The Hubble Space Telescope may soon be up and running again after a series of glitches that have left it idle for nearly a month.
On Thursday, engineers successfully rebooted its payload computer, and if that operates normally for a couple of days, they will attempt to turn on one of the telescope鈥檚 main instruments on Saturday.
Hubble has been mostly dormant since late September, when a device needed to collect and process data from the telescope鈥檚 science instruments failed.
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In an attempt to revive the probe, NASA successfully switched the device over to a back-up 鈥淏-side鈥� last week, along with other devices housed in the Science Instrument Command and Data Handling (SI C&DH) unit, Hubble鈥檚 main control unit for science instruments.
But problems with the unit sent the telescope back into standby, or 鈥渟afe鈥�, mode on 16 October.
An electrical short may have simultaneously knocked out the unit鈥檚 main computer and its data formatter, Hubble manager Art Whipple of NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland, told reporters on Thursday.
The team also found that a timing problem in the communication between devices in the telescope鈥檚 Advanced Camera for Surveys (ACS) 鈥� exacerbated by the resetting of the telescope鈥檚 master clock last week 鈥� was responsible for shutting down the camera. The team plans to change the ACS software to try to fix the problem.
Main camera
If the telescope鈥檚 science instrument computer continues to operate normally, operators will try to turn on the telescope鈥檚 main camera, the Wide Field Planetary Camera 2, on Saturday.
An ultraviolet sensor aboard the Advanced Camera for Surveys could also begin operating again next week. The sensor, called the Solar Blind Channel, is the only one that still works on the ACS 鈥� power problems knocked out the camera鈥檚 two other channels in 2007.
The agency plans to send a new ACS power supply, which would restore the other two channels, aboard the last shuttle mission to service the telescope.
The date for the last servicing mission has not yet been set. NASA hopes to send astronauts back to Hubble in February with a spare SI C&DH that has been in storage for years. Some officials say that timeline could be optimistic, as the replacement may have undiagnosed problems.
