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Space Transportation Science

British Skylon Engine Passes Its Tests 172

Posted by Unknown Lamer
from the some-hope-for-humanity dept.
An anonymous reader writes "The BBC reports that the SABRE hybrid (part air-breathing jet, part rocket) that is intended to power the Skylon single-stage-to-orbit space plane has passed its final technical demonstration test, and is now looking for money (only £250m!) to prepare for manufacturing. If this goes ahead, travel into orbit from local airports (ideally, those close to the equator) will be possible. And quite cheaply. But might it have the same legal difficulties flying from U.S. airports as the Concorde did?"
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British Skylon Engine Passes Its Tests

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  • Only £250m! (Score:5, Interesting)

    by bdevoe (1811096) on Wednesday November 28, 2012 @02:24PM (#42119937)
    I sense a Kickstarter in the offing...
    • by ackthpt (218170) on Wednesday November 28, 2012 @03:02PM (#42120519) Homepage Journal

      I sense a Kickstarter in the offing...

      What's the incentive for my $25? A free ride on cuise missile?

      YEEEEE HAAAAAA!!!

    • Press release (Score:4, Informative)

      by Keith Henson (1588543) * on Thursday November 29, 2012 @07:01PM (#42135799)
      On another list someone asked me to explain the press release. Here is my try.

      Hypersonic engines are up against hard physics. The ram air heats so much in the inlet that it's hard for combustion to add much energy to make it go faster out the back.

      The idea behind the SABRE engines is to cool the ram air before it is compressed. The heat exchanger to do this is what the press release is all about. With not much more than a ton of mass, it sucks 400 MW of heat out of the incoming air, dropping the temperature from 1500 C to -150 C in a few inches of heat exchanger that looks much like fabric because the tubes are so tiny.

      The engine cycle also uses the temperature difference between the ram air and the LH2 to run the compressor. It takes close to 2/5th of the energy from burning hydrogen to liquefy it. The engines recover much of this by running a helium turbine on the temperature difference between the ram air and the liquid hydrogen flow to the engines. The turbine powers the compressor stage that raises the pressure of the -150 C air to rocket chamber pressure.

      The design is extremely clever thermodynamics which also avoids most of the metallurgical problems of high temperature. Fabricating the air to helium heat exchanger was a very hard task. They have miles of tiny tubing, tens of thousands of brazed joints and they don't leak!

      Using these engines and breathing air, the vehicle reaches 26 km and about a quarter of the velocity to orbit giving an equivalent exhaust velocity (back calculate from hydrogen consumption) of 9 km/s. That's twice as good as the space shuttle main engines. It is expected to go into orbit with 15 tons of payload out of 300 or 5% even though the rest of the acceleration is on internal oxygen that only gives 4.5 km/s exhaust velocity.

      Leaving out the oxygen and using big propulsion lasers to heat hydrogen reaction mass, such a vehicle would get 25% of takeoff mass to LEO, reducing the already low cost by a factor of 5. That's enough to change the economics of power satellites from being too expensive to consider to a cost substantially less expensive than any fossil fuel.

      But try explaining any of this in a press release.
  • by 0123456 (636235) on Wednesday November 28, 2012 @02:25PM (#42119947)

    Last I read, developing Skylon was going to cost about ten billion pounds (or maybe dollars, though it's a big number either way). So there's a big jump from having an engine to being able to fly into space from your local airport.

    • by osu-neko (2604)

      Last I read, developing Skylon was going to cost about ten billion pounds (or maybe dollars, though it's a big number either way). So there's a big jump from having an engine to being able to fly into space from your local airport.

      But how much of that has already been spent?

    • Indeed. Even if the engine/rocket motor works as advertised, they would still need to reuse some kind of space shuttle tech to get back down. Whilst I admire (some) of the space shuttle tech, the jury is long ago in - massive expensive fail.

      • Re:One problem (Score:4, Informative)

        by Mr.CRC (2330444) on Wednesday November 28, 2012 @04:02PM (#42121409)
        The propulsion system is completely different. The space shuttle was designed in the 70s and used the materials and design techniques of 40 years ago. There is no comparison.
        • Re: (Score:2, Interesting)

          by Anonymous Coward

          The propulsion system is completely different. The space shuttle was designed in the 70s and used the materials and design techniques of 40 years ago. There is no comparison.

          ^ This. Also, the original space shuttle design was completely borked by military demands to increase its size. The shuttle basically suffered major bloat and feature creep, which was largely responsible for its ineffeciency and unreliabilty.

          • Re:One problem (Score:4, Informative)

            by Anonymous Coward on Wednesday November 28, 2012 @06:54PM (#42123841)

            Actually, the precise military design requirement that borked it was that the shuttle craft had to be capable of re-entry and landing entirely over the US continental area. They didn't want to overfly Russia, China or Europe.

            That meant that it needed to have a steep descent profile, which in turn meant a hot flight, which meant expensive and sophisticated heat protection which ended up not working very well.

            The Skylon is entirely commercial, and will have a much more sensible re-entry profile. It will be able to slow gradually in the upper atmosphere and even, with it's unique engines, start up again and fly back into orbit should it wish....

          • by dwye (1127395)

            The shuttle basically suffered major bloat and feature creep, which was largely responsible for its ineffeciency and unreliabilty.

            False. The original shuttle design was to be capable of High Earth Orbit and powered landing (i.e., could go around again if needed, just like a jet, rather than doing a dead-stick controlled crash as the shuttle-as-built did), but was Proxmired into what we got. The Dyna-Soar (the military shuttle-like design that was cancelled in favor of NASA's) was much smaller.

      • Re:One problem (Score:4, Informative)

        by Anonymous Coward on Wednesday November 28, 2012 @04:34PM (#42121849)

        Because of the low ballistic coefficient, Skylon would be slowed at higher altitudes where the air is thinner. As a result, the skin of the vehicle would only reach 1100 Kelvin (K). In contrast, the smaller Space Shuttle is heated to 2000 K on its leading edge, and so employs an extremely heat-resistant but extremely fragile silica thermal protection system. The Skylon design need not use such a system, instead opting for using a far thinner yet durable reinforced ceramic skin

  • by Anonymous Coward on Wednesday November 28, 2012 @02:28PM (#42120001)

    Is the strobing red light on the front. Seriously, what the frak?

  • Several years ago I heard that India was working on a similar engine. Never heard anything more on it, I guess it didn't work. I hope the ESA has better luck.
  • by some old guy (674482) on Wednesday November 28, 2012 @02:30PM (#42120039)

    And their legal (read: environmental) difficulties.

    Launch from somewhere accessible to the market via other modes, but with sane local regulations.

    Problem solved.

    • by h4rr4r (612664)

      You will need a specially strengthened runway, so any legal trouble would be sorted out before that is built.

      A normal airport would not be useful for skylon.

    • Well you wouldn't launch from just *any* airport... you always launch eastward to gain speed from earth's rotation. And you wanna be as close to the equator as feasible, and you want lots of ocean or non-populated wasteland to the east of your launch site in case your rocket blows up. Which is why we launch from the east coast of Florida or Texas.

      It would take at least a few minutes from liftoff to Mach 1, by which time the spacecraft will be over empty ocean anyways. So TFSummary about concorde noise is no

      • Well you wouldn't launch from just *any* airport... you always launch eastward to gain speed from earth's rotation.

        That depends on what the purpose of your flight is. If you want to get into orbit you are correct but if you just want a sub-orbital hop between two points on the Earth's surface it doesn't really matter and given the current lack of large passenger destinations in orbit I would guess that this is the most likely initial application.

      • by Catbeller (118204)

        "Well you wouldn't launch from just *any* airport... you always launch eastward to gain speed from earth's rotation. "

        Actually, it takes off - and flies - like a jetliner, so orientation of the runway is not a factor. The pilot can turn the plane eastward after takeoff, and then gun the engine.

    • Re:Screw US Airports (Score:4, Informative)

      by PPH (736903) on Wednesday November 28, 2012 @03:54PM (#42121317)

      The US "legal troubles" were a stalling tactic* back when Boeing was trying to build their own SST. The original grass roots "ban the bang" campaign was British.

      *Do you really think Congress wouldn't have lifted the landing ban had the US version made it off the drafting board?

    • by jcr (53032)

      Launch from somewhere accessible to the market via other modes, but with sane local regulations.

      So, if I want to go SFO->HKG, I'd need to hop a flight to Mexico first?

      I think that would still be a win, actually.

      -jcr

  • by vlm (69642)

    If this goes ahead, travel into orbit from local airports (ideally, those close to the equator) will be possible. And quite cheaply.

    Misdirection. Ballistic aka spacex and competitors is always going to be cheaper. This only has .mil purposes. Excellent PR work, guys!

    • by h4rr4r (612664)

      Citation needed.
      Why would throwing away half the craft and having to carry many tons of oxidizer, which the skylon does not need, be cheaper?

      • Re:.mil only (Score:4, Interesting)

        by 0123456 (636235) on Wednesday November 28, 2012 @02:47PM (#42120329)

        Fuel is cheap: rocket designers dream of a future where fuel will be the primary cost of launching things into space. Developing a space plane is not, and you have to invest all that money before you even know if it will work.

        SpaceX estimates for launches on a reusable Falcon are similar to the estimates for Skylon, and they can build up to it, starting with expendable versions that are proving the technology and making money. Skylon has the tricky 'give us ten billion and it will probably work' hurdle to jump over.

        • by phayes (202222)

          All very good points. In addition this is NOT the time to be needing a 10 billion handout from either the UK or the EU. SpaceX is progressing incrementally to reusable staged rockets and does not need any more money than they are getting from their current workload. With the Skylon precooler only just exiting proof of concept tests & really being a barely tested hurdle, I don't see it going any further in today's economic environment.

          • by Catbeller (118204)

            There will never be an economic environment that will satisfy people who don't want us to go to space. There will always be a fiscal crisis caused by people who don't want to pay taxes, worlds without end, amen. The human race also, on the vast whole, doesn't believe we are living on a planet. We're talking people, the majority, who think Jesus or Mohammed or the Messiah or the great wheel of destruction and creation is coming to end the world. They don't believe in an actual *world* - they think reality is

            • by phayes (202222)

              Go ahead & rant against the Luddites & socialists who refuse anything new or refuse to spend on space "until X is fixed here on earth", but do note that your rant is only slightly related to my post.

              Skylon is a British/European endeavor. How much the US spent on Afghanistan (or the much larger amounts spent every year on entitlements) has nothing to do with how much the UK/EU is willing to spend on a project. It's rather how much funding is left after tossing billions down the Greek sinkhole or the

        • by khallow (566160)

          Fuel is cheap: rocket designers dream of a future where fuel will be the primary cost of launching things into space.

          That will only happen, if you're not throwing away a vehicle every time you launch. Else you have to add the cost of the vehicle to the launch. This is where Skylon comes in. It's a completely reusable vehicle. What it doesn't have currently is a market which justifies spending ten billion dollars or euros. You have to have a lot of launches before the development costs become a small part of overall launch costs.

          • by 0123456 (636235)

            That will only happen, if you're not throwing away a vehicle every time you launch.

            Sure. But if Skylon meets the launch cost estimates I've seen, fuel will still be only a few percent of that cost.

            As I understand it, they want to use air during launch to allow them to carry a bigger payload in an SSTO, not to save money.

            • by vlm (69642)

              But if Skylon meets the launch cost estimates I've seen, fuel will still be only a few percent of that cost.

              Doesn't matter. Lets say you blow $10B on R+D for a launch platform. Over the life of that platform, no matter how low the fuel cost, you MUST gross more than $10B revenue before you can dream of profit.

              Competitor? Traditional tech means $2B in R+D for a launch platform. Over the life of that platform, no matter how low the fuel cost, you MUST gross more than $2B revenue before you can dream of profit.

              Normally, in aerospace, you spend more money on R+D than on vehicles. So the vehicle cost doesn't real

            • "As I understand it, they want to use air during launch to allow them to carry a bigger payload in an SSTO, not to save money."

              it can still save money and resources.

              if very least, cary more into space and make less trips.

              In any case it will still do more with less. which is good from all perspectives concerned.

              Its like saying the burn rate in modern auto engines is higher because they want more horsepower to weight rather than fuel economy, while they get both.
    • by Cyberax (705495)
      Wrong!

      Rockets can't be cheap. They are not reusable (you can try to reuse certain parts, but you're going to disassemble and reassemble them in any case) and that is ALWAYS going to put a high lower limit for their price. In the best case, you'll be paying millions of dollars for person to get to a lower orbit.

      Skylon spaceplanes can, in theory, lower that to perhaps several tens of thousands dollars. Definitely to the level of hundreds of thousands.
  • travel into orbit from local airports (ideally, those close to the equator) will be possible

    Shucks, none of my local airports seem to be near the equator. And I don't fly since the TSA started assaulting and irritating travelers.

    • Just wait until commercial space flight begins and the TSA gets authority.

      No more than 3 ounces of oxygen allowed per passenger. Must be sealed in a 2 quart size Ziplock.

    • by Jeremi (14640)

      Shucks, none of my local airports seem to be near the equator. And I don't fly since the TSA started assaulting and irritating travelers.

      I guess the previous poster should have written "will be possible for those who are willing to make an effort".

    • travel into orbit from local airports (ideally, those close to the equator) will be possible

      Shucks, none of my local airports seem to be near the equator. And I don't fly since the TSA started assaulting and irritating travelers.

      So take the train to orbit?

  • by ThatsNotPudding (1045640) on Wednesday November 28, 2012 @02:42PM (#42120253)
    Good show, old chaps, but change the name. Sooner or later, a Skylon will turn on you.
  • Misleading Title (Score:5, Informative)

    by trout007 (975317) on Wednesday November 28, 2012 @02:59PM (#42120487)

    The engine doesn't exist yet. This was a test of the pre-cooler. It is a critical component and it was important.

    • It's a critical component, granted, but only one of several.

      As an automobile analogy - this is like proving air flows through a spiffy new carburetor. Way cool, and very critical... but very, very far from a complete test of the carburetor, let alone of the complete engine.

      Sabre remains a very long way away from being proven to work.

  • Why does the input air need to be chilled? Does this have something to do with using hydrogen in a turbine engine?
    • by Shoten (260439)

      Why does the input air need to be chilled? Does this have something to do with using hydrogen in a turbine engine?

      Design considerations. The front of the engine intake is where they keep all the Coors Light.

    • Re:Dumb Question (Score:5, Informative)

      by roc97007 (608802) on Wednesday November 28, 2012 @03:48PM (#42121219) Journal

      Why does the input air need to be chilled? Does this have something to do with using hydrogen in a turbine engine?

      Covered here [wikipedia.org]. It's actually an interesting read. Put succinctly, as speed increases, the temperature of the air increases, reducing efficiency.

      • Reducing efficiency, and imposing limits on materials.

        What limited the speed of an SR-71 was that the compressor inlet temperature could not exceed 427 Celsius. Try to go too fast, and the inlet compression will heat up the incoming air too much.

    • by Kaitiff (167826)

      clip from online article regarding this intercooler:
      But its success depends on the Sabre engine's ability to manage the very hot air entering its intakes at high speed.
      These gases have to be cooled prior to being compressed and burnt with the onboard hydrogen.

      Skylon would do the job of a big rocket but operate like an airliner from a conventional runway
      REL's solution is a module containing arrays of extremely fine piping that can extract the heat and plunge the inrushing air to about -140C in just 1/100th o

    • by tibit (1762298)

      Because otherwise, once you further compress the air to pressures needed for rocket propulsion, it'll be way too hot to handle by any known materials.

    • In your basic gas turbine thermodynamic cycle, the Brayton Cycle, combustion takes place on incoming gas that has been compressed. That's what your compressor stage is for in a jet engine. In a ramjet the kinetic energy of the air is converted to pressure by a converging-diverging compression shock nozzle. (We notice Sabre has a ramjet-type compression inlet). The process is so fast its adiabatic (no heat goes in or out). The more compression you can get before combustion the higher the efficiency.

      Adiabatic

  • Hmm. Looks like kinda a mash-up of Serenity and the Pan Am Space Clipper.

    (Is it too late to say "geek alert"?)

  • by WGFCrafty (1062506) on Wednesday November 28, 2012 @04:06PM (#42121457)
    Why should we care about it being able to fly at US airports if it needs to launch from the equator?

    This is a very neat concept, and it has implications in regular jet travel as well as space travel. The ability to cool air and compress it that much in a regular jet engine could increase efficiency astronomically! The fact that this concept works could mean we see more economical jets before we see this in space travel.
  • ... for use in global warming summers to get cool air. -140C sounds terrific.

  • by GodfatherofSoul (174979) on Wednesday November 28, 2012 @05:47PM (#42122951)

    Many years ago in high school I think, I wrote a report on the X-15 rocket plane. The impression I got was that, while vertical rocket technology got us further faster in the short term, a more gradual development of hypersonic planes would've been better in the long run. We might have had a whole generation of space planes lobbing satellites and even space tourists capsules cheaper, more safely, and with faster turn-around time. I'm not an engineer, so I could be completely full of crap, too.

  • Nobody posted "....oops I thought it said 'Cylon' ..." yet.
    fooey

  • The FAA won't certify airplane engines to run on unleaded fuel because of the potential hesitation and reliability problems. They're not going to certify this. Oh maybe in a hundred years.

Stupidity, like virtue, is its own reward.

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