Risky Business: ISRU and the Critical Path to Mars

The path to Mars: Does it pass through the Moon?

The critical path to Mars: Does it pass through the Moon?

When one examines the plans that NASA devises for human missions beyond low Earth orbit, ISRU (in situ resource utilization) experiments or demonstrations are sometimes included but never incorporated into the imperative of the mission sequence, what engineers call “the critical path.”  ISRU simply means that you make stuff you need in space from resources available in space.  At current levels of development, such stuff would largely consist of high-mass, low-information materials, such as propellant and shielding.  By reducing the amount of mass launched from the Earth through the use of ISRU techniques, we would save many billions of dollars of our limited space budget.  So why aren’t we hearing more about this?

Certainly nothing in the chemistry or physics of ISRU indicates that it is impossible or unduly futuristic – most processes date back to antiquity (melting ice into water) or most recently, to 18th and 19th Century industrial chemistry (e.g., carbothermal reduction).  But ISRU has never been actually attempted with extraterrestrial materials and real hardware in space.  In other words, aerospace engineers haven’t done it; it’s too much a science-fiction concept for them (“Set the replicators on beef stew tonight, Mr. Sulu!”).  They reactively imagine potential disasters issuing from its attempt, rather than appreciate its possible benefits.  Engineers tend to be cautious when undertaking new designs that incorporate untried techniques, and in the case of human spaceflight, rightly so.  However, when caution keeps you locked in a comfort zone, initiative and programs will atrophy and cripple our space progress.

Several years ago, Bob Zubrin, my friend and sometime public debate opponent, had a key insight.  When you bring everything you need with you from Earth in order to get to Mars, the consequences of the rocket equation multiplies the gross departure weight by a large amount (it costs thousands of dollars per pound for delivery to LEO).  If you don’t bring the fuel for the return trip home with you, your departure mass is much lower.  For the trip home, Zubrin’s Mars Direct architecture utilizes rocket propellant made on the martian surface.  In one fell swoop, he reduced the amount of mass needed in LEO to go to Mars by 50 percent; a significant finding.

The current NASA Mars Design Reference Mission utilizes 8 launches of a super heavy-lift vehicle (150 tons to LEO) to construct the 500-ton Mars craft in Earth orbit (another analysis projects 10-12 launches of same).  More than 80% of this mass is propellant.  If the HLV ends up costing a couple of billion dollars each, the cost of a human Mars mission is not only unaffordable – it will never be undertaken.  And don’t think that the hallowed New Space “cheap access” to LEO will save you either; those vehicles are too small (much less payload than 150 tons) and will need to use storable propellant because the LOX-hydrogen (LH2) cryogens will boil away into space between their individual launches.  Storable propellants have much less energy than LOX-H2 and thus, besides the complexity of logistical assembly from a greater number of flights, the total required mass in LEO multiplies frighteningly.

Engineers are reluctant to mandate ISRU as part of the Mars architecture because it’s never been done (risky) and it’s never been done because it’s too risky – the classic “Catch-22.”  How can we move beyond this impasse?  We can reduce the size of the “risk” roadblock by demonstrating ISRU on the Moon.  An ISRU strategy on the Moon can be designed that not only retires risk for its future use on Mars, but can also provision the Mars trip from lunar materials, reducing even more the amount of mass needed to be launched from Earth.  But why use the Moon to document the value of ISRU, rather than a near-Earth asteroid?  Simply put, the Moon has the right materials and properties for performing this risk-reduction activity.

The results from the LCROSS impact experiment, in which a Centaur upper stage was crashed into a dark area near the Moon’s south pole, demonstrated that not only is water present in quantity, but there are other volatiles there as well, including methane, ammonia, carbon dioxide and some simple organic compounds.  On the basis of their observed abundance, all of these substances are probably derived from comets that over geological time have hit the Moon and are preserved in the permanently shadowed, cold areas near the poles.  Asteroids typically do not contain these exotic volatile substances; if water is present in asteroids, it is chemically bound in mineral structures and requires considerable energy and processing to extract and use.

Lunar ISRU can harvest not only water (and thus, oxygen) but also methane from the Moon’s polar deposits.  Methane is the propellant Zubrin’s Mars Direct architecture uses for Earth return (although as the martian crust is water-rich, LOX-LH2 could also be used on Mars, making the lunar polar deposits doubly relevant).  From the Earth-Moon L-1 point, either landing on or taking off from the poles of the Moon requires about a 2.5 km/sec change in velocity (Dv) while transfer from the surface of Mars to Mars orbit for rendezvous and return to Earth requires a Dv of 3.5 km/sec.  Thus, the transfer energies for the two missions are comparable.  This means that we can test the methane ISRU systems not only in principle – we can test the actual Mars equipment in practice three days away on the Moon and in cislunar space.

In effect, these lunar properties mean that a complete, end-to-end systems test of all the pieces of a Mars Direct-style architecture could be performed in cislunar space, overcoming the most critical obstacle – the “risk” of requiring ISRU in the critical path.  In my opinion, ISRU is the most important and game-changing technology for future spaceflight.  I will go so far as to say that a human Mars mission is inconceivable without incorporating ISRU in some form, most likely as a source of propellant but also for other potential uses (e.g., shielding, oxygen and water).

A Mars mission conducted in the Apollo mode (everything launched from Earth) is simply not possible, fiscally or politically.  A national security imperative during Apollo allowed us to bludgeon technical problems to death with money.  We no longer live in that world.  Space programs must be affordable, which means that we cannot opt for the “easiest” or most familiar way to do something – we must be clever, frugal and use what is available.

During a recent hearing on the proposed new NASA Authorization bill, the two witnesses Steve Squyres and Tom Young both opined that lunar return was not a prerequisite for human Mars missions.  They are both wrong.  The critical path to Mars goes through the Moon, although not the way most engineers have been looking at it.  They’ve viewed a lunar mission as a fancy “dress rehearsal” for the Mars mission, with people landing on the Moon to conduct a complex and carefully choreographed EVA, to practice how they plan to explore Mars, and then leave the Moon as soon as possible.  In their view, the main object of the lunar mission is to get it over with.

To realize human Mars missions, a sustained lunar return is much more valuable than a “touch and go,” a “fly-by,” or a “hover-over.”  Only on the Moon can we learn for the first time how to extract and use off-planet resources.  We permanently retire ISRU risk and open up space by using lunar resources.  We practice the entire Mars surface mission sequence with Mars hardware flying in space – from landing, to refueling and ascent.  To go to Mars without ISRU requires too much mass in LEO, needing multiple launches of expensive, disposable vehicles.  In consequence, it is unaffordable and thus, unlikely to ever happen.  Such expense cannot be justified under virtually any conceivable political circumstance, save those associated with some national emergency, certainly an eventuality not to be hoped for.

And yes, for those following the breadcrumbs, by using this process we’ll develop a system that can routinely access all of cislunar space, including the lunar surface.

Note added, 26 June 2013:  A version of this piece has been posted at Space.com

This entry was posted in Lunar development, space policy, space technology, Space transportation. Bookmark the permalink.

75 Responses to Risky Business: ISRU and the Critical Path to Mars

  1. Joe says:

    “And yes, for those following the breadcrumbs, by using this process we’ll develop a system that can routinely access all of cislunar space, including the lunar surface.”

    I was waiting for you would get to that part. Development of Lunar Resources will not only give us access to Mars, it will give us access to the rest of the Solar System.

  2. billgamesh says:

    Can’t get to Mars with chemical propulsion IMO.
    I think it will become apparent when the damage visited on the human body by such a mission is truly appreciated.
    Radiation is square one and the required shielding makes nuclear propulsion the only option.
    But this actually makes the Moon even more important because we cannot play with nuclear energy in the Earth’s magnetosphere. And the shielding- in the form of water derived from lunar ICE- is the most important ISRU option there is since bringing that much plastic or water up from Earth would be a waste of heavy lift.
    Only a base on the Moon will allow the assembling, testing, and launching of a nuclear mission to the outer system.

    But if that has to be learned the hard way then so be it.

    The ISRU work on the Moon is still required for a Cis-Lunar infrastructure since, as previously stated, nuclear activities in the magnetsosphere are verboten.

  3. DougSpace says:

    An excellent article. Very well put.

    Just to clarify, are you saying that a Mars mission through the Moon involve the ISRU production of methane from Mars’ atmosphere or that that would be produced and provided from the Moon so that lunar derived Mars ascent propellant (methane or LH2/LOX) come from the Moon?

    • Paul Spudis says:

      are you saying that a Mars mission through the Moon involve the ISRU production of methane from Mars’ atmosphere or that that would be produced and provided from the Moon so that lunar derived Mars ascent propellant (methane or LH2/LOX) come from the Moon?

      I am arguing for the demonstration of the concept of methane/LOX propellant made from local materials on the Moon. The actual Mars return flight would use methane/LOX made from local Mars materials.

      • DougSpace says:

        Got it!

        Now, might the lunar demonstration be quite different than what would happen on Mars? My understanding is that the source of carbon on Mars would be to simply suck it in from the atmosphere but that the source of carbon on the Moon would be to mine it as CO (maybe 1% by mass) from the icy regolith. So how does our demonstration on the Moon help with knowing how to produce the fuel on Mars?

  4. billgamesh says:

    “A national security imperative during Apollo allowed us to bludgeon technical problems to death with money. We no longer live in that world.”

    A true statement in that there is no acknowledged security imperative.
    However, on a larger scale than heavier doors for airline cockpits or back-up generators less vulnerable to flooding from tsunami’s, there is a security imperative actually classed far higher as a survival imperative based on the real possibility of an extinction level event. The recent multi-megaton explosion over Russia has generated little response except for a lame attempt by NASA to use it as an excuse for their useless asteroid lasso mission. Likewise there is no plan to safeguard humanity from a 100% lethal engineered pathogen. The excuse concerning a pandemic is there is no insurance which is not true. The obvious problem is that if the inevitable asteroid or comet happens to show up a month away, or a completely lethal pandemic begins- it will be TOO LATE and our human optimism bias will have guaranteed our extinction. The hope of a quiet century until we have the means to easily answer such threats is all that separates our species from oblivion. As I have commented several times, before reader’s scoff and cite comforting statistical probabilities, they might consider what the chances of those towers brought down by airliners were thought to be. The reports of large rocks doing fly-bys and possible natural flu pandemics have conditioned the public to ignore the possibility of a worst case scenario.

    The Moon is where the capability to both deflect a sudden impact threat and preserve our species from a bio-terror event resides. Not only this, but a cislunar telecom infrastructure and missions to the outer system are practical with a Moon base allowing exploitation of Lunar Resources. Not only this, but projects we can only dream about are within reach- beaming energy to the Earth and using that energy for propulsion and also enabling mega-projects such as space habitats.

    It is actually great conspiracy theory fodder that the official policy is to ignore the Moon. But the media giving so little attention to the Moon has even the conspiracy theorists uninterested; no money to be made if there is no interest to start with. Connecting the Moon with Mars might get the ball rolling.

    But about this lunar CH4 production; how would methane be manufactured on the Moon? Google failed to bring me any quick answers to this question. Methane sparks my interest greatly because of the problems with using LH2. Hydrogen is great propellant except for two really troubling properties. First, it is a couple degrees above absolute zero and does not store well. Oxygen- and methane- are a couple hundred degrees warmer and much easier to deal with. Second, when you liquefy hydrogen a small percentage is in an exothermic form and this is why you cannot simply use a compressor to re-liquefy the boil-off. The exothermic form contaminates the storage tank and makes the boil-off problem such a nightmare that only a large industrial storage facility on the ground (or on the Moon) can deal with it. As far as I know oxygen and methane boil-off CAN be liquefied without any such penalty. If I am wrong on this someone please correct me because I went though some hard to find technical sources that were pretty dense in coming to my conclusions.

    Liquid hydrogen, along with LOX, is of course the ultimate propellant combination and desirable for use in the upper stages of a HLV- and even for use in a high performance lunar shuttle- if there is a base to support a large hydrogen storage facility.

    • Paul Spudis says:

      how would methane be manufactured on the Moon?

      You wouldn’t manufacture it. It occurs naturally as one of the volatile substances in the polar cold traps. It would be harvested with and during water ice mining. On Mars, it would be manufactured using atmospheric CO2.

      • billgamesh says:

        Sorry to keep asking instead of studying;

        Is there like, hundreds of millions of tons of methane locked up in those billions of tons of ice?
        Considering the industrial method of methane production, is carbon dioxide hard to come by or make on the Moon Dr. Spudis?

        • Paul Spudis says:

          We find in the polar cold traps of the Moon all the elements and compounds that you find in icy comets. All of these substances originate in the solar nebula, the gas cloud that formed around the Sun during Solar System accretion. Volatile substances form outside the “snow line” of the Solar System (beyond the orbit of Jupiter). They were thrown into the inner Solar System by gravitational pertubations over time and eventually, hit the Moon and other rocky inner planets. If they get into a cold trap at the lunar poles, they are there forever.

          Water is the dominant species (~90% by mass) but the minor ones (ammonia, methane, CO2, CO and organics) contribute a few percent each. We don’t know their exact concentrations within lunar ice precisely, which is one of the reasons I think that a prospecting rover to the poles is the essential next step. The LCROSS results are discussed HERE.

          The methane clathrate in harvested polar ice would be separated by some chemical industrial processing (e.g., fractional distillation) after we’ve extracted the frozen volatiles from the lunar regolith feedstock.

          • billgamesh says:

            Thank you Dr. Spudis- the LCROSS article was fascinating. I read that carbon monoxide was a prominent “species.”

            I found this, which is kind of dated but now relates to Lunar Resource Utilization I think;

            http://www.uapress.arizona.edu/onlinebks/ResourcesNearEarthSpace/resources28.pdf

            It says in one part with CO you can make just about anything you want.

            About all I know chemistry-wise concerns not mixing different cleaners to mop the floor. But from what I gather the volatiles in this ice make almost all the previously assumed shortages of critical materials no longer a factor in colonizing the Moon.

            Too bad we did not have this data during Apollo- we might have kept going full speed ahead.

            The baggage from these past assumed shortages of resources is one reason the public accepts the “been there” policy. How to get rid of that baggage?

          • Paul Spudis says:

            Here’s another earlier blog post I wrote on the LCROSS results, FYI:

            http://blogs.airspacemag.com/moon/2009/11/thanksgiving-on-the-moon-a-lunar-feast/

          • DougSpace says:

            I was presenting at a Space Access conference about the LCROSS results when someone in the audience corrected me. We spoke later and he subsequently sent me an article where the corrected LRO-LAMP results were discussed. I was disappointed to learn that the non-water volatiles were significantly less than previously stated. Still enough I think to produce methane for propellant but I would think that you might end up with a lot of excess oxygen left over while making any methane. Dr Spudis, we’re you aware of the corrected results?

            http://m.sciencemag.org/content/330/6003/472.abstract

          • Paul Spudis says:

            Yes, I’m aware of it. I was citing the data from LCROSS, not LAMP. But in any event, what I am suggesting here is a validation of ISRU as a technique reliable enough to incorporate into an architecture. Yes, the collection of lunar methane is different than the manufacturing technique we would use on Mars. My point is that if we never actually use ISRU methane in space, we may never even try it on Mars.

  5. Apollo style missions to the Moon and Mars are the most geographically limited and expensive ways to explore those worlds. However, if humans and human operated robots are sent to the Moon and Mars to remain continuously on the surface, then both worlds can be extensively and continuously explored by humans and robots a lot more cheaply since they could remain on the surface for several years before returning to Earth.

    The primary reason for having a manned space program, IMO, is to find out if our species can adapt to extraterrestrial environments and, also, if human beings can utilize extraterrestrial resources for their survival and possibly even for profit. So exploiting lunar water and probable carbon and nitrogen resources should already be a priority once a simple outpost is set up on the lunar surface.

    After water is being produced for a lunar outpost for drinking, washing, and air, manufacturing extraterrestrial fuels from water should be the next step. And LOX/LH2 should be the universal fuel, IMO, for both the Moon and Mars. Why?

    1. Large quantities of ice should be available at the lunar poles and on the surfaces of Mars and the moons of Mars.

    2. hydrogen and oxygen are easy to manufacture through the electrolysis of water as long as you have power (solar or nuclear energy)

    3. water can be stored at depots as a liquid or as ice practically indefinitely

    4. oxygen is easy to liquify and store with a boil-off rate that could be as little as 0.5% per month

    5. NASA has apparently developed cryocooler technologies that could store liquid hydrogen at space depots for years rather than just a few weeks or a few months

    Large-Scale Demonstration of Liquid Hydrogen Storage With Zero Boil-off for In-Space Applications

    http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110004377_2011003898.pdf

    Zero-Boil-Off Liquid Hydrogen Storage Tanks

    http://hydrogenresearch.org/FR04/FSEC–Baik–ZBO%20Liquid%20H2%20Storage%20Tanks%20.%20.%20.%20PY2004-FY0405.pdf

    Depositing lunar water at the Lagrange points for fuel and mass shielding would, of course, be substantially cheaper than bringing it out of the Earth’s gravity well. Even sending lunar water to high Mars orbit would have a substantially lower delta-v than launching water to low Earth orbit. And producing water, air, and fuel on the surface of Mars, the Moon, and the moons of Mars should allow NASA to set up permanent outpost on the Moon and at the Earth-Moon Lagrange points and in Mars orbit and on the surface of Mars.

    Marcel F. Williams

    • billgamesh says:

       Wow! Extremely interesting stuff Marcel. Thanks.
      ZBO is probably going to be a popular term being thrown around like it is already a reality. It is not.
      I remain skeptical. It looks to be extremely complicated, fragile, and vulnerable to failure.
      And expensive; but the expense has never been a problem with me if it is worth the money. I do not believe this will be worth the trouble compared to pursuing the nuclear option.
      And it does nothing to remedy my original disqualifier; a massive radiation shield makes chemical propulsion impractical for deep space flight.
      For cislunar operations the situation is different; only chemical propulsion is allowed and there may be a niche for ZBO-LH2. I have to qualify that as a big maybe; it may turn out to be a question of accepting lower ISP numbers for a “warmer” cryogen like methane and far less difficulty in keeping the stuff cold.

      • Warren Platts says:

        The boiloff at a passively cooled LH2/LO2 depot at L2 would be less than the station keeping requirements. The white papers that discuss the details may be found at ulalaunch.com

        • billgamesh says:

          The fuel depot in space will not be needed or desirable for any purpose after it is realized nuclear propulsion is the only option for interplanetary travel. And once a nuclear mission is decided upon then Mars as a destination will also be called into question.

          If you have nuclear propulsion then it no longer matters that Mars seems “just close enough for chemical propulsion.” It is not anyway because of the radiation shielding requirement. The next closest and highly desirable place of interest will become the destination of choice. And that is Ceres. You can almost land on it in a spacesuit, probably has a vast subsurface ocean, and building a colony there makes more sense than Mars.

          Of course building a first colony on the Moon makes far more sense than all this Mars nonsense.

  6. Warren Platts says:

    Excellent article Paul! As usual! I think your idea could be the key to forging a political coalition that could unite both the Mars and Moon folks that could break the political impasse we seem to find ourselves in these days. We must keep hammering this concept home everywhere we can–including the Halls of Congress!!

    As for asteroids, I think the situation is much worse than you make it out to be. I was at the PTMSS meeting this year and was surprised to learn that no one has yet bothered to try to actually extract actual water from an actual carbonaceous chondrite. I have since learned that water CANNOT be extracted from carbonaceous chondrites simply by heating it up because all the other impurities will cause all sorts of compounds to form except dihydrogen monoxide. It will prove to be a lot more complicated than simply throwing more energy at the problem.

    @ Bill: a recent Science article states that the radiation for a trip to Mars is less than NASA’s current lifetime radiation allowance. Also, liquid hydrogen is the best radiation shielding we know of. Moreover, the LH2/LO2 powered MTV’s sketched by ULA’s engineers are capable of 11 km/sec delta v and could haul a crew of 16 people, be single stage, and fully reusable. If these could be refueled in Mars orbit, the transit time could be cut nearly in half over the Hohman transfer delta t.

  7. billgamesh says:

    “-a recent Science article states that the radiation for a trip to Mars is less than NASA’s current lifetime radiation allowance-”

    I take it you are implying it is an acceptable dose….I would never subject people to anything near, let alone close to, a “lifetime dose” of radiaton. It is permanent cumulative damage that can be avoided by “bludgeoning the problem with more money.” It is an expense that cannot be avoided IMO.
    There is no cheap.
    I give you credit for the clever wording inferring radiation is trivial but I hold the exact opposite view; it is square one and the problem that decides the entire path of human deep space flight.

    The liquid hydrogen as best shielding also borders on deception IMO; while it is excellent shielding you cannot use it for anything else while it is shielding you- and is a great deal of trouble to maintain over long periods. Water is trouble free and has great utility- and will not disappear if your no-boil-off scheme fails. Which is saying such a scheme will even work.

    • Warren Platts says:

      Uh huh, and your “concerns” are borderline hysterical. It’s not a showstopper. Obviously, you’ve never seen the proposed ULA MTV: it has a central habitable volume surrounded by 6 propellant tanks totaling about 720 mT of LH2/LO2. (They propose sending 2 at a time; clearly, that much propellant could only be supplied by the Moon.) It would be launched from L2 with a gravity assist around the Moon and Earth so that the initial burn would not be very much, leaving most of the propellant in the tanks, so it shields the passengers on the transit over, where it can then be used to park into LMO.

      • billgamesh says:

        “-borderline hysterical. It’s not a showstopper. Obviously, you’ve never seen the proposed ULA MTV: -”

        Good luck with that. Several scientists, including the acknowledged authority on space radiation- Dr. Eugene Parker- might disagree with you. Of course none of them work for ULA so what do they know?

        But you are leaving out what happens on the way back after you burn that hydrogen to get home.

        • Warren Platts says:

          I oughtta know that Eugene Parker doesn’t work for ULA since I took a class from him on planetary science at the University of Chicago. I also know that he never says anywhere that cosmic radiation is a showstopper for Mars exploration.

          And what you are leaving out is that propellant is required to insert a spacecraft into orbit….

  8. OK, this week I sat through the 2 hour NASA Asteroid cheerleading event announcing their RFI being sent out to the public for ideas to make the asteroid catch happen. Two hours of my life I will never get back. Well, they DID mention the Moon, once I think, and breathlessly stated that Mars is the goal. In my opinion, they are simply trying to “suck the air out of the room” by trying to get everyone thinking only in terms of asteroid retrieval and Mars, drawing any attention away from the moon.

    At the same time, the House was drafting NASA’s future budget, calling for congressional control over the NASA Administrator instead of the executive branch, and unfunding the asteroid retrieval mission in favor of returning to the moon in some unstated fashion. I will assume that the House will pass such a bill, but doubtful that the Senate will go along with it. Bolden has even said that if we change directions now, we are likely to get neither an asteroid, nor a lunar mission. Things don’t look very promising.

    OK, so how do we get back to the moon? Will it take a kickstarter project to build a cubsat to act as a telecom site at EML1? Perhaps a vastly simplified lunar robot such as a “strandbeest”, built on site using 3D printed glass parts? It certainly doesn’t look like NASA has, or will have, the budget or willpower to place a 1,600 pound rover/lab on the moon anytime in the next decade or two. Maybe we can get Bechtel or Mitsubishi to dust off their decades-old plans for a lunar base? Anyone here speak Chinese?

    • Robert Clark says:

      NASA’s RESOLVE mission is planned to make such a landing Gary.

      Bob Clark

    • Warren Platts says:

      Nǐ hǎo! Supposedly the Regolith and Environment Science and Oxygen and Lunar Volatiles Extraction (RESOLVE) rover is still in the works. It will have the ability to drill 1 meter deep holes and chemically analyze the cuttings and cores. It will be battery powered, so it won’t be able last long in permanently shaded regions.

    • Peter says:

      According to former JPL research scientist Dr. Donald Rapp,

      “what is required next is to send several long-distance rovers equipped with dynamic active neutron spectrometers to several of these craters, to cover a few tens of kilometers in each one to determine the local distribution of the hydrogen signal.”

  9. billgamesh says:

    “-they are simply trying to “suck the air out of the room” by trying to get everyone thinking only in terms of asteroid retrieval and Mars, drawing any attention away from the moon.”

    Perhaps they know they cannot postpone the Moon- we know how to do it. But the other stuff they can drag out till they retire with the it’s never been done excuse.

    It is either “been there done that” or “never been done, we are trying.”
    Great way to collect a paycheck. Kind of like being a weatherman in Alaska; nobody expects much from you.

  10. billgamesh says:

    “The primary reason for having a manned space program, IMO, is to find out if our species can adapt to extraterrestrial environments-”

    I would say we are adapted to a terrestrial environment and the trick is to adapt the environment to us. You want to live on Mars then you will not “adapt” to lower gravity- you will debilitate in relation to it. The human body cannot “adapt” to a higher level of exposure to radiation- it simply manifests a shorter lifespan.

    It is probably easier IMO to build a colony on a small icy moon where people can spend half their time in a circular “sleeper train” in Earth gravity completely shielded from radiation beneath the ice. That is just my guess though concerning how much time in Earth gravity is required to maintain fitness.
    The best course is to just build an artificial Earth environment like a spinning Bernal Sphere with one G on the inner surface at the equator. The more miles in diameter the better.

    The “primary reason” has never been anything but finding new worlds to live on (or “in”, in the case of habitats).

  11. Robert Clark says:

    In effect, these lunar properties mean that a complete, end-to-end systems test of all the pieces of a Mars Direct-style architecture could be performed in cislunar space, overcoming the most critical obstacle – the “risk” of requiring ISRU in the critical path. In my opinion, ISRU is the most important and game-changing technology for future spaceflight. I will go so far as to say that a human Mars mission is inconceivable without incorporating ISRU in some form, most likely as a source of propellant but also for other potential uses (e.g., shielding, oxygen and water).

    Insightful analysis. Why I consider ISRU test missions such as RESOLVE to be so important:

    NASA hopes to make water on the moon.
    By Irene Klotz, Discovery News
    15 Apr 2013 12:58pm, EDT
    “NASA is developing a lunar rover to find and analyze water and other materials trapped in deep freezes at the moon’s poles and to demonstrate how water can be made on site.
    Slated to fly in November 2017, the mission, called Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE), will have a week to accomplish its goals.”
    http://science.nbcnews.com/_news/2013/04/15/17763225-nasa-hopes-to-make-water-on-the-moon?lite

    Bob Clark

    • Gary Miloglav says:

      Mr. Clark,
      My opinion of the RESOLVE mission is, while it is a “nice” step, it is too llittle and too late. The excuse given is that’s all NASA can afford. but being able to “afford” something demostrates your priorities, and NASA simply doesn’t care about the moon and all its resources. If it did, there would be an all-out effort to return, even if it is to the exclusion of further Mars missions, the asteroid mission, other deep space science missions on the books. Once on the moon and developing its resources, the other missions would be far easier and cheaper. I have been a NASA fan my entire life, but they are going down the wrong path.

  12. billgamesh says:

    excerpt:
    “To do a mission of any significance (at the lunar poles) it would take nuclear power, but we don’t have that kind of money,” said William Larson, a recently retired project manager at NASA’s Kennedy Space Center.

    “Solar-powered missions are more affordable and that’s the way we’re going to try to go,” Larson said.

    But it will not have any significance? We can blow a billion on Mars but nickel and dime a far more important mission right in our own backyard.

    What is wrong with these people?

  13. Grand Lunar says:

    “But ISRU has never been actually attempted with extraterrestrial materials and real hardware in space. In other words, aerospace engineers haven’t done it; it’s too much a science-fiction concept for them ”

    I guess they’ve also been left out of the loop when it comes to 3-D printing.
    Imagine testing that on the moon, using the local resources as the raw material.
    Then, not only do you get propellant from the moon, but also you can build your spacecraft there too!
    I know, probably jumping too far ahead. But it is a possibility.

    “During a recent hearing on the proposed new NASA Authorization bill, the two witnesses Steve Squyres and Tom Young both opined that lunar return was not a prerequisite for human Mars missions.”

    This type of mentality is what’s killing us.
    We have to replace it, convince others that the oppisite is what we need if we really want to get “out there”.

    • billgamesh says:

      “-both opined that lunar return was not a prerequisite for human Mars missions.”

      Without ISRU manned deep space flight is indeed a far more risky- and expensive- business.

      As mentioned in another comment, ULA proposes putting close to a thousand tons of cryogenic propellant into orbit for a Mars mission. They might even use the miraculously cheap Falcon Heavy to make it all happen- using this marvelous new ZBO technology and fabulous new techniques to mitigate radiation and zero gravity debilitation. It sounds wonderful- and doomed to failure.

      Much like the Shuttle program, the mistakes being made in deciding the course of human deep space flight will be obvious in hindsight. Radiation exposure and zero G debilitation are square one- the solutions to these very first problems mean the spaceships that carry people Beyond Earth and Lunar Orbit are going to be…..huge.

      Trying to cheat mother nature and go cheap is mainly what these decisions about “prerequisites” are about. The designs will get bigger in development as all aerospace projects do- but in this case they will get bigger by magnitude as the consequences of irradiating and debilitating astronauts on such long missions become clear and the solutions are reluctantly mandated.

      In the end, lifting this as yet unknown number of kilotons of spaceship components from Earth is sure to be an intolerable expense.
      Using nuclear energy for deep space propulsion cuts heavy lift tons required at least in half. But nuclear activities anywhere near Earth are not acceptable risks and make this impossible. Going to the Moon allows nuclear systems to be assembled, tested, and launched with the only risk entailed being transporting the packages of fissionable material on site.

      Using Lunar Resources for shielding and other needs cuts the lift requirement from Earth in half again- probably much more.

      This is why going cheap more often costs several times more and ends in failure. There is no cheap and the Moon is in reality a prerequisite for success.

  14. Mike Fair says:

    Even if the chemistry for the conversion of water to fuel is well understood, and the equipment for doing it is straightforward, the equipment for using it as fuel is not. Especially storage, health monitoring, and transfer. As I read Zubrins description of all this, it made it sound so ‘ready to go’, but in the 2 decades since the proposal, a rocket has not been launched using such a system, has it?
    In your estimation, would a demonstration system on earth be helpful in reducing risk and increasing acceptability in the eyes of mission planners or appropriators for a lunar demonstration? I am thinking of a self contained system (like the proposed ERV), with the whole kit and caboodle: power supply, refining, storage, transfer, and rocket. I think it would be a worthwhile demonstration to drop such a container in a snowbank in North Dakota, and 3 months later it launched a suborbital rocket. Or setup such a container at Wallops, with only the injection of a simulated Mars atmosphere (CO2).

    • Paul Spudis says:

      In your estimation, would a demonstration system on earth be helpful in reducing risk and increasing acceptability in the eyes of mission planners or appropriators for a lunar demonstration?

      There have been a number of ISRU demonstration experiments conducted on Earth and there will no doubt be more in the future. My point is that no engineer will ever feel comfortable with putting ISRU in the critical path of an architecture until it is used in some phase of a real space mission. The Moon offers us this opportunity; asteroid missions don’t.

      • Joe says:

        Not that it is required, but having spent considerable time working on safety and mission assurance reviews I second that opinion.

      • Mike Fair says:

        Dr. Spudis, your basic point is excellent. Technology demonstrations have long been an expected type of mission or submission, aside from missions with goals directly tied to exploration, science, or national security. Seems to me that there is always a matter of degree in the debate that you are furthering with your post. That is, lunar propellant manufacture can be similar to a Martian system, in the sense that methane is the resource, but it is different in the sense of regolith vs. atmosphere. The questions are, who needs to be convinced of the risk lowering potention of a tech demo, how close does the analogue need to be, and what exactly is enabled or reduced after a successful demo.

        I would think that a human Mars mission planner would require an ISRU launch on Mars prior to PDR for the manned program. And would require lunar ISRU launch prior to a Mars ISRU demonstrator. My question is, how much risk would be reduced by doing a full ISRU rocket system on earth? Not separate chemistry, fueling demo/engine test, and rocket launch as disconnected demos; but one integrated demo with no external inputs (perhaps except power).

        Perhaps a better question might be: does anyone have pointers to papers reporting ISRU experiments targeted at fueling/launching a rocket?

  15. denniswingo says:

    Paul

    Good as always though I go much farther than you in stating without reservation that the time has come to harvest the metals on the Moon as well. Up to 1% of the regolith in the highlands regions of the Moon has meteoric metal in it. All that is needed is a magnetic rake, a bucket rover, and a thermal processor (a metal dish) to focus sunlight to melt the metal, then pour it into forms or powder it for laser sintering of parts. We are on the cusp of a revolution in our ability to live off the land on the Moon.

    In just looking at propellants, this is what Mike Duke, one of our mentor’s did as a graphic in 2004.

    http://www.panoramio.com/photo/92224273

    • Warren Platts says:

      Hopefully they will include some sort of metal detector in the RESOLVE rover.

    • Mike Fair says:

      The original post posited that a given ISRU technology (in this case propellant/oxidizer) might reduce the cost of a currently envisioned human exploration program. An extension of the argument to manufacturing other things like parts, (or even new systems like nuclear), requires mention of a specific human exploration program, whose cost will be reduced by successful use of the new tech (e.g. making parts from regolith), without increasing the overall risk of the program (by adding a low risk demonstration mission whose cost is much less than what is saved). Alternatively, some proposed programs have such insane launch needs (number, rate, and/or size) that their cost is essentially infinite, and a reduction of these launch needs returns the program architecture to the realm of the sane.
      Either way, the notion of ISRU technology demonstration should be connected to an exploration program that is currently relevant, as opposed to one that is only in the ‘inevitable era of space travel’ around the corner. Not that ‘around the corner’ is out of reach, like ‘Star Trek’ currently is. The latter is centuries away, while the ‘inevitable’ may be only decades. But neither is useful as a motivator for risk reduction activities in the next couple years.
      So what might the near term program need be for parts manufactured on the moon? One thing I can think of is trusses, useful for cut and cover methods of creating bunkers. But that would presuppose a human colony, making the proposed ISRU propellent demonstrator all the more relevant and motivating.

      • denniswingo says:

        Fortunately there are some young people who flip the bird at the pessimism that is the hallmark of this era….

        http://oooojoooo.com/your-moon-mansion-will-be-3d-printed/?fb_comment_id=fbc_526795080698104_98783112_584950631549215#fae01c36

        • Mike Fair says:

          Eventually, they all come around to implementing the engineering processes associated with huge endeavors: Proposal, funding, requirements, PDR, design, prototype, tech demo, CDR, implementation, testing, execution, exploitation. I had a friend once at BlastOff say they should’ve had 90% marketing folks and 10% engineers, rather than the reverse that they had, in order to better execute #2 in the list above. But that still assumes that a concrete proposal is the basis for all programs descriptions and designs. Followed eventually by the kind of risk reduction activities proposed above by Dr. Spudis.
          To me, there is a usefulness to imagining the future, near or far. And a usefulness to detailed design descriptions with acceptable TRL. And a usefulness to hardheaded, pragmatic politics. But the three are distinct, and don’t mix well, especially the first.

          • billgamesh says:

            “To me, there is a usefulness to imagining the future, near or far. And a usefulness to detailed design descriptions with acceptable TRL. And a usefulness to hardheaded, pragmatic politics. But the three are distinct, and don’t mix well,-”

            To less sophisticated minds like mine they are all one and the same thing; pragmatism being simply taking action to solve a problem with the first two.

      • Paul Spudis says:

        I have discussed the use of other lunar resources (primarily the value of regolith and its derived products) here:

        Regolith, The “Other” Lunar Resource

  16. billgamesh says:

    “-3-D printing.
    Imagine testing that on the moon, using the local resources as the raw material.
    Then, not only do you get propellant from the moon, but also you can build your spacecraft there too!”

    If you can refine ore and pour a metal disc a couple hundred feet across massing several thousand tons on the Moon then you have built the main part of a nuclear pulse propulsion engine- the pusher plate. For this mass of dumb metal you enable an ISP in the tens of thousands. Add a several hundred feet long truss-like structure to it and your crew compartment can stroke down it like an elevator in a shaft to absorb acceleration force. Use Moon water to partially fill the crew compartment for radiation shielding- and for supporting a closed loop life support system. And use a wet workshop scheme to convert empty stages into those crew compartments and you have built most of a spaceship capable of multi-year missions to the outer solar system.

    I am no pessimist about space travel- just about the people in power who lack the vision to do what is necessary to succeed at it.

  17. Gary Miloglav says:

    billgaesh – You really should share your ideas and designs (do you use SketchUp?) with the “Lunar Development” community on Google+.

    • billgamesh says:

      Sharing does not seem to accomplish much except to start arguments Gary.
      In my experience most ideas thrown to a committee either die there or get morphed into uselessness. What is required is leadership- someone to choose the single best path and start. There is no “flexible path.”

      The ideas I am discussing has been around for over half a century and originated in the minds of genius’s like Stan Ulam and Freeman Dyson. Endorsed by Von Braun, Clarke, Sagan….all the celebrity scientists. More recently the practical means to build true spaceships and travel in deep space are there for anyone to see in the work of people like Eugene Parker and Paul Spudis.

      Nuclear energy, radiation mitigation, lunar resource utilization; we have the technology to go now. What is lacking is the leadership. We had a President who once ordered the invasion of Nazi occupied Europe- in bad weather. He went on to end the Korean war by threatening to nuke China. He finished by warning us about the relationship between politics, industry, and the military. While that relationship helped land us on the Moon it has also- IMO- kept us from going back or doing anything meaningful in space.

      Until that relationship changes I am not going to start spending serious time attempting to design spaceships. You are free to share and sketch away though.

      I will drop you a line Gary

      Regards, Gary Church

      • denniswingo says:

        He went on to end the Korean war by threatening to nuke China. He finished by warning us about the relationship between politics, industry, and the military.

        He also kept us out of war in Vietnam when eager congressional democrats wanted us to go by demanding a declaration of war from congress before he would order troops to go.

        That is a leader.

  18. Grand Lunar says:

    “This is why going cheap more often costs several times more and ends in failure. There is no cheap and the Moon is in reality a prerequisite for success.”

    I know a group (or at least an individual) that needs to learn this.
    He thinks that Falcon Heavy can create “cheap” flights, according to SpaceX’s claims.
    But that’s more of a case of falling for hype.

    The closest to “cheap” would be to obtain resources from the moon.

    • billgamesh says:

      “I know a group (or at least an individual) that needs to learn this.”

      The psychology of the private space lunatic fringe is easy enough to understand. Most of them just want a space station vacation to a playboy club in orbit with their hero Elon.

      Musk claims he might bring launch prices down to as low as 500 dollars per pound. This is as irresistible to wannabe space clowns as space mountain at Disneyland is to children. Like the middle-aged overweight guy going to a weekend survivalist seminar because he wants to be a Navy SEAL. Like the teenager who spends thousands making his car look fast and sound loud (but not go any faster) because he wants to be a race car driver. And so on.

      Or the guy who comments all the time on a certain space blog because he wishes he was a scientist or engineer; I am not without sin either.

      But having actually read a few books on space and having some small experience in the real world with expensive extreme machines- I get upset with the stupid…stuff these people are pushing off on the public as fact. IMO it has done real and lasting harm to the cause of space exploration. And due to my planetary protection leanings I think it has endangered our species to a degree more than it already is. Serious stuff.

      There is also the Ayn Rand in space factor to reinforce the attraction to certain mindsets. A good percentage of the fringe want to do away with NASA- with all government really. They honestly believe the only possible good is what is good for them personally- that a person should do ONLY what increases their own wealth and trying to accomplish anything to the benefit of all is philosophical treason and conspiring with “looters.”

      When I comment I always try to throw in the “there is no cheap” line just because I know from past experience it drives them totally nuts.

    • Joe says:

      You might want to note to your friend that Space X still currently lists the cost of a Falcon 9 launch as $54 Million (when it was at the development stage of the Falcon Heavy – which depends on the success of the Falcon 9 v1.1, which in turn depends on the Merlin D Engine and the new octagonal configuration tankage, which just ran into trouble on the test stands – they used to quote only $27 Million).

      But in their one active contract, the CRS, they are actually charging $133 Million a launch (also note that they still promise on their website that the Dragon vehicle delivers 13,228 lbs. payload up-mass to the ISS when on CRS 1 and 2 they have delivered barely an average of 1000 lbs. up-mass each).

      That means their cost estimates (so far at least – based on their actual performance) underestimates their costs by a factor of 63.

  19. Gary Miloglav says:

    I also agree that space is not cheap, as would anyone who has estimated the cost of any project intended for launch, but really expensive space projects (greater than $1B) are just getting harder to fund. The public is more excited about the latest “reality” TV show than the grand adventures that await us in space. Unless a person is serious about making it happen, there is little that can be done to change their minds. Freeman Dyson gave an interesting viewpoint on the “space is not cheap” meme. Give a listen to this and tell me what you think.

    • VAXHeadroom says:

      I’m somewhat ashamed to admit, I thought Freeman Dyson had passed on a while back. My YouTube ‘watch later’ queue just got much bigger…

    • billgamesh says:

      Thank’s Gary, here is my take:

      Not a single word about Pulse Propulsion- the project he is most famous for. Not a word about nuclear energy- must be a pretty green crowd. He talks mostly about building bio-engineered environments with “warm blooded plants” and “the permanent expansion of life.” -Using a greenhouse and a mirror on cold bodies.

      4:10 “Apologies to the promoters of other new technologies- some of them will win and some of them will lose, the good news is cheapness now has a chance.”

      My best guess is beam propulsion using Lunar Solar Power.
      BINGO!: 23:19 “A public highway system in space will require terminals using sunlight or starlight to generate high energy beams along which the spacecraft can fly.”

      5:30 “but it is impossible to predict how long this will take- (his guess) cheap manned missions will start sometime late in the 21st century.”

      Which is about how long construction of a beam propulsion infrastructure will take.

      15:15 “That’s why human space travel won’t be cheap until fifty or a hundred years have gone by.”

      There is no cheap.

  20. VAXHeadroom says:

    The only thing in this article that twists my moustache is the use of the word ‘engineers’ (unless you put it in quotes!). In my opinion, it’s not the engineers that are risk averse, it’s the politicians and managers. Put an aerospace engineer in a room with a super risky problem and he’ll give you 3 possible architectures by lunch time. Put a manager in the same room with the same problem and he’ll tell you there isn’t enough TRL 7+ technology to do it regardless of how much coffee you pour into him.
    I was the lead flight software engineer on LCROSS, and design satellites and work on proposals for them almost every week. Mostly these are NASA missions for science and exploration although other ‘stuff’ gets thrown into the mix. And I, like Paul, believe ISRU is an absolute necessity. I also believe, unlike some here, that the “NewSpace” folks are doing good, solid, aerospace engineering, even if on the whole they are overly optimistic on price and launch date.
    Space is hard. No doubt about it. Anybody who tells you differently is trying to sell you something. But anybody who tells you it’s impossible is probably also trying to sell you something.
    LCROSS was deemed a “Class D” project, meaning, “It’s probably going to fail, but worth trying anyhow”. ( However as the NASA LCROSS program manager Dan Andrews was fond of saying, “Nothing’s ever Class D once it’s on a rocket”. )
    We need more “Class D” missions. We need – SOMEHOW – to get it into the heads of the politicians (and probably the public) that these things can be done on a reasonable budget IF they can be allowed to NOT be 98% sure-thing missions. Given a 60% success rate requirement we can get more done in a shorter amount of time on less money for this kind of research (ISRU demonstrations). OBVIOUSLY this is not how you want to do manned missions, losing half your astronauts is the wrong answer. But LCROSS showed it can be done on time and on budget – IF the politicians stay out of it. Yes, we almost lost that mission due to an engineering problem, but the smart people in the room gave us, by design, margins against just those kind of issues and we prevailed. The engineers solved the problems even before they occurred.
    Sorry I rambled a bit, but the coffee hasn’t kicked in yet.
    Follow me on twitter @VAXHeadroom

    • Paul Spudis says:

      it’s not the engineers that are risk averse, it’s the politicians and managers

      In the space business, nearly all of them are engineers by training. It is certainly true that young engineers are more imaginative and willing to take a calculated risk (the same is true for scientists, by the way), but of course, there are exceptions to every rule. Most senior types in the space business have numerous disasters under their belt and are thus, much more cautious.

      By the way, “managers” do not get a pass from me anyway. Take a look at this:

      http://blogs.airspacemag.com/moon/2010/07/nasas-new-mission-and-the-cult-of-management/

      Sorry to “twist your moustache!”

      • billgamesh says:

        Excerpt from “-cult of management- “Management fads like Total Quality Management regularly come and go.”

        I remember when TQM was adopted by the Coast Guard. We all had to take a couple days of training. Of course those of us working on airplanes had to go back and work late to catch up on the work left undone during those two days- so we were not too happy about it.

        I, being a troublemaker, actually checked out a couple books beforehand from the library and read up on TQM and how the Japanese car industry is based on it. The highest award for engineering in Japan is the Deming Award- named after Ed Deming, who taught them TQM after World War II. His portrait still hangs in the lobby of Toyota headquarters between smaller portraits of the first and present president of the company.

        Deming also tried to get Detroit interested but they told him to go away.

        The TQM the Coast Guard officers were teaching us was not the TQM Ed Deming taught to the Japanese. I kept asking questions about this every time they deviated from what I had read and they finally told me to be quiet. I was counseled about it later.

        So in defense of some “management fads”, what people do with knowledge- how much they morph it into uselessness (usually in committee)- is what makes it an agent of change or a meaningless waste of time.

        • VAXHeadroom says:

          Heh – I was on a TQM cross-discipline team a few years back. We did some good work, but probably short-circuited much of the drudgery.
          “Right Sized” processes are hard to arrive at – thorough enough to actually save you from yourself, thin enough to stay out of your way.

      • VAXHeadroom says:

        Paul, I think I’m younger than you (I’m 52) but not what folks would normally call ‘a young engineer’ And I do try to be the exception to those rules…

    • billgamesh says:

      “I also believe, unlike some here, that the “NewSpace” folks are doing good, solid, aerospace engineering-”

      The hobby rocket might be engineered well, in that it flies and does not blow up, but it uses clusters of low thrust engines and an inferior propellant in the upper stage. So is it engineered to accomplish anything worthwhile is another question.There is no substitute for a Heavy Lift Vehicle with hydrogen upper stages IMO. There is no substitute for an escape tower either. Sacrificing the most powerful design of escape system for a “dual-purpose” anemic one really designed to keep tourist hotels in orbit is……not good. So in that sense I have to disagree that it is “good, solid…

      • VAXHeadroom says:

        I certainly don’t think SpaceX is a perfect organization, but you gotta admit – 4 out of 4 launches is pretty good. They’re one of a dozen or more companies folks would lump into “NewSpace”, though of course the most visible. And many of those are reinventing the wheel to a certain extent. Still, they’re doing well for way less than it’s been done before, and some of them are doing some very novel stuff.

        If you want heavy lift, we’ll need to talk about SeaDragon.

        • billgamesh says:

          “Still, they’re doing well for way less than it’s been done before-”

          Sorry, I don’t think so. Not a fan.
          As for SeaDragon- I do not think we need to discuss that here.

    • Robert Clark says:

      Thanks for that. I consider LCROSS on a cost-to-benefit scale to be among the most successful missions that NASA ever mounted. This is because of its profoundly important results accomplished at such low cost.
      I’m looking forward to seeing the RESOLVE mission reaching the Moon and accomplishing its ISRU test goals.

      Bob Clark

  21. Grand Lunar says:

    Do you refer to nuclear thermal or nuclear electric?

    Either way, it still runs out of propellant, so a depot is still desirable.

    Just because you have a fuel efficent vehicle doesn’t mean you never have to refuel it.

    You could use a fission fragment rocket, if you want to avoid depot usage. It then transforms more to a “shipyard” usage.

  22. Grand Lunar says:

    - “The psychology of the private space lunatic fringe is easy enough to understand”

    Lunatic fringe describes this bunch accurately.
    I play along with them for fun.
    Here’s an example of the work by this person:
    http://www.buildtheenterprise.org/cold-fusion-is-nuclear-fusion-after-all

    I’ve been beating my head against the wall on this topic.

    But I digress….

    I can imagine the fun you have with the “There is no cheap” line.

    Come to think of it, cars are the same way.
    There is no cheap. Only what you’re willing to afford…

  23. Paul Spudis says:

    The discussion has wandered off topic and has gone on long enough. The comments for this thread are now closed.

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