Tacking Toward the Moon

An outpost on the Moon helps us prepare for journeys beyond.

An outpost on the Moon helps us prepare for journeys beyond.

While parroting President Obama’s well-known disinterest in the Moon, SpaceX founder Elon Musk begrudgingly acknowledged its utility during a recent CBS News interview.  In his view, a stepwise incremental approach to Mars “colonization” would involve “possibly” landing on the Moon with people.  He is careful to remind us that he’s not personally “super-interested” in the Moon because “obviously we’ve done that,” but feels that a lunar landing will test needed capability.

I won’t belabor the obvious point that nobody in the U.S. space business working today has ever landed on the Moon nor for that matter, even sent any type of landed robotic vehicle there.  Instead, I found it interesting that in an interview devoted to his Mars colonization idea, Musk went out of his way to: 1) dismiss the value of lunar return by hoisting the old “been there” canard; and 2) at the same time, acknowledge that such a return might actually have some technical value as a stepping stone toward more distant destinations.  The wind may be shifting.

Before considering this renewed interest in the Moon, I note that Musk states his mid-2030’s Mars colonization plan will require the development of launch vehicles of a size on a “bigger scale than has ever been done before.”  We know that a Mars mission staged entirely from Earth would require an enormous amount of mass to be launched; using a super heavy lift vehicle (such as the Ares V of the cancelled Constellation project), it would require between six and twelve launches to mount a single human Mars mission.  Getting “millions” of colonists to the Red Planet on this basis would be cumbersome, to say the least.  And it doesn’t help making those tickets one-way either – you still need (roughly) a million pounds in LEO to send one human mission to Mars.  Then there is the issue of learning how to land humans on Mars, not to mention keeping them alive afterwards.  Those details are left as an exercise for the student.

In recent weeks, new concepts involving lunar return have been floated in several quarters, usually under the rubric of some new, different or innovative programmatic umbrella.  NASA has recently announced a program called Lunar CATALYST (Lunar Cargo Transportation and Landing by Soft Touchdown). CATALYST is an outreach to commercial companies working on developing lunar landing capabilities.  This new program is an offer to make agency capabilities (installations, software, testing facilities) available to support commercial firms developing landers for the Moon.  While agency support involves no monetary awards, such in-kind help is extremely valuable, especially for access to environmental testing (e.g., thermal-vacuum) that would be difficult or impossible to accomplish without the specialized facilities that NASA has developed over the years.

Recent articles outline the possible benefits of lunar return, both as an enabling activity for future spaceflight and as an activity in its own right.  A piece in the Daily Telegraph discusses the advent of the CATALYST program and also takes note of international interest in human missions to the Moon, specifically as outlined in the Global Exploration Roadmap.  The scientific community has expressed its interest in the Moon via the release of an advocacy brochure on the value of lunar return from the Lunar Exploration Advisory Group (an informal group of scientists who advise NASA on issues in lunar science and exploration).  A piece in The Space Review notes the scientific rationale for lunar return is extensive and human lunar missions have been given strong endorsement and support from both internal NASA and National Academy panels convened to consider them.

Parties with an interest in space security are closely following the Chinese lander mission Chang’E 3, which touched down on the Moon last December.  It deployed a rover and has been exploring part of Mare Imbrium.  Lunar scientists have been particularly interested in this mission.  Although there are indications the rover might have malfunctioned recently, with the arrival of a new dawn at the Chang’E 3 landing site in about a week, it should start work again and we’ll know more then about its condition.  The geopolitical significance of Chinese interest in the Moon has only recently begun drawing attention, although much of the analysis so far has been relatively superficial.  It is commonly assumed that China is conducting lunar missions with the sole aim of achieving parity with past American and Russian accomplishments.  I have argued here and elsewhere that something much more profound is likely to be their primary motivation.

Interestingly, this new focus on the Moon is tacking into a subtle shift in policy emphasis.  Previously, whereas lunar missions could not be imagined in any sense other than an Apollo Redux type of “touch-and-go” sortie, we are now looking at possible activities enabled by a more permanent presence there.  Such possibilities are not without their critics; some are not able to imagine any value to a long-term presence on the Moon.  However, two primary realizations have caught the eye of space advocates.  First, human missions to Mars are too distant in the future to serve as realistic strategic horizons for a civil space program.  Political realities dictate accomplishment on time scales of less than a decade, with shorter intervals preferable to longer ones.  Second, even if we accept Mars as a long-range goal, our activities on and around the Moon offer us the opportunity to develop the capabilities we will eventually need to conduct human missions beyond the Moon.  Musk’s grudging admission indicates that even the most die-hard Mars-Firster realizes that testing equipment and procedures on the Moon reduces risk and enables better and faster development of the technologies needed for interplanetary flight.

We’ve yet to see if NASA’s interest will amount to a real program but with China’s recent landing on the Moon and their deployment of a rover (with talk of manned missions and resource utilization), the conversation has definitely taken a turn back toward the Moon.

Note:  For more information on why the Moon and cislunar space need to be our next destination, here is a direct link to all my SLR posts on the Moon, lunar return and space policy: http://www.spudislunarresources.com/blog/slrb.htm.  Along with those posts, you can find a more easily accessible table of contents of all my “Once and Future Moon” posts on these subjects at Air&Space.  Their website has recently been revamped, making it easier to find this information: http://blogs.airspacemag.com/author/paul-d-spudis/.  They are working on a few remaining issues that arose with the switchover but all in all, things seem fairly complete.  You can also view a comprehensive chronological list and access to all of my Air&Space blog posts here:  http://www.spudislunarresources.com/blog/oafm.htm

This entry was posted in Lunar development, Lunar exploration, Lunar Science, space policy. Bookmark the permalink.

18 Responses to Tacking Toward the Moon

  1. billgamesh says:

    Doctor Spudis, do you have some kind of agent or something? Could you give some of these other celebrity scientists a call and see how they arrange their PR appearances? Kaku and Tyson have the most exposure. IMO you need to jump on this and get out there before someone steals your thunder (and then messes it up in ways you would not).

  2. ernst wilson says:

    Paul, your last articles on the renewed interests on lunar initiatives as a ‘prerequisite’ to Mars missions, are remarkable; Space X’s interests have concluded the needed tests on the Moon are a necessary stepping stone towards other interplanetary destinations. With all your academic ‘enseignement’ on the Mars & lunar matter, I retain one (1) fundamental fact: it will be quasi impossible to depart the Earth with million pounds mass to reach Mars; we will never succeed in such endeavor in that mode.

  3. William Mellberg says:

    “Musk’s grudging admission …”

    It sounds like President Obama needs to have a talk with Mr. Musk. “Been there, done that, Elon.”

    Or, perhaps Mr. Musk needs to have a talk with President Obama. “Realistically …”

    In either case, they BOTH should listen to what some people (including YOU, Dr. Spudis) have been saying for a very long time.

    Bill Nye (the Science Guy) once inferred that Neil Armstrong was senile when he (Armstrong) publicly criticized President Obama’s cancellation of the Constellation Program. Mr. Armstrong (and several of his Apollo colleagues) strongly advocated a Return to the Moon — not to repeat Apollo, but to pick up where they left off.

    It is worth recalling what the late Neil Armstrong said during his testimony before the House Committee on Science and Technology four years ago (May 26, 2010). His remarks were far more thoughtful than the Mars hype spewed by Mr. Musk and others. Neil did not mention water in the extracts below, but he was well aware of the critical importance of water ice at the lunar poles. Here is part of what Mr. Armstrong said:

    Some question why America should return to the Moon. “After all,” they say, “we have already been there.” I find that mystifying. It would be as if 16th Century monarchs proclaimed that “We need not go to the New World, we have already been there.” Or as if President Thomas Jefferson announced in 1808 that Americans “need not go west of the Mississippi, the Lewis and Clark expedition has already been there.”

    Americans have visited and examined six locations on Luna, varying in size from a suburban lot to a small township. That leaves more than 14 million square miles yet to explore. There is much to be learned on Luna — learning to survive in the lunar environment, investigating many science opportunities, determining the practicality of extracting Helium-3 from the lunar regolith,
    prospecting for palladium group metals and meeting challenges not yet identified.

    The lunar vicinity is an exceptional location to learn about traveling to more distant places. Largely removed from Earth’s gravity, and Earth’s magnetosphere, it provides many of the challenges of flying far from Earth. But communication delays with Earth are less than 2 seconds, permitting Mission Control on Earth to play an important and timely role in flight operations. In the case of a severe emergency, such as Jim Lovell’s Apollo 13, Earth is only three days travel time away.

    And flying to further away destinations from lunar orbit or lunar Lagrangian points could have substantial advantages in flight time and/or propellant requirements as compared with departures from Earth orbit. And flying in the lunar vicinity would typically provide lower radiation exposures than those expected in interplanetary flight.

    The long communication delays to destinations beyond the Moon mandate new techniques and procedures for spacecraft operations. Mission Control cannot provide a Mars crew their normal helpful advice if the landing trajectory is 9 minutes long but the time delay of the radar, communication and telemetry back to Earth is 19 minutes. Flight experience at lunar distance can provide valuable insights into practical solutions for handling such challenges.

    I am persuaded that a return to the Moon would be the most productive path to expanding the human presence in the Solar System.

  4. Pingback: Space-for-All at HobbySpace » Space policy roundup – Feb.4.14 [Updated]

  5. Joe says:


    At least two of Musk’s statements are likely to make a lot of his internet fans go ballistic (no pun intended).

    (1) His acknowledgement (however reluctantly) that human lunar missions might have value, at least as a test bed.

    (2) His support for a (very heavy) heavy lift vehicle. A basic tenant of all their previous talking points has been that Elon (as they like to call him) has proved that HLVs (like the SLS) are completely unnecessary because all that is required are lots of flights of the Falcon 9 (with lots of rendezvous/docking/berthing and fuel transfers).

    Now here comes Elon saying:” Then we need to develop a much larger vehicle which would be sort of what I call a large colonial transport system. This would really be — we’re talking about rockets on a scale, a bigger scale than has ever been done before, that make the Apollo Moon rocket look small. And they would have to launch very frequently as well.”

    In other words an HLV so large it makes the Saturn 5 and the (much hated by Musk’s internet fans) SLS look small by comparison.

    He appears to be describing (whether he knows it or not) something on the scale of Phil Bono’s ROMBUS launch vehicle.


    • billgamesh says:

      I was always impressed that Sea Dragon was studied by a think tank, I think it was RAND, and they said it would work. It is just so incredibly huge it is too far out- even for me. But then those Saturn V F-1 engines were mind boggling at the time- and extremely difficult (and expensive) to make work right. But they did.

      This is what Musk should have built instead of the hobby rocket;


      A couple of these strapped on to a Nova size core are what is needed.

    • Robert Clark says:

      Keep in mind many supporters of commercial space are opposed to the SLS because of its humongous cost. The HLV of SpaceX however, based on the reduction seen in development cost under commercial space, would be much less. It may even be fully privately funded as the Falcon Heavy is expected to be.

      • billgamesh says:

        Keep in mind there is no reason to believe an HLV can be made “cheap” just because SpaceX made a vastly inferior vehicle that was subsidized in every way by NASA.

      • Annual SLS funding is less than $1.5 billion a year. The extension of the ISS at $3 billion a year as a corporate welfare program for Commercial Crew vehicles is far more expensive. So its going to cost NASA $12 billion dollars more just to stay at LEO an additional four years.

        But I’ve long suspecte that the ISS extension is really a ruse by the Obama administration to prevent NASA from having appropriate funding for beyond LEO missions in the 2020s.


      • Joe says:

        Hi Robert,

        I see billgamesh and Marcel have already answered part of the cost equation issue, but I will add a little more.

        Mr. Musk does not specify even a preliminary design for this HLV which will supposedly dwarf the Saturn 5/SLS so it is not possible to evaluate a possible cost.

        The Falcon 9 is a very middle line booster using very well understood technology and was heavily subsidized by the government. So even if you hypothetically accept that it was developed at an extraordinarily low cost, using it as a cost comparison to a new launch vehicle that Musk says would be on “a bigger scale than has ever been done before” and “would have to launch very frequently as well” is not valid.

        Additionally while some “commercial space” supporters may actually believe Musk can develop such a vehicle cheaply (and on private money) that is not the argument that they have repeatedly made. That argument (unless history is to be re-written) was that any HLV is completely unnecessary because all that is required are lots of flights of the Falcon 9 (with lots of rendezvous/docking/berthing and fuel transfers). Now that is not what Musk is saying. That was the (I think very clear) point of my post.

        • Robert Clark says:

          I don’t know if they made that argument in regards to Mars missions because the mass to orbit is so high. They may have argued for the commercial space approach to developing such a vehicle.
          In any case it is good news that SpaceX may take part in return to the Moon missions, presumably using the Falcon Heavy, especially since NASA has shown no interest in mounting such missions. Note also the time frame this would happen would be prior to 2025 since that is when the Mars missions would take place. So we could return to the Moon by the 50th anniversary of the Apollo missions!
          Important to remember also such missions would cost considerably less than the plans that NASA was proposing in large part because it will be using the FH and the launcher is always a large part of the cost of such missions.

          Bob Clark

          • Joe says:

            “I don’t know if they made that argument in regards to Mars missions because the mass to orbit is so high. They may have argued for the commercial space approach to developing such a vehicle.”

            Numerous times the argument has been made by “commercial space” supporters (on numerous websites) that any kind of an HLV is not needed for any purpose. No distinctions were made about this destination vs. that destination. It was superior to launch all payloads in Falcon 9 size increments (20,000 to 30,000 lbs) and use orbital assembly and orbital propellant depots to assemble whatever sized vehicle in-orbit was required. This provided (so it was said) greater flexibility and the very fact that so many launches would be required would lower cost dramatically. We can debate whether or not that argument is valid, but it will not change the fact that Musk is now advocating an HLV so large that (in Musk’s words) it will “make the Apollo Moon rocket look small”.

            “In any case it is good news that SpaceX may take part in return to the Moon missions, presumably using the Falcon Heavy, especially since NASA has shown no interest in mounting such missions. Note also the time frame this would happen would be prior to 2025 since that is when the Mars missions would take place. So we could return to the Moon by the 50th anniversary of the Apollo missions!”

            Let’s skip the “NASA has shown no interest in mounting such missions” part. The current administration has shown no interest in mounting lunar missions and imposed that point of view on NASA, which is not the same thing.

            The more important point is your statement about “this would happen would be prior to 2025 since that is when the Mars missions would take place. So we could return to the Moon by the 50th anniversary of the Apollo missions!”

            I do not want this to turn into an off topic back and forth about the “magic” of Space X. If you really believe that Space X is going to:
            – Develop the Falcon Heavy, a BEO version of the Dragon vehicle and a Lunar Lander. Then use that hardware to fly a crewed lunar mission by 2019.
            – While simultaneously developing an HLV that will dwarf the Saturn 5 and all the new habitation modules and Martian landers needed to begin building a Martian Colony by 2025.
            – All on private money.

            Nothing anyone can say is going to convince you otherwise.

            So why don’t we just wait and see what actually happens

    • gbaikie says:

      – He appears to be describing (whether he knows it or not) something on the scale of Phil Bono’s ROMBUS launch vehicle.


      Gross mass: 6,363,000 kg (14,028,000 lb).
      Payload: 450,000 kg (990,000 lb).
      Height: 29.00 m (95.00 ft).
      Diameter: 24.00 m (78.00 ft).

      What I call pipelauncher which was somewhat large [30 meters in diameter],
      could be used to allow this rocket to be launched from the ocean.
      Since ROMBUS is using Hydrogen it’s overall density is low-
      despite having mass of over 6000 tonnes.
      In comparison, if had 24 meter diameter cylinder which 20 meter tall which which
      filled with water, the water would weigh 9043 tonnes.
      Or 24 meter cylinder filled with air in the water can displace 9043 tonnes
      of water.
      So instead 20 mete tall if make 60 meter tall. And put a cap on one end
      of pipe, and let water in the other end, so the 40 meter of 60 meter length
      is filled with water and leaving 20 meter of it filled will air.
      Then, this would float vertically, and total weight it
      could float is 9043 tonnes. Or it needs 9043 tonnes of total weight to
      push the air below the surface.
      So it would float this ROMBUS launch vehicle.

      And if make pipelauncher have 30 meter diameter, then 20 tall would
      float 14,130 tonnes.
      Or floats more than twice as much mass as rocket or it needs less
      10 meter of pipe length filled with air to float it.
      And the air inside pipe will be depressing water less than 10 meters
      under water, which also means the air pressure needs to be less
      than 1 atm- 14.7 psi.
      10 meter under water is 1 atm of pressure.

      And if double the air pressure, it makes it goes up at 1 gee- it
      accelerates at 9.8 m/s/s.
      And continues this accelerate as long as there is twice this
      pressure and/or you run out of the pipe length.
      The “use” of pipe length is as exponential as the acceleration.
      Or with 1 gee in second one falls 4.9 meter, 2 seconds, it’s 19.6 meter, and 3
      seconds it’s 44.1 meters, and fours seconds it’s 78.4 meter.
      So a 60 meter tall only gets about 3 seconds.
      3 seconds is about 65 mph. So one have pipe length considerable
      longer than 60 meter to get a speed faster than 100 mph.
      But one could just launch it around 60 mph, and mainly using it as
      a launch pad in the water, which gives the rocket a bit of push.

      And giving a much smaller push at lift off is common with launch pads.
      Whether it’s actually pushing a bit, or coming to full power and releasing.
      Of course I am talking i much more than that, I am just as general principal
      it’s already done to some extent. Though a Polaris sub launch, would be more
      similar. Or more perhaps similar than that, a Sea Dragon launch.

    • You really don’t need a heavy lift vehicle beyond the average capabilities of the SLS to deploy a mass of more than 30 tonnes to the Earth-Moon Lagrange points. That’s more than enough to deploy a reusable interplanetary rocket capable of storing more than 400 tonnes of fuel delivered to it from lunar water resources. And the delta-v between the Earth-Moon Lagrange points and high Mars orbit is less than 2km/s.

      Check out Space Works’ huge interplanetary booster concept:

      A Study of CPS Stages for Missions beyond LEO



      • Joe says:


        A vehicle with an LEO capacity of 70 to 80 metric tons (and capable of being launched 6 to 8 times per year) will do nicely to support a large scale effort to establish lunar mining capability. As Dr. Spudis has pointed out many times the Side Mount SDHLV would have filled that role very well. Sadly that window of opportunity has closed, but the Block I SLS can meet the requirements (note that even the Block II SLS – 130 metric ton version – while nice to have is not required).

        I did not reference the ROMBUS design to either endorse or criticize it, only to use it to show the scale (actually the minimum scale) implied by Musk’s current musings. It is ironic that while his internet supporters have consistently derided the value of any HLV, he is now talking about a “Super” HLV wildly beyond anything being currently proposed elsewhere.

        Thanks for the link to the Space Works study, it is an interesting presentation.

        • gbaikie says:

          I think for settlements on Mars, you will get launcher larger
          than Saturn V. But NASA job is exploration. And if there is settlements on Mars, NASA should not exploring Mars anymore than it’s suppose to be exploring Florida.

          Settlements on Mars are markets on Mars. And to get settlements on Mars, Mars needs to be explored, and there needs to be other markets in Space.

          You get large launchers when there is more markets in space.
          Or you will get large rockets when there is more traffic to space.
          And this is exactly why NASA should not have focused on making a large launch vehicles- because inhibits NASA exploration of space.

          What both Musk and NASA fail to realize is the focus should be towards establishing more markets in space. The degree NASA and Musk have ignored the Moon is evidence of this neglect.

          I believe the first market in space will probably be the rocket fuel. NASA can start this market by building and using depots.

          It’s very unrealistic to imagine exploring Mars without having fuel depots. And not a smart idea to not to use fuel depots if you exploring the Moon to find minable lunar water.
          For lunar water to be mined, it has to be found and next one needs to establish a market for rocket fuel in space.
          Now one can imagine the market of rocket fuel in space may be only market of lunar rocket fuel at lunar surface.
          But this is not very workable. Because to mine lunar in profitable manner, one need to mine + 100 tons of water per year of time. And to mine more than 100 tons of water one needs a large demand for rocket fuel. And exporting from the moon is path to such a larger demand for lunar rocket fuel.

          Having a lunar base with say 100 people living there would also be a sizable market for lunar water and lunar rocket fuel. But a lunar base with 6 people is not much of a market for water or rocket fuel.
          Now sending 10 tons of lunar samples to earth per year, is by
          itself also not much of market for lunar water or rocket fuel.
          But it adds to the demand. But it not as significant as shipping lunar rocket fuel to lunar orbit.

          Or if one has a tourist going to moon and using lunar rocket fuel at the lunar surface and get 10 tons per year. Then if shipping lunar rocket fuel to orbit which tourist can buy, then instead 10, the tourist is buying 30 tons- without any increase to tourist costs. Or having lunar rocket fuel available on the moon significant lower costs, but whether tourist buy rocket fuel shipping from Earth to lunar orbit or buys it shipped from Moon is about same costs. So no much difference to tourist where the rocket fuel is coming from, but big difference to lunar water miners.
          And given enough time and enough rocket fuel sold, rocket fuel prices could be half their price. But 1/2 the price of rocket fuel will not make much difference to cost of lunar tourist
          to get to Moon. It’s not as dramatic as simply having rocket fuel available at the lunar surface. Nor a significant as simply having rocket fuel available at lunar orbit- and/or having rocket fuel available at LEO.
          Or the biggest affect of having cheap lunar rocket fuel will be the exporting of stuff from the Moon.
          So bigger effect would be on cost shipping lunar samples to Earth, or shipping lunar water for going to Mars.

          Because the major cost for tourist getting to the Moon when rocket fuel is available in space is the cost of leaving Earth.
          BUT if there enough traffic leaving Earth, this larger amount of traffic will lower the costs of leaving earth. And with higher traffic one part of lower the cost will be to to make larger launch vehicles.

  6. Gary Miles says:

    Dr. Spudis, have you had an opportunity to read Dr. Scott Pace’s paper “Advancing U.S. Geopolitical and International Interests in Space” published in the recent book America’s Space Futures. For that matter, care to comment on any of the paper’s published in the book? Dr. Pace’s has discussed the impact that the cancellation of the Vision and Constellation has had on US international partners.

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