Hubble re-opens an eye

• NewScientist.com news service
• Rachel Courtland

Hubble's Wide-Field Planetary Camera 2 restarted its observations on 25 October (Image: NASA)

The Hubble Space Telescope has reawakened and is taking its first pictures of the sky after a series of glitches left it idle for a full month.

Engineers successfully booted up the probe's main camera, the Wide-Field Planetary Camera 2, on Saturday. The instrument, which is set to be swapped out in 2009 during the telescope's last servicing mission, is now taking its last scheduled images of the sky.

"It is a relief that everything is working well," says Rodger Doxsey, head of the Hubble mission office at the Space Telescope Science Institute in Baltimore, Maryland. "We did a few calibration observations, which worked fine, and then restarted science observing with it over the weekend."

Hubble has been mostly dormant since late September, when a device needed to collect and process data from the telescope's science instruments failed.

In an attempt to revive the probe, NASA successfully switched the device over to a back-up "B-side" about two weeks ago. The switch also involved other devices housed in Hubble's main control unit for science instruments, the Science Instrument Command and Data Handling (SI C&DH) unit.

But problems with the unit sent the telescope back into standby, or "safe", mode on 16 October, before the probe's science instruments could be turned back on.

Now that the Wide-Field Planetary Camera 2 is operating again, mission managers are planning to switch on the telescope's two other cameras.

Infrared camera

Engineers will next attempt to restart the telescope's Advanced Camera for Surveys, which shut down last week due to a timing problem between two software routines. The camera's ultraviolet sensor, the Solar Blind Channel, is the only one that still works on the ACS – power problems knocked out the camera's two other channels in 2007.

Testing is currently being conducted on Hubble's infrared camera, called NICMOS (Near Infrared Camera and Multi-Object Spectrometer), to see if it can interface with the "B-side" of the instrument control unit, Doxsey told New Scientist.

NICMOS, which is used to observe faint, distant galaxies, has been incapacitated since September, when problems turned up in the spectrometer's cooling unit. If testing goes well, engineers will turn on the cooling unit and start the camera in the next few weeks.

The fifth and final shuttle mission to the telescope was originally scheduled to take off on 14 October, but the mission was put on hold in order to prepare a spare SI C&DH unit to be sent up on the shuttle.

A new launch date for the servicing mission has not been set, but NASA has been eyeing an opening in February. Some officials say that target could be optimistic, as the replacement part may have undiagnosed problems.

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