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Mission Status Report #109      Star Date: August 14, 2007

The End is Near

Caption: The FUSE satellite is seen superimposed on an optical image of the nearby galaxy known as the Large Magellanic Cloud, a satellite galaxy of the Milky Way. At a distance of only 170,000 light years, the Large Magellanic Cloud is of intense in this galaxy have been observed with FUSE since 1999. (Graphic courtesy NASA and Lauren Fowler, the JHU FUSE project.)

(Click image above to see larger version.)

Dear FUSE Community,

It is a sad day for the FUSE project.

As most of you know, we have been attempting to restart any of the reaction wheels on FUSE after an anomaly on July 12, 2007, shut down our last operating wheel. At least one operating wheel is necessary to point the satellite for science operations. Our extended attempts to spin the wheels have met with failure. We have made every reasonable attempt to restart the wheels, including thermally cycling the satellite hot and cold while applying full available torque in alternating directions. This has been done not only for the wheel that most recently failed but for all of the other wheels that failed earlier in the mission as well. No motion has been detected on any wheel at any time during these attempts. We are left with no options.

Earlier today, FUSE Principal Investigator Warren Moos sent a message to NASA Headquarters recommending the termination of the science mission. Shortly thereafter, NASA Project Scientist George Sonneborn sent a message of concurrence with that recommendation.

We have a number of important tasks to do over the coming months to close-out the mission and document the many lessons learned over the years as we have worked to get the most science we possibly could out of the FUSE satellite. Even though we are saddened by this situation, we are extremely proud of the accomplishments of the last 8+ years, and the teamwork that has resulted in the acquisition of over 130 million seconds of science data from this workhorse satellite. On the bright side, this entire data set is being reprocessed and will available on the MAST Archive for future users for many years to come.

It has been a wild ride, but it looks like we are pulling into the station. It will soon be time to step off this roller coaster and find a new one to climb onto.

I will post further news as conditions warrant.

Reported by: Bill Blair, FUSE Chief of Observatory Operations

Last Update: August 14, 2007

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