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Dr. Frank Martin, Tuesday, 9-23-14 September 24, 2014

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Dr. Frank Martin, Tuesday, 9-23-14


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Guest:  Dr. Frank Martin.  Topic:  The NRC “Pathways to Exploration: Rationales and Approaches for a U.S. Program of Human Space Exploration” report.  Please direct all comments and questions regarding Space Show programs/guest(s) to the Space Show blog, https://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 http://www.onegiantleapfoundation.org/amazon.htm.  For those listening to archives using live365.com 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 Dr. Frank Martin to the program to discus the NRC human spaceflight study along with all aspects of human spaceflight including various destinations and missions.  During the first segment of our 1 hour 39 minute show, Dr. Martin introduced us to the NRC Pathways study which you can download for free by using Google.  He suggested it was a dose of reality as well as optimism.  He said the study was very clear in saying “show me the money” for those wanting to do humans to Mars missions now or fairly soon and then explained some of the high costs and trades involved in these missions.  One of his overriding themes throughout our discussion was the need to manage a very large mass in LEO in order to accomplish the goals of long duration human space mission.  During our segment, we kept coming back to the need to manage a large mass in LEO and how this translated to costs as well as the need for technology advancement.  Both myself and listeners asked our guest about doing human missions cheaper by using the private sector.  This subject kept coming up during both segments of the program.  We also addressed the rational for human spaceflight.  In addition, the issue of walking away from HSF was looked at for the US as a nation as that is an option. The report attempted to address this and related issues.   Joe sent in an email about the mice on the ISS and using them to determine the gravity RX for HSF.  He sent us several additional emails on this subject as well.  This prompted comments about the need to use the ISS for research in support of long duration HSF missions.  Dr. Martin said Mars was an horizon goal.  In this context, he talked about only a few other possible destinations near us, either the Moon or an asteroid.  He then proceeded to address the issue of managing the risk for a Mars mission.  Beverly asked a budget question and taking the lead from the most recent Mike Griffin interview, she asked Frank if it really was just a choice to be constrained by budget issues.  While Frank agreed it was a choice, he said there were very good ways and choices to spend taxpayer money so he did not see significantly more money for space in the future.  Another listener talked about nuclear propulsion which also crossed into the second segment.  Near the end of the first segment, we got a call from a New Zealand listener.  During his call, the idea of the Buzz Aldrin Mars cycler came up and there was a question or two about fuel depots.

In the second segment, I asked Dr. Martin why the study took 18 months, then SLS John called the program.  John wanted to talk nuclear propulsion thinking it would be a cost saver but what was not known was the accurate cost of the R&D program or the cost for jumping through political hurdles.  John suggested a new administration would make a difference and I challenged that.  I asked Frank given all his years of space industry experience if it was reasonable to expect big changes in space policy due to a change in administrations.  Don’t miss Frank’s reply.  Dwayne called back to question the HSF rational. One of the points made by Dwayne was that cooperation with the Russians on the ISS does not modify Russia’s behavior other than for space.

Please post your comments/questions on TSS blog.  You can reach Dr. Frank Martin through me at drspace@thespaceshow.com.


1. DDAY - October 2, 2014

I mentioned during a call in to the show that a NASA study several years ago seemed to indicate that the nuclear thermal option was not considerably better than the chemical option for a human Mars mission. If you look at slide #3 on this presentation, it shows a 2009 NTR study coming in at about 800 tons to LEO, with the chemical option coming in at about 1200 tons to LEO for a Mars mission. That’s pretty good. It is possible that what I heard was an initial study (that showed that NTR was not all that great) whereas a follow-on was better. I don’t know. If you can save a third in launch mass with NTR, it still might not make sense because of other factors, like high development cost and testing cost. NTR also comes with handling and operational risks, and you would want to prove it before relying on it. The flip side is that NTR also can provide faster transit times, so that it could reduce some risk.

Much more recently Boeing’s studies indicate that a hybrid using chemical and SEP might be as good as NTR. Considering that this combination has not really been studied much, it’s worth looking into more extensively.


Dan Adamo - October 3, 2014

Dwayne, I recently updated a white paper advocating interplanetary human spaceflight transport using nuclear thermal propulsion (NTP) with water as propellant. Part of the update is a plot of total transport mass versus NTP specific impulse appearing as Figure 15 on p. 33. This plot indicates total transport mass is reduced from 832 t at Isp = 440 s to 357 t at Isp = 900 s. Short of transporters and warp drive, getting > 600 s specific impulse with something like 330,000 Nt thrust from water remains my fondest astronautical dream. The paper may be downloaded at http://www.spaceenterpriseinstitute.org/2014/07/aquarius-a-reusable-water-based-interplanetary-human-spaceflight-transport/.

2. Dan Adamo - September 28, 2014

As a reader of and commentator on the NRC “Pathways” report to which Dr. Martin contributed, I enjoyed listening to this show very much. I invite Dr. Martin and “The Space Show” audience to read my op-ed on exploring and pioneering in space at http://spaceenterpriseinstitute.org/2014/08/should-nasas-human-spaceflight-strategy-be-to-explore-or-pioneer/. The report’s two “enduring questions” figure strongly into this op-ed’s reasoning.

I’m also willing to share my 9-page critique of the “Pathways” report with Dr. Martin if Dr. Livingston is willing to act as intermediary and forward it. Although this critique expresses my specific views on human spaceflight pathway options, it also points out technical errors in the NRC report. Since this report has a “prepublication draft” status at The National Academies Press website when it’s downloaded, my hope is the errors I point out in the critique will at least be considered for correction before the report is finalized.

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