Paul Allen proposes new space launcher Microsoft co-founder Paul Allen is indulging his enthusiasm for space travel with a new project: a giant aircraft designed for mid-flight rocket launchers. And he doesn’t think small: under a new company, Stratolaunch Systems, Allen plans to put together the “biggest airliner ever built” using six 747 engines to haul SpaceX …
An air-launched vehicle? I'm not an engineer but I really don't see that this is such a good thing.
It lifts your rocket & capsule/cargo up above the densest part of the atmosphere, true but... the difference between the amount of energy the orbital vehicle (OV) needs to go from stationary to orbital velocity really wouldn't, IMHO, be that much different from the amount of energy to go from, say, 450kph to orbital velocity.
The (probably highly complex) aerodynamics of a mothership/air-launched orbital vehicle would, probably, limit the size of the capsule/cargo you could get up into orbit. 10 tonnes payload, MAXIMUM in my opinion.
Not to mention that you'd be paying for an enormous aircraft that would be specialised for one thing, would be manufactured in very small quantities (say... 3? At most?) and so would likely be very expensive to design, develop, test, maintain, insure and run.
And once you've finished paying ALL THAT, you've got to start handing out cash for the OV's design, development, testing, maintainance, running costs, insurance etc...
It might work and even be profitable IF you're prepared to write off the entire development & initial manufacturing costs...
Other articles I read declare the OV will be a SpaceX Falcon 9 with some aerodynamic surfaces to get it pointed up. The aircraft development will only be the airframe as the engines/ avionics/ everything else will be taken from existing commercial airliners.
As for getting a leg up to space, my quick calculations suggest the carrier plane could provide 0.000003% of the energy the OV will need to get to LEO. The reasoning for this approach must lie elsewhere.
To Kharkov.... Paul Allen is passionate about aviation and I'm sure he is fully prepared to lose the "pocket change" this venture will cost to pursue. If you haven't followed some of his other ventures of passion...here's my favorite:
http://flyingheritage.com/
I'm fortunate to live near this collection!
The good thing about this setup, is that the rocket/spaceship doesnt have to carry all that heavy oxygen, you're already partways out of the gravity well, and into the thinner air, so the spaceship can carry a lot less fuel, meaning it will be lighter, meaning it can carry even less fuel.
In stead of having a 3 stage rocket, you can have the big mothership do the heavy lifting, and get rid of 1 or 2 stages.
They used to use B52 bombers for this kind of trick.
Take a B52, hook an X15 onto it.
Start B52,
reach altitude
launch
(nice pics on the wiki page: http://en.wikipedia.org/wiki/North_American_X-15 )
Part of the SDI program, (not sure if it ever was life tested or paperplans only) used F15's with a satelitekiller missile under it's wings.
The F15 would speed to it's highest flight altitude, and from there launch the spy-sat killer rocket, which would blast off and kill the satelite.
Wiki : http://en.wikipedia.org/wiki/McDonnell_Douglas_F-15_Eagle#Satellite_killer
The big benefit is that you're not restricted to one or two launch sites. You might still have only one or two launch bases, but a carrier based in Florida could fly down to the equator to launch the rocket and gain the same sort of lift advantage over a Kennedy launch that an Ariane out of Kourou does, or one in Florida can fly out into the Pacific for an eastwards launch instead of being restricted to polar orbits from Vandenberg.
The carrier is being sized to launch the SpaceX Falcon 9 which can already put over 10 tonnes into LEO. This would make it possible to put the same or more into the ISS orbit, or put larger satellites into GEO. I suspect the attachment points designed in for the Falcon 9 Heavy are also ideal for attaching to the carrier.
The aerodynamics are well understood, Pegasus has been launched this way for years and Rutan has done a lot of work on the White Knight carriers for Spaceship 1 and 2. If you look at other reports, some of which include pictures, this is another in the White Knight series.
Hmmm, still no Rocket Science icon...
Just found some more info on this over at
http://www.nasaspaceflight.com/2011/12/stratolaunch-rutan-designed-air-launched-system-falcon-rockets/
It's a Burt Rutan thing. They're talking about approx. 5 tonnes of payload. The article I gave mentions the Falcon 4 or 5 (so named for the number of engines on the rocket, presumably a version of Falcon 9) being slung under a MUCH larger SpaceShiptwo derivitive.
A new, really big specialist airplane carrying rockets, now I REALLY don't see this as saving money or making getting to orbit cheaper.
Yes, you can fly from the assembly point to whatever latitute you want and so easily get the orbital inclination you want but apart from the mothership (expensive to get, as I said in my earlier post) you're still using up a non-reusable multi-stage rocket and all so you can get about 5 tonnes into LEO.
I retract my earlier statement. No way this turkey's going to make a profit. In fact, no way this is even going to get built.
Mid-1963 to 1965, where no American flew into space either.
Although in both that and the Apollo-Shuttle pause, the follow-on program was much more advanced when the previous one stopped.
Bah! Both with Apollo and Orion NASA rejected the better designs: GE Apollo (http://www.astronautix.com/craft/apollod2.htm) and Lockheed Martin CEV (http://www.astronautix.com/craft/cevkheed.htm). Whatever happens it's their own fault.
Air launching grants you an extra deltaV of roughly 300 m/s over ground launch, but you also get a small 100m/s reduction in aerodynamic drag, 100m/s reduction in gravity loss, and an ability to use increased expansion ratio on your engines allowing a much higher specific impulse. Overall you get about 800 m/s for free. The exponential nature of the rocket equation means that this is a substantial increase in payload. The rocket itself is going to use existing engines and tooling, an existing second stage, and the Dragon capsule is being developed on NASA's coin.
The real story is that the small deltaV boost from airlaunch may allow a methane fueled stage to be operated as a reusable SSTO. Perhaps if SpaceX had the sense to be designing a vertical landing system and a staged combustion engine...
Great that they can make it out of bits already lying around, a bigged-up scrapheap challenge?
How big it would need to be to assist a Saturn V equivalent?
Why not go the whole hog, or perhaps that'll be next if successful?
(I think you mean 100m/s gained by starting from a higher potential. Difference in g over 10km is not too much!)
How massive would the Earth have to be to make it impossible to leave by chemical rockets? (ie. a ballistic black hole)
I can't do the maths, but I imagine that Earth is fairly close to that limit and that we are lucky we can leave it at all. Perhaps 1.5g?
Yes, the Shuttle was expensive and not altogether reliable. Yes, it was little more than a gliding iron and without computers it would never have landed unscathed. Nonetheless, watching a Shuttle launch was, as far as I am concerned, one of the most beautiful sights I have ever seen.
Ungainly and expensive as it was, the Shuttle served faithfully for years and allowed Humanity to stay in space for extended periods. It pained me when NASA mothballed it.
Yet, one is forced to recognize that, now that NASA no longer has the monopoly of space flight, interesting projects are seeing the light of day under private management. Allen may be a blowhard in some people's opinions, but rich people are used to such accusations, I suppose.
Meanwhile, he is going to spend a lot of money to try yet another way of keeping humans in space, and for that, I can only say good luck !
..."Paul Allen proposes new space launcher - Stratolaunch building BLOODY BIG 747-powered lifter"...
I had visions of skyscrapper buildings being fitted with (Bloody Big) jets and/or rocket motors; an incarnation of the spaceships described in Iain M Banks' "The Culture" series of scifi books, perhaps. Of course, there would also be a need for field generators to be invented/realised, in order to keep containment...
The actual article was much more mundane than that as well as being scant on detail.
Oh well...
SHADO Moon Shuttle
http://www.cloudster.com/Sets&Vehicles/UFO_MoonShuttle/UFO_Conflict_129.jpg
http://www.cloudster.com/Sets&Vehicles/UFO_MoonShuttle/UFO_Conflict_131.jpg
Gives truth to that saying "There's nothing new under the sun". Or even the far side of it if you were to journey there.
For those of you getting that last reference, mine's the one with the coloured sleeve.
Taking a wild leap, I'd assume this aircraft is designed to take off with rocket and land ONLY without it's payload. That means that each flight/launch has got to be successful. No last minute holds or delays. Once the aircraft's wheels leave the ground, that rocket's either going into orbit or into the ocean.
Now that sort of dependency is probably OK for a mature launch vehicle: one that's had, what? several dozen successful lunches - but to assume that from day#1 the number of "ooops-es" will be low enough to not have customers running back to conventional players is quite a lot to ask for.
Short production runs of highly specialized aircraft is what Scaled Composites *does*. That's BAU for them.
It's not clear if they just using the engines or keeping the fuselages as well.
As others have pointed out you gain some velocity (up to c300ms) and avoid some losses *but* not enough to eliminate a whole *stage* (AFAIK they are still talking TSTO).
It's not clear if you can use the nozzle developed for the Merlin vacuum variant or need another nozzle entirely. Which up's the development bill.
While Falcon 5 was *planned* it's unclear how far it's development has actually gone, while "Falcon 4" would seem to be a *completely* new vehicle.
That said given Spacex's highly modular approach to development *should* make the shift fairly easy.
*However* that leaves the problem that it's *very* doubtful any Falcon was designed to be carried *horizontally* while fully loaded with a payload attached. Might have enough margin that it's no big deal. Might not.
Not totally new maybe, but it gives you the flexibility to launch in any azimuth at essentially any point of the globe. So you don't have to first adjust your orbit inclination like you do when launching from the Cape into, say geostationary orbit, or into the Space Station one. What's more, you get to the altitude where you can optimise your rocket nozzle to work best in (almost) vacuum, gaining some efficiency (specific impulse). Yes you also launch above the weather, another point in favour. So yes, if they get around the (more or less) obvious engineering challenges, it'll be worthwhile.
If only all these successful researchers and engineers and investors and entrepreneurs and mutibillionaires would read the register and see how they've utterly failed to think about their new ideas for even 5 seconds and missed all those glaring, catastrophic problems. If only they'd come here and see the error of their ways and not piss all that money away.
Or, y'know, maybe the fact that the venture is with a notably successful rocketry company they may have done the absolute bare minimum due diligence with regards to cost savings and efficiencies. Between the winner of the X-prize and one of the richest people on the entire planet, I think they can just about manage to understand, between them, basic finance and engineering.
What on earth is wrong with all of you?
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
