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[Chicago Astronomer - Astro Joe]

Engineers try to figure out why Hubble camera stopped working

BALTIMORE -- The main camera on the Hubble Space Telescope, which has revolutionized astronomy with its stunning pictures of the universe, has stopped working, engineers who work on the camera said Saturday.

The Advanced Camera for Surveys, a third-generation instrument installed by a space shuttle crew in 2002, went off line Monday, and engineers are still trying to figure out what happened and how to repair it.

Engineers are hopeful the problem can be fixed, said Ed Campion, a NASA spokesman at Goddard Space Flight Center, which is managing the Hubble.

A bad transistor could be causing the trouble, Campion said. If so, a backup could be used. Another suspicion is that some of the camera's memory was disturbed by a cosmic event. That could be fixed by reloading the memory.

Source : tinyurl.com/l75gw

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Not good news, but I am intrigued about the possibility of a "cosmic" event knocking out the memory. Let's hope for a quick fix and speedy Shuttle repair mission.

[Chicago Astronomer - Astro Joe]

Hubble Main Camera Experiences Power Problem

Washington DC (SPX) Jun 26, 2006
The Advanced Camera for Surveys, the main instrument aboard the Hubble Space Telescope, shut itself down last week and despite repeated attempts by ground controllers to revive it, continues to hibernate in a safe mode, SpaceDaily.com has learned.

"It sounds like a power-supply problem, which is now being diagnosed," Ray Villard, a spokesman for the Space Telescope Science Institute in Baltimore, Md., which manages the spacecraft's science activities, told SpaceDaily.com. "We have a redundant power bus as backup."

The backup system is meant to power the camera if its main power supply fails. If engineers at NASA's Goddard Space Flight Center in Greenbelt, Md. - which manages the spacecraft - determine they must resort to auxiliary power, then the ACS will have no alternative remaining if it malfunctions again.

The ACS is Hubble's most valuable instrument, not only because of its exquisite sensitivity, but also because the camera can detect images in a wide range of electromagnetic wavelengths, from far ultraviolet to infrared.

Installed aboard the orbiting telescope during a space shuttle servicing mission in 2002, the camera actually is a combination of three instruments, including a wide-field camera, high-resolution camera, and solar-blind camera.

The wide-field camera on the ACS can capture a panorama twice as wide as Hubble's Wide Field Planetary Camera 2. The high-resolution camera can take extremely detailed pictures of distant objects, such as the two newly discovered tiny moons of Pluto, which have just been named Nix and Hydra.

The solar-blind camera blocks visible light to enhance the telescope's sensitivity to UV light. The instrument specializes in detecting hot stars radiating in UV wavelengths.

Ever since the space shuttle Columbia disintegrated over Texas on Feb. 1, 2003, during its re-entry into the atmosphere, and NASA grounded the fleet, Hubble scientists and engineers have lacked the means to service the telescope, which remains - and will continue to remain for the foreseeable future - the best visible-light telescope available.

Along with the ACS power supply, Hubble faces deteriorating gyroscopes - which are essential to maintaining its steadiness and correct position while collecting images - as well as aging batteries. These factors also could bring to a sudden end the spacecraft's extraordinary performance over the past decade and a half.

Meanwhile, Hubble controllers are planning to attempt to restart the ACS using the auxiliary power system sometime this week.

More here: www.spacedaily.com/reports/Hubble_Main_Camera_Experiences_Power_Problem.html

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[Chicago Astronomer - Astro Joe]

Hubble Telescope's Main Camera Not Working

Hubble Telescope's Main Camera Has Stopped Working; Engineers Trying to Determine Cause

BALTIMORE Jun 24, 2006 (AP)— The main camera on the Hubble Space Telescope, which has revolutionized astronomy with its stunning pictures of the universe, has stopped working, an instrument specialist who works with the camera said Saturday.

The Advanced Camera for Surveys, a third-generation instrument installed by a space shuttle crew in 2002, went off line Monday, and engineers are still trying to figure out what happened and how to repair it.

"It's still off line today," Max Mutchler, an instruments specialist at the Space Telescope Science Institute in Baltimore, said Saturday.

Engineers are hopeful the problem can be fixed, said Ed Campion, a NASA spokesman at Goddard Space Flight Center outside Baltimore, which is responsible for managing the Hubble.

A bad transistor could be causing the trouble, Campion said. If so, a backup could be used. Another suspicion is that some of the camera's memory was disturbed by a cosmic event. That could be fixed by reloading the memory.

"Both possibilities are things that can be resolved here on the ground," Campion said.

The camera sent messages Monday indicating power supply voltages were above their upper limits and causing it to stop working.

"At this point, the ACS is in a safe configuration, and further analysis is ongoing," according to a statement by the Space Telescope Science Institute.

The Advanced Camera for Surveys consists of three electronic cameras and a complement of filters and dispersers that detect light from the ultraviolet to the near infrared.

It was installed on the Hubble during a servicing mission by the crew of the space shuttle Columbia. Development of the ACS was a joint operation among Johns Hopkins University, Goddard Space Flight Center, Ball Aerospace and the Space Telescope Science Institute.

Hubble, launched in April 1990, needs new batteries and gyroscopes if it is to keep working beyond next year.

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Gee...I hope they can fix the camera with the next few Shuttle missions.

[Maddad]

dsc.discovery.com/news/2006/06/28/hubblefixed_spa.html?category=earth&guid=20060628093030

They would not have risked human lives on repairing the Hubble. Fortunately power has been re-routed to the Hubble's main camera, so it will be back online by Monday, July 03, 2006.

[Chicago Astronomer - Astro Joe]

Power restored to Hubble camera detector

Debris stuck in a switch is believed to have caused a voltage drop that shut down the Hubble Space Telescope's main camera for the second time this year, the operators of the orbiting observatory announced Friday.

Power was restored to one of three detectors on the Advanced Camera for Surveys after an electrical relay suspected as the cause of the shutdown was toggled on and off.
NASA engineers believe the debris interfered with the electrical contact, the Space Telescope Science Institute said in a statement.

The institute said the performance of the detector will be monitored for the rest of the week. Observations will resume next week if its performance remains stable.

The Baltimore-based institute coordinates use of the orbiting telescope, launched in 1990 by the space shuttle, which has revolutionized astronomy with some of the most striking images ever seen in space.

NASA has scheduled a meeting Oct. 27 on the safety of a shuttle mission to service the Hubble to keep it working until a replacement is launched in 2011. The agency canceled a previously scheduled Hubble mission following the loss of the shuttle Columbia in 2003. That decision prompted an outcry from scientists and the public and forced NASA to reconsider.

Source: news.yahoo.com/s/ap/20061013/ap_on_sc/hubble_trouble

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Debris from where?