NEW YORK and WASHINGTON –NASA scientists and engineers were still working the week of July 13 to determine the exact nature of the problem that caused them to suspend operations of a key instrument aboard the Hubble Space Telescope July 6, according to a program official.

Edward Ruitberg, deputy project manager for Hubble at NASA’s Goddard Space Flight Center, Greenbelt, Md., said members of the Space Telescope Imaging Spectrograph (STIS) team were scheduled to meet July 20 to determine a course of action, whether that be gathering more data or taking steps to resume operation of the instrument. He said he did not have sufficient information to offer a prognosis for fixing the problem, but added that the glitch is limited to only one of the sensor’s two detectors.

Originally installed aboard Hubble in 1997, the STIS is designed to break light into its component wavelengths to reveal information including the chemical content, temperature and motion of planets, stars, galaxies and interstellar gas. The instrument shut down in 2004 due to a power supply failure but was restored to operations during the final Hubble servicing mission this past May.

In an interview July 16, Ruitberg said the STIS has two main detectors: a charged coupled device for detecting optical and near-infrared light; and a multi-anode microchannel array (MAMA) for detecting near- and far-ultraviolet light. The glitch affects the MAMA detector, or more specifically, its electronic interface, he said.

The charged coupled device detector can be turned back on even if the problem affecting MAMA cannot be solved, Ruitberg said.

The team made an attempt to fully recover the instrument July 10, but was unsuccessful.

“We’re making sure we understand it fully,” Ruitberg, said in an earlier interview.

“We’re not going to turn it fully operational until we know [more about the problem],” he said.

While the glitch has delayed the preparation of STIS for science operations, “it doesn’t affect the other instruments,” Ruitberg said.

The STIS glitch came a few weeks after a separate glitch that froze the observatory’s new data handling unit, installed by shuttle astronauts during the May servicing mission. That glitch was resolved in mid-June.

A third glitch, with one of Hubble’s cameras, has been resolved.

Operations of Hubble’s Advanced Camera for Surveys were suspended June 24 after the instrument’s flight software detected a problem in its new electronics box. Mission controllers were able to revive the camera July 6.

“We basically just had to re-initialize the instrument and it came back up and running,” Ruitberg said.

The Advanced Camera for Surveys has finished its Servicing Mission Observatory Verification program and is ready to do science, though there is still a chance that the glitch could occur again. The team is working on mitigation strategies in case that happens, Ruitberg said. The camera has been on Hubble since its launch in 1990 and was revived by the shuttle astronauts during their 13-day service call.

“Everything else is going very well,” Ruitberg added.