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Space Science

Launching Spacecraft From Aircraft 149

Posted by timothy from the while-you're-up-there dept.
Embedded Geek writes: "New Scientist has an article on a proposed launch scheme named 'Bladerunner' (presumably, someone is a P.K. Dick fan) that would use a pneumatic launcher to shove a launch vehicle out the back of a military transport aircraft at high altitude (40,000 feet/12,000 meters). As with all the new systems (such as this one) the goal is to reduce launch costs to more reasonable levels (to about $6K/kilo from today's $11-44K). An existing Pegasus system uses dedicated B-52s with the vehicle slung underneath, but Bladerunner would be an improvement by not requiring dedicated planes (the launcher could be set up on a transport in 24 hours) and also could accomodate larger vehicles (since it wouldn't be slung underneath)."
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Launching Spacecraft From Aircraft More

Launching Spacecraft From Aircraft

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  • At least a peacefull use of those aircrafts.
    • Unless of course they are used to launch attack satellites into orbit.
    • Yeah, ever seen "Space Cowboys" ??

    • Re:B52's (Score:2, Informative)

      by L0C0loco ( 320848 )
      Orbital uses their own L-1011 to launch the Pegasus these days. The B-52 was used during their X-Plane phase before they knew it would work and could make them money.

    • Re:B52's (Score:2, Informative)

      by jonerik ( 308303 )
      Though unfortunately not available online, the June/July 2001 issue of Air & Space has a nice article on NASA's B-52B that's used for launching experimental aircraft. According to the piece the plane is a vintage plane buff's wet dream, with the vast majority of the avionics dating back to the '50s, unlike its younger USAF siblings, whose electronics have been pretty regularly upgraded since rolling off the assembly line in the '50s and early '60s.
      Apparently NASA has been in the market for a newer B-52 for some time since their plane is so old that spare parts are becoming something of a concern, but so far the USAF hasn't lent them a potential replacement that they've really liked.
    • At least a peacefull use of those aircrafts.

      Peaceful???? Bah! This will only increase the amount of noise they make!
    • it's not about b52's.

      This is about C17's and other heavy transports.

      the b52 pegasus launches are old news

      And for all Galaxy and Starlifters carry troops around you'll find that across their lives they've done far more disaster relief around the world.
  • ...but this won't work with larger spacecrafts ?
    I can see them using this for smaller satellites
    but they'll have a hard time to fit a shuttle into a military transport (ok, they might saw off the wings)
    • Are you kidding? There is a 747 specificly designed to carry the shuttle from the west coast landing back to florida for launch. Don't even mention the An-124 Condor.
      • Um, the shuttle rides on top of the 747. This article is talking about putting vehicles _inside_ the transport.
    • ...but this won't work with larger spacecrafts ?
      Larger than the current birds which can be sent up by Pegasus, for sure.

      A Pegasus is carried under one wing, where it presents an asymmetrical load. There is only so much that an aircraft can carry that way. Its drag is also asymmetrical, and there are ground-clearance and interference drag issues. This limits how fast the carrier aircraft can fly, how high it can go before launch, and even if it can get off the ground with a heavier load (if it can't rotate to takeoff attitude without scraping the rocket's tail on the ground, you can't take off).

      Putting the rocket inside the aircraft creates one problem, which is a mechanism to extend the wing; there may also be some issues with drag from the modified cargo doors. Other than that it's all positive:

      • The weight is carried in the center, where it is symmetrical.
      • Nothing extends beyond the aircraft; there are no new difficulties with ground clearance.
      • Drag isn't changed much, so the aircraft can launch the spacecraft from a greater speed and altitude. This improves the spacecraft's performance and carrying capacity to orbit.
      While the price drop probably isn't enough to create much new market for launch services, it's a good start.
  • I was watching a program about the first man in 'space'. In 1960 this American chap went to 115000 ft (~20miles?) in a balloon. He then did the longest freefall parachute jump. Amazingly for the first 4 minutes, he felt nothing (no 'air' to provide turbulence) !!

    Anyway, why can't spacecraft be taken to great heights by disposable ballons then launched from there?
    • Cause of the weight, you still need lots of fuel to get from 20miles to 60miles (edge of space?)
    • It's been done many times; it's called a "rockoon". It doesn't work so well for heavier rockets, though; high-altitude balloons can't support very much weight per unit volume. Launching the balloons can be a real challenge too.

  • Pegasus uses Lockheed L-1011, not B-52s (Score:5, Informative)

    by richie2000 ( 159732 ) <rickard.olsson@gmail.com> on Wednesday November 28, 2001 @07:38AM (#2624007) Homepage Journal
    According to the Pegasus link in the submission, the Pegasus system uses a modified Lockheed L-1011 airliner jet named Stargazer, not B-52s. Methinks someone has overdosed on CNN again...

    • Re:Pegasus uses Lockheed L-1011, not B-52s (Score:4, Informative)

      by Detritus ( 11846 ) on Wednesday November 28, 2001 @07:56AM (#2624032) Homepage
      The early launches were from a B52. Later on, they switched to the L1011 for the launch platform.
      • I believe the reason why Orbital Sciences switched to a modified L1011 for its launch platform was the fact they didn't want to rely on NASA's NB-52A to launch the rockets, given that the NASA plane is often used for other research.
      • Yep, Orbital didn't own that plane; they own the L-1011. You can both at a non-official site here [astronet.pl].
        Did anyone notice how close the rocket is to the ground on the L-1011? The body is close, but the fins are even closer! The top fin sticks into the body of the plane. I don't think I'd want to be on that plane when it lands -- the 43,457 pounds of propellent in that missle makes it too close to a bomb. Incidently, landing with the rocket is SOP - it's used to ferry the rocket to the launch and/or integration sites.

        Incidently, a friend was at one of the launches. There were two fighter jet chase planes - one NASA owned, and one military (air force?). The NASA guys used the whole runway for takeoffs and landings; the AF guy used as little as possible. Interesting difference.

        Don't miss the Pegasus User's Guide [orbital.com] -- it's an interesting read.
        • It leads to tighter clearances, literally, on landing approach I imagine. However, the Pegasus doesn't use liquid-fuel rocket motors the way most other commercial launchers do (some do use solid propellant but generally in strap-on boosters; the main ore is liquid-propelled). This is less of a danger because the solid propellant won't ignite until a jet of flame shoots down the centreline of the motor from the ignitor (this is near the nose of the SRBs of the Space Shuttle). Care is still required but it's not as dangerous as, say, JP-1.

          From the User's Guide:

          "The three solid rocket motors were designed and optimized specifically for Pegasus and include features that emphasize reliability, manufacturability, and affordability. The design was developed using previously flight-proven and qualified materials and components. Common design features, materials, and production techniques are applied to all three motors to maximize cost efficiency and reliability. These motors are fully flight-qualified.
          Pegasus is currently under investigation [spaceflightnow.com] for a failure of its last flight (video here [spaceflightnow.com]. The long smoke trail is a dead giveaway of a solid-propellant rocket motor.)
    • If I recall right, alot of the x planes, like the X15, etc were launched from planes like the B-52s etc. Proof of concept was achived long ago for just about any large aircraft as a launch platform.

      The task of getting it into orbit is likely somewhat trivial. As a cost cutting measure, I can see not having to use a booster stage.

      but then you would not have all of those fancy PR events for Nasa to toot its' horn

      • Re:x-15, etc (Score:2, Insightful)

        by phayes ( 202222 )
        What complete Tripe.

        The NB-52 is uniquely qualified for this task due to it's high wing configuration, multi-ton capable hardpoints, ability to reach high altitudes and instrumentation. No other large aircraft is so equipped. The L1011 that OSC modified for the Pegasus has encountered more problems than the launcher itself! Alot of the x planes, like the X15, etc were launched the two NB-52's that Nasa has owned. One was only used early in the X15 program and was retired long ago but the other has soldiered on and is still used in drop tests like the X33.
        As for "The task of getting it into orbit is likely somewhat trivial", coming from "Alien54", I suppose it could be for you, but it certainly is not for us humans.
        • As for "The task of getting it into orbit is likely somewhat trivial", coming from "Alien54", I suppose it could be for you, but it certainly is not for us humans

          Humans _have_ solved the problem, and have been doing it for almost 50 years. Of course, it has not been solved as far as making it truly cheap and convenient for everyone. This is more a matter of cost and local politics than it is of technology.

          perhaps you would prefer phrasing it as "easy enough given an extra billion or so in spare cash."

  • Imagine if NASA spent some of their cash on this (Score:4, Insightful)

    by joshv ( 13017 ) on Wednesday November 28, 2001 @07:44AM (#2624016)
    Instead of on massive boondoggles like the ISS. What people don't seem to get is that it all comes down to price per kilo to orbit - if we can't get that price down we are never going to have a sustainable presence in space.

    NASA has absolutely no incentive to reasearch alternative (and cheaper) launch methodologies because they are politically committed to the space shuttle (another massive boondoggle).

    I say we tell NASA they can keep the ISS, if and only if they can produce a launch vehicle which is capable of sending a thousand pound payload into orbit for 1/10th the current cost. Then we might see some progress on this front.
    • Price per kilo to orbit is NOT the only hurdle! I can see three major obstacles off the top of my head:
      No Funding: Who in this age of recession is foolhardy enough to finance such a venture after all the venture capital firms got burned in last years crash?
      Payload design: Modern satellites are custom designed to match their launchers. Diameter, mass, etc are optimized during the design stages to the specifications of the intended launcher. Who exactly is going to redesign their multi-million dollar satellites for the unique constraints used in this design?
      Market: Who will be buying? Any air lauched design is going to be limited by the launch aircraft, in Pegasus's (L1011) case by aircraft's undercarriage, and in Bladerunner's (Which aircraft? C131/C5/C17's? Good luck in convincing the USAF to lend you one, they are waaay overtasked already.) by cargo bay weight constraints. Since Iridium chapter 11'ed the market for lightweight sats in LEO has almost completely evaporated.
      • Which aircraft? C131/C5/C17's? Good luck in convincing the USAF to lend you one, they are waaay overtasked already.

        The Russians have some huge [aeronautics.ru] ex-military transport planes that they rent out for large payloads.

      • Funding: there's ways of developing it that don't cost too much money. They're slow, and they require volunteer time from engineers (which can be obtained for working on a cool project, so long as there's not too much pressure from management), but they can be done [erps.org].

        Payload design: ok, so build your launcher to the same specifications as existing ones, and treat them as de facto standards. That's what standards are for: to allow people to build to then instead of vendor-specific specifications.

        Market: this is the most significant of these three challenges, though there are solutions even here. Space tourism, for instance, though you need to really get launch costs down (to below $100/lb) before this becomes viable. And if you've designed to, say, NASA"s specs and can outperform NASA, there may well be some US gov't contracts who wouldn't mind not dealing with another beauracracy - so long as you can put up with their beauracracy, of course.
    • I saw a test firing of a rocket motor that is proposed to be used in a new program that is a replacement for the Pegasus. The motor is made by Thiokol and is very similar to the motor for the Peacekeeper missile. The rocket was to be carried on a 747. There is a series of illustrations of the concept here [spaceflightnow.com] and another article on it here [spaceviews.com].

      The test firing (it was about this time last year I think) must have been important because all sorts of VIPs from NASA and the Air Force showed up, which didn't normally happen.

      I've said it before and I'll say it again: Test firings are cool! The shockwave hitting you is really a unique experience.

    • NASA has absolutely no incentive to reasearch alternative (and cheaper) launch methodologies because they are politically committed to the space shuttle (another massive boondoggle).

      Half true. The shuttle is a huge political stone around NASA's neck, but there is still a strong desire in most of the agency to get launch costs down and reliability up.

      The simple reality of the situation is that rocketry is hard. Here's a partial list of commercial enterprises trying to get in on it:

      And of course the big boys like Boeing, Lock-Mart, and all the various non-Amurrican folks like Russia, China, Japan, and the EU.

      Any of these enterprises would be, er, on top of the world if they could develop a low cost launch vehicle. It's much easier to grumble about how expensive access to space is than it is to actually do something about it. Whether NASA is going about it in a sensible way is a separate question, but it's not like all they're just sitting on their duffs waiting for the right incentive.

    • Who do you think buys the majority of Pegasus launches? NASA.

      I worked a couple of summers at Orbital on the SeaWIFS satellite, to be lauched on a Pegasus XL (bigger launch vehicle). That satellite, along with the majority of other satellites we were working on, were being launched for NASA.
    • I think that the shuttle needs to be privatised. But who would take it?

      The way you sell it is to give a guaranteed launch contract i.e. all the dough the government would have paid out anyway for the next few years as a sweetner.

      After the contract has run out, then the company will either have made the shuttle cheap enough to continue to fly, or THEY will shut the shuttle down. Either way the government has clean hands... and their favourite boondoggle the ISS can continue on and give something to launch TO.

      It also gets the government out of the launch platform business- which is deeply unprofitable right now anyway for them; but that's Ok, the current contractors in the US can keep on launching fine; they're growing atleast.

  • What about airships? (Score:4, Insightful)

    by Jon Chatow ( 25684 ) <slashdot@jdforrester.org> on Wednesday November 28, 2001 @07:47AM (#2624021) Homepage

    IIRC, airships are much cheaper per kilo than other aircraft, so surely they would be more suitable for slinging great big pneumatic guns on if you're going for the ultimate cheap solution? Of course, airships are quite slow, but they can carry heavy loads - e.g. the CargoLifter [cargolifter.com], mentioned here [slashdot.org].

    Of course, a space-lift would be both much cooler, and much cheaper (ISTR figures of $210 per human for an up-trip, or $40 for a round trip, as on the way down your delta-GPE could be converted back into electricity; presumably this is ignoring R&D and build costs). NASA was mumbling about this about a year ago, but surely such a project would cost billions (and with the US governmental system, it probably won't happen unless a forthcoming, insightful (gasp!) President decides it's important for the future of the US, and can convert/convince a whole lot of people...

    • They lack one important ingredience :

      SPEED

      An airship will fly about 150 km/hat best, the jetplane delivers at 800 - 1000 km/h

      Also don't I know any airship design capable of climbing to FL 400 (~12000 m)

      Every tick of initial speed saves fuel in the launcher as does every meter of launching altitude

      Hans-Peter Eck
    • I guess the extra 700 kph helps (cruising speed of the cargo lifter is 90kph say it can go flat out at 130?) The article says the transport would be flying at near the speed of sound (say 835 kph for the Globemaster III).

      Not sure how much difference the additional velocity would make but it must help a bit.
    • Of course, a space-lift would be both much cooler, and much cheaper (ISTR figures of $210 per human for an up-trip, or $40 for a round trip, as on the way down your delta-GPE could be converted back into electricity; presumably this is ignoring R&D and build costs). NASA was mumbling about this about a year ago, but surely such a project would cost billions...

      If you mean a space elevator as in "Red Mars" or that Arthur C. Clarke book, it'd cost a lot more than "billions", unless you mean "1000's of billions" by that. I don't think there's any material yet developed that could accomodate the engineering demands of such a project, and is available in such massive quantities. Plus all the orbital infrastructure needed to build the sucker, and all the spacecraft needed to transport things to orbit, and/or mine asteroids for raw materials. A vast undertaking, to say the least. Needless to say, it WOULD be the most economical way to reach orbit, on a per-kilo basis. Human society would be revolutionized - I hope to see such a project given serious consideration within my lifetime, but I suspect the political will to do so is lacking.

    • An airship (blimp, zeppelin, etc.) or balloon can start the rocket above most of the atmosphere. A big cargo jet also gives it 550 knots initial velocity, which saves a significant amount of fuel. And there is better infrastructure available for handling jets. The only thing I'm not sure about is how available jets are with a tail cargo door that can be opened fully in flight.

      I'm dubious about airships having higher lift capacity than the big jets. The C5A lifts well over 100 tons. It takes an awfully big gas bag to displace 100+ tons of air. Airships do have a definite advantage when the load is some big odd-shaped thing that has to hang below instead of riding inside: a jet can't fly with a Victorian mansion (for example) hanging from the belly, but an airship is less sensitive to messy aerodynamics in the first place, and can go as slow as necessary so aerodynamic forces on the load aren't an issue. Nor are you limited by undercarriage height when picking something up with an airship -- if you want to pick up a house, you just anchor it well, come in with gasbags half deflated or lots of ballast, tie to the house, then add gas or dump ballast until you get sufficient lift and release the anchors. (Winds have to be low so the airship isn't getting bashed around during this, but in most cases you can wait for a calm day.) That makes an airship perfect for moving something that really wasn't built to fly, but rockets tend to be long, skinny, and streamlined, a decent fit for an airplane cargo bay if the fins are folded.
  • With what we've been reading about research into ScramJet vehicles, recently, it seems like this may be a good way to launch them. Taking off is a challenge, as you need significant airspeed to use the engine, but if you could start at 40K feet, you could trade some altitude for airspeed and possibly start the engine that way, instead of having to have a secondary form of propulsion to get started...

  • (OFFTOPIC) I don´t want to be picky, but... (Score:4, Interesting)

    by the cleaner ( 1641 ) on Wednesday November 28, 2001 @08:01AM (#2624039) Homepage Journal
    The term "Bladerunner" is imho not a P.K.Dick-Term. The Story is entitled "Do Androids Dream Of Electric Sheep", the title "Bladerunner" was first used in the movie by R. Scott.

    Can anyboy enlighten me where it is from?

    .
    • I don't have my copy in front of me, but it MAY be that the slang term for Deckard's job is a "Bladerunner" - hence the film title.

    • Re:(OFFTOPIC) I don´t want to be picky, but... (Score:4, Informative)

      by albino eatpod ( 242140 ) on Wednesday November 28, 2001 @08:30AM (#2624086) Homepage
      Apparently you are correct. This FAQ entry [brmovie.com] says that the term is not used in the book at all.

      This link [brmovie.com] gives details on where the term comes from.

      The title can be traced back to a book by science fiction / fantasy writer Alan E. Nourse who rote a story called "The Bladerunner". The story dealt with an impoverished society where medical supplies were so scarce they had to be supplied by smugglers known as "Blade Runners".
    • Ridley Scott paid Francis Ford Coppolla for the right to use the name "Bladerunner" for the movie. Coppolla had bought the option rights to the book of that name but had no plans to make it into a film.

      Just FYI.

    • Re:(OFFTOPIC) I don´t want to be picky, but... (Score:4, Informative)

      by BIGJIMSLATE ( 314762 ) on Wednesday November 28, 2001 @08:54AM (#2624120)
      I believe it was Producer Hampton Fancher that suggested the title to Ridley Scott. He had apparently seen some book or something at the local library, and while he said the story sucked, he really liked the title and suggested they use it instead of their original screenplay title, which I believe was called "Dangerous Days". Scott agreed, paid the guy some $7,000 for the rights, and then went on to make the movie. I'm sure that guy was laughing when the movie bombed, but is mentally damaged when the movie became the cult hit that it is today.

      But I agree with you. If they were true PK Dick fans, it would've been called the "Do Androids Dream Of Electric Sheep", or at least "The Man In The High Castle" or "Confessions of a Crap Artist". :p
    • At a guess, I'd say that the term came from the studio marketing dept. :)

      "Hmmm. Whaddaya think guys? Can we fit 'Do Androids Dream of Electric Sheep' on a marquee? Can we get it out there without people thinking it's some sort of perverted SF porn film? Nah. Someone come up with a cool name that's 15 characters or less."
    • I know that beat writer William S. Burroughs has a book called Blade Runner [amazon.com] - I stumbled across it in the library while looking for Junky - and having just seen the movie, I sat down and read it. All I remember is that it was short and had absolutely nothing to do with the movie.

      I think someone else in this thread incorrectly attributed the story of teens smuggling medical parts to another author.

  • Just flying up and dropping the test craft always seemed kinda crude to me.

  • CG (Score:2, Interesting)

    by Detritus ( 11846 )
    How does the pilot of the launching aircraft deal with the huge changes in the center-of-gravity when a large missile (Pegasus XL weighs about 50,000 lbs) is ejected from the rear of the aircraft.

    • Re:CG (Score:1)

      by flewp ( 458359 )
      Just a thought but... If the missile's center of gravity is aligned near the center of gravity of the airplane, (forward and back, not left/right or up/down) wouldn't this not be too much of a difference? Sure, the center of gravity would move upwards on the jet, but I don't think this would be much of a problem.

    • Re:CG (Score:2, Interesting)

      by ivrcti ( 535150 )
      Just before launch, the pilot puts the plane in a slight nose up position, with full military power. This normally allows gravity to do most of the ejection work. As the cargo slides out, the center of gravity moves back, pitching the nose up further. The pilot eases forward on the yoke, keeping the plane slightly nose up. The biggest challenge occurs during the ~.5 second as the cargo leaves the lip of the ramp. The center of gravity suddenly shifts back forward. This shoves the plane nose down, but at the altitudes in question, it's easy to recover. What the pilot doesn't want, is side to side shifting during the ejection. If that occurs, the plane can start to slip sideways, and a spin is likely.
      • Tossing something like 50,000 to 100,000lbs out the back door of a C-5 or C-17 is not for the faint of heart. The Angle of Attack change you mention would likely rip the wings of one of these boys.

        Such large objects heaved out the rear are tricky, and made more so at 40,000ft where you need all the lift you can get because the jets are not making too much thrust. The change in fore to rear weight distribution as this thing moved would be a tough thing to handle, especially given that the heavyest bit is at the front of the rocket (the last bit to leave) hence has the greatest moment.

        The L1011 launches its Pegasus from the underside of the aircraft so it will just respond by climbing. Opening rear doors and ejecting a larger mass will not be the same.
      • Just a few nits:
        1. Civilian planes don't have military power; a likely aircraft for this would be an older Boeing 7x7.
        2. The article said that the rocket would be ejected by compressed air. This means that gravity doesn't have to do the job, and the spacecraft and carrier plane will have what is known as "positive separation".
        3. A shift in attitude at such altitudes wouldn't be a big deal; there is plenty of airspeed and time to recover even if the wing is stalled. The two things that have to be respected are maneuvering speed (the indicated airspeed below which the wing will stall before the airframe is overloaded), and that the worst-case upset doesn't move the aircraft to an attitude from which it cannot be recovered.
        4. Ejecting a center-mounted load directly rearward isn't going to apply a yaw torque, so a spin is extremely unlikely (a spin requires an asymmetrical stall condition in the first place).
        Just some questionable wisdom from a pleasure pilot.
    • The change in CG is temporary. If the rocket is ejected by compressed air at 1 G, it will be 145 feet behind its starting point in 3 seconds. The pilot can apply down-elevator to compensate for this, but it's probably not necessary. It may not even be desirable, as you want the rocket sliding out the back of the aircraft smoothly and not hanging up due to torque forces. For that scenario you could begin by flying a small arc with the nose pitching downward just as ejection begins, reverse the pitch change during ejection, and then pitch down again after ejection. Really figuring this out needs a bunch of aircraft experts with a good computer simulation, not a single-engine-land guy with a physics habit doing hand-waving on Slashdot.
    • See LAPES: Low Altitude Parachute Extraction System. Put the cargo on a pallet with a bunch of crushable stuff under it, attach parachute, fly at ~50 feet altitude, drop back door, toss out parachute. Works pretty well: I've seen it done with light tanks which weigh ~10 tons. Higher weight should be possible with a bigger plane, and you've got a lot longer time to recover if you're launching a satellite.

      Of course, it's not without risk: the day before the demo I saw a C-130 took an excursion into the woods when they did it. Killed everyone on board. Then again, you're doing major CG shifts 50 feet off the ground...

  • Because they used all base 11 numbers for cost statistics. Which means some engineer just did an off the cuff calculation. Which means the bean counters have not thrown in their 600% markup for administrative costs. And the congressmen have not thrown their 50 state's billion dollar pet rocks aboard "for safety" and doubled the cost again.

  • Not exactly a new concept, but a newer technique (Score:4, Informative)

    by henley ( 29988 ) on Wednesday November 28, 2001 @08:24AM (#2624079) Homepage

    The US Military (who else?) tried this in the '60s with Minuteman ICBMs. Except they used a C5 Galaxy transport and a parachute. I believe the few tests worked well enough, but it was never adopted as an operational launch method: to be effective for nuclear deterrent would have required a fleet of C5s (only ~50 were built and they were built for heavy airlift), continuously airborne. Turns out to be cheaper to stick the Minutemans on the back of a train and drive it around the country (who'd a thunk?).

    Anyway, as a commercial enterprise for smallsat launches, this would appear to be a workable solution - use a ram instead of expensive parachutes, and fly the transport down to the equator before launch (same trick that SeaLaunch uses). I just hope the launch vehicle is a bit more reliable than the competitor - Pegasus. They've had a bit of a run of bad luck recently...

    • Yup, I've got pictures of one of those Minuteman tests in a 1975 Jane's Weapon Systems.
      • Missile coming out the rear cargo door, dragged by parachute.
      • Missile suspended by parachute.
      • Smoke trail twisting up into the sky.
    • There was only one test. Even though it was successful, Air launched ICBM's were never pursued as that wasn't the main objective of the program for the USAF. The REAL objective was to get the Navy to stop telling congressmen that the bomber leg of the nuclear triad (Bombers/Sub lauched Ballistic Missles/ICBMS) were obsolete as they would probably be shot down before reaching their objectives. The Navy had been trying to Hijack the USAF's bomber budget to build more Tridents but when faced with the threat of air launched ICBM's, they quietly backed off...
    • I wonder what they patented. Maybe they patented their pneumatic launcher, rather than using the military's launch method of tossing the parachute out the rear cargo door.
    • What run of bad luck are you referring to?
      according to orbitals website:
      "30 missions conducted; flawless record since late 1996"
      Either their website is not up to date or their record is phenomenol.
    • Actualy there were about 120 C5A's built. I think 2 have been destroyed in operations over the years.

  • Spaceshuttle original (Score:3, Interesting)

    by JJ ( 29711 ) on Wednesday November 28, 2001 @08:43AM (#2624103) Homepage Journal
    The space shuttle originally was supposed to operate this way, with one plane carrying the spacecraft part to high altitude and then rocketing from there. It was rejected because it required developing a big plane as well as the shuttle. This method may be an improvement over that proposal.
    • I don't think that the space shuttle was ever designed for a horizontal takeoff in any of its myriad design phases. At one point in time, most of the engines were supposed to be on what became the external tank/SRM stack and this booster also landed horizontally (I believe it was manned as well.) It was killed when it became obvious that the cost of this kind of system would never fly in Congress. The nice thing about this system, in twenty-twenty hindsight, was that there would be no SRMs, thus no O-rings, and no Challenger.

      The bad thing was that there would be many more moving parts, and the Russians have showed us that rockets with lots of engines are hard to produce. See any source on the N-1.

  • Besides the wonderful loss of mass from dumping the payload - which I believe should not be a major issue, the article fails to tell how this pneumatic expulsion of the rocket will affect the launching aircraft.

    Wouldn't this put a lot of stress on the launch craft? Let alone the requirement of moving near the speed of sound (I would think 500+) would also be an issue for the plane.... I cannot imagine what happens to the plane if something if the pneumatic process goes awry...

    IOW - I would not fly with it .. un uh... no way
    • I think the "pneumatic expulsion" is a fairly generous description of the plane/rocket seperation. The rocket comes out of the plane tail first and flies in the direction of the plane. Logically, you wouldn't want the rocket expelled at a high speed as it would just reduce its forward momentum and put too much stress on the carrying aircraft.

      The entire description of the system sounds like a lot of marketspeak. The only advantage I see over the Pegasus system is that it doesn't require a fixed launch system underneath the plane, but somehow the developers of this system seem to think that this will cut launch costs five times? (Pegasus is $33K per kilogram; this system hopes to be $6.6K)

  • do the math. (Score:2, Insightful)

    by tony_gardner ( 533494 )
    For an orbit at 200km, the required energy to raise the satellite is 2MJ/kg. The required energy to accelerate the satellite from zero to the orbital velocity is 28MJ/kg, or only 24.5 MJ/kg for an earth-rotation assist from cape canaveral.

    In any case the energy savings by lifting the payload to 20km are minimal at best. Most of the advantage comes from being weather independant, due to being above the clouds.

    It's pretty clear why there's no great energy being directed at these systems.

    • Re:do the math. (Score:5, Insightful)

      by FTL ( 112112 ) <slashdot@neil.frase[ ]ame ['r.n' in gap]> on Wednesday November 28, 2001 @10:48AM (#2624421) Homepage
      > In any case the energy savings by lifting the payload to 20km are minimal at best. Most of the advantage comes from being weather independant, due to being above the clouds.

      Nice point. However, I'd think that there are more important saveings than a 20km lift and weather independance:

      • Equator. You get to launch exactly on the equator, instead of having to burn fuel in dog-leg maneuvers to get there.
      • Horizontal speed. An old German V2 can get to space, but it can't get to orbit. A launch is a little bit of up, and a whole lot of sideways. If you dump the rocket out of the plane while traveling at Mach 0.75, that's 3% of your velocity taken care of.
      • Engines. The real reason rockets stage is to swap out engine nozels. The bells that work at sealevel are ill-suited to vacuum operation. By launching above most of the atmosphere you can just use a single stage.
      • Friction. A good portion (numbers anyone?) of the energy of a lunch is devoted to plowing through the air. Something that's not an issue when you start 20km up.
      • > A good portion (numbers anyone?) of the energy of a lunch is devoted to plowing through the air.

        I'm convinced Slashdot is dropping vowels. :-) It's a conspiracy I tell you!

      • The real reason rockets stage is to swap out engine nozels. The bells that work at sealevel are ill-suited to vacuum operation. By launching above most of the atmosphere you can just use a single stage.

        I thought that getting rid of the (now useless) mass from the heavy boosters also had something to do with it?
        • > I thought that getting rid of the (now useless) mass from the heavy boosters also had something to do with it?

          Not really. When you drop a stage, what exactly are you saving? You aren't dropping any payload. You aren't dropping any fuel. You are dropping a very heavy set of engines, but that's a complete waste since if you only had a single stage you wouldn't have a redundant set of engines to drop in the first place. The only thing you are able to drop is an empty fuel tank (aluminum cans are very light, no big savings). Splitting a rocket into stages isn't done to save weight (the extra engines weigh more than the tanks). The only reason to stage is to swap out the engine bells with ones that are more suitable to the current atmospheric pressure.

          That is what was so exciting about the (now cancelled) aerospike engine [boeing.com] was that its geometry was perfect for any altitude.

          • A SSTO rocket needs a mass ratio of at least 20:1. That's fueled weight:dry weight. Engines, fuel tanks, payload, and control system all come out of the short end of that ratio. One thing this means is that very tiny weight savings help quite a lot. It doesn't help the shuttle all that much weight-wise to ditch it's rebuildable boosters and disposable external fuel tank, but at anywhere near full payload it wouldn't make it to orbit otherwise. (Not that I think this was a great design decision, but apparently given the military's specification of a 60,000 pound payload, and the decision to not launch from a custom made carrier airplane, that was the best the engineers could do.)

            Another effect of this is that engines that are barely big enough to lift the rocket off the launch pad become ridiculously oversized as fuel is burned off. If you kept a single set of engines running at full power for the whole takeoff, and takeoff was at merely 2g, the rocket structure would have to be built to stand up to 40g when the tanks were almost empty. And it's weakest with empty tanks, so you definitely cannot push it at 40g when the only heavy parts left are engines in the tail and the payload in the nose. (Liquid rocket fuel/lox tanks are essentially aluminum balloons. So are beer cans. Fun science experiment: find one of those idiots that likes to crush empty beer cans with his forehead and switch the empty with a full one without him noticing. It's a good idea to move and change your name before he comes out of the coma. 8-) If you are throttling engines back or turning them off later in the flight, you might as well toss them out and save the extra weight. It's different for re-usable shuttles where ditched engines add cost to the next launch, but most space shots are still single-use rockets.
      • Somewhere slightly under a fifth of the delta V comes from plowing through the air. Frankly, all the minor benefits of a 20 km launch seem to not add up to nearly as much as the cost (in money, especially for maintenance, and mass) of the systems to link the two craft and release them when desired. Then again, I'm also of the opinion that fuels that need extensive cryo (like liquid oxygen or nitrogen) tend to require more, in terms of their heavy cryo systems, than they gain in terms of better specific impulse.
    • By way of analogy, the total fuel required to launch a vehicle into orbit will follow a shape rather like that of the Eiffel Tower. Anything you can cut from the base is better than the apparent savings in energy of your calculation because you are not using fuel to lift fuel.
  • Pegasus uses a dedicated L1011 not a B-52 (check the picture and text on the link)

  • Don't Forget About Black Horse... (Score:4, Informative)

    by cybrpnk ( 94636 ) on Wednesday November 28, 2001 @09:53AM (#2624246)
    Another idea along this line is the joint MIT / US Air Force project called Black Horse [mit.edu]. The key idea behind the Black Horse is that it can be aerially `refueled' from a tanker such as the USAF KC-135. This has caused some people to describe it as `stage-and-a-half' rather than a true SSTO vehicle. It will take off and land horizontally from a runway, and will be piloted by human pilots. Two demonstration vehicles were planned as stepping stones to the Black Horse, called the Black Foal and the Black Colt. The Foal would demonstrate aspects of the technology and provide proof of concept. The Colt would fly to half orbital velocity and utilize an off-the-shelf `kick-stage' to put satellites in orbit.

  • the potential to slash satellite launch costs from the $11,000 to $44,000 per kilogram it costs today to under $6600 per kilogram.

    I don't get it. How do you cut the price in half just by getting the first 40,000 feet out of 200 miles free? Do the special nozzles make up half the cost of traditional flights?

    • Re:Half the cost is first 40K feet? (Score:5, Informative)

      by Buran ( 150348 ) on Wednesday November 28, 2001 @12:27PM (#2624908)
      I don't get it. How do you cut the price in half just by getting the first 40,000 feet out of 200 miles free?

      Most of the fuel use by a modern rocket occurs just getting off the launch pad. Current launch systems work by placing the rocket in a vertical position on the launch pad before liftoff, and the rocket lifts straight up before performing what's called a "roll maneuver" (this is unmistakable on the Space Shuttle, but "regular" cylindrical rockets do it as well) to get into the correct attitude for the rest of the flight. This is an incredibly energy-inefficient method, but the rockets are designed to work this way.

      Consider also that most launches take place from sea level (the Sea Launch converted oil platform is a perfect example) where the earth's atmosphere is thickest, causing a lot of reistance that has to be overcome by the force of the rocket motors. At 40,000 feet, the atmosphere is far thinner (consider that humans have to wear breathing masks above 10,000) so there's less fuel used just burning through the lower atmosphere.

      There is also a velocity bonus that comes from launching this way. A rocket lifting off from the earth's surface is only getting a "free" boost from the speed at which the ground moves at that latitude, explaining why the equator is the best latitude for launches and why Sea Launch tries to get as close to it as possible. An air-launched rocket like Pegasus gets the "free" velocity bonus from the launching aircraft in addition to that from the earth's rotation.

      So... let the aircraft, which costs far far less to operate (we don't have rockets in every garage, but I know a few pilots) do most of the hard work and then let the rocket literally piggyback on that. (Yes, I know full well that Pegasus rides under the L-1011!)

      • Most of the fuel use by a modern rocket occurs just getting off the launch pad.

        Incorrect, if you mean "getting from the launch pad into space before acquiring orbital velocity". Less than half of the fuel is used in that stage; it's actually more like a third. Still non-zero, true.

    • Half your mass can be spent in 40,000 feet. (Score:5, Informative)

      by Spamalamadingdong ( 323207 ) on Wednesday November 28, 2001 @12:51PM (#2625048) Homepage Journal
      Buran didn't get it quite right, so I'm going to see if I can briefly but accurately sum up why this is an improvement.
      • When a rocket takes off from the ground, it is throwing away gas at many times the speed of sound while it's moving very slowly. If you calculate the amount of energy which actually accrues to the rocket versus what disappears as heat and noise with the exhaust gas, the efficiency is dismal. Launching from an aircraft allows the rocket to begin operating at a much higher efficiency; indeed, the air-launched rocket starts at a speed and altitude that the ground-launched rocket may have to burn half of its mass to reach.
      • Nozzles cost about the same, but a nozzle with a bigger bell can expand the gases more and get more thrust out of them. More thrust for the same fuel means more payload to orbit, and costs go down. You can't use a large-bell nozzle on a launch from the ground because the gases would be over-expanded, separate from the nozzle walls and cost you badly in efficiency and thrust. This means that the rocket launching from high altitude has an advantage which goes well beyond starting a bit higher.
      • The payload at the end of a rocket burn is an exponential function of the delta-V (the more speed you have to put on, the more of your vehicle has to be fuel and the less is payload); getting a 550-600 MPH or so head-start helps a lot. So does the aerodynamic lift of the wing, which is effectively "vertical thrust" that comes for a fraction of the fuel required to produce the same with rocket fuel.
      Hope that helped.
  • Wouldn't the momentum of slinging a rocketship forward at several km/s totally reverse the path of the B-52? Seriously.
    -Rob
    • The airplane is shoving the rocket out the back, meaning that if anything, it will only make the airplane go faster in the direction it's already travelling.

  • A better plane to use... (Score:1, Interesting)

    by Anonymous Coward
    might be a Ukrainian-built An-225 "Mriya". It has a larger payload capacity and might be more suited for the purpose, having been used to transport the Russian shuttle in the past.

    Here [airliners.net] is one of the photos.
  • Why use an airplane for this sort of job? Why not use a tethered helium balloon instead? Balloons have great lifting capabilities, can go much higher than a conventional airplane, and would be much cheaper to operate. Have a balloon hoist the rocket up to 100K feet and shoot it out from there.
  • "As with all the new systems (such as this one) the goal is to reduce launch costs to more reasonable levels (to about $6K/kilo from today's $11-44K). "

    If this works, the price of marijuana on the international space station should finally be dropped to manageable levels. At long last I will have clients again!

  • ..to about $6K/kilo from today's $11-44K..

    If wonder space tourists will also one day be charged per kilo

    Guess I'll have to start dieting , just in case...

  • I seem to recall that DoD experimented with a similar idea in the '60s. A Polaris-like missile was pulled from the back of a cargo aircraft (C-130 or C-141) and, once hanging suspended, fired. The idea was dropped for several reasons, one of which was that it was not possible the accurately position the missile (vagaries of wind, chutes, etc.) accurately enough for accurate targeting. Perhaps modern computers can compensate for this.

  • Russians looking at "Airlaunch" too (Score:1, Informative)

    by Anonymous Coward
    A russian company, Airlaunch, is developing a system [airlaunch.ru] to launch LEO sats by dropping them out the back of an AN-124 cargo aircraft. From the site: "The Antonov An-124-AL Ruslan heavy-lift aircraft will carry a two-stage launch vehicle (LV) internally to a specified ocean or land area and eject it at an altitude of approximately 11,000 m."
  • Actually that would be "a William S. Burroughs fan." Burroughs came up with the name "Bladerunner". If they were Philip K. Dick fans, they would have called it, "Electric Sheep". Which would also be a cool name. But harder to get funding for, I bet.

  • Canada's DeVinci Project (Score:3, Informative)

    by SubtleNuance ( 184325 ) on Wednesday November 28, 2001 @12:42PM (#2624990) Journal
    Slashdot has reported [slashdot.org] on the Canadian entry into the XPrize contest. The DeVinci [davinciproject.com] project intends to raise there rocket to high altitudes via baloon and launch from there. Perfect example of the KISS principle well applied.

    Good Luck to them.

  • ...that would use a pneumatic launcher to shove a launch vehicle out the back of a military transport aircraft at high altitude (40,000 feet/12,000 meters).

    Shoving is the answer!

    Shoving will protect you from the terrible secret of space.

    Do not trust the pusher robot.

    - insert witty sig here
  • I seem to recall this sort of system being considered for use with the Avro Arrow - at least during the CBC 'Arrow' docu-movie, mention was made of it. At 70,000 feet, though!

  • Does anyone remember the Avro Arrow?

    I seem to remember that these guys toyed with the launch vehicle concept back in the 1950's. The Arrow had a huge internal missile bay, larger than that of a B-29.

    Yes, it was scrapped, and the people there mustn't have had much talent. After all they did end up contributing to the Concorde, Mercury program, Gemini spacecraft, Lunar Orbit Rendezvous (LOR), lunar module, Apollo program, and Mission Control.

    Learn all about what almost was... courtesy of your neighbors to the north:

    http://www.exn.ca/FlightDeck/Arrow/ [www.exn.ca]

  • The MX-Missile's steam cannon launch [eprimeaerospace.com] already works economically and reliably. Scaling it up should be relatively straight-forward, as long as you avoid the fate of Gerald Bull [std.com].

  • Won't help all that much (Score:2, Informative)

    by Anonymous Coward
    The problem with such air-launch schemes is that to achieve orbit, you really need to be going freakin-fast, and that airplane is going nowhere near that fast.


    To reach orbital velocity of several times your exhaust velocity, about 80 percent of your rocket needs to be fuel (and you need high specific impulse fuel to boot). Engineers build rockets that are 20 percent structure and 80 percent fuel, but you have to launch 'em verticaly because you can't lay 'em on their sides. And you have no payload.


    So you stage two 80 percent mass-fraction rockets, the second stage being itself 20 percent of the first stage, and the payload being 20 percent of the second stage. Your payload is about 4 percent of the whole shebang, but at least you get a payload. Your payloaded mass fraction is down to 66 percent for each stage, and taking inefficiency of the vertical launch and less-than-ideal specific impulse, you reach orbit.


    Since the rocket equation is logarithmic and since each ''payload'' is in the same ratio to the stage underneath, your booster stage (fuel, structure, and motor) is about 80 percent of the whole stack. Owing to the inefficiency of the vertical launch and air resistance in the lower atmosphere (which you are climbing like a bat-out-of-you-know-where to get through with as little loss as possible), the first stage does not take you to quite half of orbital velocity, but it takes you well out of the atmosphere and at many multiples of the speed of sound. This is well beyond the performance of any jet plane.


    In fact, the early 2-stage Shuttle proposals followed this ratio of stages quite closely. The consequence was that the first stage was this behemoth -- roughly the outlines of a 747 but much heavier when loaded with fuel -- that had to fly an exoatmospheric and hypersonic flight profile much like the X-15. The real show stopper on the 2-stage Shuttle was not ol' Dick Nixon's parsimony and hatred for Kennedy-Johnson lead space programs. It was that no one built something with the performance of the X-15 (and with comparable reentry thermal requirements) that was several times heavier than the biggest aircraft ever built.


    When they built the current Shuttle, they went with solid rocket boosters with not nearly a typical first stage performance, but they had to go with a disposable tank and with really stressed rocket engines to essentially make a single-stage to orbit, with the SRB's giving the rocket thrust to lift the thing off the ground. Even so, those SRB's are a larger mass fraction than you think because they are denser than liquid fuel rockets, and they take the Shuttle well past the flight envelope of that plane we are talking about.


    When you are talking single-stage air-launch, you are really talking single-stage to orbit with a little help from the air launch, and you have to achieve 80 percent fuel mass fraction with a vehicle that has to be carried on an airplane.


    If you are interested in the space-launch problem check out http://www.ghg.net/redflame/launch.htm. If you are interested in a much more practical solution see
    http://www.fourmilab.ch/documents/rocketaday.htm l.

  • Air drop boosters (Score:2, Interesting)

    by SimCash ( 107073 )
    When I was working in AF as an analyst (mostly orbital mechanics stuff) they tested dropping a Minuteman booster (possibly just the first stage) out of the back of an airplane and bringing it vertical then igniting it.

    Can't remember if the energy saved from the gain in altitude was enough to offset the other problems.

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