One of the biggest concerns about going out beyond lower Earth orbit is the radiation. We find that exercise seems to counteract a lot of the negative effects of space flight, like bone loss and muscle atrophy and cardiovascular systems issues. We exercise two hours a day on the station, which is a huge hit out of your day. It's great for staying in shape, but you know, it cuts into the productivity of the crew and if you look at how expensive it is to get a crew into space, if we can keep them healthy and have them exercise, but spend less time doing it, we can get more done.

The ultrasound that has application not only in space for a long mission or for a mission to the Moon or Mars, but also in remote areas on the Earth. Not even just - I'm not even talking about expeditions like to the Antarctic, but just a remote area, a small town somewhere. The local doctor is not going to know everything, and so if that person can link in with a diagnostic ultrasound to the hospital in New York City through the internet, then they can do a very quick diagnosis of something that's wrong with someone that's in this remote area.

The neatest thing about research and science is we don't necessarily know what's going to come down the pike. We think we know what we're working on. Oftentimes, discoveries are made when you're trying to discover something else. You end up accidentally discovering a different thing. So, one of those things might happen that enable us to have more efficient rockets.

Cooperating in something as visible as space exploration and space flight can only improve relations between the two countries because what happens is, you're working on a common project in a very visible light and so, you're motivated to not have conflicts with each other in other areas. And bringing up China is a good example. In the early '90's, China got serious about wanting to launch astronauts into space and they were actually quite successful in launching many communication satellites. They went ahead and in 2003 they launched their first astronaut into space.

Two years ago, China tested an anti-satellite weapon that actually caused quite a bit of controversy and one of the controversies is that by blowing up a satellite, you are creating more space debris which is a hazard to satellites and spacecraft in lower Earth orbit and if they had been a partner, you'd have to do an experiment, and if they had been a partner in the international space station, would they have really done that test? They would have really thought twice about creating that tension between the countries and potentially endangering a project that they were a part of.

We were trying to do as much science as we could because that was the main purpose of the international space station. But without the shuttle to bring up heavy laboratory equipment and bring back samples, we were limited by what we could do, but I was proud that we actually accomplished more science that was planned for the flight. And I got a chance to do two Russian spacewalks on that flight, I had become an expert in U.S. spacewalks and using U.S. suits and techniques, and this was a chance to put on a Russian Orlan suit and do two construction space flights outside of the space station.

Rockets have remained fundamentally unchanged, except for a few exceptions for the last almost 50 years. So, for there to be a fundamental shift in rocketry and getting into space, there almost has to be a breakthrough in propulsion. Either in how to bring the price down, or how to more efficiently get people up into space and the key barrier is the expense of a rocket.