Paul Allen, Burt Rutan, and SpaceX team up for new space venture, Stratolaunch

[Video Link]

Billionaire Microsoft founder Paul Allen has teamed up with spaceflight pioneer Burt Rutan and Elon Musk's SpaceX to develop Stratolaunch, new launch system with “a gross weight of more than 1.2 million pounds and a wingspan greater than the length of a football field, making it the largest air launch system ever developed”.

It will be the largest aircraft, by wingspan, to ever fly, and will do so with a rocket strapped to its belly. It will carry satellites, cargo, and tourists. Allen is committing some $200 million of his wealth to the venture.

Lots of news coverage today: AP,, LA Times, Wall Street Journal.

(Thanks, Noggin)


  1. SpaceShipOne seems to be scaling up pretty well after all. A lot of people seemed convinced this design would never work for orbital payloads.

    1. The SpaceShipOne design really can’t scale up, but this idea can. The original SS1 only achieved a fraction of the change in velocity, delta-v, needed for orbit. And I mean a fraction, like 3%. What SS1 did was a piece of cake, really. Throw something up there and have enough drag high in the atmosphere so that you spread the heat load of reentry over enough time that you don’t burn up or melt on the way in. Bid deal. 3%. Nobody should care.

      At the low end, that is. The rocket equation is exponential in the delta-v required to get to orbit. This is why getting to the Moon required a Saturn V, but getting off the Moon only took that little fart of an engine on the landing module. If you can knock even a few percent off the delta-v at the top end, say 3%, you get a sizable increase in payload. On top of that, engines with an area ratio designed for the vacuum of space perform terribly at sea level, and vice versa.

      If you can launch from the stratosphere, the penalty for having a vacuum-optimized engine is much less. You can bet on an extra 10-13% benefit from launching from that altitude, from engine efficiency alone. Add it up and you’ve shaved 13-16% or so off the bad end of the rocket equation, even before you run the drag budget and take in to account the reduced fairing mass. It’s not long before you’ve cut your vehicle size in half, at that rate.

      Combine this with SpaceX’s reusability plans and you’ve got a real winner.

      1. I don’t mean the SS1 vehicle/rocket/reentry design specifically, I mean the idea behind the launch system. I’m sure that an awful lot of what Rutan’s team learned while building that “piece of cake” and its larger SS2 cousin is making its way into this vehicle.

    2. As has already been pointed out- SS1 can’t scale- it doesn’t have the delta-v (which would entail staging or immense cleverness) and it doesn’t have the thermal protection. This doesn’t really share much DNA- it’s fundamentally a SpaceX Falcon I. The idea didn’t start with SS1- air launch has been a regular occurrence thanks to Pegasus (a little solid launcher dropped from an L-1011) for 15 years now, and there was a prototype air-launched ICBM, Skybolt, 50 years ago. Even the gargantuan twin-body carrier aircraft has been round the horn before- with proposals involving B-52s and enormous An-225s.

      Now, the performance benefits have been discussed, but there’s been back and forth on that when it comes to low-altitude, low-speed staging like this. It’s clearly worth it if you launch your rocket at Mach 10 and 100,000 feet, but the tradeoffs have been less clear in this performance envelope. The big win that you get regardless, and seems to be their big justification, is that it removes orbital inclination and weather restrictions from your launch site. Right now, for instance, the US maintains two different launch sites- Caneveral and Vandenberg- for reaching equatorial and polar orbits, respectively- and we’d like to launch further south than the Cape, but the real estate is hard to come by. And there are the hurricanes. With this- you grind through the weather on time like any airliner, head to an appropriate patch of ocean, and launch away, on schedule.

      1. OK, I won’t pretend that I have any kind of background in aerospace. But it sure does look like a ginormous mutant version of the White Knight launch system.

        1. You’re both right – the launch vehicle is just an embiggened White Knight, but the rocket has nothing in common with SS1.

    1. ahh, but ideas are worth nothing. Functional implementations are everything.

      The idea has been around for a long time, and it has been done on a small scale from modified B52s, but making a practical and functional mothership is tricky business and hasn’t really been done successfully until Rutan’s WhiteKnight. It has taken some interesting use of materials and a seriously weird understanding of aerodynamics, all coupled with vision and the courage to design from pure aerodynamic and engineering standpoints and move away from the traditional way of thinking (which is really all about what is simplest to build using the facilities we already have).

      THAT is why this is clever.

  2. For good or bad, it seems they aren’t squandering much of the $200m on computer graphics.  I guess it really isn’t necessary when all of your funding is in place and you don’t need to wow prospective investors.     The plane’s design (or lack thereof) is a bit saddening – from an aesthetic perspective, I love Rutan’s curvaceous airframes …

    1. sure, but Rutan’s designs have NEVER been designed with a goal of being pretty, have they. The weird prettiness has always just emerged from the unusual approach to engineering strength and aerodynamics into the thing.

      We’ll see if it doesn’t end up being a little smoother in reality, but just the sheer scale of this is so crazy that it will be interesting regardless.

  3. This idea has been revisited hundreds of times since the 1940’s (earlier, if you think about some of the twin/parasitic aircraft tests done in the 1930’s). It looks viable enough, but I worry that, like so many of those ideas, it may never really see the light of day (recommended reading; “The Dream Machines” by Ron Miller, a history of the spaceship in fact and fantasy, 1994. It is beautiful and somewhat heartbreaking).

    1. Yeah, but this time it’s being designed by a guy who has actually built a couple of these things before. On a much smaller scale, true- but Rutan isn’t just another dreamer with ambitions that far outstrip his track record.

    1. Yeah.  Just imagine the fun the roving hordes of bored, illiterate teenagers would have trashing the newly-refurbished buildings, and the money they could make ripping out the copper wiring to sell for crack money… Meh.  Been there, done that.

          1. Have some imagination, y’all. Rebuild” doesn’t necessarily and only apply to “buildings.” How about starting a rebuild of a school district? 

    2. …and how do we change society? How do we overcome cultural and societal malaise? Look at parts of Germany, Russia and even the UK; they started some fantastic urban renewal projects only to have them be ignored and ultimately vandalized. I hear what you’re saying, I heard it thousands of times when I was heavily involved in space activism (which I am no longer), but the simple fact is that you can throw gobs of money at these projects but unless some sort of change comes from society it is all for naught. I for one would prefer that money be spent on space exploration, because it hints at the possibility that we hairless apes can aspire to greatness and perhaps one day find a way to prevail and not spend out our entire existence on the surface of this planet. We need to have dreams, some to aspire for. I know that coming from my poor background (classic hillbilly family) the space program gave me something to believe in. While I do not agree with much in the way many of the space projects are being run (hence my no longer being so heavily involved), I still think that they are perhaps money better spent. Yes, we need to have people minding what happens to our cities, but we should not content ourselves with simply staying put.
      We have to have dreams. We should be allowed to have both.

    3. Give a man a fish, and he won’t be hungry for a day.
      Teach a man to fish… and he’ll get bored of fish pretty soon.
      But teach a man to fly into space, and he can precision-strike the slippery fuckers from orbit!

    4. Imagine if someone instead spent $200 million on rebuilding an inner city or two.

      We spend untold billions of taxpayer dollars on inner city problems, the problem is that most of it goes to the War on Drugs. At least space exploration doesn’t make the lives of poor people appreciably worse.

      1. How about spending billions instead against the ongoing War on Urban Children? The U.S. could start by funding public schools equally, instead of on the basis of residential property values, so that suburban kids, for example, don’t get an automatic leg-up just because of the geographic location in which they happen to have been born. Also, of course, we could raise teacher salaries so that teaching can better compete with other careers for talented brains, along a host of other familiar remedies we hear about, but never seem to see enacted in any significant ways. 

        The decades-long, multiple-leveled neglect of urban America constitutes a set of human causes. To wash one’s hands of the resultant problems as hopelessly unfixable is, at best, to ignore those human causes, and to ignore as well the ability society does have to fix them.

        1. I agree completely. I just think blaming the space program for those problems is blasting the wrong target, especially when the amount we spend on it is so small compared to other wasteful activities (like our bloated military and the aforementioned War on Drugs).

          [edit to add:]

          Do you really think that if we suddenly cut all funding for space exploration that money would suddenly go toward helping poor people? You’re right to suggest our national priorities are totally screwed up, but the problem isn’t that going to space is a bad thing. The problem is that we’re neglecting to do a lot of GOOD things. There’s no reason we couldn’t rebuild inner cities and develop low-cost space launch systems.

          1. I agree completely. I just think blaming the space program for those problems is blasting the wrong target, especially when the amount we spend on it is so small compared to other wasteful activities (like our bloated military and the aforementioned War on Drugs).

            Hmm. And someone rich–let’s say, Lady Gaga–can say, “No, I’m not ‘rich.’ Look at Bill Gates. Now THAT’S someone who’s rich!”

            [edit to add:]

            Do you really think that if we suddenly cut all funding for space exploration that money would suddenly go toward helping poor people?

            No, I don’t think in those zero-sum terms. I do think that Gil Scott-Heron made an awesomely astute and enduring observation, though, about the clothes-less state of the emperor, and about race and economics more specifically. His point applies to just about any large-scale expenditure with such abstract, long-term goals toward the betterment of humanity, while certain readily identifiable blocks of humanity continue to languish in egregious and relatively fixable neglect.

          2. There’s no reason we couldn’t rebuild inner cities and develop low-cost space launch systems.

            Sure, but it’s the fact that so many get so much more excited about the former than the latter, and that the former seems so much more possible than the latter (while the latter is actually much more readily achievable), that’s so galling. Desparing, even. 

      2. I never understand why the zero-sum budgetary discussions seem so relentless drawn to space travel. Never ceases to confuse me. I don’t know if all the cool, save-the-day shit that happens in space with pragmatic things like weather, imaging and communications is just not sexy enough, or if all the pure research side with telescopes and probes and astronauts just doesn’t sell for the same reason any other bit of pure research doesn’t- despite the fact all of that ends up saving the day when you least expect it- or what, but a person can cheerfully go through their day watching $100M Hollywood movies, or shopping in $10M retail establishments, or be glad they are finally sinking in $50M into road repairs, or cheer when their kid in the military gets a ride in a $60M aircraft, but when rockets come up, ahhhh hell, we’re robbing poor people. Maybe it’s just because they go up and don’t come down?

        And here’s the thing- I’m in a pretty much perpetual fury about the American distribution of wealth, and dereliction of public services, and the massive moral and market failures in our dealing with the very poor, and the environment, etc., etc. I’m the guy in the corner furiously working the white board and combing the literature for the neat fixes that would make the current political culture lose it. The Big Picture on homelessness today nearly made me cry. It’s just that I don’t understand the fixation- public and commercial spaceflight is such a small, innocuous, variously fascinating and useful bit of infrastructure, but like a moth to flame, you mention rockets and someone will lob in a zero-sum guilt bomb about the poor, as though in the world of trillion-dollar tax loopholes, someone starting up some medium-cap business like this was relevant to the discussion.

        Rockets, why you no fix homelessness?

  4. Man I love Scaled Composites and SpaceX.  Maybe some of the private space exploration science fiction I’ve read over my 48 years of life will actually come true while I’m alive.

    If I remember correctly, at least one of the proposed designs in the program which eventually led to the space shuttle used a runway-launched carrier which delivered a smaller vehicle to the edge of the atmosphere for orbital insertion using its own engines.  I always liked that design, and was sad to see it replaced by the final shuttle launch design.  While thundering into orbit with rockets is certainly spectacular, it can also fail in spectacular ways.  Taxiing down a runway, climbing smoothly to altitude (with the option to just _land_ again if things aren’t going well) and dropping the payload there has always felt much more sane to me. 

    I really hope they can pull this off.  It would be amazing.

  5. the corporate life form must not be allowed to escape the planet! it is an infection, a cancer on the universe! they will turn the wonders of the universe, the adventure of space migration into just another shopping experience!

  6. I’m no engineer, but that thing looks like a catastrophe waiting to happen. The stress on those two main wing/fuselage connection points has to be gargantuan during takeoff and landings. I’ll wait a while before buying my ticket.

  7. There is a (very good) reason why everyone stays well clear of a launch-site during take-off. When these rockets fail, they do so spectacularly and quite catastrophically. I’d hate to be be in that plane if things do not go  by the book when the rocket’s engines light up. 

    1. You’d be fine. The rocket is dropped long before ignition, and would be thousands of meters away if anything went wrong.

      How many escape pods did the Mayflower have, does anyone recall?

  8. Here comes my minor contribution:

    I’m trying to figure out just how much extra mass can be launched with the boost given by the airplane, compared to if the rocket was conventionally launched from a standstill on the ground.  Here’s what I’ve come up with:

    According to the Stratolaunch article on, the rocket weighs 500,000 pounds when dropped from the airplane and ultimately gets 13,500 pounds into low earth orbit.  The ratio of those two numbers is 37:1.  So, for each pound launched into LEO, there’s 37 pounds of rocket at initial drop.  OK.

    Is 37:1 a particularly high or low ratio?  I have no idea.  So I keep digging and guessing…:

    Over at, there are vital stats for their similar-technology Falcon 9 rocket.  It weighs 735,000 pounds at launch (from the ground) and ultimately gets 23,000 pounds to LEO, or a ratio of 31:1.

    As for the smaller Falcon 1e rocket, it weighs 78,000 pounds at launch and ultimately gets 1,000 pounds into orbit, or a a ratio of 78:1.

    o Falcon 1e: 1,000lb at 78:1
    o Falcon 8: 23,000lb at 31:1
    o Stratolaunch: 13,500lb at 37:1

    So.  According to these numbers, launching from the airplane, instead of from the ground, doesn’t make much of a difference in terms of how much mass is launched per pound (~= per $’s worth) of rocket.

    Ergo, as was pontificated above, the real point of doing it this way must be because of practical reasons like
    o fewer launches scrubbed due to weather
    o you can launch into any sort of orbit
    o you can launch comfortably out over the very remote ocean

    Hm.  Well.  If anyone can help support or trash my line of reasoning here, I’d very much appreciate it.

    1. That’s not a bad analysis for a quick look around. The trouble is, as you can see, is that big rockets- to a point- have a better mass ratio, the two big drivers being the diminishing fraction occupied by fixed mass components (a rocket twice as big doesn’t need a guidance package twice as big, for instance) and ordinary scaling laws applied to the tanks- the surface area of a tank (and thus its weight) doesn’t increase as fast as its volume. But the rocket is essentially the same booster as their cancelled Falcon V, and doing a little digging reveals a nearly identical mass ratio. Most analysis shows that you need to be much higher (to cut gravity drag, atmospheric drag, and engine specific impulses losses) or much faster (to get an actual increment on your delta-v) to win on that side of things. But it might still help a hair.

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