2) Mass drivers/railguns/coilgun launchers. Unfortunately, the big
electromagnetic launchers that can fling a spaceship into orbit
without turning passengers to goo is really, really long, like 600-700
miles for a 3G launch.

Mike Miller, Materials Engineer

AFAIK, if a human being is suspended in a fluid (easily deformable
medium) which has the same specific gravity as the mean specific
gravity of human tissue, then g-loadings on face down prone
individuals can be very high for periods of several seconds and even
minutes before significant short term ill effects are seen. I cannot
recall the source, but believe the Air Force looked at "wet" cockpits
to permit pilots to sustain maneuvers of many tens of g's, and
determined that while the costs outweighed the benefits, no plane
could be built which would overstress the pilot during the duration of
the ACM that might be required.

Perhaps 100g's for very short times would be tolerable. Certainly
blood pooling of short durations is an acceptable risk for many when
the destination is considered.

Can anyone say how seconds a human being so supported can tolerate
being accelerated at 10, 100, and (doubtfully at all) 1000gs.

If I remember it ok, 10 seconds is little trouble indefinitely, 100 is
barely doable for tens of seconds, and 1000 is out of the question
(bones falling through soft tissue, etc.).

Thank you, Tom Perkins