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Launching Spacecraft From Aircraft
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)."
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...
Money for nothing, pix for free
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.
-- Instant Karma's gonna get you! [320848 = 2*2*2*2*11*1823]
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...
--
I'd rather have a bottle in front of me than a frontal lobotomy
Apparently you are correct. This FAQ entry says that the term is not used in the book at all.
This link 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".
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.
:p
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".
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.
Lasers Controlled Games!
Another idea along this line is the joint MIT / US Air Force project called Black Horse. 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.
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.
A russian company, Airlaunch, is developing a system 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."
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!)
i am a soviet space shuttle
That's Buran, the Soviet space shuttle. This photo is showing the Russian/Soviet equivalent of the U.S. Shuttle Carrier Aircraft. I do believe the An-225 might have been custom-developed for this purpose, an extremely expensive proposition. The United States, on the other hand, transports the shuttle orbiters on a widely-available commercial aircraft -- in fact, the early photographs of the SCA clearly reveal American Airlines markings faintly visible on the skin of the plane! (Both 747s have since been repainted white with a blue stripe.)
They are not stock, though:
Modifications to tail to counter increased wake turbulence from Orbiter
SCA without orbiter, displaying attachment fittings like those on External Tank
SCA carrying orbiter Enterprise about to land
N905NA served with American until 1974. The other, N911NA, is from Japan Air Lines and was acquired by NASA in 1988.
I've got pictures of one of the Buran test articles if you're wondering how this Soviet version of the Space Shuttle looks from up close.
i am a soviet space shuttle
Slashdot has reported on the Canadian entry into the XPrize contest. The DeVinci 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.
- 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.Scientists restrict study to entire physical universe; creationist
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/
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.ht