Guest: Dr. Jeffrey Hoffman. Topics: space walks, space tourism, solid rocket boosters, space policy, space vision. Dr. Jeffrey Hoffman was our guest for this Space Show program. In our initial segment, we discussed the Hubble Space Telescope and its repair missions, training for the repair missions, and what its like to do work in space outside the spacecraft. We asked Dr. Hoffman about any sense of speed or height when doing a space walk and if space tourists could do an EVA. He suggested a possible way for the space tourist to be able to go outside their spaceship while still connected to their ship's atmosphere and environmental systems. Check out this discussion. During the second segment we talked about the Vision for Space Exploration (VSE) and we addressed solid rocket boosters for human spaceflight. As you will hear, Dr. Hoffman said that the SRB was the most reliable rocket in the world with a track record to support that claim. This comment led to a comprehensive discussion regarding SRBs and liquids so don't miss it. Space vision came up and we talked about going to Mars as the primary vision though the incremental steps getting there would include working on the Moon, in LEO, and elsewhere in space. A listener asked about hybrid rocket engines and the subject of heavy lift rockets came up. As you will hear, our guest supports the need for a heavy lift vehicle. Toward the end of this segment, NASA budget costs and potential increases were discussed. During the early part of the third and final segment, we talked about the extensive international interest in human spaceflight and space exploration, specifically human spaceflight as a catalyst for inspiring and motivating students to study the STEM courses in college. Dr. Hoffman was asked about a killer application for human spaceflight and this led to a discussion about the purpose of human spaceflight as well as for robotic spaceflight. You do not want to miss Dr. Hoffman's comments on this important subject. Later in this segment, we asked our guest about some of the human factors facing long duration spaceflight and settlement, including radiation and bone loss. Our guest brought us current with some of the research in these fields and how solutions might be realized. If you have a questions or comment for Dr. Jeff Hoffman, please send it to me at drspacespace@thespaceshow.com. In addition, as you will hear him mention near the end of the program, his MIT website is easy to find and it contains additional contact information.