Broadcast 1915 (Special Edition)

15 Dec 2012 Gwyn Rosaire, Tabitha Smith
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Guests: Tabitha Smith, Gwyn Rosaire. Topics: Nuclear propulsion, Project Bifrost, Icarus Interstellar. Please direct all comments and questions regarding Space Show programs/guest(s) to the Space Show blog, 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. We welcomed Tabitha Smith and Gwyn Rosaire to our program to discuss Project Bifrost and nuclear space propulsion. For more information and to contact our guests, visit If you are interested in joining Project Bifrost, or have suggestions, please use the "here" email link on the webpage. During our first segment, Ms. Smith started by giving us the origin and meaning of the project name, Bifrost (pronounced BEEFROST). This discussion included Icarus Interstellar and mention of the Darpa 100 Year Starship Program (100YSS). I asked Gwyn about our technical status in having a nuclear thermal rocket and he said we had more of an economic problem with nuclear propulsion than a technical problems. We talked about the lack of a mission for a nuclear rocket and that such a mission would be generated from the White House on down. Nuclear fuel was a topic as new research is focusing on tungsten fuels rather than graphite though our caller Dr. Jim Dewar suggested new opportunities existed with modern graphite fuels. Other listeners emailed in both questions and comments about fuel. Another topic included a discussion about a much larger payload to Mars with a nuclear thermal rocket (NTR) than a chemical rocket so I asked our guests about economic trades as to what would eventually be less costly, multiple chemical rocket launches or the use of a NTR. Using the Saturn V for our chemical rocket, We carried our analysis to the point of including additional launches to cover for a launch failure and also the human factors side in that a shorter trip means less radiation for the astronauts, thus less shielding and potentially less mass. I think you will find this discussion and analysis most interesting, including the NRC equation for astronaut exposure to radiation. In Dr. Dewar's call, he also talked about the B4 core concept & the progress made with NERVA. We got emails from Bruce in Canada plus other listeners advocating private sector development, a change in ITAR, and the radiation policy changing after Fukushima per this article,, and the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). In our second segment, Michael called in to ask about Russian outreach and the Russian nuclear propulsion program. We then asked our guests for the future Project Bifrost plans. We learned of several major issues. One issue centered on U.S. export control. Our guests also noted that the Russian economy was actually gaining in strength and this might cause them to think its better to go it alone than team up with a weak international partner. Other listener emails inquired about time lines for operation. It was suggested that about ten years would be needed for the NTR if all goes well. As for more routine Mars flights, it was suggested that it would take about twenty years after the first human flights to Mars to really have the program operational. We talked about the private sector and our guests suggested that the private sector will play a strong role in developing and using nuclear propulsion. Moving on, the second project our guests mentioned had to do with ablation technology using NASA Ames facilities. The third and final project mentioned was at Huntsville, the Decade Module 2 fusion project at Marshall. During both the first & second segments, our guests talked about Jupiter radiation and magnetic shielding. John asked about this when he called in the second segment. Doug inquired about Dr. Zubrin's Mars plans & possible trajectories that could be used with the pros and cons for each. Bruce inquired about fuel vibration problems, then Tim called wanting to know about tours at the Marshall facility & the level of power needed for interstellar travel. As we were ending, our guests said we needed breakthrough propulsion or new physics for interstellar travel. Both our guests left us with important closing comments relevant to Project Bifrost & nuclear propulsion for our future with space development. Don't miss what each had to say as we brought our discussion to a close. Post your comments/questions on The Space Show blog. You can email our guests through me or through the above website URL for Bifrost.



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