14 thoughts on “A Cheaper Lunar Mission”

  1. Reusable space planes can be a viable way to send humans into LEO. They aren’t likely to be all that useful for quite some time at launching significant payloads into LEO. We need both capabilities.

  2. I didn’t think that planes worked at all well in a vacuum. Their wings and landing gear add a lot of mass to the craft as well, reducing the payload mass available. The wings and landing gear also provide single points for catastrophic failure which cannot be mitigated, unless you are talking bi-plane or tri-plane. Space bi-planes, that’s the ticket.

    1. I think a catastrophic failure is going to be catastrophic no matter how many wings you have, but a biplane does offer the odd advantage of the top wing being in the hypersonic re-entry shadow of the bottom wing, so it won’t need the high-temperature thermal protection. It would allow the bottom wing’s size to be cut almost in half without increasing the landing speed.

      I’ve wondered if re-entering upside-down would avoid some of the problems with the basic Shuttle configuration, with the craft rolling over to become a high wing for landing, with the gear coming out from around the payload bay, and the payload bay opening underneath like a conventional bomber.

      But looking at all the things it took to let the Shuttle fly back and land on perhaps three runways on the planet, versus capsules which can safely land just about anywhere, I’m wondering if the convenience of a runway landing is worth it.

      Another thought is that if the craft is using a PICA heat shield on its wings, which is a waterproof composite anyway, would it make sense to dispense with landing gear altogether and just make it a flying boat?

      1. Reducing exposed area for reentry isn’t always a good idea. Less area for drag means more concentrated heating, and possibly a higher area density for the heat shield. There are cases of steel fuel tanks from rockets, with very low density, surviving reentry fairly well intact.

        1. Well, the Space Shuttle I think is about 120 lbs/sq ft and Apollo was 100 lbs/sq ft. If the biplane concept worked the top wing would add very little weight, the re-entry flat plate area would be the same, so the thermal protection would weigh about the same, but the landing speed should drop from about 200 knots to around 140 knots, cutting the rollout distance from about 10,000 feet to 5,000 feet. That would allow the vehicle to land on commercial runways.

          On the downside, the wing would double the drag and center of pressure problems during the launch phase.

          A really bizarre concept would be to make the heat-shield shaped like a parasail (a section of a sphere, or nearly so) being the heat shield and top surface of the wing. After re-entry, the vehicle flips nose down and what was the heat shield becomes the lifting surface, even accordioning out into two or three sections to form a biplane or triplane parasol. The top wing would be from the heat shield and the lower wings lightweight composite sections that were used as the heat-shield structural support, all forming undercambered airfoils for landing. Of course that’s harkening back to the idea of a Ragola wing Gemini or a parafoil for a capsule.

          There’s more than one way to skin a cat, but none of them are pretty.

  3. “I didn’t think that planes worked at all well in a vacuum. Their wings and landing gear add a lot of mass to the craft as well, reducing the payload mass available. The wings and landing gear also provide single points for catastrophic failure which cannot be mitigated,”

    And all that is true (as well as thermal protection material), as long as you don’t ever intend to return to the atmosphere, land, and do it all again. Frequently. There’s a reason we don’t put landing gear on cruise missiles.

    Arguably, every system, every structural element is ‘dead weight’…until the moment you need it.

  4. I’m a bit skeptical of prizes as the gap between the development costs and the prize money gets wider in absolute dollars. Scaled Composites was rumored to have developed SpaceShip1 for about $25M, so the X-Prize of $10M reduced the cost of development to $15M. This was a perfectly reasonable gamble, especially since the team had a private customer on the hook. If they’d lost the prize, it would have pushed a return on investment out by a year or two, but the gap between winning and losing was small enough that the business model was reasonable.

    Miller’s piece is hopelessly vague about what the benchmark for the prize would be, but I’d guess that he’s talking about something with a payload big enough to enable a permanent lunar presence, and that’s gonna cost a lot more than $1B to develop. Suppose it only costs $2B: the gap between winning and losing the prize would be 67 times bigger than the gamble that Scaled Composites took. Even worse, the number of potential customers to use a system that didn’t win would be substantially smaller than what Scaled was looking at. There’s a big difference between losing $25M and losing $1B. At some point, your investors simply aren’t willing to accept the gamble.

    Hybrid models might work better, where NASA subsidizes a few ventures at significantly less than cost, then offers a prize for the first guy to get there. The trick is to make the risk-to-reward ratio low enough that your financial modeller is going through less than a bottle of antacids a day.

    1. There’s a lot of implicit assumptions in the proposal that need to be made explicit. What do you need to do to win? Simply building a highly reusable spaceplane is insufficient, since it’s quite possible to meet that goal without actually being able to deliver payload to orbit cheaper than existing vehicles on a per-kg basis.

  5. The problem I had with the article is that the solution, is of course, this “magical thing”, that if we just made it, would solve the problem. The magical thing in this case is a fully reusable “space plane”.

    We don’t have and probably never will have a space plane because what is really needed is frequent, reliable, and consistently cheaper at the margin launchers in three different varieties: one that can launch humans and very precious hardware; one that can launch other hardware that doesn’t go up with humans and one that is just good enough to launch consumables on a regular basis. No single launch system is going to do it. A system does not necessarily have to be re-useable to be cheaper or more reliable.

    1. A system does not necessarily have to be re-useable to be cheaper or more reliable.

      But a reusable system is likely to be cheaper than an expendable system given a high enough flight rate.

      1. That’s what they thought with the Shuttle, but it depends on more than just acquisition costs. If you can build a new, simple rocket cheaper than the re-usable craft can be turned around for another flight, then the expendable wins. The Shuttle obviously failed at cost reduction, in part because it was a first attempt and in part because of the various design constraints imposed on it.

        A series of detailed studies would probably have to weigh the reusability of various components on a cost basis, but since the data will just be estimates at first, and likely be far off the mark, we should plan to obsolete the early attempts.

        It’s not unlikely that fight rate isn’t the big issue, it’s design rate. The first designs will be expensive and underperform, but they’ll be lessons for how to do it better. By the time the tenth design rolls out, things should be looking much better.

        One advantage of expendables for the early attempts is that since they get expended, the option to replace them with a better design is always on everyone’s mind and the production lines don’t close down for decades after building just three or four vehicles.

  6. Here’s part of the article by Charles Miller, which I found at ConservativesWithNewt http://conservatives4newt.blogspot.com/

    Charles Miller, at The Wall Street Journal:
    “As a former NASA executive, I am saddened by the media response to Newt Gingrich’s proposal that we return to the moon. The mockery and ridicule does America a great disservice. Space exploration and development is an important national issue. It’s not only possible and necessary to safeguard our future — it can be a lot cheaper than anybody dreams.”

    Dr. Robert Zubrin, president of Pioneer Astronautics:
    “The American manned space program has not gone anywhere in nearly 40 years, and currently it intends to spend yet another decade mired in low Earth orbit, achieving nothing, at a cost to the taxpayer on the order of $100 billion. In contrast, for a small fraction of such a sum, the Mars Prize would unleash the courage and inventiveness of the American people, mobilize our technology, grow our economy, inspire our youth, and endow us with great new space capabilities, new knowledge, and a new world and a new frontier of unknown but vast potential. The American people want and deserve a space program truly worthy of a nation of pioneers. In setting forth the Mars Prize, Newt Gingrich has finally put one on offer.”

    Here is Newt’s speech. “NEWT’S TOWN HALL MEETING ON SPACE POLICY” http://conservatives4newt.blogspot.com/2012/01/video-newt-gingrich-town-hall-meeting.html – January 25, 2012 – Cocoa, Florida – 33:42

    In it, Newt says how model should be the Wright brothers and the early development of airplanes in WWII, with LOTS AND LOTS of experimentation. He points out that people worked on many planes. He said the pace of innovation ahs slowed down today so that a person is lucky to work on more than one plane. He says we need to have 6, 7, 8 launches a day in order to be accelerating, learning, innovating at the needed rate.

    This is not something to ridicule. This is something to fervently hope to get to do.

    Don’t you remember your dreams when you got into science and technology? Your love of the open frontier?

  7. Actually, upon reading the comments here, I see that no one is ridiculing the ideas.

    Sorry! I posted this after having read the comments at http://www.transterrestrial.com/?p=40274&cpage=1#comment-267927 Here, you are discussing idea, which I love.

    And thank you for an enlightening discussion. That’s what I love about Transterrestrial Musings, I learn something.

    And yes to Pro Libertate, yes, yes, yes, that’s the beauty of a private space plan.

    Wouldn’t it be awesome to work with people who are not mindless bureaucrats? Newt intends to train all Federal employees, all appointees, all cabinet positions, in Lean Six Sigma. Think what it would be like if, every day, the supervisor’s job included asking the ones they supervise, “What do you need from me today so that you can do your job better?”

    Even if it is imperfect, it will be such a huge improvement.

    Newt is the antithesis of a bureaucrat. Newt says the Establishment is right to oppose him, because Newt is going to break up the Establishment, and put a stop to the corrupt New York to Washington Corridor of Power Gravy Train.

    Please watch Newt’s speeches. It’s in the speeches. Here are some links: http://newtgingrich360.com/profiles/blogs/2012-victory-or-death-newt-s-speeches-links-to-17-speeches

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