The team of scientists and technicians who manage FUSE, the Far Ultraviolet Spectroscopic Explorer, have received a double dose of good news.
NASA selected the FUSE team for a Group Achievement Award, an honor that Bill Blair, research professor and FUSE chief of observatory operations, accepted recently in a D.C. ceremony; and formal approval for a three-year extension of the orbiting observatory's mission arrived July 15. Originally scheduled to end in April 2003 after three years, FUSE's mission will now likely extend to September 2006.
FUSE, which is operated for NASA by Johns Hopkins, is an international collaboration between NASA, Hopkins, the Canadian Space Agency and the Centre National d'Etudes Spatiales (France). Astronomers use the observatory, launched in June 1999, to study ultraviolet emissions that are blocked by the upper layers of Earth's atmosphere. The emissions are rich with information on the makeup and temperature of stars, planets, active galaxies and nebulas.
Formal approval for the FUSE mission extension came from a NASA senior scientific review committee that evaluates active NASA missions every two years. It's standard NASA operating procedure, but that doesn't make the positive outcome any less sweet for FUSE team members.
"We're very pleased with the recommendation of the senior review committee," Blair said. "This is the scientific community--our peers in astronomy--saying 'FUSE is worthwhile. FUSE is worth supporting.' "
FUSE also receives support from Canadian and French space agencies, and these agencies have confirmed their support for extending FUSE operations to 2006. The last two years are contingent upon another senior scientific review in 2004.
Six months ago, FUSE's fate was far from certain. A breakdown of the satellite's guidance systems in December 2001 forced a six-week shutdown that had many in the astronomical community doubting FUSE would ever again be used to make observations.
Scientists and engineers at Hopkins, NASA's Goddard Space Flight Center, Orbital Sciences Corporation and Honeywell Technology Solutions Inc. worked long hours to develop a new technique for controlling the pointing of FUSE using equipment already aboard the satellite. When FUSE managers first announced their successful return to science operations earlier this year, they were able to use the new guidance technique to observe targets across about 45 percent of the sky. Blair and FUSE principal investigator Warren Moos proudly report that as of July FUSE was able to access targets in 75 percent of the sky, and access to 100 percent may be "around the corner."
FUSE began its three-year science mission on Dec. 1, 1999. Moos said astronomers have used FUSE data to produce more than 100 papers that have appeared in peer-reviewed journals and that many more are in the works.
"The scientific peak of FUSE just hasn't happened yet," Moos said. Included among the peaks to come is further resolution of one of FUSE's primary objectives, study of a form of hydrogen known as deuterium. Created only in the Big Bang, the cataclysmic explosion that astronomers believe started the universe, deuterium is converted to other elements in stars. Astronomers are using FUSE to amass a detailed assessment of the relative amounts of deuterium and hydrogen in order to infer more about conditions in the early universe shortly after the Big Bang and to glean important insights into how various elements are created, distributed and destroyed by star formation.
Blair said deuterium observations should wrap up this winter, with continued analysis of the extensive data they have collected to continue for months or even years after that. As FUSE shifts into its mission extension in 2003, Blair said the observatory will be completely opened for observations proposed by the astronomical community at large and selected by NASA.
"These types of observations currently account for about 75 percent of our science operations, but when we get in the mission extension, that will go up to 100 percent," Blair explained. "We'll be running just like a public, ground-based observatory works, except our telescope is 500 miles up."