But here's where the "swell guy" part comes in. Walheim liked your questions as much as I did, so he set aside a half hour for us last week, to answer some of the queries we couldn't get to during the first interview.

There's some really great stuff in here. Want to know what songs to listen to in space? Curious about what the ISS smells like? Perhaps you'd like to know why Rex Walheim thinks politicians should have to spend some time orbiting the Earth? Read on for a candid look inside the life of an astronaut.

Rex Walheim: [The idea of being an astronaut] was something I liked as a kid but I didn’t take it seriously until later. By the time I went into the Air Force, though, that was my intention. I wanted to be a test pilot and astronaut and that went well through ROTC. Then I went on to pilot training and did a physical for that where they found a heart murmur. That knocked me out being a pilot. I had to re-evaluate what I wanted to do. I could still be a backseater, a flight test engineer. So I did that for a while. But I did try again for test pilot school and got accepted on the second try. That time, they didn’t see the heart murmur at all, and that opened the door to astronaut. But it was not the path I had expected to take. For quite a while, I thought being an astronaut was impossible for me.

RW: No, I love flying. But it turns out that I’m a better engineer than I am a pilot. To be an astronaut, I’d have had to be one of the best of the best as a pilot. And I'm not. But I am a really good engineer. So I could climb that ladder.

RW: Yes that happens. It is very rare, and it is unfortunate. It keeps you up at night. I was an astronaut for five and a half years before my first flight. For a while, you spend a day in space for every year on earth as astronaut. But I decided that if I love the job supporting space flight program, I was in the right place. I already knew what disappointment was like from being rejected as a pilot. So even if I'd never flown, I’d still have enjoyed being in the space program. In fact, I might not get the chance to fly again. But I'm still busy. There are lots of different jobs on the ground. You can work in mission control, talking to crew, and developing procedures for the space station. I'm working on the Orion vehicle and some advanced space suit stuff now.

RW:Absolutely. I think it’s the next generation and a step we need to take. We need to develop that capability to send people into space and I think these companies have good ways of getting there. It frees up NASA for deep space trips. We have the technology and it warms my heart to see commercial crews trying hard to do what we need to do. And there are partnerships happening on this. Astronauts and former astronauts are working for these companies. Even those without an astronaut, if they’re working closely enough with NASA we can help them out and answer questions. That's not something I'm heavily involved in, though, so I don't know specifically what we've helped them on.

RW: That’s a good one. I think you feel smaller. It’s such an incredible expanse that you can see. It’s an overwhelming experience when you have time to look out, especially on your first flight. Space is more than just dark, it’s a void. You really get the sense of Earth hanging in the void. It’s amazing. I can see why it might make you feel large, but for the most part being so far up and moving so fast makes you feel small.

RW: There’s a lot of songs that I like. The wake-up call I chose was"More" by Matthew West. He's a Christian artist and he talks about looking at the mountains and oceans and deserts and seeing how big and awesome they are, and seeing God there. I also like to listen to Tom Petty "Free Fallin'". We had some great wake-up calls on the last mission. Paul McCartney did "Good Day Sunshine" for us. Elton John played "Rocket Man". It’s neat to listen to music, and it's sometimes hard to sleep in space. I’d often wake up before the wake-up call and couldn’t get back to sleep. So I’d put my iPod on and listen and it was the only time I could really unwind. It gave me a chance to relax. Other than that, it’s go go go. [What are wake-up calls?] The sleep schedule for the crew is pre-determined. You get 8 hours. So you know when wake up is supposed to happen. But mission control plays music for us at that time. It comes over the air-to-ground channel, so it can be a little grainy. But it's meaningful. It might be a song your family has picked out for you.

RW: I think it would do government officials tremendous benefit. Not just in the United States, but all over the world. The experience reinforced and made it obvious how interconnected we all are. You look down at conflict prone areas and you don’t see borders. You can only kind of see cities. You realize there’s no borders and we’re all in this together. You can see a good portion of the planet and you realize we really are a spaceship. I know it’s trite to say, but you really do get that feeling. You see how fragile the environment is as well. You can see this little thin band that’s our atmosphere and it looks so tenuous like it could just blow off in a stiff wind. The other thing you get from working in the ISS is this experience with a multinational crew. We have Japanese, Russians, Americans. We all work together and we’re one big team. You can really get good teamwork and understand people better that way. The more people get that God's-eye perspective, yes I think the better the ability to work together."

RW: I’d say that you have to have some kind of sci-tech background, but then what you do with it is also important. There's a variety of fields, but one key thing we look for is whether they’ve shown an interest in space program. Is this something they just decided on recently or have they been pursuing it for a long time. You have to excel at what you do, too. So you have to have had a significant enough carreer, but we also look at did you work for a commercial space company, or for NASA, and that helps too. Even you don’t have aeronotical engineering background having exposure to the space program makes for a stronger application. I saw that someone asked whether it feels like a "closed circle" in space and the answer is absolutely not. Even within a field you have completely different experiences and sub-specialties. Pilots are very operations oriented. Engineers more technology oriented. Both may have an aeronautical engineering background. And there's people with completely different experiences, too. Kate Rubins has been doing infectious disease research in Africa.

RW: I think it’s personal. It’s one of those things where people more relate that one-on-one with people. You are a little worried of offending your audience or NASA. And I think it’s just a piece of your whole experience. It does change you. But I don't think it changes your whole outlook. For me, as a Christian, it reinforces the beauty of the Creation. It’s just awesome. But it’s personal and people are reluctant to talk about it in a big venue.

RW: There are noises. What you hear are the fans mostly. The space shuttle almost sounds like an airplane, it's about as loud. I sleep with ear plugs. It's fairly noisy, but you get used to it and you stop noticing. Then, when you change out the lithium hydroxide canisters that clean our air, you turn off the fans for a minute and it gets so quiet and that's when you notice how loud they really were.

The ISS does have a distinctive smell. But it's not bad. I think it’s the hygiene products we use. They make it smell like home and that makes you comfortable. The Russian segment smells more like the Russian training modules in Russia. As for the smell of space, I think there is one. When we bring people back in from a space walk there’s a smell on the suit, like a burnt smell.

There's not much of a smell inside the EVA suit. You're breathing pure oxygen for 8-9 hours, though, so you notice the smell of space station much more after you come back inside. What you hear in the EVA is the fan. I had a little electrical problem on the mission before last and when I switched power sources the fan wasn’t on. That silence is a bad sounds in the EVA. The fan is comforting then.

RW: The biggest benefit, to me, is that you're giving everybody a chance to experience being in space, even if for just a short period of time. It's a transformative experience. That’s the first step, suborbital flights. And then hopefully that will bring the cost of orbital down. That’s also one of the benefits. And hopefully we'll get some benefits to passenger jet design and that will help as well. As for the consequences, well, it will be tough to do. I wish them all the best. I hope they’re taking all the precautions they can. It’s very possible they could have an accident and then it's all about how they regroup after that and become safer and safer. Going to space is not risk free.

RW: I think it is a little hard for some people. I mean, what do you do to top it? Going to space really is addicting to some people. At first you’re so worn out when you come back that you can’t think about doing it again. But after a few months you want to go back. It’s an absolutely incredible experience and hard to duplicate. And it's not just the trip itself. You've got a whole year of being assigned and trained and then going, and all of that is an incredible experience.

A lot of people stay on with NASA, which works out great. Some go to the aerospace community. Some go on to med school and start a whole new career. And, of course, there’s a risk to going to space, too. So there is a part of you that breathes a sigh of relief, and thinks, "I survived my flying career."

How do I feel about it? I would love the chance to fly again. I’m happy with what I had, but there are parts of me ... you think about the view and what you’d like to do and it does have a tug on you. But you have to make the best decision and deal with the cards you’re dealt.

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Rex Walheim is a veteran of three shuttle missions, including the last flight of the space shuttle program in July, 2011. You can read our previous interview with him—Five Questions With Astronaut Rex Walheim. All the reader questions in this interview, and that previous one, were gleaned from an earlier post—Ask Astronaut Rex Walheim a Question.

Walheim reached those heights the old-fashioned way: Air Force test pilot school (plus a masters in industrial engineering). But his isn't the only path to the stars. Today, NASA has Walheim chatting with lots of different news outlets about the astronaut recruitment process and what it takes, in the modern world, to have the right stuff. I got to talk to him this morning. Walheim was kind enough to answer five questions, submitted by BoingBoing readers, about astronaut training, the astronaut selection process, and how the Earth-bound can recreate some of the astronaut experience in our daily lives.

Maggie Koerth-Baker: This question comes from reader kansas: When you're going through the selection process, hoping beyond hope to be chosen to train as an astronaut, would you admit to being afraid of anything, or would than seem not very astronaut-like? Is there a place in the training for people to admit to having fear?

Rex Walheim: I think it would depend on how you talk about something like that. If you say, "I'm scared to death," you might not make it. But you can say, "I'm concerned about my safety." Frankly, if you're not concerned about sitting on 10 stories of high explosives, you're not thinking hard enough. The funny thing is, after 5 years of training, it actually doesn't cross your mind too much.

I remember my first flight. You're so excited. You've been wondering, is it ever going to really happen. You never know whether launch day will actually be launch day. I remember that I felt the engine sart and the rocket boosters start, and I thought, "I really get to do this today! Nobody can stop me now!" That was an incredible adrenaline rush. On simulations we have things breaking and going wrong to test us. But on the real day nothing went wrong. I had the chance to look around and think, "Oh, this is kind of dangerous." But 8.5 minutes later we were at 17,000 mph and in orbit. You're so trained to do the job, you just kind of put the danger aside. The harder time is leading up to the mission, when you're with your family and thinking about what could happen several weeks and months ahead.

MKB: Reader penguinchris wants to know: What can we average folk do (within Earth's atmosphere and outside NASA training centers) that most closely simulates the various sensations of space flight? I mean, most of us have experience with g-forces, including brief moments of zero-g/freefall on roller coasters. But what I'm really wondering is if there's something here on the ground that we regularly experience that reminds you, an astronaut, of space flight. Not necessarily just the physical sensations, but perhaps mental state of mind.

RW: The first thing that comes to mind is actually finals week in college. On the space shuttle program, we're sprinting the whole time. We have so much to do. I was on the final mission and there were only 4 people to get everything done in 13 days. We're moving so fast and have so much do concentrate on. The mental frame of mind is that you're doing this hugely important job and doing it quickly.

On long duration stays, you get time to enjoy it a bit more, free time on weekends and whatnot. Then it's like being in the mountains, where the views are spectacular. It's incredible, being able to see 1000 miles in any direction. Incredible. But it's that, plus all the support you're getting from Earth. You have an internet phone to call people anywhere. It's great to be able to call somebody on their cell. They might be on a ski lift in Colorado and you can talk to them from ISS. And you can talk to celebrities and people you wouldn't normally get to interact with and they're really happy to hear from you.

MKB: Here's what Scratcheee asked: Who is the least stereotypically astronaut-like astronaut you know?

RW: There's really a lot of variety of people. But one of the best is Don Pettit. [Pettit was a chemical engineer at Los Alamos before entering astronaut training — MKB] He's launching in just a few days, actually. He's the professor, and the nicest guy you'd want to meet. He knows all sorts of things, on lots of different subjects. And he does Saturday Science on board the space station with things we just have on hand, like what happens to Alka-Selzter in water in zero-g. He's just got an incredible curiosity. He's not the steely eyed test pilot, but he's so much fun to have around.

MKB: Here's a question from spocko: We all loved the Apollo 13 story about creating a C02 detox filter using duct tape and notebook binders. In your training do they ever run "MacGyver drills" where you need to fix things with improvised parts?

RW: I think that is part of space station training, because on long duration stays, over 6 months, you do have to fix things. One of the first things I learned is that duct tape holds the space program together. So you have this maintenance training. They do get into that. You have to fix a lot of stuff. Mike Fossum was telling us recently that that's the great thing about being in the space program: One day you're walking in space, and the next day you're fixing a toilet.

MKB: It looks like we've got time for one final question, so let's try this one from ganman: What reason for candidates getting the axe surprised you the most (or was the most surprisingly frequent)?

RW: Unfortunately, it's the medical stuff. You get people who look perfectly healthy, and tests during training find things they didn't even know about. It's frustrating sometimes, because you'll say, "That person was perfect!" but there's this medical issue that counts them out.

• • • •

•NASA is now taking applications for its astronaut selection program.

• Kansas, penguinchris, Scratcheee, spocko, ganman, and (although we didn't have time for your question) Titus: Please contact me at maggie.koerth@gmail.com. You've all won an awesome BoingBoing sticker and Jackhammer Jill pin. Thanks to you six, and all the readers, for submitting such great questions. It was a hard choice to narrow them down.

Image: Rex Walheim at work on a spacewalk during STS-122 in February 2008. NASA photograph.