DaveC426913 said:It is my expectation that, in a military setting, the troops would be pushed a lot harder than 3Gs for the sake of tactical advantage.
Fighter pilots are actually a lousy analogy here. They're nothing like the passengers in this scenario, and I listed them as an example of the lower end of the limit of g's. As I mentioned, troops are essentially cargo until they make landfall, so they can be prone (or better yet, supine), which dramatically increases their tolerance to G forces (no danger of black outs, since the heart and head are at the same level.) But above and beyond that a lot of resources would be put into the landers to facilitate the best - yet still within safety tolerance - mission plan. In fact, thy don't have to even be able to move for those few minutes of planetfall. You could essentially encase the troops in tanks of incompressible water.
I think 3g's is dramatically underestimating the likely levels they would be put through. Frankly, I'd say even 10gs is not out of the question, considering how much freedom and resources and motivation designers have to max out tolerable g's.
The problem isn't in the magnitude of forces, it's in the disparity between different parts of the body.GTOM said:Even if they are in water, won't they experience the same pushing force, after they reach the wall of the tank? For significant delta-V, it isn't enough to withstand high G-force only for seconds.
mfb said:Getting the spacecraft to the tip of the rotating tethers would need some time - of the order of minutes. More than 3 g could be tolerable in the right position and/or immersed in water, but the crew certainly has to be able to breath for a while during the process.
Extreme high altitude sky dive, we can do it from 128,000 feet now.johnandersoni said:I'm working of a short story of the sci-fi nature, and I'm indecisive about one of the finer details. The plot of the short revolves around combined arms warfare in the future. The particular operation in the narrative involves an insertion of men and materials from orbit. (Kind of like paratroopers, only from much higher.) Capsules would carry men, equipment, vehicles, UAV/UGV's, etc. from orbit into the area of operations on the ground.
So, the problem I'm running into is heat, heat shields, and stealth. I find it pretty implausible that any kind of heat shield material or shape could be made in such a way that it would be radar absorbent, refractive and stealthy. Also, if the targets on the ground see a batch of bright falling stars, I think they'd surmise what is happening, and begin calculating possible landing zones based on the trajectory of the falling objects. So far, I'm thinking that an insertion from orbit cannot be completely stealthy. So I'm looking for the best insertion path, a wide shallow entry where your fall rate is less than your linear flight rate, or a steep entry where you punch right through the atmosphere until you slow down? Perhaps somewhere in-between? I think the shallow entry would reduce the amount of heat required to be dealt with, but the steep entry would get the window of vulnerability over with much quicker. The answer may be a bit subjective, but the ultimate goal would be to enter dark, atmospheric/slow flight as quickly as possible, so that the radar reflective heat shields could be jettisoned, the re-entry capsules aren't bright flaming orbs in the sky, and the stealth design of the re-entry vehicles can hide the trajectory of the craft from radar.