a rocket-launched spaceliner: combining the worst of both worlds

February 5, 2013

spaceliner render

If you ever explored the pages of popular science magazines from the heady days of the Space Race, inspired by novels of the Golden Age of science fiction, you’ve no doubt seen proposed ads for space planes taking busy commuters around the world in mere hours. It sounds like the perfect solution to spending as much as a day locked inside a flying metal tube filled with stuffy recycled air. And the Noodly One forbid you have to make the trip in coach. Ugh. Unfortunately, hypersonic jets are really difficult to build and the sonic booms they would create would quickly run afoul of local noise ordinances. This is not to mention that airport runways would have to be a lot longer to help them build up speed and the air and space routes would have to be mapped in completely new and different ways. But all this we could deal with to make sure that a venture designed to shuttle people around the world in no time at all is a viable business and taking any space plane is as easy as taking a commercial jet liner today, although a lot pricier.

Yes, making suborbital flight an easy and convenient proposition is diffciult and expensive. But that doesn’t mean that a European start-up’s plan to attach a space plane to a rocket, fire it off like a space shuttle, and have it glide back down to Earth at 15,000 miles per hour is any better than having to redesign major airports to support hypersonic planes. According to the company, using proven rocket technology would mean that the plane would begin daily service in 2050. If we actually do a little research about hypersonic flight and rocket launches, it would mean that a plan resembling anything like the venture proposed is dead on arrival and should come with an obligatory DNR order. This idea effectively combines the biggest, most expensive hindrance to cost-effective suborbital, and adds a layer of regulatory issues, as well as logistical pains which would drive potential customers to simply fly on an existing aircraft because they would get there much faster. It’s in no way commercially viable or safe for the passengers since there’s a really, really high chance that the space plane will disintegrate as it glides back down to Earth.

But let’s backtrack for a moment. Consider the issue of starting a trip with a rocket launch. Last time most of us checked, rockets cost millions and get thrown away after each use. SpaceX has been working on reusable rockets, so that may bring down costs substantially, but there would only be so many flights it could make before the repeated stresses render both it and the space plane unusable. Furthermore, it means that the proposed SpaceLiner would have to launch in a small time window at a spaceport built well out of the way as not to interfere with air traffic over a major city or transport hub, precisely the places where you should be offering the flights to make it easy to get to the space plane. If you miss a window due to a mechanical issue, you could end up wasting the entire day rather than just reschedule for the next flight since the next window for the trajectory you need may not come for the next few days. By this point, if you were willing and able to spend the hundreds of thousands of dollars for a SpaceLiner ticket, $15,000 for a typical long haul first class flight on a conventional aircraft would sound like a decent bargain.

And, of course, there’s the whole possible disintegration thing. You see, gliding at 15,000 miles an hour through the atmosphere isn’t exactly what happens when you’re going that fast. No, it’s more like plowing through miles of gas that’s exponentially increasing in density while the heat generated by air compression is trying to engulf your craft. DARPA tried the exact maneuver the SpaceLiner is expected to do with one of the most advanced hypersonic bullets ever built. It did not end well. The entry vehicle’s skin came off its body. There’s a non-zero chance that even a shielded SpaceLiner would face stresses that would either melt its skin right off, or kill whoever was on on board should the glide back down to the ground hit a rough patch somewhere. Again, the slow jet sounds like a good deal, doesn’t it? Especially an advanced supersonic design that muffles the noise of its sonic boom by its shape and the angles of its flight surfaces which would let it catch on in a way that the Concorde never could due to its engines’ piercing shriek.

And if that supersonic jet could get you halfway across the world in five hours from your nearest airport with a much, much smaller chance of a fiery, explosive death as it blazes through the air during its descent, why would you want to pay about ten times the price of a first class ticket on such jets to schlep out to the middle of nowhere to try and catch a rocket and shave off three or four hours of the final leg of your trip if you do manage to launch in your window? By the time it’ll touch down at another spaceport in the middle of nowhere, you could have been relaxing in your hotel room or home half a world away for hours. Other than the novelty and complexity of going by SpaceLiner, you would’ve gotten nothing out of the trip that a supersonic plane couldn’t have given you safer, cheaper, and more efficiently. Now if you were going to the Moon or an orbital hotel room, that would be a different story. Maybe the company behind the SpaceLiner proposal would want to take aim at the Skylon concept rather than trying to challenge Virgin Galactic and every major airline with a caveat-laden offer to its potential customers 37 years from now. Then again, it’s likely that today’s space tourism companies would dominate that market by then…

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  • TheBrett

    I don’t get the obsession with space planes, or with “reusable” rockets. If the disposable rockets are much cheaper, why bother? It’s not like there’s a great call for “reusable bullets”.

    Especially an advanced supersonic design that muffles the noise of its
    sonic boom by its shape and the angles of its flight surfaces which
    would let it catch on in a way that the Concorde never could due to its
    engines’ piercing shriek.

    I’m still not sure it will actually be profitable as an airline. “Cost” seems to be the overwhelming factor in people’s decisions on which airline to use, and you’d have to really want to get somewhere in the world in five hours as opposed to ten if it’s going to mean ticket prices an order of magnitude larger (or more).

  • gfish3000

    If the disposable rockets are much cheaper, why bother?

    But that’s the problem, they’re not. Space planes and reusable rockets built up to spec can fly multiple times, allowing you to amortize the costs of building and maintenance over multiple launches. The problem with the SpaceLiner idea is that the launch costs would still be in the tens of millions and while that’s a massive discount for a space agency or a wealthy university, for your casual space tourist or commuter that’s way too much for a ticket.

    “Cost” seems to be the overwhelming factor in people’s decisions on which airline to use…

    … and yet enough people fly first class and work in lines of business which take them all over the world and in which time is money to make sense for companies to start doing feasibility studies into commercial supersonic flights.

  • TheBrett

    But that’s the problem, they’re not. Space planes and reusable rockets
    built up to spec can fly multiple times, allowing you to amortize the
    costs of building and maintenance over multiple launches.

    That’s the idea, but in practice refurbishing the spacecraft after their re-entry from space tends to be so expensive that you don’t end up saving money doing it. In fact, your launch schedule tends to be worse.

    … and yet enough people fly first class and work in lines of business
    which take them all over the world and in which time is money to make
    sense for companies to start doing feasibility studies into commercial
    supersonic flights.

    That didn’t save the Concorde, and it hasn’t saved many of the “higher-end” airlines (such as Virgin, which is circling bankruptcy). Time is only money up to a certain degree, and that’s only going to be tighter as teleconferencing technology (for example) gets better.

  • N.

    Why should there be a small takeoff window. Australia is not Mars.

  • gfish3000

    There’s a number of reasons. You have passing aircraft, the weather conditions need to be just right, etc. Flying a rocket to the edge of space and gliding it back down isn’t easy, especially when you have to travel alongside of through normal air traffic and avoid storms and high altitude weather phenomena.

  • gfish3000

    Considering that reusable craft have been tried with a couple of 1970s and 1980s era demonstrators, and highly compromised space shuttle designs with a throwaway launch stack, I don’t think there’s sufficient grounds for you to so blithely state that reusable spacecraft can’t work cost-effectively.

    As for the Concorde, remember that only a dozen were built and when they were, the reaction of airports around the world with a couple of exceptions was “oh hell no! too loud!” so the economies of scale never kicked in and the prices never came down. Regulation killed mass supersonic flight.

  • TheBrett

    Considering that reusable craft have been tried with a couple of 1970s and 1980s era demonstrators, and highly compromised space shuttle designs with a throwaway launch stack, I don’t think there’s sufficient grounds for you to so blithely state that reusable spacecraft can’t work cost-effectively.

    Lockheed-Martin tried it with more recent technology during the VentureStar project in the 1990s, designed to create a re-usable replacement for the shuttle. It turned into an expensive disaster that ultimately sank because the technology wasn’t there to do it cost-effectively.

    We use older, tried-and-true technology because we know it works in space, and because the space environment is incredibly harsh on hardware. It can also be quite cost-effective;disposable rocket and capsule Soyuz (now nearly fifty years old) is still easily the most cost-effective and reliable way to send people into orbit.

    In fact, Soyuz is an argument for just using disposable rockets in space. You could also point to the Ariane rocket family, all of which have been relatively affordable and reliable disposable rockets (the latest, Ariane 5, is man-rated, assuming someone ever develops a capsule for it).

    As for the Concorde, remember that only a dozen were built and when they were, the reaction of airports around the world with a couple of exceptions was “oh hell no! too loud!” so the economies of scale never kicked in and the prices never came down. Regulation killed mass supersonic flight.

    The low order number mattered, but the travel distances limitations aren’t just a factor of arbitrary regulation. There’s really no point for supersonic hops over short and medium distances, which includes most domestic flights in the US and North America. Assuming that technology you talk about ever pans out (a big assumption), it’s still going to have to make a profit off of the same type of long-distance flights that Concorde was flying.

  • Paul451

    Lockheed-Martin tried it with more recent technology during the VentureStar project in the 1990s

    VentureStar was to be a single-stage-to-orbit spaceplane. It was, like the shuttle itself, orders of magnitude harder than what went before it. There was a shopping list of things that could be done to the shuttle that would make them better and cheaper, a shuttle Mk2 or even Mk1.5. But that was always shot down for fear it would work and take money from the NewShinyThing they wanted to build, like VentureStar or NASP or… This has been a problem infesting NASA since Apollo. (**)

    Had the shuttle slowly built up in multiple versions from Apollo (reusable capsule, then reusable first stage, then reusable space plane on that first stage…), and after the prototype full-sized space-plane continued to develop through similarly incremental versions, we might have something like VentureStar now (or more likely, something completely different that actually works.)

    (** Prior to Apollo, incremental development was standard through the agency, both in the manned program, and on the unmanned side. After Apollo, the mentality is develop a design with a hundred new systems over ten years, if it works, operate it for ten years (thirty for the shuttle), then start from scratch on a new system ignoring everything you’ve learned.)

  • Paul451

    Assuming the space-port operates away from major flight-paths (like every space-port so far), closing airspace long enough for launch/reentry won’t limit you severely. Nothing to stop you launching hourly, if demand was there. You’re only limiting traffic to/from the space-port itself, which will be integrated into flight schedules. And once you’re above the bulk of the atmosphere, there’s no interference with air-traffic below, any more than normal aircraft affect road traffic.

    But… Two hour commuter flight to the nearest space-port, an hour to suit up, 90m flight, 30m to “safe” the fuel tanks, two hour commuter flight to final city. 7 hours plus customs plus delays. More than NY-LA, about the same as NY-London. Certainly puts a limit on the number of routes where it would be worthwhile.

  • TheBrett

    I agree with you there. It’s not just a problem with NASA – aerospace development in the US seems to be wedded to the “Big Bang” model of developing new planes. It’s why the F-35 is taking so long.

  • http://www.portablepartitions.com/ Versare

    Space is the last place I’d want to go. Second-to-last being the bottom of the ocean.

  • gfish3000

    Having worked in aviation, I can tell you that simply shutting down an airport for 15 to 20 minutes on a regular basis is going to send airlines into fits of rage and the FAA will be both very busy and very unhappy with the mess. Schedules are planned to the minute and there’s a fairly complex logistical and fiscal choreography that has to take place for a plane to take off.

    You would have to keep the traffic moving and set up a slotting system like the type used in Europe to minimize the resultant delays. This means, you’d have to create alternative routes and build redundancy into a very crowded system in which all the major players are broke and can’t pay to adapt to new ways of doing things.

  • gfish3000

    In fact, Soyuz is an argument for just using disposable rockets in space.

    Soyuz is not a cheap and effective way to get into orbit. It still costs around $200 million or so per launch. A reusable system that survives about 30 or so flights could bring the costs down to $50 million per launch on the conservative end. A space plane like the Skylon concept could lower launch costs to $15 million per launch. India can launch for cheap, as little as $100 million with disposable rockets, but those rockets don’t get very far and aren’t exactly all that capable.

    Assuming that technology you talk about ever pans out (a big assumption), it’s still going to have to make a profit off of the same type of long-distance flights that Concorde was flying.

    We kind of have supersonic flight down pat and we know what it takes to build new kinds of flight surfaces. Quieter supersonic planes aren’t as big of a reach as space planes, not by any means. And considering that people shell out about $10,000 for a trip from NYC to Helsinki on a fairly regular basis, that’s very close to Concorde kind of money. You’re very severely underestimating the demand for such services.

  • TheBrett

    Soyuz is not a cheap and effective way to get into orbit. It still costs
    around $200 million or so per launch. A reusable system that survives
    about 30 or so flights could bring the costs down to $50 million per
    launch on the conservative end.

    On paper, and with a lot of assumptions. I’m skeptical after the experience with the Shuttle and VentureStar.

    As for Soyuz, it’s still the cheapest way to get people up – and $200 million is far higher than most other estimates I’ve seen on Soyuz launch cost.

    We kind of have supersonic flight down pat and we know what it takes to
    build new kinds of flight surfaces. Quieter supersonic planes aren’t as
    big of a reach as space planes, not by any means.

    I never said they were.

    And considering that people shell out about $10,000 for a trip from NYC
    to Helsinki on a fairly regular basis, that’s very close to Concorde
    kind of money. You’re very severely underestimating the demand for such
    services.

    The question is whether or not your supersonic airline can actually be profitable on such flights at such a price-point. Concorde could never pull it off, and as Paul points out elsewhere, there’s really no point to having supersonic flights for shorter flights (including most domestic flights).

  • Paul451

    and as Paul points out elsewhere, there’s really no point to having supersonic flights for shorter flights

    I think you mis-read me. I was talking about using space-planes for hypersonic ballistic flight. Quiet supersonic aircraft should do fine. NY/LA is five hours conventional, 99% at cruising speed, if you can half that time, there’ll be a large market.

    Concord failed because it was banned from overland flights and from most airports due to noise, and lacked the range for trans-Pacific routes. That basically restricted it to a single trans-Atlantic route: London and Paris to New York. It was therefore never successful enough to justify a quieter, cheaper, longer range successor, unlike conventional aircraft.

    Like the Shuttle for reusable launchers, you are condemning the entire category of supersonic flight because of one primitive example done badly.

  • Paul451

    Space-port, not airport. I assumed these ballistic space-planes would be operating out of specialist space-ports far away from major flight-paths. (That’s why I allowed two hours to fly in and out of the space-port.) So the only conventional air traffic is for the space-port itself, customers and senior staff, limited and controllable.

    If they are to operate out of conventional airports, they’d need to be a safe to handle on the ground as conventional jets, plus they’d need to fly like conventional aircraft at take-off and landing. Both of which would be fantastic advances, but seems unlikely for the first few generations.

  • Paul451

    Re: Reusable SpaceX launcher

    I’m skeptical after the experience with the Shuttle and VentureStar.

    The shuttle was a prototype 130+ tonne-to-orbit space-plane, built by people who had never built any working space-planes, nor reentered any object larger than the Apollo capsule, nor built any reusable systems at all. And all using 1970′s technology, while dealing with the sharpest budget cuts in the agency’s history.

    VentureStar, as I said elsewhere, is even worse. An giant SSTO. Having never build even a small SSTO, and having not built a new launcher since the shuttle, nor even a variant of the shuttle.

    SpaceX OTOH will be regularly flying its Falcon 9 launcher, will be working on variants like the Falcon Heavy; likewise it will fly Dragon capsules repeatedly before attempting to fly a reusable variant, just as it is flying a cargo version before attempting a crew version. They will have a strong understanding of their launcher and capsule before trying to build a reusable version.

    [No one before SpaceX has tried to build a reusable "stick" launcher, nor a reusable basic capsule. Nor a recoverable upper-stage. And those are the most basic things NASA should have done before starting on the shuttle. (Hell, NASA didn't even fly a cargo version of the shuttle-stack before building a crewed orbiter.) A reusable upper stage would have led to the core systems of the Orbiter, the reusable capsule would have led to its crew areas. The reusable first stage would have led to the boosters for the main stack. Incremental development, with each step leading to a useful product, as well as seeding the next step.]

  • gfish3000

    I’m skeptical after the experience with the Shuttle and VentureStar.

    It puzzles me why you point one or two demonstrators that were, to be blunt, designed to fail and teach aerospace engineers what not to do when building a real space plane, and declare that because they didn’t soar into orbit, the entire concept is unworkable.

    As for Soyuz, it’s still the cheapest way to get people up…

    At $50 to $65 million a seat? Yes, a few space tourists got a bargain at $20 million, but that’s not a scientific mission on a Soyuz costs. Resupply trips can cost as little as $40 million per launch, but I assumed we were talking about sending people up, not just supply missions.

    The question is whether or not your supersonic airline can actually be profitable on such flights at such a price-point.

    See Paul’s reply. He basically said exactly what I was going to say here.