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Dr. Donald Rapp, Monday, 4-20-15 April 21, 2015

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Dr. Donald Rapp, Monday, 4-20-15


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Guest:  Dr. Donald Rapp.  We discussed using indigenous resources to facilitate HSF to Mars, then the great climate change debate based on facts not agendas.  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 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 back to the show Dr. Donald Rapp to discuss two important topics.  In the first segment we addressed using indigenous resources to facilitate human spaceflight to Mars and the MOXIE experiment on Mars 2020.  In the second segment, Dr. Rapp examined the climate change debate without out preconceived belief systems by an honest examination of the data.  To start our first segment, Dr. Rapp talked about the massive amounts of propellant needed for a human mission to Mars which then led us to discussing using resources on Mars to make propellant for the return to Earth.  Our guest was asked about going to Mars via the Moon and using lunar ice to make propellant for the Mars mission.  This proved to be quite a mini-discussion as Dr. Rapp was skeptical about the use of lunar resources including water ice as an assist for a manned Mars mission.  Many listeners asked him challenging questions about his position and conclusions do don’t miss this important discussion.  Later in the segment a listener asked Dr. Rapp about the potential benefits of using nuclear power and nuclear propulsion.  This too was a fascinating mini-discussion so don’t miss it, especially the call on the subject from listener Kris.  Dr. Rapp was asked about the MOXIE experiment which we talked about at length, then he was asked about the need for heavy lift rockets to Mars.  Our guest supported heavy lift which he defined as a 100-120 tons to LEO.


In the second segment, climate change was our main topic.  Here he talked about extreme agendas by both the climate alarmists and the climate skeptics and said a new group was emerging which he called the “lukewarmists” who actually and honestly evaluated the data without a preconceived belief system.  Dr. Rapp went through the known facts, the history of the subject, the warming periods, the CO2 levels and where on Earth warming mostly took place though there has been no warming from 1998-2015.  We talked about sunspots and climate change and the impact of El Nino and La Nina.  He also talked about global energy usage and the projected increases for the 21st century and beyond.  The increasing use of power and pollution by China and India were important factors in this discussion.  Listeners had many questions for him including many wanting a way to deal with excessive, costly and unscientific regulations that are forced on the people by politicians who don’t know the facts and have an agenda to their behavior.  No solutions were offered.  A teacher wrote in about the challenges she has teaching factual climate change to her students because parents on both sides of the issue come in and complain that the “truth” was not being taught in the class.  Dr. Rapp offered us concluding remarks around the basic idea that everything is complicated including sending humans to Mars and dealing with climate change issues.


Please post your comments on TSS blog.  You can contact Dr. Rapp through me.


1. B John - April 24, 2015

Re: climate change, here’s a recent interview on the topic with Freeman Dyson: http://www.vancouversun.com/technology/Conversations+that+matter+Earth+actually+growing+greener/10944052/story.html

Matt - April 24, 2015

Yhe, it great. Observed CO2 increase helps plants to increase its grow by 20%.

2. Andy Hill - April 23, 2015

I have come to think that Mars has become an obsticle rather than a goal of human spaceflight.

It stops the incremental development of capability because its requirements are so high, it focuses people’s attention on what can be done in 30 to 50 years rather than what can be done now and becomes an excuse for not going anywhere.

Everyone jumps on the Mars train that never leaves the station.

Matt - April 23, 2015

I could not say it in a better way, Thanks.

B John - April 23, 2015

But there are useful short term stepping stones to a manned Mars mission. Not least the construction of a new space station in LEO which would basically be a prototype of a Mars crew transfer vehicle. It could simulate gravity and (almost) fully recycling life support systems and time delay communication with Earth. And training for the crew of a real mission to Mars, while still protecting them from the radiation and distance dangers of a real Mars mission. We could’ve done that instead of the ISS.

If human space exploration (or settlement, really!) had been motivated properly, then we would’ve had a space”ship” instead of a space “station” in LEO today.

Matt - April 23, 2015

I see no urgency to go to Mars surface (let us skip it for 50 years), but I would support LEO missions, which enable the gain of long flight experiences, artifical gravity and development of life-support systems for later deep space missions (for example to Mars’ moons. However, most important would be the development of a new manned lunar lander, which can be combined with Orion and a more capable service module for Orion. ISS is a mess, it has and it costs much money, however, we shall it use it for specific purposes, because it is exist.

B John - April 24, 2015

Mars surface is a great motivator for politicians and the general public. It is easier to get more money to go to the surface, than less money to circle around Mars, like a Martian version of the ISS going nowhere.

ISS is a failure, although it has been lucky to avoid any serious accident. But it has been a very valuable lesson. If, 40 years ago, the Shuttle and ISS had been replaced by a manned mission to Mars, I think it would have encountered even more problems than the Shuttle and the ISS have, and that we would still be in LEO. A lunar lander and ascent vehicle is the obvious next step to take in human spaceflight. I’m sure that the physical reality ensures that it will happen, no matter who wants what. And it should be doable in less than 10 years within today’s NASA budget.

Unfortunately, Orion has no airlock. The entire crew must suit up during an EVA and the air can only be replenished once. So it needs an airlock module too, no big deal. The lunar lander and ascent vehicle should be designed around the Orion. It could then support a crew of 7 on the lunar surface for an entire lunar day (half a month). Then some real work can be done on the Moon! Not only science, but construction and resource extraction.

Matt - April 24, 2015

Yeh, you are right, but Orion’s service modules needs more propellant/delta-vee capability!

B John - April 24, 2015

Yes, but costs don’t seem to matter when it comes to SLS/Orion… I see that it weighs 21 tons with the service module, compared to the 4.7 tons dry mass of the Apollo ascent stage. But an Orion could support about 15 times as many man hours on the surface as an Apollo lunar module. I don’t know if it is feasible to design a lander around the Orion. I suppose specialized vehicles are superior.

NASA will probably go back to the Moon in exactly the same way that Apollo did. Human spaceflight is very retro, just see SLS, Orion, ISS. Bigger versions of the same gadgets that were used in the 1960’s (1980’s for the SLS). Russia and China are even less innovative. Sad state of affairs.

Matt - April 24, 2015

What about Golden Spike lunar lander? Do you see a chance for realization? By the way, NASA did already spend much money on development of LOX-methane descent engine for a lunar lander about 10 years ago. I reviewed a number of papers on the topic last year. It shall be quite easy to relaunch the program. That would be better as develop three manned capsules at once (Orion, CTV, Dragon). This is at least one capsule too much.

Andy Hill - April 24, 2015

Mars surface is a motivator for politians to be able to spend money on projects that go nowhere or get cancelled after years and millions of dollars being spent. There is no risk involved in any of this happening so they use it as an excuse to spend the money in their districts.

The ISS is a failure from only some perspectives, it enabled fuding to be channelled to certain districts for decades and kept people employed. It kept the shuttle program flying for a long period and it is now giving a destination for commercial crew which would not be happening if it wasn’t there. Not to mention keeping all those pesky soviet scientists from colaborating with less than desirable nations,

From these points of view it has been a great success.

3. J Fincannon - April 22, 2015

I can’t say I agreed completely with the guest on lunar resource utilization and climate change, but I like his skeptical viewpoint. Its very hard to predict technology advances. But I do wish him luck on his ISRU demo.

Doug Plata had commented that he thought there were lunar “peaks of eternal light”. There are no such locations at either pole. It is a fiction that has been disproven by NASA and JAXA. I will however accede that are “quasi-permanent light areas”.

Ken Murphy - April 22, 2015

I don’t disagree re: ‘Peaks of Eternal Light’, but would note that you don’t have to build up very far to peak over the horizon, even with librations. Should be much easier in the 1/6th gravity and ‘weather’-free environment of the Moon.

As for power transfer, why not put parabolic mirrors or light pipes on the power towers to funnel the light to where it’s needed.

Once we get there, the Moon is going to be a civil engineering playground unlike any other.

Ken Murphy - April 22, 2015

‘peak’ s/b ‘peek’

J Fincannon - April 23, 2015

No, people always think that you can build a little tower (a few 10’s of meters) at get “into the eternal light”, but this is not the case. Such a small tower does help avoid nearby shadow castign terrain, but you need at least 1.5-3 km of tower at the best spots (North and South Pole respectively) and likely more for other spots to avoid distant high terrain (like Malapert mountain). I have done the calculations using Earth based radar data of the poles and others have used more recent LRO laser data.

As for reflected light, I do like the idea since it has been done on Earth.

Matt - April 23, 2015

I assume if you consider several places nearby Moon’s southpole at once and install infracstructure there, it maybe sufficient for eternal light combined.

J Fincannon - April 24, 2015

That’s another thing Bussey and Spudis have suggested. At the south pole they used Clementine imagery data (1999) to propose that you can get 98% illumination when connecting spots 10 km away from each other. When I used Earth-based radar lunar topography data (2007) to assess this, assuming I could link sites with cable that were separated by 10 km, I still could not get 100% illumination/power (only 84%). Bussey used Kaguya data (LIDAR) to show that connecting two spots 10 km apart could give you 94% illumination (2010). Using LRO imagery data, Robinson (2013) connected three sites separated by 4 km to get 92% average illumination for the South Pole but the North Pole did not offer similar spots.

If you have towers and even further separation (using beamed power) you could improve these numbers, but it is likely not worth the effort (i.e. launch mass for towers, power transfer losses and development cost for beamed power). You simply power down for the brief darkness period (~two days) and use batteries or fuel cells. Some have proposed thermal storage in the ground of properly treated regolith to hold the necessary heat to reduce needed heater power.

Matt - April 24, 2015

I had also the idea to store heat from day time in treated regolith (similar to Earth type applications) even for general use on “normal” Moon locations. Maybe it is possible in a later stage of Moon colonization to guide light around the complete Moon (or from poles) by help of fiber cable to the required place in order to illuminate.

J Fincannon - April 27, 2015
Matt - April 29, 2015

Great. Thank you very much.

Ken Murphy - April 24, 2015

“a few 10’s of meters”


Thank you for a good belly laugh. “a few 10’s of meters” Snicker. Yeah, that’s why I pointed out the 1/6th gravity and ‘weather’-free environment of the Moon, and that it “is going to be a civil engineering playground unlike any other”.

For “a few 10’s of meters”. lol Too funny…

J Fincannon - April 27, 2015

I guess I do not see the humor. One CAN build very high towers in the low gravity of course, not just 10’s of meters. It may just not be worth the effort since servicing and maintaining a large solar array at the tip of a 1 km tall tower may be too risky or impractical. Far simpler to just have energy storage carry you through one or two days in a year.

Matt - April 22, 2015

Dr. Spudis says the following video (see link below), that there are places in the polar regions, which are illuminated 95% of the complete year. Not bad would I say. It starts about 13:40 min

J Fincannon - April 23, 2015

Yes, even if you are not in “eternal light” you can likely live with that. Just bring some batteries or fuel cells.

B John - April 24, 2015

And then there’s the problem of having line-of-sight to Earth for communication. If the first 3-4 missions to the Moon must be communications satellites that can manage station keeping in the uneven lunar gravity field, then the threshold for getting started, even robotically, at the lunar poles is pretty high.

J Fincannon - April 24, 2015

This can be worked around. But you need a highly placed relay antenna on the surface if you are located near the poles. Obviously if you are on the “far side” of the Moon the situation requires relay satellites.

4. Matt - April 22, 2015

After listening to that show with Dr. Rapp, I am becoming more and more convinced that a manned mission to Mars:

1. Is at least about 50 years away from now.

2. Shall be use nuclear driven propulsion for transfer Mars and back as well as for landing and relaunch/ascent from Mars surface (a nuclear steam rocket could be used for this purpose, which can develop high thrust on cost of Isp, use of water would ease much propellant processing from Moon as well as from Mars ressources). May it is possible to use even directly water as propellant for Mars/Earth or Earth/Mars transfer injections, if a water depot is put into Mars orbit in a precursor mission before the manned Mars landing mission.

3. Shall be part of incremental path way to a space-faring mankind, which starts its journey on Moon by establishing there a permanent supported infrastructure/outpost on Moon. That is much more important as “stunt/flag”-Mars mission.

4. A whole bunch of technologies required for Mars can developed and tested on a permanent settled Moon, including life support, waste management, radiation protection, use of advanced robotics, nuclear technology and others.


B John - April 24, 2015

Re: 4. The difference between Mars and the Moon is much greater than the difference between the Arctics and Sahara. Not much equipment are common for expeditions to those two destinations. A Mars mission must start from scratch, even if we have a lunar base. Gravity, temperature variations, atmosphere, length of day, insolation, resources, dust environment, distance from Earth are some of the most important differences that affect the design of almost every item.

Matt - April 24, 2015

A small comment (maybe my last for some time – I am too busy). I feel that you (B John from Sweden:-)) may see the differences to stringent. I see much communality between Moon and Mars needs for an outpost/life support, even if it is not in first order about specific life support technology details, but about mastering such technology as such in respect to base the decision “Moon first”. For example, the usefulness of radiation protection, advanced robotic support, advanced nuclear/energy systems, use of regolith/soil as construction material, construction of pressurized buildings …


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