Broadcast 2465 (Special Edition)

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Guest: Brent Sherwood. Topics: Human spaceflight, The year of the dwarf planets, Pluto, Ceres, budget math for space. 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. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See For those listening to archives using and rating the programs, please email me as to why you assign a specific rating to the show. This will help me bring better programming to the audience. We welcomed back Brent Sherwood for updates to his human spaceflight analysis work previously presented on The Space Show. During the first segment of our 1 hour 48 minute discussion, Brent started out with a brief discussion on scientific missions and the year 2015 being the Year of the Dwarf Planet. He talked about the Dawn Mission and Ceres, New Horizons and Pluto, and the oceans on the outer planet moons. Exoplanets and the habitable zone were also part of this discussion which included an assessment of just how our knowledge has changed regarding the compositing of the solar system. To redirect the conversation to the purpose of today's show, human spaceflight (HSF), I asked Brent when we would see HSF beyond LEO (BLEO). I asked about what seemed to be a new space advocacy push for space settlement. Brent then examined why HSF and referred us to his earlier work and the four reasons for HSF which were explore, exploit resources, to experience space, and settlement. He said settlement was clearly part of the debate, talked about earlier workshops which would avoid the topic and then spoke to the recent Pioneering Space meeting held in Washington, DC where there was a consensus reach for space settlement. He had good things to say about the meeting and the consensus resolution and talked about the broad space industry representation at the meeting as it was not just NewSpace. Don't miss what he had to say about it and space settlement. Brent was also asked if our National Space Policy Act needed to be amended to reflect space settlement as the official goal of NASA. Later, he was asked about the stepping stone or incremental approach to HSF development. He supported this approach, spoke to the challenges for HSF such as life support and more. As we were closing out the first segment, he offered us valuable insights on this topic so don't miss what he had to say. In the second segment, John from Florida called in to ask about grand space visions like an O'Neill orbital colony. Brent proceeded to discuss grandiose visions in the context of how challenging they were plus their replacement cost. Here, he used the replacement cost for Manhattan as an example of what he was talking about. He cited a different type of example, the NASA Ames Space Settlement Contest that had nearly a thousand entries this year from 21 countries with the winner writing a 247 page grand space vision report. Brent also spoke to the inspiration factor when talking about this contest. A variety of listener emails were read on air for Brent to respond to, then I asked him if he thought Mars was the Holy Grail for HSF. He said no so don't miss why he said that. He was asked about nuclear propulsion, then we talked about returning to the Moon , cislunar development, and then back to Martian settlement. He was asked about going to the moons of Mars and he said there were two ways to settle Deimos. Don't miss his comments here either. Near the end of the program, he said the physics of HSF were good but the problem was centered in being grounded in what he called program or budget math. The budget math for HSF simply does not work, especially for a commercial venture. He closed on the reality check of being grounded in budget math and the difficulty in going to Mars with humans. Please post your comments/questions on TSS blog above. You can reach Brent Sherwood through me at



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01 May 2015 Brent Sherwood
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