Development Info J.E. Sawyer & Sean K. Reynolds on Van Buren vehicles

[mr. lamat]

you could always just shoot the modules into space and have the robots put them together.

if the magrails were going to shoot the spacestation out of orbit, why isn't there a tonne of dead bodies at the station when the bullet train leaves tokyo for kyoto? i'm honestly curious as i don't know anything about how anti-gravity works, other than the principle of gravity itself, or how magrails would work.

 

[Psilon]

Newton's Laws of Motion. Specifically, his second and third laws. Launching something, whether via magrail or solid-fuel booster, imparts the same force to both the launch site and the projectile. That's the Third Law. Second Law tells us that the consequent accelerations are proportional to the masses involved. The Earth is very, very massive (approx. 6*10^24 kg), so it doesn't really move appreciably if it launches a 10^5-kilogram payload at reasonable speed. A space station isn't anywhere near Earth in mass (Skylab was 5*10^5 kg, for instance), so if it shoots the same payload at the same speeds, it's going to fly backwards with one-fifth the acceleration of the payload. Kiss your orbit goodbye, or else prepare to expend the same amount of energy trying to compensate for the maneuver.

As for why the Bullet Train doesn't leave corpses in its wake, that's pretty simple. First, you're not really moving THAT fast (270 km/h on the Nozomi, according to Google), and second, the track and train are anchored to a really large mass. Factor in constraints imposed by the passengers (no thorax-crushing accelerations) and bystanders (noise limitations, etc.) and there isn't really that much happening.

Antigravity is completely the province of space operas at this point, but it would presumably obey the same inverse-square laws as gravity itself. An inertial damping field would also provide a workaround, but that's Star Trek-level technology as well.

 

[Walks with the Snails]

Which would have worked once the station was in place, but not before it was working. While the space station were in construction, those magrails wouldn't have existed at some point, would they?

On the ground, I presume. I guess Lamat's talking about shooting ships into space with a magrail runway from the ground. Not sure that's possible without so much G-force your passengers are a pink mush when it's all over. Part of the reason we still go with rockets with continual thrust is just that reason.

Also, shooting a huge rocket off a stable orbitting space station has all kind of problems with it as well, because a space ship has a great deal of mass and the "kick" from shooting it off mag rails would result in an impulse force on the station itself. In laymen's terms, it would have pushed the station out of it's orbit.

Why would you shoot the damn thing from the station? For re-entry, you're trying to reduce all that potential and kinetic energy you built up slow enough not to burn up. Giving the ship even more energy just makes the situation worse.

if the magrails were going to shoot the spacestation out of orbit, why isn't there a tonne of dead bodies at the station when the bullet train leaves tokyo for kyoto? i'm honestly curious as i don't know anything about how anti-gravity works, other than the principle of gravity itself, or how magrails would work.

Anti-gravity is just a sci-fi thing, it doesn't exist at this point. Real world magrails just work on magnetic repulsion. If the magnetic field between the rails and the car is greater than the gravity field betwen the train and the earth, poof, it floats, a little. Magnetic fields dissipate exponentially with distance, though, so eventually you just float a little above the track when the magnetic force pushing the train up and the gravity force pulling the train down are equal. Same idea as floating a magnet in the air by putting one on top of another one with opposite polarity. It don't fly off into the stratosphere, just hovers a few millimeters.

 

[Saint_Proverbius]

you could always just shoot the modules into space and have the robots put them together.

Shooting them in to a stable orbit? That would be rather tricky. It gets even trickier when you have to shoot multiple things in to orbit close enough and moving at the same speed as one another in the exact same path so that something can move them together and splice them. We're talking about pieces of a space station here, which is quite a bit of mass in a high enough speed to stay in a stable orbit - beng launched from Earth. If you're off by a tenth of a degree along the horizon, you're talking about missing the target point by dozens of miles.

Walks,

Actually, there have been some interesting experiments done with using magnetism to suspend gravity.