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Space Plane to Offer 2 Hour Flight around the World
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."
Well, let's see. x=(a t^2) / 2. Let's say a = 3.2 ft/sec^2 (1/10 g), so we're not talking real heavy acceleration here. t = 1 hour = 3600 seconds. (We'll use the other hour to decelerate.) Then...
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.
Jetlag isn't about acceleration per se - it's about desynchronization of your circadian clock with that of your surroundings.
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.
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The discussion might have been a lot better if the article (or rather the blog entry) weren't so sorely lacking in details. Kind of makes me miss Roland Piquepaille. You can get a lot more information by Googling "suborbital airliner."
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.
For the full defencetalk.com article that this GoogleAds blog entry seems to be summarizing, go here . Lots more information. Found the link on Fark don'tcha know.