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Compton Gamma-Ray Observatory Science Support Center
CGRO Users' Committee Meeting
Portsmouth, New Hampshire
September 14, 1999


In Person:
  Kevin Hurley - Chairman
  Volker Schöenfelder - COMPTEL
  Gottfried Kanbach - EGRET
  Dave Bertsch - EGRET 
  Bob Sodano - GSFC
  Brenda Dingus - University of Utah
  Don Kniffen - NASA Headquarters
  Edison Liang - Rice
  Jim Kurfess - OSSE
  Chris Shrader - GROSSC
  Dick Kroeger - OSSE
  Jim Ryan - COMPTEL
  Jerry Fishman - BATSE PI
  Bill Paciesas - BATSE OI

Via Phone:
  Neil Gehrels - GSFC
  Jay Norris - GROSSC
  Guenter Riegler - NASA Headquarters

WELCOME - 9 a.m.

A GRO USERS meeting may be scheduled for early next year to prepare
for the 2000 senior review if required.


PI team reports.  Representatives were asked to discuss:

  Instrument status
  Manpower and budget situation for the coming years
  Key projects planned
  Highlights of recent results


EGRET is not operating full-time during Cycle 8. 
EGRET has 8 weeks of scheduled observations in Cycle 8 with 3
remaining to be done.

There is no scheduled time in Cycle 9 (only ToO's), with the exception
of a calibration period where the target is near the Crab.

Last full gas exchange 4 years ago.  Accumulated 605 days of running. 

Failure of Chamber B in 1997.
Four of the coincidence phototubes have now failed.  The 28 remaining
are okay.
The rest of the hardware is functioning well.

Instrument Efficiency:
Study of instrument efficiency as a function of time and energy was
recently completed.

The efficiency is now a strong function of energy.  The efficiency is
about 23% of that at launch.  

Despite poor efficiency, it is still possible to detect strong sources
in a reasonable length of time, and to make useful measurements.

Other than civil servants, EGRET employs one full-time datatech, and
a payload specialist/programmer (working less than 20% of her time).
There are 2.3 FTE civil servant scientists at GSFC. 

Cost of FY00 of manpower and lab taxes totals $103K.

Key Projects Planned:
EGRET will only be operated in ToO mode in Cycle 9 with the main
emphasis on the sun.  EGRET can be triggered by BATSE.  If the sun
is very active, EGRET can be turned on in anticipation of a flare.

Recent Work:
Third EGRET Catalog has been published.
In-flight calibration paper for the period through Phase 4.
Working on reclaiming data that was rejected due to poor tracks
resulting from the low chamber efficiency.

Sensitivity undiminished.
Enhanced high-level scientific products via Web.
Analysis software developed and available.

Lost gain control of one detector (LAD 7) the result is some
degradation in quality, but no significant impact on science.

Instrument Efficiency:
Unchanged since launch.

  10 Contractors
  4 C/S
  2 other support

See chart for budget; BATSE team desires flat ~$500k funding rate
through 2005 (real dollars):

BATSE has greatly decreased its cost rate in recent years, but not as
fast as the funding level.

Key Projects Planned:
5th GRB catalog.
Rapid burst response:
  LOCFAST-I automated, GCN computer, ~ 2 minute delay
  LOCFAST-II automated, new computer, ~5-30 s delay
Occultation monitoring.
Pulsar period/intensity tracking.

All systems functioning without failures or degradation.
Continuing normal operations.
No backup systems have been activated.
Instrument background elevated since 1997 re-boost.
Manual screening of data is a bottleneck with current manpower
limitations and it may be discontinued.

2-1/2 FTE for instrument operations, production data processing,
manual data screening, data archiving.
Partial support for postdoc.
Approximately 0.5 FTE science support from GI program.

Planned Budget FY00-02:  450/500k, 350/450k, 300/400k.

Key Projects Planned:
Cycle 9 time awarded to extend observations of 511 keV and postronium
continuum along Galactic plane.
Solar monitoring.
The committee encouraged the OSSE team to publish results on
gamma-ray burst afterglow observations.

Recent Work:
Data products delivered per PDMP guidelines.
Manual screening of data continues.

Instrument is stable with the exceptions of rare anomalies, which
are fixed.
All 7 D1-Modules are operating.
2 of 14 D2-modules are not used.
At present, a special solar flare mode is in effect:
  Special TOF window
  Special PSD window
  Higher D1 threshold to lower D1 counts

Raw data processing - 2 MPE employees.
Science data analysis  - 50% reduced:
  MPE - 4
  DLR - 4 (reduced 4-3 positions in 2000)
Launch of INTEGRAL in 2002 will lead to further reduction of staff.
UNH - reduced.
SRON - 50% reduction.
SSD involvement very low.

Key Projects Planned:
Solar flare observations in solar cycle 23.
ToO observations of nearby SNe and novae.
AGN observations in correlated multiwavelength campaigns.
Extended observations of selected objects.
Deeper exposure of sky regions which are underexposed so far.

Recent Work:
500 publications since launch.
All-sky maps.
Source catalog.
Verification tests confirm validity of 44-Ti results.
Stringent upper limits to 56-Co line.
Detected pulsed emission for PSR 1509 and obtained quasi-simultaneous
X-ray and gamma-ray spectrum of 3C 273.
Recent interpretation of the diffuse Galactic continuum emission.
Deeper study of the diffuse cosmic background.

Mission Status:
All operations are nominal.
Some noise on Gyro 3, but not increasing.
GRO lifetime expected to be about another 8-10 years.

Flight Operation Team Support:
Significant reductions.
7 full-time personal.
On 3-15-99 automated operations with the ROBOTT system were begun.

Required by NASA - must have controlled re-entry.
GRO predicted to survive re-entry.
Uncontrolled re-entry could prose a potential safety hazard and
significant bad press/politics for NASA/GSFC.
GRO system has met its mission requirements and is continuing to
collect valuable science data.

GRO spacecraft is aging and systems are degrading thus increasing the
risk of an uncontrolled re-entry.

Possibility of retrieving the spacecraft to study it?  JSC and MSC
would greatly like to observe the mechanics parts and solar panels.
Smithsonian would like to have the entire spacecraft to display.

Information on the Leonid Meteor shower was presented.  A low-level
storm is predicted.

Y2K testing continues, no problems found or anticipated.
High-gain antenna anomaly now understood and solved.  Not a spacecraft
emergency since omni-antenna was operating.

Cycle 9 Peer Review:
Declining Budget and limited use of EGRET led to fewer proposals (94).
Review completed in 1.5 days.
Cost $32k.
Smaller Committees (4 committees, 5-6 people).

Many Proposal were continuations.
About 1/2 pointed observations.
Rejections sent - no protests received.
Average Grant $9k.
5 solar proposals, overlapping goals and requirements.  Rated highly.

ToO funds and observations time are allocated based on a committee -
defined "trigger probability" - thus, less than the full $450k has
been allocated.

There are about $150k of potential ToO awards.

There remains about $70k to fund ToOs and for an overguide pool (as
outlined in the NPA and notification letters).

Cycle 10 NRA:

In Cycle 10, funding devolves to the ADP.  There will be a GRO-
convened peer review for the scientific aspects of the proposals.
One exception, however, are the gamma-ray burst proposals, which
would be scientifically reviewed by the ADP. 

Should consider extending the length of proprietary period (currently
3 months) in lieu of ADP merge?

Senior review of mission in 2000.

Solar max 2000-2003, thus solar flares still important for next
senior review.

GRO budget taxed $700k per year for ADP.
(Addendum:  This sum has now been determined to be $500k.)

CGRO is expected to be in orbit until > 2005.

Other GRB/Solar Missions not in competition with GRO that are
complimentary are:
  HETE-II - 2000
  INTEGRAL - 2001
  HESSI - 2001
  Swift - 2003

Solar flare considerations for next senior review:  
New solar flare results from CGRO may be in hand.
CGRO has flare capabilities that HESSI, Ulysses, and Yohkoh do not.
Flare community will be active in this period.
Flare capability was well regarded in 1998 Senior Review.

GRB Considerations for next senior review:
BATSE will remain most sensitive GRB instrument.
All CGRO instruments have unique GRB capability.
CGRO rapid trigger and response is important.
GRB's are currently a hot topic.
CGRO has unique SGR capability.
GRB capability was well regarded in 98 Senior Review.

Other considerations:
BATSE provides unique all-sky monitor for other missions such as
COMPTEL has unique wide-field capabilities.
OSSE has unique continuum spectral capabilities.
EGRET will serve as a bridge to GLAST.


See handouts and viewgraphs.

Astrophysics Data Program and GI budget:

See handouts and viewgraphs.

GROSSC Activities:

See handouts and viewgraphs.

Severe Reduction in NASA's year 2000 budget being discussed:
  1) Technology
  2) New mission studies
  3) Discovery/Explorer missions
  4) Mars program
  5) Salary for civil servants

However, no cuts foreseen for operating missions and data analysis.
"Comfortable" amount of money for next senior review to allocate
through FY04.

Chandra and HST will be included in the next senior review, but they
have separate budgets.  Data centers will also be reviewed.

Review will be in June/July 2000 - RFP in March/April.


Cycle 9 Timeline:

See handouts and viewgraphs.

If you have a question about CGRO, please contact us via the Feedback form.

This page was last modified on Monday, 01-Aug-2005 13:42:41 EDT.

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