NASA Racing to Repair Hubble Before Aging Telescope Fails

Anxiety is high as NASA prepares for a rush repair job on its beloved Hubble Space Telescope.

Hubble’s pointing system could die any day, halting all astronomical observations. So NASA is sending astronauts to the rescue in October, eight months earlier than they were supposed to go.

The spacewalkers will not only install new gyroscopes for precision pointing, they will replace Hubble’s brain--its main computer--and patch Hubble’s peeling skin.

“It’s got this added drama to it,” says Steven Smith, a veteran Hubble repairman who will lead the spacewalking team. “Any time you’re working toward a goal and it becomes more urgent, it’s a little bit more exciting.

“But on the down side, something’s wrong with this national asset. That’s bad, and there are thousands of people in the United States who are going to have to work a lot harder than they were going to have to originally work in the next five months to get us ready.”

Record-Setting Mission

NASA has never put together a shuttle mission so fast.

Smith and the three other astronauts assigned as spacewalkers have been training since August. But the flight crew was not chosen until March, a few days after NASA decided to split the originally scheduled June 2000 repair mission into two.

The first thing newly appointed commander Curtis Brown Jr. told his crew was: “Grab ahold of something, because here we go! We only have 28 weeks to launch and we have all the training to get done.”

Brown is confident they’ll be ready for an Oct. 14 liftoff aboard space shuttle Discovery. Three and possibly four spacewalks are planned for the nine-day mission.

“Out of seven people on board, we have 18 shuttle flights. We have a lot of experience on board,” says Brown, an Air Force officer who will be making a record-tying sixth shuttle flight.

NASA managers as well as astronomers around the world are keeping their fingers crossed that the $2-billion telescope will keep operating until Brown and his crew get there. The mission cannot be pushed up any earlier, even if something else breaks.

No Shortcuts, NASA Says

“There’s an edge [of tension], but we haven’t shortcut anything so far,” says John Campbell, NASA’s associate director for the Hubble Space Telescope. “That’s why I’m unwilling to move it any earlier. Then I feel we’d have to start shortcutting.”

The problem is with Hubble’s gyroscopes, needed to aim the telescope and hold it steady as it scrutinizes the universe. Three of the six have failed because of corroded wires. One more failure and astronomical observations will cease, although the telescope itself will be safe in orbit.

“If you believe the statisticians--and I don’t--they say there’s a 70% chance we’ll make it to October,” says Ed Weiler, head of NASA’s space science program.

That’s why Weiler and other scientists consider this an emergency mission.

Cmdr. Brown bristles, however, at that description.

“Let me start my crusade right now,” he tells an interviewer. “This is not an emergency mission, OK? This is a science mission and a repair mission and it’s not an emergency mission.

“If another gyro fails right now as we speak, Hubble would go into a safe mode and the Hubble Telescope would be perfectly fine until we got up there. It’s not going to hurt itself or anything.”

For now, the three working gyroscopes show no signs of degradation. (Two are originals, launched with the telescope in 1990.) But the wire corrosion that knocked out the three other gyroscopes seems to occur at random with little, if any, warning.

All six gyroscopes will be replaced with improved units during the upcoming mission. (They come two to a pack.) Smith and his spacewalking partners also will install a new computer, radio transmitter, guidance sensor and data recorder, and fix some of the tattered thermal insulation.

Weiler says it will be difficult work, though not nearly as demanding or stressful as it was when astronauts had to correct Hubble’s blurred vision during the first repair mission in 1993.

This will be repair mission No. 3.

Replacing the gyroscopes will be tricky because the chamber in which they’re housed is cramped and holds extremely fragile instruments. Replacing the computer will be even trickier because of seven cables that the spacewalkers must connect with their gloved hands; each connector has 20 to 40 tiny pins.

“There are so many little things that, if we do wrong, can really damage the telescope,” says Smith, who flew on the last Hubble repair mission in 1997.

The most formidable work--installing new solar panels, an advanced camera and a cooling unit for an idle infrared camera--won’t be tackled until 2001. All that had been crammed, along with everything else, into the original June 2000 mission. A record six spacewalks were planned.

“It would have really driven us really hard” to accomplish everything in a single mission, Smith says. “So in some ways there’s a blessing with a silver lining here that we’re actually going to have two flights go to Hubble.”

Splitting one repair mission into two will cost NASA an extra $125 million or so, Weiler says. But he’s quick to point out it’s money well spent.

“The scientific community is enamored with Hubble,” Weiler says. “I mean, we have enormous rejection ratios. That is, four or five proposals out of every six are rejected. So it’s greatly oversubscribed. Any loss in scientific productivity, you’re not earning.”

Among Hubble’s more recent discoveries: a galaxy 13 billion light-years away that’s the most distant object ever detected, and dust rings around two remote stars that may have been gravitationally sculpted by planets.

NASA hopes to keep Hubble working until 2010. The last repair mission is slated for 2003.

“Hubble has a limited lifetime. I mean, it’s not going to be up there forever,” Brown says. “So every day, every month, that it’s not operating is a day of lost science that we could have.”

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Hubble Dates

A brief look at the Hubble Space Telescope’s past and future:

April 1990: Hubble launched into orbit aboard space shuttle Discovery.

December 1993: Astronauts conduct five spacewalks to correct Hubble’s blurred vision and make other repairs.

February 1997: Astronauts conduct five spacewalks to add or replace 11 major Hubble parts, including two new science instruments.

October 1999: Astronauts to conduct three or four spacewalks to replace all six gyroscopes, main computer, radio transmitter, guidance sensor and data recorder, and patch peeling insulation.

Early 2001: Spacewalking astronauts to install new solar panels, advanced camera and cooling unit for idle infrared camera, and finish patching insulation.

2003: Spacewalking astronauts to install new camera and new spectrograph to enhance imaging, and replace all worn-out parts.

2010: Hubble to return to Earth aboard space shuttle.

Associated Press