The Hubble Space Telescope should soon be back in business, thanks to NASA's ability to reload the spacecraft's Intel 486-powered computer and switch to a backup data-control system.

Last night, scientists at the Goddard Space Flight Center switched the Hubble's control and data-handling functions to a backup system that had sat unused throughout the space telescope's mission. Wednesday, they were able to reload data to Hubble's computer, power up the redundant system, and verify that it could interface with Hubble's main scientific instruments, the Advanced Camera for Surveys (ACS), Wide Field Planetary Camera 2 (WFPC2) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

The instruments were then put into safe mode, to be activated for calibration and testing later today. Internal test exposures will be taken and compared with exposures previously supported by Side A. If all checks out, Hubble will be back to a full schedule of science operations by tomorrow.

The backup system, known as "Side B," replaces the primary "Side A" system, which had been in operation since Hubble's launch 18 years ago. In late September, Side A's Science Data Formatter (CUSDF), which collects data from the spacecraft's various instruments and formats it for relay to Earth, failed, necessitating the switchover. Side B hadn't been tested since 1999, when a repair mission upgraded Hubble's computer to run a 25MHz Intel 80486 CPU with 2MB of RAM. Even in 1999, that system was very dated--it takes about 4 years for NASA to test a computer's ability to survive a Shuttle launch and bombardment by radiation once in space.) Most of the Side B components hadn't been powered up since Hubble's launch.

A Space Shuttle mission that was due to launch on October 14 to perform unrelated repairs on Hubble to extend the space telescope's life until 2013 has been postponed until at least next February.

Post by Tony Hoffman