Number 3 November 1998


1) Problem found with the satellite gyros 
2) Phase 2 submissions - Fixed Target GIs and Moving Target/TOO GIs
3) Puerto Rico ground station update
4) FUSE satellite testing

1) Problem found with the satellite gyros

        A problem was discovered last month with one of the inertial reference 
units (IRU) for the FUSE spacecraft.  Each IRU contains 3 ring laser gyros.
Thermal vacuum testing of one of the IRUs by the FUSE team revealed that the 
laser intensity is slowly decreasing in two of the axes during normal 
operation.  While operational at the present time, if uncorrected, the IRU 
would fail prematurely in orbit, well before achieving the three-year mission 
lifetime.  A team, with members from several organizations including the 
manufacturer, the FUSE team, and GSFC is working to find a timely solution to 
the IRU problem.  We expect to know in about 30 days if FUSE will make the 
scheduled launch date of March 18, 1999.

2) Phase 2 submissions - Fixed Target GIs and Moving Target/TOO GIs

        The first phase 2, GI deadline passed on Oct. 9.  Almost all of the 
concerned GIs met the deadline (thank you!).  
The FUSE Mission Planning staff will be reviewing your inputs in detail, and 
will contact you directly if any clarifications are needed.  Please support 
them by answering any questions or providing any additional information in a 
timely fashion.

        The deadline for Target Of Opportunity (TOO) and Moving target (MT) 
programs is coming up soon, on the 13:th of November.  Those of you with 
programs in this category should hopefully be close to finishing your inputs.

For questions and/or further information see the web 
( or contact us at 

3) Puerto Rico ground station update

        As you may recall from the October newsletter, the FUSE ground 
station in Puerto Rico was rather severely damaged by hurricane Georges.  We
are now happy to tell you that it will be fixed!  A new dish as well as a
protective radome will be installed at the original site at the University of 
Puerto Rico, Mayaguez (UPRM).  Very recently the damaged antenna mount was 
removed from the rooftop at Mayaguez and shipped to California for 
refurbishment.  A new reflector (dish) is being fabricated.  The new antenna 
will be re-integrated in Puerto Rico by late January. 
Should the UPRM site not be fully commissioned at the time of launch, the 
Hawaii station will become our primary satellite communication station with 
some support from the LEO-T site at Wallops.

4) FUSE satellite testing

        FUSE is currently installed in a vacuum chamber at GSFC. A collimator
with a UV line lamp is mounted above FUSE and will be used to measure the 
focus, alignment, and UV throughput during thermal-vacuum testing scheduled
to begin during mid-November. The Comprehensive Performance Test (CPT) 
concluded last week, and Mission Simulation Tests (MSTs), in which typical
mission timelines are simulated, are underway.

As usual, information on the test results can be found on the Satellite
Status page:

The Observer's Electronic Newsletter is published Monthly by the FUSE project
and is aimed at the FUSE user community.

Editor: B-G Andersson, FUSE Guest Investigator Officer.

The FUSE Project is managed by Johns Hopkins University's Center for 
Astrophysical Sciences in Baltimore, MD, for NASA's Goddard Space Flight 
Center.  The FUSE Principal Investigator is Dr. Warren Moos, the FUSE Project 
Manager at JHU is Mr. Dennis McCarthy, and the NASA Project Scientist for FUSE 
is Dr. George Sonneborn.

Further information about the FUSE Guest Investigator Program can  be
obtained from:  Dr. George Sonneborn;

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