Broadcast 3085 Dr. Haym Benaroya

20 Mar 2018 Dr. Haym Benaroya
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Guest:  Dr. Haym Benaroya; Topics: We discussed his new book, "Building Habitats On The Moon: Engineering Approaches to Luna Settlements," lunar habitat knowledge & engineering, challenges, and more.  Please direct all comments and questions regarding specific Space Show programs & guest(s) to the Space Show blog which is part of archived program on our website,  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

We welcomed back Dr. Haym Benaroya to a two segment 1 hour 47 minute comprehensive discussion regarding building and engineering lunar habitats based on our knowledge and experience as of today.  Please note that we had multiple cell phone feedback issues causing interruptions in our connection with our guest. Please excuse the show interruptions which you will hear during the first part of our program.

I started our discussion with Dr. Benaroya by talking about his Concluding Thoughts chapter in his book starting on page 307.  The summary he provided of the takeaways from his book tied together what was needed plus the best approach possible for developing, engineering, and establishing lunar basis.  We discussed his concluding themes so for sure don't miss this very important part of our discussion.   As our guest delved into the takeaways from his book and his recommendations, we explored the best type of structures to start out with, constraints due to the lunar environment, human needs and more.  For example, our guest suggested we would start out with what we know best from the terrestrial environment which we could apply to the lunar environment.  The preferred structure would be a pressurized cylinder which Dr. Benaroya described in details.  He said it would be rigid, covered with regolith, anchored to the lunar surface (he told how that would probably be done) and how it would need to accommodate human locomotion requirements for the 1/6th gravity.  Listeners asked him about doing things more advanced such as what ESA says will be the way they construct the Lunar Village but Dr. Benaroya pointed out many of the technologies talked about by ESA are not yet available.  He thought they would be much later but stuck by his suggestion for the pressurized cylinder as the starting structure for a lunar habitat and lasting for probably a decade or maybe two.  Barbara in Nebraska emailed our guest about incorporating artificial gravity in the pressure cylinder but our guest said initially there would not be artificial gravity.  That would come later.  Ted from San Diego sent in a note about the power requirements for the initial lunar habitat.  Don't miss what Dr. Benaroya said about the power needs but note that this was one of those areas there very little data exists. 

Due to the persistent cell phone feedback issue, we took an early break to attempt to establish a better quality phone line.  Unfortunately the better quality line lasted just a short while so later in the show you will hear us pause and make a switch to his digital line which fortunately worked well for the balance of the program. 

In the second segment, I noted the section in his book about soils issues.  I asked about guest about soils engineering and what was being looked for, comparing it to building and engineering terrestrial projects which always require soils reports and analysis.  Our guest talked about lunar soils or regolith analysis, the purpose and issues related to habitat stability.  Listen to the issues and concerns he raised regarding the lunar regolith.

Listener David in Seattle both called and sent in several emails during the show.  One of his emails asked our guest about the possibility of using shuttle external tanks that once held fuel as a component of the initial type of lunar hab.  Dr. Benaroya explained why it was not such a good idea and I recalled external tank discussions years ago when they were proposed for a space tourism hotel.   3D printing came up again, especially using the regolith as feed stock for the printers.  Our guest thought this would be an important technology in the not so distant future but it was not yet ready for prime time.  Haym also talked about the importance of ISRU and robots but not for the first habitat.  When asked if the habitat would be built by robots or people, he suggested both but later on it should be done by robots as the robot and AI technology advances for the lunar environment.

Marshall called to talk about bathrooms.  We got silly in this segment, especially talking about various kinds of pressure and waterless toilets.  Marshall suggested the space station baggy approach would not be tolerated that well by tourists or the lunar settlers.  In one of my silly moods, I suggested that the baggy approach was well and good as I see hundreds of people all the time using doggy poop bags to clean up after our dogs, then to discard them in municipal environmental cans placed in areas where people walk and play with their dogs, myself included.  Of course this opened up a broader range of discussion topics for space bathrooms and waste removal. Despite the baggy solution silliness, Haym had much to say about low gravity and materials flow within piping, plus he talked a lot about 1/6th gravity and what that might mean for plumbing and lunar bathrooms/toilets.  He also talked about the likely need to recycle the waste for valuable products, including some dealing with food and nutrition.  He did not foresee big sewage plants on the Moon.   Before ending this part of the discussion, composting was talked about as well as the role of good bacteria and as we know because Marshall talks about it frequently, the need to grow food on the Moon.

Spike sent in an email, one of many, asking about the location of the first settlement or lunar hab.  Haym said there were several suggested sites including the South Pole of the Moon but he did not think that would be the best spot.  Don't miss what he said about citing the initial lunar habitat.  He mentioned the lunar equator.  What do you think?  Let us know by posting your opinion on the blog.

I switched topics and asked Haym about a chapter in his book on performance based engineering.  I wanted to know what it was.  Our guest spent some time explaining performance based engineering with terrestrial examples and then extrapolating to the lunar habitat.  He said part of the problem was the lack of real data on the Moon so the assumptions to be made and the formulas to be used would at first largely be guesswork.  This was a very interesting discussion with I suggest you listen to very carefully. 

Jack in Dallas wanted to know about the differences in the early lunar hab from the early Mars hab.  Our guest spent several minutes responding to this email question.  He listed advantages and disadvantages of both and was asked after his discussion, if he still thought the Moon could be a stepping stone to Mars.  He said yes but he did qualify his answer.  Listen carefully to see how best to use the Moon as a stepping stone for humans making the trip to Mars.  One thing he suggested was that we would probably need to spend about ten years on the Moon to figure it all out for going to Mars!  In summarizing this discussion, he introduced us to both psychological issues and psychosocial issues, comparing those associated with the lunar environment to those associated with going to Mars and the Martian environment.

Seattle David brought ups the idea of using composites for lunar habitat construction. We talked about composites used in the aviation industry and I mentioned the dental industry though with dentistry, composites seem to have a finite lifespan.  Of course there would be significant differences with composites used in aviation and dentistry compared to those used in space. 

Kirk called in from Virginia to talk human locomotion needs in the pressurized cylinder.  He mentioned the way the Apollo astronauts seemed to bounce in their spacesuits when they walked and wondered if the habs would have higher than normal ceilings, maybe extra width, grab bars to pull yourself along rather than trying to walk.  He suggested there would be "rules of thumb" regarding height and gravity.

Near the end of the discussion, I asked our guest to mention the personal interviews that were in the book in various chapters.  Our guest went through the interviews, told us something about each person and why the interview was in a specific chapter.   Tim from Huntsville then called us wanting to know about the lunar space elevator.  After Tim and Haym went over the pros and cons of the lunar space elevator, I asked Haym about his chapter on Lessons Learned from the aviation industry.  Our guest said it was important that for space settlement, we learn what aviation learned and that was for high reliability and safety, each new version of the aircraft was an incremental change, not a huge step or giant leap.  Our guest discussed this concept in detail so please pay attention to it. It was important.  Haym also said that in aviation, after a bad crash the industry does not shut down and we needed to learn from that model with space.  We discussed this to some degree but since in space there has been only one vehicle, it might be different from aviation.  We talked about the need for multiple spacecraft and competition.  It was pointed that some models of aircraft are grounded depending on why or what happened in a specific accident.

Before the end of the program, Peggy asked Dr. Benaroya for his thoughts on LOP-G (Deep Space Gateway).  Haym said he was OK with it as it did represent an option but then he listed the advantages of actually going to the lunar surface.  He also mentioned that building, managing, operating a space station would be more complex and costly than a structure on the lunar surface.  Don't miss this final discussion point.

Please post your comments/questions on TSS blog for this show.  You can reach Dr. Benaroya through me or his Rutgers University faculty website page.




Dr. Benaroya's latest book, lunar engineering and more

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