I found a thread on air launched SSTO, but nothing on plain old simple air launched TSTO.
I was wondering whether it would be possible to air launch 8 tons to ISS orbit?- 8 tons, because that's a useful payload and the mass of Dragon.- Air launched, because I think there are advantages in cost and safety - I believed t/space's speel.As a baseline, I took the An-124 which can in theory carry 150 tons of cargo. This is the most of any plane with a rear loading capability, and they're only about $30 million. I'm not sure if it can air drop 150 tons, but I've assumed it can. If extra cargo mass, extra range, or maneuverability is required, then the engines could be replaced with Trent 800s. (The Soviets were meant to make good airframes and crap engines).Swift Launch and the air launched Polyot http://www.sciteclibrary.ru/eng/catalog/pages/5322.html describe a means to launch the rocket. The Polyot concept was not using the larger Antonov, so assumed a launch mass of 100 tons and a 3.5 ton payload.
Swift launch paper says that air launch saves about 1,200 fps off 29,000 - 30,000 fps needed for a surface launch. So converting into understandable measurements, and assuming two stages, with Delta V evenly split, Specific impulses of 346 seconds and 353 seconds, and a structure & rocket mass of 5%, I get the following results:
Are these figures realistic?
Any one know if air launch corporation are serious?
Is any one serious looking at this concept?
alexterrell - 23/3/2008 1:59 PMAs a baseline, I took the An-124 which can in theory carry 150 tons of cargo. This is the most of any plane with a rear loading capability, and they're only about $30 million. I'm not sure if it can air drop 150 tons, but I've assumed it can.
Jim - 23/3/2008 1:59 PMQuotealexterrell - 23/3/2008 1:59 PMAs a baseline, I took the An-124 which can in theory carry 150 tons of cargo. This is the most of any plane with a rear loading capability, and they're only about $30 million. I'm not sure if it can air drop 150 tons, but I've assumed it can. Bad assumption. The aircraft can't let go of that much weight at once
Jirka Dlouhy - 23/3/2008 2:29 PMDo you rate with Antonov An-226 Mrija ?
meiza - 23/3/2008 2:50 PMYou could ask people with more experience from aircraft what it would take to redesign the An-124 for various airlaunch drop masses.
Eerie - 23/3/2008 3:39 PMTrying to fit existing airplane to drop rockets is wrong. It must be a special airplane. Supersonic, making 5 mach. Then we are talking...
alexterrell - 23/3/2008 9:28 PMQuoteJirka Dlouhy - 23/3/2008 2:29 PMDo you rate with Antonov An-226 Mrija ?Unfortunately there's only one of them. I always thought this was a weakness of the Interim Hotol project.
meiza - 24/3/2008 10:58 AMWhy Mach 5, why not Mach 10?Mach 5 aircraft etc are pipe dreams, rockets do better by then. Subsonic air launch has substantial altitude (higher ISP, less drag) and positioning (catch right orbit, avoid range issues) advantages. And can use existing or only slightly modified aircraft.
HMXHMX - 23/3/2008 11:16 PMA few insights from AirLaunch LLC:Yes, we are serious...The An225 can't deploy anything (unless it is done "Enterprise" style). It has no aft cargo door. The An124 can probably deploy 100-150 tons but would need modifications, since the ramp couldn't take the loads. We deployed 72K lbs. from the C-17 without any zero-g maneuver or any impact on the aircraft whatever; pilots reported the drop as very smooth, a non-event...For t/Space we did look at a 747-200 modification and a belly drop. We could deploy at least 100 tons that way, and flying the simulator (full motion) was uneventful. Pretty much any pilot could handle it.If you want to go above a launch mass of 100 tons, then you need a new custom aircraft. That was the original t/Space plan, until the NASA CE&R contracts were swept aside by the incoming new administrator in favor of a pre-ordained solution. I leave the design of such an aircraft as an exercise for the reader...
"t/Space's partners demonstrated the technology that would ensure that it could deliver a launch system that would deliver a crew of four to orbit at a cost of $20 million per launch within three years of go-ahead. This was less than 10% the cost and half the time that NASA planned to spend on its own CEV approach. Naturally this was of no interest to NASA and further contracts were not forthcoming."
meiza - 23/3/2008 7:58 PMWhy Mach 5, why not Mach 10?Mach 5 aircraft etc are pipe dreams, rockets do better by then. Subsonic air launch has substantial altitude (higher ISP, less drag) and positioning (catch right orbit, avoid range issues) advantages. And can use existing or only slightly modified aircraft.
I was thinking it might be best to make the rocket weigh zero with a parabolic manoeuvre. I doubt the An-124 can do that with a full load at 10,000m, but put 4 Trent 800s and it probably could.
Eerie - 24/3/2008 11:08 AMQuotemeiza - 23/3/2008 7:58 PMWhy Mach 5, why not Mach 10?Mach 5 aircraft etc are pipe dreams, rockets do better by then. Subsonic air launch has substantial altitude (higher ISP, less drag) and positioning (catch right orbit, avoid range issues) advantages. And can use existing or only slightly modified aircraft.Come on, everything is a pipe dream until it gets built.