NASA will need at least six months to prepare a spare part for launch to the Hubble Space Telescope, delaying the last shuttle mission to revamp the probe to no earlier than May 2009, agency officials announced on Thursday.
The fifth and final shuttle mission to the telescope was originally set to take off on 14 October.
But it was postponed to no earlier than February 2009 when a device used to collect and process data from Hubble鈥檚 science instruments failed in late September, shutting down the probe鈥檚 science operations.
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Hubble now has only one working version of the device, so the agency has been preparing a back-up part for launch.
The spare, called the Science Instrument Command and Data Handling (SI C&DH) system, has been at NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland, since 1991.
Unfortunately, tests of the part turned up problems, Hubble manager Preston Burch of Goddard told reporters.
The problems could mean the spare will not be ready to ship to NASA鈥檚 shuttle launch centre in Cape Canaveral, Florida, until at least April 2009.
Possible cancellation
鈥淩ight now we鈥檙e confident we鈥檒l have the SI C&DH ready to fly,鈥� says Jon Morse of NASA headquarters in Washington, DC.
But if the spare proves unsuitable, NASA may have to decide between moving forward with the shuttle mission or cancelling it entirely. 鈥淲e鈥檒l cross that bridge if we get to it,鈥� Morse said.
Hubble, which launched in 1990, is showing its age. Half of the telescope鈥檚 six gyroscopes, which are used to point the probe at targets of interest, are broken. And the telescope鈥檚 batteries, which were once anticipated to lose their charge capacity as early as this year, have an uncertain lifetime.
The battery capacity has not declined much in more than a year, but it is now half of what it was at launch. 鈥淗ubble batteries are operating in unchartered waters, and we have no idea how much longer they may last,鈥� Burch told 快猫短视频 after the briefing.
Power failure
Failure of all the batteries is unlikely before the servicing mission, Burch says. But the telescope could not be revived if it lost all power.
Since the failure in September, NASA has rebooted two of Hubble鈥檚 main science instruments, the Wide-Field Planetary Camera 2 and one of three remaining channels on its Advanced Camera for Surveys.
The ACS ultraviolet sensor, the Solar Blind Channel, is the only one that still works on the camera 鈥� power problems knocked out the camera鈥檚 two other channels in 2007.
NASA will next attempt to restart Hubble鈥檚 Near Infrared Camera and Multi-Object Spectrometer, which is used to observe faint, distant galaxies. The instrument has been incapacitated since September, when problems turned up in the spectrometer鈥檚 cooling unit. If testing goes well, engineers will turn on the cooling unit and start the camera in the next few weeks.
