UA, NASA scientists hope to get NICMOS into focus

"It's not a complete calamity," said Marcia Rieke, deputy principle investigator for NICMOS. "It's just an annoyance."

The Near-Infrared Camera Multi-Object Spectrometer was installed on the Hubble Space Telescope in February to give astronomers a closer look at some of the most distant galaxies.

One of the three highly sensitive detectors on the $105 million instrument is out of focus.

"We've known about it for some time," Rieke said from the Space Telescope Science Institute in Baltimore.

Erick Young, an associate astronomer on the NICMOS team, said the instrument was launched in a "glorified thermos," which cooled the instrument to minus 200 degrees Celsius by evaporating a solid block of nitrogen.

Young said the nitrogen redistributed itself, moving one of the detectors out of focus.

Rieke said the science team readjusted the camera once last fall before the launch. However, the problem worsened once the instrument was in orbit.

Scientists are waiting for more of the nitrogen to evaporate and possibly reduce the amount of pressure on the camera, Rieke said.

Once that is done, she said the camera might come back into focus on its own.

"We have to keep our fingers crossed," Rieke said. "That it was going to be this bad was totally unforeseen."

Rieke said solid nitrogen has never been used before to cool instruments in space, so it should not be surprising that some problems arise. She added that less than 20 percent of the scheduled observing time has been affected.

Two other solutions for the out-of-focus camera exist.

A command was issued from the Goddard Space Center in Maryland to the instrument telling it to refocus camera three, Young said.

Young said it could take months for the instrument to refocus the camera.

Another solution would be to command the Hubble Space Telescope to refocus the NICMOS camera.

Rieke said there is a calculated risk involved in that solution. By commanding Hubble to refocus the camera, other instruments could be affected.

The Hubble command will not be issued immediately since the decision is a joint negotiation between the Goddard Space Center, the Space Telescope Science Institute and NASA headquarters, Rieke said.

If the command is issued in the future, Rieke said the Goddard Space Center would issue it.

"Right now we're just rearranging the order in which we take our data," she said.

Rieke said scientists are making optimum use of the telescope's other two cameras until camera three comes back into focus.

"The other two cameras are giving beautiful images," said John Hill, director for the Large Binocular Telescope and a member of the NICMOS science team.

"I want to emphasize that we do expect some breathtaking images with it," Young said.