Michael Price of Vancouver asks: Why has America lost its nerve in space? Why is it ceding superiority to the Russians, the Chinese, the Indians, and the Japanese?
Chris Hadfield: Michael: It hasn't. Next year I am going to ride a rocketship from a standing start to 28,000 km/hr in 9 minutes, and then live on an International Space Station orbiting the Earth 16 times a day for 6 months. That takes nerve. Your follow-on question completely depends on your definition of superiority, but I think that a quick look at the ISS and planetary probes will show tremendous current proven capability. The Shuttle was a very capable and visible vehicle, but it was never the only vehicle.
Mahesh Yadav asks: Can you see the stars with the naked eye in the black sky in the direction opposite to the sun during the space walk or through the windows of space shuttle or space station? If so, how good is the visibility as compared to ground-based dark sky observation?
Chris Hadfield: Mahesh: yes, you can, but like night vision on Earth you have to wait long enough for your eyes to adapt, like walking from a sunny day into a dark theatre. Once your eyes get adjusted, the view is fantastic - a crystal clear view of the Universe, where the stars don't twinkle with no atmosphere in the way.
John Kable of London, Ont. asks: What type(s) of navigational software do you use on the space station and shuttle? Are they a NASA product, or commercially produced? And how about star maps? Also NASA, or commercial products? I know that is more than one question, but all part of the same overall question.
Chris Hadfield: John: We use several types, depending on flight phase: gyroscopes and accelerometers, GPS, star trackers, optical sights, radar, TACAN, pitot-static sensors and ground tracking. The GPS and TACAN are commercial/gov't, the rest are specifically built/used for the Shuttle.
Claire Eagle asks: Public interest in space has notoriously declined in the last few decades. Do you see this picking up, with increased R&D, exploration, and funding to come in the future? Or do you think that politically, we will remain more focused on problems on earth? Also, do you believe that public perception of nuclear energy and recent growing distaste for it will impact future space exploration at all?
Chris Hadfield: Claire: I disagree. Nearly 1,000,000 people came to Florida to watch the last Shuttle launch - that is a direct indication of interest! The facts are that public and government support has been steady. Remember that even in the absolute heyday of early spaceflight, the Apollo Program and after the 1st Moon landing, public attention naturally wandered. The last 2 Apollo missions were cancelled, and even by Apollo 13 interest had dropped way off. There's a difference between space exploration and space entertainment; we are not doing it to amuse and entertain, though sometimes exciting things catch the public's attention. The key is to continue doing good work, to keep setting barely-attainable goals, and to keep expanding our understanding of the universe around us.
Your second question is a key issue - power generation. To launch from Earth and to explore require a compact and efficient power source, and nuclear energy is an option. In order to use any power source we need to be efficient, and to guarantee safety. No system is perfect and all have trade-offs, just like on Earth. Public perception is important, and so is good engineering. But the impact of nuclear power is minimal on space exploration - we seldom use any form of it, and never for human spaceflight.
John Read of Halifax, N.S. asks: Mr. Hadfield, SpaceX, Dream Chaser, Boeing and Blue Origin recently received funding to construct vehicles that will carry astronauts to the International Space Station. Which of these upcoming private space launch systems are you most anticipating and why?
Chris Hadfield: John - I am most anticipating watching Canada's new astronauts, David Saint-Jacques and Jeremy Hansen, as they and other astronauts work with the manufacturers to make these initial designs operational. All vehicle designs are strong contenders, and it will be great to see the final result fly. What we need is simple, reliable and safe space transportation, and what we have learned from the Shuttle, Soyuz, Apollo and other spaceships will be invaluable in getting there.
John Thurston asks: Why is heat only a problem on re-entry and not on liftoff?
Chris Hadfield: John - because during launch the engines push us straight up until we are above the air, and only then do we accelerate to orbital speed of 8 km/s, up in the vacuum of space.