The “Hubble Status Report #3” called “Hubble Science Operations Deferred While Engineers Examine New Issues” states that “The first event [anomaly] occurred at approximately 1:40 PM on Thursday [October 16] when the Advanced Camera for Surveys (ACS) suspended operations due to indication that one power source in the Solar Blind Camera’s low voltage power supply failed to turn on."

And, "This was the first turn on of the Solar Blind Camera since its last use prior to the safing of HST’s NASA Standard Spacecraft Computer, version 1 (NSSC-1) on 9/27. (The NSSC-1 is Hubble’s science computer.) The Solar Blind Channel is the only part of ACS in use since a power failure in January 2007 halted most ACS science observations.”

NASA began to investigate this first anomaly when another anomaly occurred.

As reported by NASA, “During the briefing, at 5:14 PM, a still-undiagnosed problem affecting the Science Instrument Command and Data Handling (SI C&DH) system caused the NSSC-1 to stop issuing its keep-alive signal."

And, "The Hubble spacecraft computer (HST486) detected the cessation of the keep-alive signal as a failure of its Processor Interface Table (PIT) toggle test."

Further, "The absence of the keep-alive signal for twenty seconds told the HST486 to issue commands to safe HST’s science computer and science instruments.”

The initial thoughts by Hubble investigators as to the cause of the problem is found on page two.

---

NASA officials state that they think the problem lies in Side B of the Computer Processing Module (CPM-B).

They report, “The CPM-B had not been used on orbit prior to Wednesday evening’s activation of Side B of the Science Instrument Control & Data Handling (SIC&DH) unit.”

NASA is considering using Side A for part of the operations and Side B for its other components.

A test of this Side A/Side B dual configuration was performed in a Hubble mock-up at the Goddard Space Flight Center. The results of the test are forthcoming but not yet available.

These scientists and engineers at Goddard are continuing the investigation with the hope they can solve these problems so Hubble can get back to work.

More details later as they become available on the status and future operations of NASA's Hubble Space Telescope.

Background information on the Hubble problem is found on the iTWire article “NASA engineers re-boot Hubble with 486 computer.”