The human body has a limit of being able to withstand, roughly, 2g for very long periods without causing too many health problems.

An engine technology, that could produce constant thrust producing acceleration of up to this limit for a crew, would be able to accelerate a craft toward a target in our solar system then have to turn around on its trajectory and decelerate that craft for arrival to orbit or for a surface landing, all the time NEVER exceeding the safe acceleration limits for a living crew.

How fast could safe journeys actually be made in our solar system and what's the safe minimum transit times to the major planets or interesting minor planets?

  • 1
    $\begingroup$ Also related: Maximum survivable long-term g forces. The most comfort will come from a 1 g powered flight. $\endgroup$ – Deer Hunter Jan 17 '15 at 19:34
  • 5
    $\begingroup$ Except for a few minutes during launch and entry, the problem with human spaceflight isn't too much acceleration. The problem is that every technology known to humankind results in far too low of an acceleration. A constant 1g acceleration would get people anywhere in the solar system in short order. We haven't the foggiest idea about how to make that possible. $\endgroup$ – David Hammen Jan 18 '15 at 0:14