[sehugg]

I think the real problem is stability, i.e. how do you keep aerodynamic forces from spinning the (unguided) capsule too fast during reentry? If you look at video of Baumgarter's free-fall he is spinning very fast -- a couple RPM I'd estimate -- when he begins his deceleration after the near-vacuum free fall.

Orbital reentry would last for minutes and at much higher velocities. The centrifugal forces generated by unchecked rotation could cause blackout or even death. You'd also need to figure out what happens if your heat shield is not heated evenly due to rotation.

Guided reentry is a solution, but then we're talking RCS thrusters, fuel tanks, guidance equipment -- maybe something you can strap onto a spacesuit, but approaching a spaceship. And then you need one for each astronaut, increasing weight and complexity.