Bad news for astronomers and fans of gorgeous astronomy pictures. The most important camera on the Hubble Space Telescope, the Advanced Camera for Surveys (ACS), has broken down. Again. It’s the third outage in less than a year and the problem seems to be worse than the last two times. A NASA Anomaly Review Board will try to determine what happened and whether the camera can be turned back on.
More details are available in the article “Telescope News: Advanced Camera for Surveys Suspends Operations” on the Hubble website (retrieved Jan. 30, 2007):
Hubble’s Advanced Camera for Surveys (ACS), the instrument whose work has dominated the telescope’s observation program, is currently not operating.
On Jan. 27, Hubble went into a self-protective hibernation called “safe mode.” This happens whenever Hubble’s computers measure a serious anomaly in the spacecraft’s operation. A pressure sensor located in the section of the telescope that houses the science instruments had detected a rise in pressure. At the same time, an electrical fuse blew in the ACS, probably as the result of a short circuit.
Hubble is currently out of safe mode and functioning normally. Science operations will resume this week.
Hubble still has significant science capabilities. The Near Infrared Camera and Multi-Object Spectrograph (NICMOS), the Wide Field Planetary Camera 2 (WFPC2), and the Fine Guidance Sensors (FGS) are all working. ACS was installed in 2002 and has met its expected lifespan of five years.
NASA has convened an Anomaly Review Board to attempt to identify the precise cause of the ACS problem and determine whether it is safe to return ACS to operation. It will also help establish whether there is any prospect for repairing ACS, if it cannot be turned back on, during the upcoming mission to service Hubble in 2008.
In the likelihood that ACS remains inoperative, several steps will allow NASA to proceed with the best possible science program with the telescope.
Observations that had been scheduled for the still-working instruments will be moved, when possible, into the time slots left empty by ACS’s breakdown. All the current ACS programs will be reviewed to determine which observations might be transferred to other instruments — most likely WFPC2.