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Classroom with Drs. John Jurist and Jim Logan, Tuesday, 12-17-13 December 16, 2013

Posted by drspaceshow in Uncategorized.

Classroom with Drs. John Jurist & Jim Logan, Tuesday, 12-17-13


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Guests: Dr. Jim Logan, Dr. John Jurist. Topics: This was a Classroom show on radiation issues for deep space travel, Mars and Moon settlements. Please direct all comments and questions regarding Space Show programs/guest(s) to the Space Show blog, http://thespaceshow.wordpress.com. Comments and questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright and are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See www.onegiantleapfoundation.org/amazon.htm.

We welcomed Dr. Jim Logan and Dr. John Jurist to this special 2.5 hour Space Show classroom in-depth discussion on space radiation. We focused our discussion on deep space, Mars, the Moon and BLEO missions. Note that on both The Space Show blog (see above) and The Space Show Classroom blog (https://spaceshowclassroom.wordpress.com), Dr. Jurist has a Power Point presentation on radiation. During the program, our guests referred to specific slides that you will want to check out. In our first segment, Dr. Logan started out by telling us about his interest in the subject, why he has been writing a paper on the subject for publication, and how this Classroom show came about. He cited our short duration spaceflight experience, the Apollo missions, Space Shuttle flights, and then how things started to change when we had six month ISS visits. Dr. Logan also made it clear that space was not a benign emptiness type of environment. He said the reality was that interplanetary space was a sea of disruptive ionizing radiation wrecking havoc on biologic systems. We moved forward in our discussion from that point. We talked about the findings of the MSL RAD instrument regarding radiation on the way to Mars and on the surface of Mars. Both John and Jim spent some time putting the RAD numbers through analysis to let us know what this means for human missions to Mars. We talked shielding, possible materials, passive and active. We talked extensively about water and the use of hydrogen as well for shielding. Our guests addressed the two types of radiation, the GCR (galactic cosmic rays) and the CME/solar flare. Here, John suggested listeners look at his slide 13 as we talked about protons and neutrons. Jim said there was no magic bullet and talked about shielding effects of Earth’s atmosphere. Pay attention here as Jim introduced us to the RP scale. For being on the surface, he said nothing less than RP100 would suffice. For the vehicle, an RP5 was required. John introduced us to career limits for radiation for men and women astronauts of different age but the career limits are for LEO and not BLEO. BLEO limits are expected to be more restrictive when made public in April 2014. Earth Mars transit times were discussed, especially in the context of Brian’s email that suggested a 180 day transit time. Both our guests said that was unlikely with chemical propulsion and all of us again stressed the need for nuclear thermal propulsion. Microgravity was talked about, especially in the context of side effects due to the radiation environment. Jim then brought up the EVA subject and spacesuits. Briefly, Jim said that quite possibly the ISS construction represented the zenith of EVAs which may become a thing of the past. Don’t miss why he said this plus his description of serious spacesuit limitations. We talked about life support to Mars and here Jim suggested we should use Open Loop! Again, listen to the rational behind this recommendation. Don’t miss what our guests said about theories & movies making it sound easy to go to Mars and that the radiation would be nothing more than just a few more cigarette packs a year. Our last topic addressed informed consent issues.

In the second segment, I asked our guests for a readiness timetable were there sufficient funding and technology advancements. I also inquired if Russia, China, and others assessed the radiation risks in a similar way to the U.S. We then talked about radiation and space pregnancy, fetus development, birth, and informed consent for the fetus, a baby, and a child under 18. Ethical issues regarding child birth and space pregnancy were talked about as well. Curt had sent in email questions which our guests answered, especially about drinking irradiated water and microgravity DNA damage & what this may mean for radiation effects. Next, I asked Jim and John to tell us their 2-5 steps for the start of designing a Mars human mission. Jim went first and listed Day 1 and Day 2 activities, John listed his top three priorities which were different than those suggested by Jim. Don’t miss this discussion as its very instructive as to how to do or at least start mission planning for a human mission BLEO. Roger sent in a question asking if the crew should be senior citizens since they have more resistance to radiation. Don’t miss what our guests said about this idea. It may surprise you. Our next topic was would going to Deimos be easier. Yes, it would but it would be a very different kind of human mission. Jim had some great comments about Mars gravity. Briefly, he said it was the “best.” Later, when asked to compare the Moon and Mars, our guests said lunar radiation was worse than Mars. Also, the Mars atmosphere does provide limited shielding while there is no such thing on the Moon. Jim had earlier talked about a sphere being the perfect shape for an interplanetary spaceship. Shelia emailed in wanting to know if heavy lift made a difference and if the sphere was so good, why were capsules being used? Don’t miss the response. We then talked about the complexities of rendezvous and docking, especially in the context of fewer launches (heavy lift) as compared to many more launches (smaller rockets). Near the end, I asked our guests if either thought our nation, the public, NASA, our leaders and politicians were sufficiently motivated to do a human Mars mission. Jim did not think so and had much more to say in reply to this question. John was more pessimistic. Both thought it was more likely that the private sector would mount a human Mars mission rather than our seeing a government mission, but raising the needed capital might turn out to be a show stopper. The three of us then talked about what it was like growing up in the 40’s, 50’s, and 60’s as compared to today. John and I (John is a bit more than 2 years older than me) were probably more harsh than Jim in our assessment of today, but we all realize that the younger generations will be taking us to space, building the next smartphone and more. I talked about my visits to Google, Apple, SpaceX, etc. and the excitement in the air in belonging in their work forces which does not seem to exist with NASA. This opened the door for Jim to put it on the line about his NASA experiences and the potential opportunities providing NASA can somehow reorganize. He did not think the type of reorganization he was talking about would happen. Both our guests left us with excellent takeaway points and concluding pearls of wisdom.

Please post your comments/questions on the blogs. You can reach either of our guests through me.


                                                     Radiation Biophysics and Human Spaceflight

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