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Q: Cheap Space travel from an EMF monorail Multiple Rail Launch ( No Answer,   4 Comments )
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 Subject: Cheap Space travel from an EMF monorail Multiple Rail Launch Category: Science > Physics Asked by: allworldskates-ga List Price: \$10.00 Posted: 28 Nov 2005 09:26 PST Expires: 28 Dec 2005 09:26 PST Question ID: 598554
 ```I would like a precise calculation of the economics of the rail launch. Precisely how much payload and fuel will be saved if we launch the shuttles from a monorail launch system that launches off the Rocky Mountains? Assume the rail will launch the shuttle from about 700 MPH or more. What are the cost savings and will we be able to launch multiple ships within seconds of eachother? What is the payload increase and what is the fuel savings? The technology is the Colorado Monorail Initiative. Does this concept bring our space program into the Star Trek Level? Does it blow NASA away?```
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 ```What you've asked really is too inspecific. You need at least to spell out the payloads you want to boost. Within some spectrum of payload masses, there *may* arguably be some benefit from such a device. If the mass is trivially small, it's conceivable that it'll be overkill, since every payload destined for a stable elliptical orbit must carry with it its own rocket stage, to adjust the orbit away from its initial Earth-intersecting path. Too much payload mass, and it becomes possibly not usable at all for this purpose. The reason being that a magnetic impellor will only be able to deliver momentum up to some limit. It'll be accelerating the payload against irreducible resistive forces and will reach a terminal velocity. And this is not even mentioning the finite length of the rail. Also, speaking of finite rail length, if you want to launch people, then there's a definite ceiling on the allowable acceleration. If you launch a steady customer base of average specimens, then 3g is about as high as it can go. But the rail can only be up to some length; we can't have it monopolising the countryside for hundreds of miles. The velocity attainable at 3g over a politically viable length won't be spectacularly high. It's not really a good idea to be launching from the Rocky Mountains, since failed payloads will be crashing onto towns downrange. It needs to launch from near the east coast over the ocean. This certainly limits how tall the exit terminal of the rail can be made. By the time the payload leaves the rail it needs to be traveling at some angle between 0 & 90 degrees from the horizontal. If the angle is too shallow, then the payload will be slicing through a lot of air on its way to high altitude. In fact, when satellites are launched from the ground there's a godo reason why they always start out pointing straight up. It's to get as much atmosphere below it as quickly as possible. As the air gets thin then it pitches over gradually as it approaches closer to the target orbital altitude. But anyway- the rail won't get awefully far above sea level because it has to hug the east coast. This puts a lot of constraint on how much velocity it can impart to the payload. And finally, it's unlikely that orbital spacecraft will be launched one after the other rapidly, like airplanes do from a busy airport. Orbital mechanics is very exacting. Presumably the payload spacecraft will have some destination. There will only be certain "windows" during which it is optimal (or often even possible) to launch and rendesvous with an orbiting target given the very limited propellant budgets of spacecraft. It's not as if a spaceport can be operated like an airport, with ships just coming & going pretty much all the time. It all has to be scheduled rather tightly and efficiently. And even if a launch window is long enough to conceivably launch several craft in quick succession, it's not probably a safe thing to do, having all those spacecraft on converging paths in close proximity.```
 ```Escape velocity from the sruface of the earth is 25000 mi/h. Significantly higher than your proposed 700MPH. I am assuming that acceleration stops as soon as the end of the rail/top of the mountian is reached. If you are considering accelerating the payload with rockets after it leaves the rail then i'm not sure how those equasions work out.```
 ```Certainly I imagine a rocket powered launch after the initial launch catapult. The specific payloads I am considering are 1. Water, 2. Food, 3. a lightweight foundry for smelting raw materials and a fabrication facility. This should start us off with a space or moon platform from which to launch into deep space!!??!?!?```
 ```As far as the "Star Trek level" goes, the answer is a big NO. In Star Trek, they traveled the galaxies searching for new life and new civilization as they boldly went where no man had gone before. The star ship Enterprise took its crew from 1 colonized planet to another in a matter of hours. Your scenario still gives absolutely no way to get a spaceship beyond (or even anywhere near) the speed of light. The nearest star to us is over 4 light years away... so even if we happen to reach half the speed of light (doubtful in my lifetime), it'll take 8 years to reach even 1 other star. And we're quit certain that there is no life there. Do keep in mind that Star Trek was set in the ... 23rd century I think it was. We've got quite a ways to go before that kind of space travel. But we are developing technology in other areas that rival theirs: laser weapons communication devices interactive computers I'm sure there are trekies around here who could list many more.```