ScienceNow Looks at Rescuing the Hubble

JUDY WOODRUFF: And one more item tonight: a behind-the-scenes look at the effort to save the Hubble space telescope. That's the subject of tonight's edition of "Nova," which chronicles this year's complex attempt by NASA astronauts and engineers to repair Hubble during a 12-day mission.

Here's an excerpt looking at what space-walking astronauts Drew Feustel and John Grunsfeld faced.

The narrator is Rushmore DeNooyer.

DREW FEUSTEL: I'm ready, John. Let's go do this. Oh, this is fantastic.

RUSHMORE DENOOYER: Drew and John's first task is the number-one science priority for the mission: install a much more powerful wide-field camera.

They'll loosen one bolt, remove the old camera, insert the new camera, and re-tighten the bolt. It's one of the simplest jobs on the entire mission.

But, early on, there's a big problem. When Drew tries to loosen the bolt holding in the old camera, it refuses to budge.

DREW FEUSTEL: No turning.

RUSHMORE DENOOYER: If Drew can't get this bolt loose, the first job on the first space walk will grind to a halt.

JOHN MACE GRUNSFELD: Mass, the MTL is slipping.

RUSHMORE DENOOYER: The only people who can solve this are the ones outside with their hands on Hubble, John and Drew. Yet, they're not alone. A space walker with a problem has a vast network supporting him, five astronauts inside the shuttle, Tomas Gonzalez and Christy Hansen in mission control, and, behind them, engineers who know Hubble better than anyone else on the planet.

MARK JAROSZ, Goddard Space Flight Center: We know the telescope. We know what hardware is broken. We know what the interfaces are. We need a -- a flathead screwdriver or a certain kind of wrench or whatever.

RUSHMORE DENOOYER: Now, as Drew struggles to loosen a stuck bolt, engineers call up all the information they have on that bolt, starting with its torque, the turning force needed to loosen it.

No room for mistakes

RUSHMORE DENOOYER: To make sure Drew can't over-torque the bolt, his wrench has a torque limiter on it called the MTL. When it reaches the limit, the MTL will slip to protect the bolt from breaking.

DREW FEUSTEL: Mass, I put in three attempts, got three MTL slips, and see no motion on the A-latch bolt.

RUSHMORE DENOOYER: The only option now, get rid of the torque limiter.

MASS: Try it without a MTL at all.

DREW FEUSTEL: What are the implications if I over-torque and break the bolt?

MASS: You sure you want to know?

RUSHMORE DENOOYER: If Drew breaks the bolt, the old instrument will never come out. Hubble will be stuck with an obsolete digital camera. The new state-of-the-art wide-field camera will return to Earth unused.

JOHN MACE GRUNSFELD: My heart was absolutely as low as it can be. The potential of wide-field camera three for discoveries, you know, was slipping away.

DREW FEUSTEL: All I could do was apply the best technique that I could.

OK. Here we go. I think I got it. It turned. It definitely turned.

MAN: Yes!

NASA SPACE SHUTTLE MISSION CONTROL: We copied and saw that. That's great news.

JUDY WOODRUFF: It makes you want to watch. "Nova" can be seen on most PBS stations tonight. Check your local listings for the time.

For more on Hubble, follow a link from our Web site, NewsHour.PBS.org, to "Nova"'s.