But robotic mission may yet save the telescope
One of the Hubble Space Telescope's four scientific instruments has shut down and seems unlikely to be resurrected.
Astronomers are not optimistic about repairing the Space Telescope Imaging Spectrograph, one of the telescope's workhorses. “There's some hope, but it is small,” says Bruce Margon, a science director at the Space Telescope Science Institute in Baltimore, Maryland.
The spectrograph, which records specific frequencies of visible and ultraviolet light, failed on 3 August owing to a faulty power unit. Project officials are currently mulling over the few options open to them. The instrument has a back-up power supply, but that has not been used since it was repaired in March 2002 and engineers are not sure whether it will work properly.
The instrument has already lasted two years longer that it was designed to do. Astronomers had come to rely on it: at present, it features in some 30% of planned Hubble science observations.
If the device cannot be revived, the onboard Advanced Camera for Surveys could provide limited spectra images. Hubble's data could also be supplemented with spectra taken from the ground.
The Cosmic Origins Spectrograph, due to be installed on Hubble during a repair mission in 2006, could perform a few of the imaging spectrograph's functions. But NASA is currently reviewing plans for the 2006 repairs and deciding whether astronauts or robots should do the job, or whether it should be cancelled altogether. The agency said this week that it would start developing plans for a robotic mission, but would not make its final decision until next year.
NASA has also awarded a study contract to a team at the Johns Hopkins University in Baltimore to see if the Cosmic Origins Spectrograph and another camera planned for Hubble could fly on a separate satellite instead.