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Mission Status Report #84      Star Date: April 1, 2005

FUSE Restart Continues!

Caption: FUSE "First Light" (for the third time!) spectrum, compares the spectrum of a previously observed FUSE target (red) with a newly acquired spectrum from March 30, 2005. See text below for details. (Graphic courtesy of B-G Andersson, FUSE project, JHU.)

(Click graphic above to see larger version.)

(Because of the date on this report, I feel compelled to tell you this is not an April Fool's joke!)

As I reported last week, is well on its way toward the recovery of science operations. Major additional steps toward recovery were made this week, after spending nearly three months in a safe mode configuration due to a hardware problem that occurred on Dec. 27, 2004. (See this earlier Status report.)

Much of Friday March 25 and Monday March 28 were spent on slew testing and initial analysis of the resulting data. Some of the slews worked as predicted and others deviated, providing lots of good test data for analysis. For the time being, we are keeping FUSE pointed near the south orbital pole while these data are fully analyzed.

In parallel with this analysis, we have finished bringing the scientific instrument back to life for initial testing as well, as evidenced by the figure above! On Tuesday, March 29, 2005, we opened the telescope doors and performed fine guiding tests with the new controller software. On Tuesday and Wednesday, we ramped up the high voltage on both of FUSE's microchannel plate detectors for the first time since December 27, 2004, and they behaved nominally. So it was time to take a spectrum!

Luckily, there was a reasonably bright star that had been observed previously by FUSE near to the south orbit pole position on Wednesday. The central star of the planetary nebula IC2448 had been observed for a guest investigator back in March 2002. This is just what we needed to make a comparison of our current sensitivity to what we could do before the long hiatus. Wednesday afternoon and evening, FUSE was pointed at this target for 12,500 seconds (comparable to the previous exposure). The figure at the top of this page shows the previous data in red and the newly acquired data in blue, processed in exactly the same manner. The comparison is beautiful, and indicates that the FUSE science instrument is clearly in good health!

Caption: Views of Control Center during initial recovery operations on March 22, 2005. (Photos by Bill Blair, FUSE project, JHU. Click to enlarge.)

While this result is extremely encouraging, we are not quite ready to declare ourselves open for normal science operations just yet. We need to gather more experience with the new operating system and further develop the planning tools we will need to select targets where we can point stably and make quality science observations. But we are close! For the next week, we have prepared a schedule that includes a few additional observations of previous FUSE targets near the orbit pole. We also plan to undertake a procedure to find and align all four FUSE dectector channels in preparation for the resumption of science operations.

We've come a long way, but we still have some work to do! 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, for their tremendous effort so far, and for their continuing work as we learn to use the new system.

Reported by: Bill Blair, FUSE Chief of Observatory Operations

Last Update: April 1, 2005

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