After several years of uncertainty following the Columbia shuttle disaster, NASA this week gave the go-ahead for a shuttle mission to replace and repair parts on the 16-year-old Hubble Space Telescope and install new detectors that would vastly improve the capabilities of the aging observatory.
“This is fantastic news,” says Matt Mountain, director of the Space Telescope Science Institute in Baltimore, Md. “We’re getting a completely new telescope.”
The shuttle flight, scheduled for sometime between May and October of 2008, will endow Hubble with the most sensitive ultraviolet spectrograph ever flown. The device will probe the large-scale structure of the universe by tracing the distribution of galaxies and intergalactic gas. The crew will also install a camera with exquisite sensitivity ranging from ultraviolet to infrared wavelengths. The more distant an object, the more its light is shifted to redder wavelengths. The new camera’s infrared capability will therefore enable Hubble to record galaxies even more distant than the ones it’s now able to image.
“We’ll be looking further back into cosmic history than we’ve ever seen before,” says Mountain.
The crew will also revitalize Hubble’s system for pointing the telescope and replace all six gyroscopes, which are critical for the observatory’s steady gaze. Two of the six gyroscopes are broken, and in an effort to preserve the remaining devices, Hubble since August 2005 has operated using only two of them instead of the usual three. That limits when observations can be scheduled.
The astronauts will also attempt to repair Hubble’s imaging spectrographs, which stopped working in August 2004. The task will require the crew to loosen a lid with 111 screws not designed for manipulation in space.
NASA Administrator Michael Griffin approved the flight, the fifth such mission to repair Hubble. Safety concerns and the push to finish building the International Space Station by 2010 had put the Hubble repairs on the back burner. But now, after two successful flights to the space station this year, NASA decided to press ahead with the Hubble mission. Former NASA Administrator Sean O’Keefe had deemed a shuttle flight to Hubble too risky, even after a National Academy of Sciences panel found that the mission was about as safe as going to the space station.
During the 2008 Hubble mission, a second shuttle will be on the launch pad in case something goes awry and the astronauts need to be rescued.