Given that our scientists keep finding more and more large planets (those being the easiest to find), including some that may be in the habitable zone for their stars, I have to ask the question: how much gravity is too much? Could humans adapt to live on a planet with twice Earth's gravity? Four times? Eight? What about with genetic engineering?

Just as importantly (or possibly more so), even if we could survive there, is it reasonable to colonize? What I'm basically asking here is, would we be able to take off again if we landed there? On a planet with twice the gravity of Earth, a rocket would require a ridiculous amount of fuel just to reach orbit. A space elevator (with our current estimates of strengths of materials) would be impossible.

How much is too much?

While I generally agree that technological advances will increase our abilities to operate in more varied environments, in this case I think it is important to recognize the difference between higher gravities and higher pressures. Each poses unique challenges that will require different and specialized engineering solutions. Likewise, with regard the topic of Pressure, we need to consider the challenges posed not only by higher pressures, but lower pressures as well. That said, the same goes for gravities.

Really, this topic is two questions:

1. What gravity and pressure ranges are feasible for a) entry into an environment or b) exit from an environment; and what is required for each

2. What gravity and pressure ranges are feasible for a) human life b) augmented human life; and what is required for each

The same questions need to be asked of all Support Systems. The responses to those questions help to determine mission parameters (Requirements.) All that aside, perhaps there are some doctors, physiologists, physicists, etc. that we could tap for this (now that we have the Project Manager perspective.)