NASA will switch on a backup power supply to try to resuscitate the Hubble Space Telescope鈥檚 main camera, the Advanced Camera for Surveys, officials said on Friday. If the fix works, the camera could resume making observations by Sunday.
The ACS shut itself down on 19 June when it suffered a problem with its low-voltage power supply (see Hubble鈥檚 key camera stops working). NASA engineers have since been working to find the source of the problem, and now they say it appears to be an electronics component that supplies power to two of the camera鈥檚 three detectors.
鈥淭he power source is where we think the problem lies,鈥� says Ed Ruitberg, deputy associate director of NASA鈥檚 astrophysics division.
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Fortunately, the ACS has a backup power supply. NASA is now sending commands to Hubble to turn on that system, which has never before been tested in space. 鈥淲e expect the reconfiguration will likely clear the problem with the ACS,鈥� Ruitberg said in a telephone briefing with reporters.
If so, the telescope could resume making observations on Sunday at about 2000 EDT (0000 GMT on Monday). It would then split its time over the next week or so between observations and recalibrating the camera.
Heavily used
If switching to the backup power supply does not fix the problem, NASA will spend at least a week trying to determine other ways to get the camera up and running again. The ACS takes one or two dozen observations per week and is the most heavily used instrument on Hubble.
The $86 million camera was installed in 2002 during Hubble鈥檚 fourth shuttle servicing mission, and it doubled Hubble鈥檚 existing field of view. It also records information more quickly than the telescope鈥檚 other optical camera, the Wide Field and Planetary Camera 2 (WFPC 2).
Hubble managers insist the problem is not a sign that the 16-year-old telescope is beginning to fail. 鈥淭his is not an indication of the telescope ageing,鈥� says Ruitberg. 鈥淲e鈥檝e experienced problems all along the way, and we鈥檝e always figured out a way to solve those problems.鈥�
Life extension
In fact, the electronics on the telescope鈥檚 Space Telescope Imaging Spectrograph, which was installed in 1997, failed after four years of operations. So engineers switched to spare systems, which extended the instrument鈥檚 life for another three years. The second set of power converters failed in August 2004 (see Shelved instrument could restore Hubble鈥檚 UV vision).
Hubble鈥檚 other instruments, an infrared camera called NICMOS, the WFPC 2, and fine guidance sensors, are all working. And NASA believes all of the observations that had been scheduled since the camera shut down on 19 June can be made later in the year.
These observations include follow-up studies of Hubble鈥檚 Ultra Deep Field, the deepest view made of the universe in visible light (see Hubble delivers best-ever view of early Universe).
Whether or not the ACS can be fixed, another camera is waiting in the wings that could take some of the same observations. The instrument, called the Wide Field Camera 3, could be installed on Hubble if NASA sends another shuttle to service it 鈥� a possibility the agency is considering.
