Caption: The FUSE satellite is seen superimposed on an optical image of the nearby galaxy known as the Small Magellanic Cloud, a satellite galaxy of the Milky Way. At a distance of only 200,000 light years, the Small Magellanic Cloud is of intense in this galaxy have been observed to date. At far right is the globular cluster 47 Tuc, whose UV_bright stars have also been studied with FUSE. (Graphic courtesy NASA and Lauren Fowler, the JHU FUSE project.)

FUSE has continued operating 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 year to bring FUSE back into science operations after the loss of the third out of four reaction wheels that normally control the satellite pointing.

It is hard to believe that it was just over one year ago (March 22, 2005) that we uploaded the first version of the one-wheel control software. While it worked at some level, the continued improvements over the last year have finally gotten up back to being a viable scientific satellite again. For instance, back in those days, we sometimes found it difficult to move our pointing direction by 5 or 10 degrees. Since the first of the year, we have changed hemispheres four times, involving motions half way across the sky (180 degrees). In recognition of these accomplishments, and the substantial improvements we have seen in actual science data gathering, press release in late February declaring our return to full operations.

Just one week ago (March 28, 2006) we uploaded the latest versions of two sets of software to the satellite that should be the backbone of operations for the foreseeable future. The Attitude Control System (spacecraft computer) and Instrument Data System (science instrument computer) both got "brain transplants," in a coordinated "operation" performed from the Satellite Control Center at JHU.

Since operations were going well, why did we mess with a good thing, you might ask? These software loads include a number of improvements that should allow the satellite to handle a lot of the small control issues that are now handled by ground intervention. Thus we are taking steps toward making FUSE more self-sufficient again so we don't have to watch it so closely from the ground. Testing over the last week looks good, and we have returned again to the science timeline.

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 efforts so far, and for their ongoing efforts as we continue to improve FUSE operations.

Reported by: Bill Blair, FUSE Chief of Observatory Operations

Last Update: April 5, 2006

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