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Mission Status Report #97      Star Date: July 5, 2006

FUSE Completes Seventh Year in Orbit!

Caption: The FUSE satellite aboard its Delta-II rocket disappears into the hazy blue sky above Cape Canaveral Florida on June 24, 1999. (Photo courtesy NASA and the FUSE project.)

(Click image above to see larger version.)

Friday June 24th marked the seventh anniversary of the launch of FUSE aboard a Delta-II rocket into the roughly 500 mile (800 km) orbit above the earth. Since that time FUSE has orbited the earth every 100 minutes, totalling some 36,820 orbits and some 980 million miles (1.5 billion km) travelled. From that vantage point, FUSE has been used to observe over 2700 unique science targets for over 57 million seconds of science observing time, quite a remarkable achievement.

FUSE has continued operating very well in the one-reaction-wheel control mode since my last report. This it is great news to those of us who have worked so hard over the last 18 months to bring FUSE back into science operations and optimize its performance after the loss of the third out of four reaction wheels that normally control the satellite pointing. Pointing is now maintained by a combination of a single reaction wheel, and magnetic torquer bars (basically electromagnets) that are used to push and pull against the earth's magnetic field. Carefully planned pointing sequences are now used to manage the varying speed of the wheel to keep it well within the limits of its operation. The system is working so well that in June 2006, over 1 million seconds of science data were gathered!

At this writing, we are preparing the call for the 8th round of FUSE proposals. At this juncture, it appears likely that this will be the last opportunity for the astronomical community to propose for new FUSE observations. Partially offsetting this fact, the last observing round is likely to be for an 18 month period, covering the period from March 2007 through September 2008. Given our current rate of scheduling science observations, we can still perform a significant number of new science observations over this time frame. But unless NASA's budget situation improves significantly, September 30, 2008, is looking like the nominal end of FUSE operations. If you are a FUSE user, put on your thinking cap and get ready for this proposal cycle! Cycle 8 proposals will be due September 15, 2006, and more information will be forthcoming soon on the FUSE Guest Investigator site [no longer active].

I offer continued thanks to all of the FUSE Sciences Operations team, including our partners on the Mission Operations Team from Honeywell Technology Solutions, Inc., and our colleagues at Orbital Sciences Corporation, as well as the JHU operations staff, for their ongoing efforts as we continue to improve FUSE operations.

Reported by: Bill Blair, FUSE Chief of Observatory Operations

Last Update: July 5, 2006

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