[stillonaroll]

Could a human survive aboard a spacecraft moving near light speed? Wouldn't the G-forces of acceleration be crushing?

[generally]

It’s the acceleration that is the problem. If you accelerate gradually, no problem.

Think about traveling 60 mph in your car. Once you’re traveling at a constant speed of 60 mph, you don’t really feel anything. But if you go from a dead stop to 60 in a very short time, you feel the crushing sensation. If you accelerate slowly, you don’t feel it.

Same for an airplane - even higher speeds.

So theoretically, if you accelerate slowly, you could travel at near light speed with no crushing.

[Mycroft Holmes]

It isn't the speed that produces the G-forces, it is the acceleration. You can specify acceleration in G. For earth it is 32ft/sec/sec or about 9m/sec/sec.

You can approach C (lightspeed) in about 2 years at 1G with this reservation. Math heavy at link.

[Future Snake Eater]

Wouldn't the G-forces of acceleration be crushing?

Not with Starfleet's finest inertial dampeners installed on your spacecraft!

[OldNavyVet]

Wouldn't the G-forces of acceleration be crushing?

The simple equation that relates force, mass and acce;eration is F = MA, and remembering that fact reminds me of a first-day physics question proposed to a classroom full of unicversity freshmen. The instructor pressed his hands hard against a wall and asked a question ...

"How much force am I exerting on this wall?"

The answer is simple ... Give it a try.