By Tim Ventura | 23 December 2019
Toxic dust & cosmic radiation make the human exploration of Mars difficult, but our robotic children already call the planet home. We’re joined by Dennis Bushnell, Chief Scientist at the NASA Langley Research Center to discuss the challenges with the human exploration of Mars, and the advantages of machine exploration of the solar system.
Dennis, let’s start out by asking about the Vision for Space Exploration and how that relates to human expeditions to Mars. Taking into account all the political & economic uncertainty over the last few years, are human missions to Mars is still a definite yes for NASA?
Mars is a definite yes — it’s not a matter of ‘if’, but ‘when’. We need to do Mars both safely and affordably, but with today’s technologies what’s safe is not affordable and what’s affordable is not safe.
What we’re trying to do right now is to invent new technologies to reduce the cost sufficiently so that we can afford the right safety, and then we can go. The estimates are that it will take 15 years to complete the research and another 15 years for development — that puts us about 30 years out from Mars.
You sent me a document to review before our interview entitled Advanced-to-Revolutionary Space Technology Options — The Responsibly Imaginable. One thing in this report that concerns me is the possibility of hexavalent chromium making the Martian soil and atmosphere poisonous. Can you tell me a little bit more about this?
My understanding is that hexavalent chromium, which is an industrial chemical, is the most potent carcinogen. Very trace amounts of it produce cancer. So if we go to Mars, if that stuff is there — and it appears to be there — then we’re going to have to go dust free. That means going dust free for habitats, transport vehicles, suits, and everything else. This is not simple to do, going completely dust free.
Well, do you think it’s achievable to be able to completely reduce the dust? From what I’ve read, it sounds like it may be possible to take it down to trace amounts below the carcinogenic threshold.
Yeah. The carcinogenic threshold is at least parts per billion, and I don’t think anybody’s sure whether parts per trillion would do it. However, you can take it down that far — it’s just a matter of engineering craftiness, invention and cost.
The major health issue actually isn’t hexavalent chromium, but instead the effects of partial-G on the immune system. We know micro-G decimates the immune system, but partial-G is still an unknown.
After that there’s the radiation. Mars has very little magnetic field except for very locally. It’s different from Earth, and it has very little atmosphere. So you’re subjected to about 80% of the 30- to 50-GeV of iron nuclei from galactic space radiation. This of course is carcinogenic, and also decimates the immune system.
One reason to terraform is to melt the water, which is under the C02 at the poles, and there’s enough there to put a shallow ocean on the planet. Then we could add biology and produce some oxygen to get some air to breathe, as well as get some density into the atmosphere for some protection from the radiation.
— SPACE.com (@SPACEdotcom) July 26, 2020
Isn’t the low planetary mass an issue for Mars though? If we do eventually pursue some kind of terraforming, will there be an issue with having the atmosphere slowly boil off?
Yes, so we can start by converting the soil into oxygen which is what plants do. You know, plants for planets, with genomic & synthetic biology using extremophiles. We can probably produce atmosphere about as fast or faster than it boils off.
Now in terms of radiation exposure, I understand you’ve been looking into the possibility of DNA self-repair and ways to advance healing times for astronauts, right?
Yeah. What you want is DNA repair which occurs faster than the radiation damage accrues. About 12 years ago, there was some genomic research up in the Boston area where they were able to develop genomic treatments for people undergoing radiation therapy for cancer to protect the non-cancerous tissue.
That research was all conducted at therapeutic radiation levels, though, which is orders of magnitude less than galactic space radiation. We’re still doing research into whether this may work for very high radiation levels — but it looks like we may have some partial success so far.
I think that’s really valuable because a lot of people forget once you start getting out past Mars, you get out towards Jupiter. Don’t those radiation levels jump way up?
Well, it really depends. There are two types of radiation — solar particle events and galactic space radiation. The galactic space radiation is actually pretty uniform — and that’s the high Z stuff, the really high-energy cosmic rays.
In contrast, solar particle events actually reduce the further away from the sun you get, but those are very episodic and actually easier to protect from in the first place.
You’ve written about the cost of space-travel, especially in terms of man-rated systems. It seems like cost-effective solutions aren’t in the near term, but there are a lot of options further out.
Well, one thing which we need is a transportation system that will give us fast transits, which will provide all kinds of benefits in terms of cost, psychological benefits, health benefits, and so on. Chemical propulsion is probably not the best approach, and it would be nice to find something that gives us faster transits.
The VASIMR propulsion system looks interesting. This is a high thrust MHD device, but it requires a lot of energy, which probably requires carrying extra weight for nuclear reactors to power it.
There are a lot of future possibilities. There’s anti-matter, particularly anti- electrons & positrons, which people are starting to store as positronium. If we can harness this, it is 10⁹ times more efficient than chemical propulsion, whereas conventional nuclear is only 10⁷.
🔧 Perseverance will carry the most sophisticated set of tools ever sent to the Red Planet to seek signs of ancient life. Tune in to the #CountdownToMars: https://t.co/5iRJ0sdUJ7 https://t.co/5iRJ0sdUJ7
— NASA (@NASA) July 27, 2020
Additionally, there’s also low-energy nuclear reactions (LENR), which we’re working on here. We’ve got 22 years and hundreds of experiments now on low-energy nuclear reactions which indicate that this is real. Plus, we now have a theory that indicates that it’s condensed-matter nuclear physics.
So LENR appears to be collective effects, not particle physics. It seems that you can get around Coloumb barrier by forming ultra weak neutrons using heavy electrons. This not only enables you to form the neutrons, but also convert the gamma radiation from beta-decay into thermal energy so that you don’t need as much radiation protection. LENR is expected to be anywhere from 20,000 to 3 million times chemical efficiency, and if we can get that in place it will truly revolutionize space.
I didn’t realize the LENR was being investigated that heavily by NASA.
Well, it’s not heavily, I mean we have a $200,000 to $300,000 a year effort. We’re also cooperating with people on this, but I can’t divulge details under cooperative agreements.
LENR purportedly also produces transmutations, which is quite interesting. For in-situ resource utilization, if LENR works, perhaps we can take elements on the planet and possibly transmute them into something we need.
What about something like the IEC Polywell reactor that Dr Robert Bussard was working on for the Navy? Is that worth pursuing?
Yeah, I’m very familiar with the Bussard stuff. That’s aneutronic fusion, using pB¹¹ or D-³He, and it may be possible. It’s yet another of five or six very advanced energetics technologies that we need to study more heavily than we are now.
I just read about the 100 Year Starship program, so hearing you discuss MHD, LENR, anti-matter and other advanced propulsion makes me wonder if NASA isn’t going back to the drawing board in some ways.
Well, if you look at space access, it’s essentially done today the way it was done in the ’50s. These are basically ICBMs — modernized versions of German V2 rockets. It’s chemical propulsion, and we’re out at the ragged edge of the performance of chemical rockets. We need something a lot better than that if we’re going to make spaceflight safe and affordable.
What we’ve realized at NASA is that if you’re going to do safe and affordable manned space exploration, then you’re going to need another whole level, another whole generation of the technology.
Back in the Bush-era space program when 100 YSS was launched, this vision was put in place with essentially conventional technology. Over the years and in many, many projects, NASA has warned that if you want revolutionary goals like humans in deep space you need revolutionary technologies. These aren’t cheap to develop, and we had to divert resources into developing them, which we’re doing.
You’ve written that there are many invisible components to a successful launch — such as vehicle maintenance, support infrastructure, etc. Will the technology development NASA is engaged in help with these as well?
Getting into space is a big part of getting to Mars — climbing out of the Earth’s gravity well. The in-space propulsion transfer is another 35%. The life support systems — including habitats and space-vehicles is about 25%, and the rest of it is, you know, the marching army. Getting into space is a really big deal.
— SPACE.com (@SPACEdotcom) May 19, 2020
If we go towards fusion rockets and things like that, those can’t be used in the atmosphere, can they?
Fusion rockets, particularly aneutronic versions, as well as LENR could be used in the atmosphere, if we get that. At one time people were working on a nuclear rocket called Timberwind that they thought might be safe in the atmosphere, but other people not so sure. There’s one more we haven’t discussed yet, which is energy beaming.
You can beam energy up from the ground to the vehicle through rectennas. The idea is that you take the beamed energy onboard your vehicle, and then use it to amplify the energy of conventional fuels, which may give you something like 2,000 to 2,500 seconds of ISP.
Would that be like the Lightcraft?
Not, no, no. The Lightcraft is a different propulsion system entirely — and it has problems with net payload. The beamed energy that I’m talking about takes the energy onboard and uses it to energize a high thrust MHD device.
Basically, you’re still burning fuel, but of the 2,500 seconds ISP, only about 400 seconds comes from the fuel itself. The rest of it comes from the beamed energy accelerating what is now propulsive mass.
What’s the cost factor for this? You’ve written that if NASA is able to reduce costs in the fabrication of components & systems, then we can bring the cost down to get things into orbit.
It’s a far more than that. For instance, with Space X, a lot of their cost reduction comes from having a really small launch crew. Now for NASA, using the shuttle as an example, the marching army costs for people on the ground was about 45% to 48% of the cost of a shuttle launch.
So if you went with the robotics we’re now developing, particularly farther term, you can robotically design, fabricate transport erect & launch space vehicles without people, and much lower costs.
Dennis, you told me something on the phone a few years ago that I wanted to touch on. We were talking about robot exploration of space, and you described robots as being the children of mankind. It stuck with me, and put what we’re doing on Mars in a new perspective for me.
Well, that quote, robots being the children of mankind is actually from Hans Moravec, from Carnegie Mellon. He’s written various books on this topic — the one that comes to mind is called, Robot, written in the early 2000’s. His premise is that we are currently becoming cyborgs at a very fast rate.
For instance, the IBM Google Brain Project which is nanosectioning the neocortex and replicating it in silicon has made such good progress that they are claiming in 12 to 15 years they will be able to market a Biomimetic, human level machine intelligence. The nano-functionalization of robots is continuing a pace very rapidly.
So there’s no reason why in 15 to 25 years that exploration can’t be done very well with robots, and done at a cost that’s 1,000 times less than sending humans.
So one way to do this exploration of Mars is in three stages: First, send the nano robots and instrument to planet and send back the data. The Brits demonstrated five senses recently in virtual reality: haptic taste, touch, smell, sight & sound. A system like this would let everyone explore Mars anytime they wanted to at one 1000th the cost of sending people.
Second, you send other robots to terraform Mars, and by the time that’s done, we’ll also have developed the energetics so that people could go very safely and inexpensively.
In other words, you’re saying that robots & AI will remain at the forefront of space exploration, with virtual reality allowing us to participate in their exploration. I guess the question then is, does it diminish the achievement if robots do it instead of people?
Well, Tim, it’s all in our head, okay? I mean, the rest of the body is there so that we can get the head working. There’s a generation coming up now that’s used to living on electrons. People tell me that five year old kids are out on the school playground texting each other across the playground instead of going over and talking. There are already millions of people worldwide who are spending more time on Second Life and in other virtual worlds than they are in the physical world.
We’ve already entered the virtual age — and it’s transforming our lives rapidly. We are tele-everything. We have some 48 million telecommuters, almost one third of the workforce. We use online shopping, virtual education, and there’s a trend towards telemedicine as well. This is where society is going, why should space be different?
It sounds like the robotic exploration you’re describing is already underway. I mean, we already have a communications infrastructure in place on Mars. We have robots on the ground, orbital satellites & communications repeaters back to Earth. So it seems like those first steps are already underway in terms of robot colonization.
Yes, of course. However, we need to get the robots smaller, and need to get the cost down. That way, instead of just crawling around a couple of hundred yards we can explore & instrument the entire planet. But yes — the robots are there, doing the work already, and at lower cost & greater efficiency than a manned mission could hope for. It’s their planet, at least for now.
About Our Guest
Dennis Bushnell is the Chief Scientist at NASA Langley Research Center, and is responsible for technical oversight & advanced program formulation. Bushnell obtained his M.E. from the University of Connecticut in 1963 and his M.S. from the University of Virginia in 1967, both in Mechanical Engineering.
Reprinted with permission from the author.
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