Space Plane to Offer 2 Hour Flight around the World 214
secretsather writes "Two hour flights to the other side of the world may seem like a scene from a science fiction movie; but the technology is in place, and a plane that can do just that is currently in development. While it looks like a scene from a flight simulator, the Astrox space plane is the real deal, and the Astrox Corporation says it could revolutionize the transportation industry. Traveling as fast as Mach 25 with at least 30 minutes of space shuttle-like views while in orbit is the highlight of this plane, and The Astrox Corporation, along with their partners, are claiming to have finally overcome their largest problem, mixing fuel."
Re:Jetlag was bad? Watch out for ScramJet lag (Score:5, Informative)
x = 20,736,000 feet = 3927 miles. The whole, two hour flight would be 7854 miles. Not quite halfway around the world (12000 miles).
To do halfway around the world in 2 hours, we need to get 6000 miles = 31,680,000 feet, accelerating from zero, in 1 hour = 3600 seconds. For that, we need a = 2x / t^2 = 4.89 ft / sec^2 = 0.15 g.
Whether that's too much to be comfortable or healthy, I don't know.
Jet lag isn't about acceleration.. (Score:5, Informative)
I can get you jet lagged by putting you in an isolation suite and resetting the clock you pay attention to, no acceleration involved.
That being said, the human body takes about a day to resynchronize from a shift of an hour.
I suppose you need to accelerate to get that far that fast if you do it by travel, but you can put away the equations that figure the precise acceleration of this plane to discuss jet lag.
Pulsejets vs. Ramjets (Score:3, Informative)
Re:Scramjets? (Score:3, Informative)
Re:Something flying (Score:3, Informative)
And none of them are going to. One of the limitations of scramjets (and the earlier ramjets) is that they have no static thrust: they have to be hauling considerable ass before they'll even start up. They have to serve as auxiliary propulsion for a vehicle that is launched by something else.
rj
Re:It would still take 6 hours to get there (Score:1, Informative)
Additional information (Score:4, Informative)
The blogger suggests that this vehicle is basically a very fast airliner, but this is far from the case. It's a sub-orbital craft that would fly on a parabolic course, thrusting up out of the atmosphere and then coasting the rest of the way. What makes it economically feasible is that a brief, steep climb uses less energy than horizontally plowing through the atmosphere for hours. Most proposed designs use a two-stage launching system. One calls for the airliner to climb to about 50,000 feet and do a midair refueling from a tanker. In another the airliner is carried up by a larger plane and released. In either case the airliner then goes into a steep climb for about 20 minutes and then shuts off its engines, coasting until it nears its destination. It would carry only enough fuel to maintain a holding pattern in case of airport traffic.
Passengers would be strapped into their seats for the entire flight. No food or beverage service, no restrooms. People most likely will take some sort of medication to avert motion sickness, as they would be weightless for much of the flight. There is a lot of research going into the human factors such as the several Gs acceleration and dealing with weightlessness. The bit about space-shuttle views of Earth kind of mystified me, because in all the designs I've read about there would be no windows. Maybe they were talking about view-screens.
It's a pretty interesting subject, and almost certainly will be the way we will fly long distances in 20 or 30 years.
Operate at Mach 9.6, not Accelerate To (Score:3, Informative)
However, the X-43 was a very, very far cry from a commercially viable transport. It was 12 feet long and had something like a 100 pound usable payload, dedicated entirely to instrumentation. It was a single use, throw away, test plane. The engine only ran for just over 10 seconds (the goal was not to accelerate the plane to Mach 10, but to prove it is possible to operate the engine at Mach 10...imagine a candle in a hurricane). It required a $30 million Pegasus rocket to accelerate it to stated speed. When NASA first started toying with scramjets, they created the X-30 concept, which would've been basically what the article is describing but more realistic. Then they got to look at actually making a scramjet work and haven't really talked about the X-30 since. The X-43 is far less ambitious, but is still a tough project.
Aside from the very substantial technical hurdles, what do you think the commercial market is for a 2 hour flight to anywhere in a cramped capsule moving so fast that if there were an accident, there might not even be teeth left to identify you with? Even the Concorde couldn't pay for itself, and it cut the trip time for a very busy route in half. For comparison, Virgin Galactic is planning on offering suborbital joyrides that peak out at 3000 mph and don't actually get you anywhere for $200,000 each. Supposing that $200,000 per ticket were achievable, I doubt anyone can justify saving 10 hours at that price, even really important business executives. Even if they're time were that valuable, it's not like they couldn't get work done in the air on a suitably equipped business jet.
Re:Jet lag isn't about acceleration.. (Score:2, Informative)
Complete Article is on DefenceTalk.com (Score:4, Informative)
Re:The Rotor (Score:2, Informative)
The problem wasn't that the forces due to the acceleration were too hard to handle, but the spinning DOWN made me nauseous because of what was happening in my inner ear(s). I also clearly remember that the 'world' look 'tilted' once the thing had spun up... It was kind of fun as an experience, especially when trying to fight the centri-something force. But I must admit I stay clear from them now... oh well, maybe I'll give it a try sometime later, when the kids grow up and I have to act the cool dad =)
>> The biggest problem would probably be obese people.
Actually, we had a 'well-breasted-lady' (otherwise slim, think Heidi Klum but 20cm smaller, and with black hair, and not as famous, and
Re:Additional information (Score:3, Informative)
This sort of proposal has been around for a long time. Boeing had a proposal for a giant delta back about 1970. The problem has always been the need for different engine geometries for all the stages in the journey. You can use a complicated piggy-back aircraft design, which has been done - for example the Maia and Gaia flying boats, or the Hotol 2 to be launched from a giant Antonov - but is usually the last desparate attemt to make some record-breaking distance at any cost, rather than somethng commercial. What is really wanted is some variable geometry engine.
A few bits about Concorde...
Concorde flew at about twice the height of regular aircraft. There is a constant rain of debris from space that erodes paintwork and engine parts. If you fly higher, you meet less of this dust because it is falling faster through the thinner air. Concordes that had been flying for 25 years had a lot less of this wear than a commerical jets half its age. Weird, but true.
Concorde was allowed to jump the queue in holding patterns because it used up fuel fast in low level flight and didn't like carrying too much anyhow. A large delta craft might have to be given the same priveleges. You would know exactly when they would turn up because they won't be held up by headwinds, and you can reserve a slot for them.
The Concorde's jet engines had a variable geometry. They acted as conventional turbojet engines at low speeds, and at supersonic speeds, a standing shock wave decelerated and compressed the air on entry. This is a lot sompler than a scramjet, but not good enough for atmosphere skipping aircraft. The Skylon projects SABRE engine (http://en.wikipedia.org/wiki/SABRE) is a plausible alternative.
The original Concorde design was somewhat inefficient. It was like a sports car - tiny on the inside, and all engine. This is hardly surprising, because almost everything in it was unique. There were plans for a 'B' model in the late seventies (http://www.concordesst.com/concordeb.html). Supersonic flight need not always be a rich kids toy.
The aircraft will get hot on re-entry. Concorde got up to about 130c at the tip. A re-entry system will get a lot hotter. The Space Shuttle was designed in anticipation of some super high temperature materials that never happened, which is why it always has a lot of trouble with its tiles. If you made something a bit more aircraft like, you could probably keep the maximum surface temperatures below 1800c, and most surfaces way below that. Plus, the Space Shuttle is usually coming from higher up, and has more energy to lose.
Atmosphere skipping aircraft should be possible within 20-30 years. However, for something to happen, we have to have the will to build the things, and I can't see that happening just now. A pity - the Skylon is just so 'Flash Gordon'.