Technical troubles delay data release from Gaia space telescope

New Scientist : Launched in December 2013, the European Space Agency’s Gaia is on a mission to compile the most accurate and extensive catalog of our galaxy’s stars. But fulfilling that mission has been delayed because of several problems . Most important, excessive stray light has been entering the telescope. In addition, water that was trapped in the spacecraft before launch has been outgassing and freezing on the telescope’s mirrors. Although researchers tried to deal with both potential problems before launch by installing a sunshield to keep out stray light and heaters to melt the ice, the spacecraft has taken in more light and accumulated more ice than had been anticipated. Researchers are looking into modified observing strategies and computer software to optimize the data that are collected. However, mission managers say that even if the problems can’t be fixed, only the quality of the data collected for the faintest stars will be affected.