Talk about a silver lining. When a $1 billion solar observatory spun hopelessly out of control in June and lost power, astronomers feared that extreme heat and cold would ruin its dozen sensitive instruments. But this week, researchers announced that all the instruments are fine--and one sophisticated telescope aboard the Solar and Heliospheric Observatory (SOHO) is working even better than before the accident.
Scientists use the instrument, called the Extreme Ultraviolet Imaging Telescope, to study the sun's corona, fiery plumes, and other features. Though it has produced an array of spectacular images since SOHO was launched in 1995, the instrument has been plagued by contaminants--including frozen water vapor and hydrocarbon residues--that reduced its sensitivity. When SOHO was disabled, however, the craft turned on its side, placing its electricity-producing solar panels edge-on toward the sun. That deprived it of power, but bathed the telescope in constant sunlight, heating it to more than 30oC. The long bake apparently evaporated the contaminants.
While the telescope is still not perfect, the 60% improvement in its sensitivity has it performing markedly better than in the past, says a pleasantly surprised Joe Gurman, a SOHO scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.