NASA continues to work on an issue with the Hubble Space Telescope payload computer. The operations team will perform the tests and gather more information about the system to further isolate the problem. Scientific instruments will remain in safe mode until the issue is resolved. The telescope itself and the scientific instruments remain healthy.
The computer shut down on Sunday June 13. An attempt to restart the computer on Monday June 14 failed. The first indications were that the computer’s memory module had deteriorated because the computer’s resource had shut down. When the operations team tried to switch to a memory backup unit, the start backup unit command could not be executed. The two modules made another attempt on Thursday night to get more diagnostic information while again trying to connect these memory modules online. However, these attempts were unsuccessful.
The payload computer is the 1980s NASA Standard Spacecraft Computer-1 (NSSC-1) housed in the Science Tool control and data processing unit. The purpose of a computer is to control, coordinate and monitor scientific instruments for health and safety purposes. It is completely redundant because the second computer, as well as the associated hardware, is in orbit on which it can switch in the event of a problem. Both computers can access and use each of four independent memory modules, each containing 64 KB of additional metal semiconductor (CMOS) memory. The payload computer uses only one unit of memory at a time, with the other three serving as a backup.
Launched in 1990, Hubble has made a huge contribution to our understanding of the universe over the past 30 years.