Astronaut Jeff Williams and Miles O'Brien: Space talk on the spacewalk

Jeff Williams is a NASA astronaut. He was part of the third Shuttle mission devoted to International Space Station construction. In that flight, Williams logged over 236 hours in space, including 6 hours and 44 minutes of EVA (space walking). Miles O'Brien is space correspondent for CNN News Group and is primetime co-anchor with Andrea Thompson of CNN HeadlineNews.

CNN: Greetings and good day to astronaut Jeff Williams and CNN's own space enthusiast Miles O'Brien. Welcome to our chat audience, too!

JEFF WILLIAMS: I'm happy to be here today to talk to you a little about EVA (extra-vehicular activity) and space in general and answer your questions.

MILES O'BRIEN: Greetings, fellow space cadets!! We hope you've been enjoying watching the space walk on CNN all morning, and this is a good time to ask questions, because Jeff has been there and done that!

CHAT PARTICIPANT: How cold is it out there in space?

WILLIAMS: Well, it can get close to 170-200 degrees below zero fahrenheit, but in the space suit, you feel very comfortable. Sometimes your hands can get cold, but we wear glove heaters if that occurs.

CHAT PARTICIPANT: How long does the prep work for a space walk take?

VIDEO Watch a NASA animation of the installation of the Early Ammonia Servicer on space station Alpha. Play video (QuickTime, Real or Windows Media) Watch a NASA animation showing the locations of the MISSE experiments. Play video (QuickTime, Real or Windows Media)   RESOURCES Message Board: Space Exploration   Mission Guide: STS-105

WILLIAMS: It takes a couple of hours to prepare the equipment, get in the suits, and prepare to depressurize the airlock to open the hatch.

CHAT PARTICIPANT: What are the detrimental effects on the human body in regards to long term living in space?

WILLIAMS: Well, long term.... we have documented that there are several effects on the body. For example, as you might expect, muscles atrophy and become weaker, due to lack of use. Also, the calcium density in the bones decreases. The other effect has to do with your vestibular system and your sense of balance, and you feel that when you come back to earth, primarily. The good news is that people recover over a relatively short period of time to their full capacity.

CHAT PARTICIPANT: I just switched on and I noticed the spacewalk story. What is the primary goal of it?

WILLIAMS: Today's space walk has two primary objectives. The first one was the installation of what we call the "early ammonia servicer." It will be used to service the ISS ammonia system in the event of a leak. Ammonia is used to cool the station's systems. ...much like freon in your home air conditioner. The second major objective that they're working on as we speak, is the installation of an experiment. The experiment is called the "Materials ISS Experiment," and it will expose many materials to the vacuum of space over several months, so that we understand the effect of the space environment on those materials over a long term.

O'BRIEN: If you wanted to make an analogy to help people under MISSE, if you've ever noticed while driving along the highway, those places where they test various types of paint for the road markings. This is their way of testing some materials in some harsh conditions, and the winners get the contract.

CHAT PARTICIPANT: What does the space station look like inside?

WILLIAMS: I was there when it was relatively small. It's much bigger now. It's basically a long corridor made up of several modules linked together. There are hatches between each module. When you go from the Russian segment to the U.S. segment, the look and feel changes. For example, the color changes. It is tan in the Russian segment, and mostly white in the U.S. segment. There is a cloth on the walls in the Russian segment, and the U.S. segment has metal walls. There are many cables strung along the walls, and other equipment and supplies and cameras, etc.

O'BRIEN: It's sort of like being inside a giant tinker toy creation! Lots of long tubes with connecting wheels, although I have yet to experience it first hand. That is to come!

WILLIAMS: CNN in space!

CHAT PARTICIPANT: Hi Jeff and Miles! How many walks will be done on this visit to the station?

WILLIAMS: There will be two space walks performed during STS-105. The second one will be conducted on Saturday.

CNN: How do astronauts train for spacewalking?

O'BRIEN: Very carefully!

WILLIAMS: On average, you'll spend 10 hours in the swimming pool training, for every hour in space. During that time, we perfect the procedures, the tools, the sequence of events, and the details of the hardware that we are working with. We also work out the protocol and coordination with the rest of the crew inside the shuttle, as well as the flight controllers in Mission Control. All of this occurs over six months to a year prior to flight.

CHAT PARTICIPANT: How do you walk in space? It must be hard to do, due to the weightlessness -- or is it easy?

WILLIAMS: In some respects it's hard, in some it's easy. Walking is a misnomer, obviously. You're actually crawling with your hands. It's very easy to move around, because of the weightless environment in one sense. But it's difficult in another sense, because of the bulky suit and the pressurized gloves that you have to work your hands in.

CHAT PARTICIPANT: We heard a lot about a "bullet hole" they found this morning. Can you explain to us what they meant by that?

WILLIAMS: I was listening to the same thing as it was talked about. It sounds like it was what we call a micro-meteorite hit. It could have been a small particle from the debris of another space craft among the space junk in orbit.

O'BRIEN: Jeff, given the potential there, should that give us some concern for space walkers in general? How big a risk is it -- a space walker being struck by a similar "bullet" if you will?

WILLIAMS: There is a definite risk of being hit by debris in space. NASA studies the probability of that risk, and we consider the probability low, but it is there. Of course, when you're out there for a relatively short duration, the probability goes down even more. The suits are designed to withstand a small particle hit. That helps mitigate the risk as well.

O'BRIEN: I'm sure you'd feel it, though!

WILLIAMS: Either you'd feel it, or not feel it!

O'BRIEN: [laughing]

CHAT PARTICIPANT: What is the longest amount of time a human has spent in space continuously?

WILLIAMS: Well, let's see.... There's a Russian cosmonaut that spent jsut over a year in space.

O'BRIEN: Four hundred something days.

CHAT PARTICIPANT: Since the space station is international, whose laws govern it when people are there?

WILLIAMS: We have international agreements among the partners of the ISS as to how we operate the Space Station. There are no "laws" per se.

O'BRIEN: There are memorandas of understanding, which cover crew conduct and various inter-crew activities, to insure that everybody straightens up and flies right. :) In the strictest sense of the word!

CHAT PARTICIPANT: Jeff, after returning to earth from the ISS, in what way has your life changed given the fact that in outerspace you were able to see our planet from a different perspective?

WILLIAMS: Being in space and seeing the earth below was a very humbling experience. ...to see just how small and relatively insignificant we are, relative to God's creation. It was also very apparent to me that there was vitality or life in the Earth, seeing the blues and greens and browns of the ocean and land forms and clouds, as well as the very thin atmosphere on the horizon, and the multiple colors that it displayed.

O'BRIEN: I'd be happy to wax eloquent, but I haven't been there! But I did find those stats... The longest single space flight occurred on MIR (RIP) from May 1994 to February 1995. Valery Polyakov spent 438 days on MIR. Just last week, he started walking. No, just kidding! He's doing fine! The endurance record for a woman was Shannon Lucid, from March through September of 1996. She spent 188 days on MIR.

CHAT PARTICIPANT: The International Space Station is approaching operational status which will free up NASA assets to pursue other things. What would you like to see NASA focus on in the near future?

WILLIAMS: That's a good question. Sometimes we tend to forget that the ISS is not the end, but a means to an end. It will enable us to understand many of the things it will take to go beyond earth orbit. Our vision is to return to the moon, on hopefully a permanent basis, and then go on to Mars. And perhaps even the asteroid. This is just the current chapter of human exploration.

O'BRIEN: I totally agree, and it's interesting how frequently we forget that the Space Station is just the first step. It is, after all, 245 miles above us, no farther than from New York to Boston, sort of on the very edge of the shore of a vast ocean, but until some time has been spent there, we would be foolhardy to go much farther. Sometimes it's easy for people to be blase about it, because after all, they watch Star Trek or Star Wars, and expect that to be reality. But the real thing is much harder than Hollywood would make it out to be.

CNN: Any final thoughts Jeff or Miles?

WILLIAMS: This mission culminates a very critical phase of the assembly of the International Space Station. The beginning phases suffered some delays due to various reasons, but over the last year, it has been incredible, the progress that the team has made in getting to an operational phase of the International Space Station.

O'BRIEN: This is actually day 1000 for the Space Station. The first piece, a Russian piece, which was launched in November of '98. This is an important milestone. If you'd told me then that the construction would go this smoothly, I would have called you a liar. It's amazing how this challenge has unfolded before our eyes, and it turns out that the real problems have been earthly ones, of budgets, politics, and whether to let rich people visit! So, we could solve all the ISS problems... ...by sending ME. :)

CNN: Thanks for joining us today Astronaut Jeff Williams and CNN's own self proclaimed "space cadet" Miles O'Brien.

O'BRIEN: Thank you!

WILLIAMS: Bye!

Miles O'Brien joined CNN.com Newsroom via telephone from CNN Center in Atlanta. Jeff Williams joined via telephone from Houston, Texas. CNN provided a typist for both.