The Hubble space telescope has stopped transmitting data back to Earth after the data formatting computer on the operational Side A went kaput on Saturday the 27th of September 2008.  The Control Unit/Science Data Formatter (CU/SDF) typically receives data from the telescope’s five main instruments and formats it into packets for transmission back to Earth.  But it broke.

NASA staff seems to think that the Side A unit failed from prolonged operation at the typical high operating temperature in the satellite.  Or it could have been that nasty space radiation just finally put it out of commission.  Both are pretty good excuses for a computer orbiting the planet to fail.

In theory NASA could just switch it over to the spare processing computer on Side B.  Onlythe Side B systems haven’t been turned on ever since Hubble went into orbit, way back in 1990.  Eighteen years later, there’s a considerable possibility that the computer on Side B might simple no longer want to boot up.  How old is your computer?  Now imagine how flaky one built in the late ’80s and floating around in space for almost two decades could be. It’s a risk.

Further, even if the Side B unit can be convinced to start up, all systems onboard will have to be re-routed to use the Side B system instead of the Side A system.

To that end, NASA is modifying the Altantis shuttle mission that was slated for launch on October 14th.  It would have been the first manned mission to Hubble since March 2002.  But now is scheduled for something more like February of next year, so that astronauts can practice installing a replacement Side A unit as well as do the repairs and maintenance that they had already planned for the Hubble telescope.

So if the Side B unit refuses to start up, or NASA ground control runs into any other problems, it could be half of a year before the Hubble telescope sends any new data back to Earth.  Let’s hope the redundant unit is still functional after all of these years.