Photo: John Grunsfeld

Photograph by Michael Soluri

By David Roberts

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Photo Gallery: John Grunsfeld repairs the Hubble >>

Around NASA, he’s known as “the Hubble Repairman.” And last May, on his third visit to the orbiting space telescope, John Grunsfeld pulled off the repair to end all repairs. Working at zero gravity some 350 miles above the surface of the Earth, the astronaut restored sight to a half-blind Hubble—called the greatest scientific instrument ever invented—and ensured that it will continue to send back the stunning images and mind-boggling data that have transformed our understanding of the universe.

Having just turned 51, Grunsfeld has spent his career championing manned space exploration. At a time when astronaut-led programs are being called into question, Adventure tracked down Grunsfeld at the Johnson Space Center in Houston to learn about his May mission and why going manned matters.

Q. After the Columbia disaster in 2003, NASA announced that there would be no more manned fixes of Hubble. What happened?
A. That was the official line. I got so despondent, I nearly resigned. But instead, I worked behind the scenes, and in the end we got approval to go back to Hubble with astronauts.

Tell us about the mission last May.
The ACS—Advanced Camera for Surveys—had failed. Something like one-half of all the science out of Hubble had come from the ACS. We didn’t have time to build a replacement. And we couldn’t remove it in space—it was too hard to get to. So when I was there, I had to cut into an aluminum panel, unscrew 32 tiny number-four screws, and remove four circuit cards. I couldn’t see all the screws. Some I had to remove by feel, with my space suit gloves on. I practiced for months beforehand. Every night, I’d review the procedure in my head, step by step. You’ve only got so many hours in space. The clock’s ticking.

How dangerous is a space walk like the one you performed?
It’s always scary. The biggest risk is getting a tear in your space suit. You’ve got 11 layers of Dacron and Gore-Tex; 4.3 pounds of oxygen per square inch inside, a vacuum on the outside. Even a small cut may not be survivable.

Or you could get hit by a piece of space debris. The junk is flying by at seven to ten kilometers [four to six miles] a second. Hubble’s had lots of debris hits over the years. But the odds on any given space walk of an astronaut getting hit are only one in 20,000. On the other hand, NASA has calculated that the chances of what they call a “probability of loss of crew” on any given space mission are one in 70. I worry about that before every shuttle launch we make.

On a space walk, another big concern is that you lose things. You let go of a wrench and it’s gone for good. The worst thing, of course, would be if it’s you that’s gone. There are a lot of operations where you have to switch to a new tether. You think you’re tethered to something but you’re not, and when you let go, you’re gone. We sometimes have a backpack with jets on it so that if you became separated, you have one chance to fire these little rockets and get yourself back—but not on this mission.

Does adventure alone drive you?
I’m an incurable romantic. But I’m not an adrenaline junkie. I don’t particularly want to jump out of an airplane with a parachute if I don’t have to. I don’t want to go bungee jumping. I like adventure with a real purpose that I can buy into. To help enable the kind of science Hubble is performing makes my life worthwhile.

What’s the future of space exploration?
I think we should clearly declare Mars as the next big goal. We need to do it. We need to move off the planet. And Mars is the next best place.

Manned or unmanned?
I was talking with Steve Squyres [principal investigator for the Mars Exploration Rovers mission]. I said I thought that when you broke it down to cost per unit of science done, it came out about even between robots and humans. I said, “I’ll bet a 90-day mission by robot could be accomplished in two hours by a human.” Steve thought a minute, then said, “Nah, probably more like two minutes.”

What about the danger?
One of my pet peeves is that to get the American public behind space exploration, NASA has deliberately downplayed the risk. That’s why there was such an outcry after the Challenger and Columbia disasters. Of course it’s risky to go into space. But we do it for the same reason that Lewis and Clark crossed the continent. The push to go out and find new places is important to humankind. If we’d had live helicopter coverage at Donner Pass, we’d have stopped exploring.

There’s been talk about a “one-way” expedition to Mars, staffed by astronauts willing to die there. What do you think?
There’d be no shortage of volunteers. But I think we’d be disappointed. Consider Lewis and Clark. We needed them to come back as well as go out.

I’d certainly like to go to Mars myself. I’d volunteer in a heartbeat. But I’d like it to be a two-way trip.

This mission to Hubble was deemed the last ever. What’s the prognosis?
It was a perfect fix. We have every expectation that Hubble will continue to operate for three to five years. And it’s within the realm of possibility that it can go on for 15 more years.

Did anything go wrong last May?
The only glitch happened when there was a distraction in the cabin. I lost focus for a minute. My backpack grazed the antenna and knocked off a “bottle cap” put on to protect it years ago. The ground crew in Houston reassured me that Hubble was still operating perfectly, but I felt bad about bonking his antenna.

“His” antenna? Sounds like you’re talking about an old friend.
When it was time to say goodbye, I laid my hand on the telescope, and I said, “Sorry, Mister Hubble.” Then I let go and whispered, “Have a good voyage.”

Originally published in the December 2009/January 2010 edition of National Geographic Adventure