Broadcast 1365 (Special Edition)

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Guests: CLASSROOM: Dr. Jim Logan, Dr. John Jurist. Topics: Lesson 8, Human Factors Part Two. Drs. Logan and Jurist returned for this Classroom program which focused on long duration human spaceflight. As we started our first segment, I asked our guests what constituted long duration spaceflight. The working definition centered around spaceflight more than six months to a year in duration and any human spaceflight going beyond LEO. Both our guests said there were no show stoppers regarding Life Science in short term space flight but that it was very different in the long duration flight with the two major issues being radiation and microgravity effects, specifically bone issues. During this first segment, we focused on the bone loss issues. Our discussion with Dr. Logan and Dr. Jurist was comprehensive and detailed, explaining the problems, the facts about exercise (you will probably be surprised at what you hear on this topic), and counter measures such as artificial gravity, centrifuges, bisphosphonate usage, and more. Because of the bone loss issues, Dr. Logan said that some destinations in space would probably be classified as a civilization destination while others would be typed as a sortie destination. We talked about the lack of knowledge for the gravity prescription and what that really means for human spaceflight. In discussing artificial gravity which was typed as pseudo gravity by our guests, we learned that it was not the same as natural gravity on Earth and the lack of knowledge about it was a problem. You will certainly want to hear this comprehensive discussion on this and the other topics in this segment. Our second segment focused on space radiation issues. The two major types of radiation were identified as cosmic rays and the solar wind. Dr. Logan gave us some interesting facts for comparison in shielding on Earth versus shielding in a spacecraft, a space habitat, and a spacesuit. You will want to pay particular attention to the percentages Dr. Logan provided as this information was used throughout this segment. Our guests brought up the solar cycle, solar modulation from all directions, the LRO mission and its data findings, and the geometric issue for radiation shielding. We also talked about magnetic shielding and noted that when the spacecraft size decreases, the radiation field needed to deflect particles increases. Don't miss this discussion and explanation. Dr. Rowe asked about radiation and the early Apollo missions. Joe asked as question about the atmospheric particles and could they be used for shielding. Don't miss the answer to these questions. Much of our discussion centered on possible mitigation techniques. We went over many of those suggested but Dr. Logan suggested that the ultimate answer would not be in the form of a silver bullet but more likely a multiple faceted solution, a type of sandwich of solutions mixed together. Near the end of the program, our guests responded to a medical treatment question for a long duration spaceflight crew member with a heart attack. Pharmaceutical usage in space was talked about and our guests brought up the fact that humans were the weak link in the spaceflight chain. Fly By Wire was used as an example. Please remember to visit The Space Show Classroom Blog at Post all your comments and questions there. Any comments or questions sent to me will be posted to the blog under the name of the sender.



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17 May 2010 Dr. John Jurist, Dr. Jim Logan
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