Former astronaut Piers Sellers’s last mission on the space shuttle Atlantis was in May 2010. Between that mission and two other shuttle flights, Sellers logged nearly 35 days in space and clocked one of the longest cumulative spacewalking times, with 41 hours over six walks. When he retired from the astronaut corps to become the deputy director of the Sciences and Exploration Directorate at NASA’s Goddard Space Flight Center in Greenbelt in June, Sellers was 56 years old, the oldest serving astronaut at that time.

The new job is a return to Goddard for Sellers, who researched the climate there for 13 years before becoming an astronaut in 1996; he has a doctorate in biometeorology from Leeds University in the United Kingdom. Born in Great Britain, he became a naturalized U.S. citizen in 1991 to help him realize his dream of being a NASA astronaut.

We spoke to Sellers about his memories of space flight and the end of the U.S. shuttle program.

Rachel Saslow

Piers Sellers thinks Americans should be immensely proud of the space shuttle program. (NASA/NASA)

What does it feel like to be launched on a shuttle?

It’s like a small nuclear bomb going off under your back. You watch the count go down and the instruments go from zero to 100 percent thrust. There’s an enormous bang as the rocket boosters fire and you’re shoved up in the air and you’re hammering uphill, just hammering, being bounced around in your seat. There’s a lot of noise and vibration, and you look out the windows and the sky goes blue, blue, blue, black.

When did you decide that you wanted to become an astronaut?

When I was about 7. My dad told me about the first guy in space, and I remember thinking, “Gosh, that’s really exciting.” At school, I followed the Gemini and Apollo missions, and it was so fascinating and new. It fired me up.

Do you think that without the shuttle program, fewer kids will want to become astronauts?

I don’t think so. If you’re a kid and you’re interested in this stuff, there’s plenty to watch (except for moon landings, which were mind-blowing). We’re learning more about the solar system and seeing these beautiful pictures from Mars. Kids should go for it! I’m saying from my desk here to go for it.

In a 2006 interview with KidsPost, you talked about the logistical challenges of urinating in space. How did people respond to that after it was published?

I went into hiding.

Is that one of the common questions that kids ask you about space?

They ask that a lot! So do adults.

What was it like to walk in space for the first time?

You swing the hatch open and then you’re looking down 200 miles, and there’s China sailing by and the Pacific and it’s a beautiful day down there. You slide out and before you know it, you’re hanging out on the bottom of the space station, holding on with one hand.

You don’t ever let go, though, to float around?

No, no! Don’t let go. It’s bad form, though we’re tethered, like mountain climbers. And we have a small jet pack in case the tether breaks — unlike mountain climbers.

Does it give you any new insights to see Earth from above?

The world really is round. It’s a big, blue ball just bowling its way around space, absolutely beautiful. The other thing was that the atmosphere is incredibly thin, like an onion skin around the Earth. That was surprising. It also makes you think the world is very small. It’s not very big, and there are all these people on it.

Do you try to find your home town?

Oh, yes, we play geography all the time. “What’s that? What’s this?”

How do you feel about the end of the shuttle program?

I’ll be very glad when [Atlantis] has landed and the program has finished successfully in a blaze of glory.

What do you think about the fact that there’s so much uncertainty about what comes after the shuttle program?

It’s not the way any of us wanted it to turn out. It’s unfortunate for it to happen that way. I’m hopeful there will be enough national will to get a reliable replacement.

Where will you be watching the last shuttle launch on July 8?

I will be down there [at Kennedy Space Center in Florida] helping out a TV crew, broadcasting the launch count and watching it all unfold.

What will it be like to watch the final launch?

During the launch, I’m always a little tense. I like being launched myself, but I’m not so crazy about watching my friends being launched. It’s exciting, of course, but I’m glad when they get to MECO, the main engine cutoff, which happens at about 81 / 2 minutes.

How do you think the shuttle program will be remembered in history?

I think it was a smashing success, really. It had some stumbles. We got a beautiful space station out of it, and we learned an awful lot about engineering and construction in space. It’s an incredible technical feat to make a space plane so big and so technical that worked.

I think the legacy is the [international] space station, Hubble and all the science that got done. We got a lot done in 30 years. It was worth it.

What do you think the shuttle program means to Americans?

Americans should be immensely proud of it, immensely proud. The effort and genius to design and build something so complicated and beautiful — no other country could have done it at the time. It’s the most complicated machine ever made by man. There are 3 million parts in each shuttle, and all of them have to work. Americans should be immensely proud. I am.