of 4 orbits on average for which the southern auroral viewing is optimal and the imaging period covers the first 2 hours of Earth horizon acquisition, the remaining time will be spent in Mode 2 to allow the in-situ instruments to observe magnetopause crossings from 7.0 RE inward.  The northern auroral oval will be tipped away from Polar on this orbit and the auroral view will be poor and can better be used by the in-situ instruments to capture large compressions of the magnetopause.

 

Representative plots of 4 consecutive orbits indicating Science Mode telemetry and data priority are available at the web site.

2004/048-19:42

2004/049-14:27

2004/050-09:24

2004/051-03:48

 

Sun Angle Maneuvers and Plan

As expected, the EFI shadow spikes resumed on 27 December, however a planned maneuver on 7 January was completed successfully, and currently the EFI shadow spikes are not an issue. A further attitude adjustment maneuver on March 1 will ensure that this continues through the winter/spring season on the dayside. With the maneuver planned on March 1, EFI is expected to remain outside of the shadow through the summer and early fall.EFI shadowing is expected to begin again in November 2004. The impacts of the shadowing on the EFI data are illustrated in these two figures:

Two minutes of EFI data

Twenty seconds of EFI data

 

For the period beginning in November, 2004, the long range plan for sun angle maintenance and propellant use needs to be formulated to optimize the science data acquired.

 

Option 1. Maintain the spacecraft attitude to keep EFI out of the spacecraft shadow region on a continuing basis. This option would maintain the sun angle at greater than 91.4 degrees through December 2005. In January 2006, the sun angle would drop below 87 degrees and the spacecraft batteries would die from overheating. The downsides to this are more frequent maneuvers, running out of fuel in October 2005, and the spacecraft dying due to thermal conditions in January 2006.

 

The plot for Option 1 shows the EFI shadowing zone in yellow. The blue vertical lines indicate the dates for Polar at local noon, while the dark red vertical lines indicate the dates for the Polar orbit at midnight. Discontinuous jumps in the plotted curve occur at maneuvers.

 

Option 2. Maintain the spacecraft attitude to keep UVI out of thermal danger and giving a best effort to keep EFI out of the spacecraft shadow. UVI requires the sun angle to be greater than 89 degrees. This option would stretch the mission lifetime to December 2007. The downsides are limiting magnetopause observations in early 2005 to a 2-month window, no magnetopause observations in 2006 and 2007, seasonal EFI shadowing during some other periods, and Polar may be turned off well before then.

 

The plot for Option 2 shows some operation in the EFI shadowing zone in yellow. Again the blue vertical lines indicate the dates for Polar at local noon, while the dark red vertical lines indicate the dates for the Polar orbit at midnight. Discontinuous jumps in the plotted curve occur at maneuvers.

 

Education and Public Outreach Update

 

Plans for the "Best of Polar" DVD are still moving ahead and we are now working with a group of graphic artists and animators to create the necessary visuals. A number of PI teams have been asked to assist with this effort and we appreciate any help that you are able to give the team.

 

 

On March 5, 2004, the Polar team will be supporting a COMCAST/Discovery channel Space Academy event hosted by the Johns Hopkins University/Applied Physics Laboratory. The topic is Space Weather and Polar is the main featured mission. The day involves about 120 middle school students from Maryland and includes a briefing on Space Weather, a student ãpress conferenceä (where students have the opportunity to ask panelists questions regarding space weather, and the Polar and TIMED missions, in the format of an official NASA press conference), and tours of the space department featuring science demos, space environment facility, TIMED MOC, communications center, and viewing of the MESSENGER spacecraft.

 

SCOSTEP Climate and Weather of the Sun-Earth System ãCAWSESä

 

The Polar mission will be supporting the 1^st CAWSES space weather campaign, which will be running in association with the campaign of CPEA (Coupling Processes in Equatorial Atmosphere) and the ISR World Days in March or April 2004. The focus of the campaign will be the coupling between the high- and low-latitude ionospheres. The Campaign period is dependent on the magnetic activity but has been scheduled for March 29 - April 2 in order to accommodate the availability of the Arecibo radar (April 19 ö 23 is the fall back period should there be no geomagnetic activity during the earlier time). These campaigns are briefly described at http://www.haystack.edu/schedules/worldays_2004.html

 

An end-to-end modeling capability is the ultimate goal of solar terrestrial physics so that physical processes can be tracked throughout the entire Sun-Earth system. With CAWSES, the crucial need for a systems approach in solar-terrestrial physics is recognized. It is proposed to implement CAWSES in the period 2004-2008 to foster a scientific approach to understanding the short term (Space Weather) and long term (Space Climate) variability of the integrated solar-terrestrial environment, and for its societal applications. These include human activities in space, the need for increased reliability of technological systems whose performance depends on variations in the solar-terrestrial environment, and global changes in climate and ozone. Education will also play an important part in CAWSES.

 

CAWSES will accomplish the following specific objectives

• Articulate timely outstanding scientific questions in the connected Sun-Earth system, particularly in cooperation with other ICSU programs.
• Coordinate international aspects of specific national programs when the participating nations find this desirable.
• Provide a forum to bring together the international solar-terrestrial science community to help define future programs.
• Continue to help developing nations to participate meaningfully in international solar-terrestrial programs.  
• Provide scientific inputs for the purpose of specifying the environment for technological systems whose performance critically depends on solar-terrestrial variations. 
• Provide a coordinated environment in which computer modelers work within observational and analytical programs to achieve validated, reality-based end-to-end models of the entire Sun-Earth system, and then assist in the transition to applications. 
• Provide scientific inputs that help ensure human safety in space, since humans will be spending increasing amounts of time there. 
• Contribute solar-terrestrial information to the Global Change community.  
• Actively help international science education by providing solar-terrestrial information to the international educational community and promote scientist-and-student interactions. 
• Systematically review the quality of solar-terrestrial databases and derived information and improve metadata for solar-terrestrial products so that they meet scientific community needs. 
• Guide the World Data Center system of ICSU in providing needed STP data and information collecting, processing and archiving services in the modern Internet era.

 

  The first stage of CAWSES, is an activity to collect data records to document with increasing fidelity various aspects of the Sun-Earth system. Data records will be quality controlled to enable subsequent research to determine real variations separately from those resulting from data problems. A particular challenge will be the extraction of trustworthy geophysical trends from well-calibrated data sets. These data sets will then be disseminated via the World Wide Web to the international solar-terrestrial research community. Also, SCOSTEP will continue to cooperate with the World Data Center system of ICSU and to use its services.

    Along with the data intensive phase, the capability of using physically based models for assimilating observed data and deriving enhanced outputs for segments of the solar-terrestrial system will be assessed. This is a required step before physical models can be combined to form an effective end-to-end model of the solar-terrestrial system.

    Finally, it is of primary importance that participants in all SCOSTEP disciplines should welcome and support the program and participate in it from planning through implementation and utilization. In this way, the program will mobilize SCOSTEP researchers to work together to understand variability throughout the entire solar-terrestrial system.