The Hubble Space Telescope’s primary camera is offline, with some science capabilities likely lost for good, NASA officials said Monday.
An electrical short in the backup system for Hubble’s Advanced Camera for Surveys, or ACS, pushed the orbiting telescope into a protective “safe mode” over the weekend and prompted the formation of an Anomaly Investigation Board on Monday, NASA officials said.
The incident, the third since last June to hobble Hubble's ACS, occurred at 7:34 a.m. ET Saturday. By Sunday, engineers managed to switch the space telescope back to normal operations, with the exception of the ACS, and they hope to resume science observations with the observatory’s remaining instruments later this week.
NASA's investigation board is to study the latest malfunction and present its results by March 2.
“Obviously, we are very disappointed by this latest event because of the popularity of the ACS instrument with astronomers,” Preston Burch, Hubble program manager at NASA's Goddard Space Flight Center in Greenbelt, Md., told reporters Monday during a teleconference.
It was the Advanced Camera for Survey's wide-field channel, for example, that allowed astronomers to generate Hubble’s Ultra Deep Field — the deepest view into the universe to date. But that channel, plus a high-resolution channel used to study stars surrounded by planet-forming material, are likely lost because the latest glitch has cut off power to their systems, Hubble managers said.
“We’re not optimistic at all that those will be restored,” said David Leckrone, NASA’s senior project scientist for the Hubble Space Telescope at Goddard. “The saving grace here is that we have a superb new wide-field camera coming along that was originally designed, in fact, to be a backup for ACS in case ACS failed. It was designed to work in tandem with ACS if [it] was fully alive.”
Hubble engineers hope they will be able to reactivate the ACS' third channel — the solar blind channel used recently to study auroras on Jupiter and Saturn — by February to aid NASA’s New Horizons mission, which is due to make a close flyby of Jupiter on Feb. 28.
“As soon as we’re confident that everyone has done their homework on that, we could very have the solar blind operating by the end of February,” Burch said. “That would be the hope.”
Hubble’s other instruments — the Wide Field Planetary Camera 2, the Near Infrared Camera Multi-Object Spectrograph and the Fine Guidance Sensors — are unaffected by the Advanced Camera for Survey's recent glitch.
Hubble’s camera troubles
The ACS has been working on its backup, or Side B, system since the instrument’s primary Side A electronics package encountered a malfunction in June 2006. In September, an electronic hiccup again knocked the camera offline, but the system recovered a short time later.
NASA's Hubble managers said the most recent glitch is not connected to the earlier problems. “It’s very different,” Burch said, adding that the current anomaly’s signature is very different from those seen last year.
Hubble managers had prepared about six observation surveys that would not require the ACS, just in case the finicky instrument went offline. Those research projects will now be implemented while the camera is unavailable.
The ACS anomaly came just two months before the instrument’s projected five-year warranty expired, Hubble managers said. Spacewalking astronauts installed the camera on March 7, 2002, during NASA’s STS-109 mission aboard the Columbia orbiter. Launched in 1990, the Hubble Space Telescope has been billed as one of the most valuable astronomical instruments of all time and is the product of a partnership between NASA and the European Space Agency.
“It’s certainly been an astounding success as an instrument,” said Rick Howard, acting director of the Astrophysics Division at NASA Headquarters in Washington. The camera met about all of its initial science objectives before its recent failure, he said.
Repair may not be an option
Because of the camera’s hard-to-reach location on Hubble and the already-packed five-spacewalk schedule for next year's final servicing mission to Hubble, adding a new and complicated repair job to the spaceflight is not an attractive option, Burch said.
“Servicing Mission 4 is a very full mission with installing new batteries and gyroscopes, installing one of the fine guidance sensors and two new instruments,” Burch said. He noted that NASA had planned no ACS-related additions during the upcoming Hubble overhaul.
Leckrone said that the new instruments to be grafted into Hubble next year will almost completely restore the telescope’s lost ACS abilities, though the new Wide Field Camera 3 will take longer to generate its predecessor’s stunning views of the universe.
“The successful completion of SM-4 and insertion of Wide Field Camera 3 will take us fully back to not only where we are now, but where we want [Hubble] to be in the future,” Leckrone said.