5 ms·

Hmm. Precious cargo would require gradual acceleration.

gnode 7y ago
Fragile cargo at least. For some otherwise fragile things, you could submerge them in an incompressible fluid of similar density to reduce the difference in force throughout them. Your brain's tissue is very soft, yet by being buoyant in its cerebrospinal fluid it becomes capable of withstanding much higher acceleration.
- cjensen 7y ago
  You're correct but... the effect cushioning the brain is insufficient to withstand the rapid deceleration of a car accident. It would be hard to imagine a mass driver with low enough force that a human could live through it.
savethefuture 7y ago
What defines precious cargo? Satellites and astronauts seem to do alright going into space attached to a giant rocket, but I will admit I'm not well versed on the forces created from a electromagnetic launcher.
- savethefuture 7y ago
  Asks a real question about whats precious cargo, downvoted.
  - RocketSyntax 7y ago
    fragile =)
- icegreentea2 7y ago
  I suspect it means humans. So here's one way to think about the accelerations. To a first approximation, you need the same total change in velocity to go from standing on the surface of an object to be in orbit at a given altitude. You can choose to spread that change in velocity over any given time and distance interval (those two terms are linked). So if your mass driver accelerates your payload to final velocity in 1/10th the time (and more or less distance), you will get 10x the acceleration. So the forces you would be subject to will be more or less directly related to how large of a mass driver (in terms of track length) it is relative to the mass of the object you are leaving.
- scrooched_moose 7y ago
  Rockets are actually relatively gentle in comparison, generally <3G for humans. This is because you can apply constant thrust the entire way to orbit (>~400 km on Earth) With a Mass Driver, you can only apply acceleration for however long your driver is, so you have to get up to speed in a much shorter distance. If you build a 4km driver (length of Heathrow Runway), you have to get up to speed in 1/100th the distance causing drastically higher accelerations. (note, some poor assumptions here because horizontal distance =/= vertical distance, but the general idea is correct).

Fragile cargo at least. For some otherwise fragile things, you could submerge them in an incompressible fluid of similar density to reduce the difference in force throughout them. Your brain's tissue is very soft, yet by being buoyant in its cerebrospinal fluid it becomes capable of withstanding much higher acceleration.

cjensen 7y ago
You're correct but... the effect cushioning the brain is insufficient to withstand the rapid deceleration of a car accident. It would be hard to imagine a mass driver with low enough force that a human could live through it.

savethefuture 7y ago

What defines precious cargo? Satellites and astronauts seem to do alright going into space attached to a giant rocket, but I will admit I'm not well versed on the forces created from a electromagnetic launcher.

savethefuture 7y ago
Asks a real question about whats precious cargo, downvoted.
- RocketSyntax 7y ago
  fragile =)
icegreentea2 7y ago
I suspect it means humans. So here's one way to think about the accelerations. To a first approximation, you need the same total change in velocity to go from standing on the surface of an object to be in orbit at a given altitude. You can choose to spread that change in velocity over any given time and distance interval (those two terms are linked). So if your mass driver accelerates your payload to final velocity in 1/10th the time (and more or less distance), you will get 10x the acceleration. So the forces you would be subject to will be more or less directly related to how large of a mass driver (in terms of track length) it is relative to the mass of the object you are leaving.
scrooched_moose 7y ago
Rockets are actually relatively gentle in comparison, generally <3G for humans. This is because you can apply constant thrust the entire way to orbit (>~400 km on Earth) With a Mass Driver, you can only apply acceleration for however long your driver is, so you have to get up to speed in a much shorter distance. If you build a 4km driver (length of Heathrow Runway), you have to get up to speed in 1/100th the distance causing drastically higher accelerations. (note, some poor assumptions here because horizontal distance =/= vertical distance, but the general idea is correct).