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AFRL BladeRunner
- Thread starter Mr London 24/7
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Riverghost
I really should change my personal text
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How efficiently does a swing blade wing like this generate lift? i remember seeing the NASA swing blade test-beds, but cant remember what the ultimate outcome of those experiments was (except for proving the principle 'sound' )
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Mr London 24/7 said:
That sentence sorta contradicts itself. Putting it inside a cargo bay still limits the volume of the vehicle. It also imposes other limits as well. And air-launched vehicles have limited growth potential (you cannot make it longer than the cargo bay, for instance).
Air launch just isn't attractive. At first glance it seems like it should be. It seems like using an air-breathing vehicle to get the rocket to altitude should save some costs and provide some performance improvements, but it just never works out, which is why after nearly sixty years of shooting things into space there is only one very lightly used air launch space vehicle.
Stratolaunch is cool. It won't be successful. Air launch just doesn't work out as a good idea.
blackstar said:
Air launch has a few possible benefits, but they aren't really related to vehicle performance. You don't need a ground launch facility, which cuts down on real estate costs and makes some aspects of security easier (both in terms of just keeping curious onlookers out of the blast radius, and hiding activity from someone with less pure motives). You get freedom of launch azimuth, which is often restricted at fixed launch sites. And if you're trying to hit a specific orbit it can give you a more flexible launch window.
Such benefits only really appeal to customers who are willing to pay a little more (or sacrifice something like payload) to get them. Most customers aren't willing to do so.
gtg947h said:
Not really. There is no net gain or benefit from those aspects. The vehicle still needs a build up area, a staging area and a runway, which are no better from real estate costs or security than existing or new vertical launch bases.
sferrin said:
Ok, not the most "sound". It would need a parachute storage, deployment and restraint system (this affects the structure design, tension is not a typical launch vehicle load). It would need some sort of landing system to protect the stages (since a parachute landing still involves some velocity). The stages would need to be retrieved since they are not returning to the launch site. And even if they did, they still would need some cranes and carrier to bring them to refurb facility.
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gtg947h said:
Byeman already covered this, but I'll just jump in anyway--you may not have a pad, but you still need all the things that a pad and launch range infrastructure provide. Your rocket is carrying a satellite. Well, that satellite has to be integrated onto the rocket someplace. So you're going to need a facility that can provide those services, which may include clean rooms, special electrical connections, the ability to handle toxic fuels, etc. You're going to need to fuel that rocket, so you're going to need a place that can provide that fuel. Those things tend to be specialized and non-mobile, so they're going to be built in one place to support the air-launched rocket. As for security, it is far tighter on a military launch range than it is on non-military airports. And non-military airports bring their own restrictions as well, like noise abatement, commercial traffic, etc. Military airfields of course require some kind of special arrangement.
And of course the bigger the rocket, the bigger the infrastructure required to support it (a small rocket underneath an airplane can maybe be fueled from a truck, but a big one may require tanks and piping at a fixed location).
As for the ability to launch from different azimuths, well, maybe. But you still need to issue NOTAMs and you're probably going to want somebody patrolling downrange to make sure that there are no sailboats in the downrange debris area. An air launch cannot just head off the coast and fire from any place they choose. Generally they're going to be confined to certain areas.
Fixed launch sites have their costs and their limitations. But they also provide a lot of support that may be essential to a launch.