The recent demonstrations of successful rocket recovery by Blue Origin and SpaceX herald a new era of space exploration and development. We can expect, as rocket stages routinely return for reuse from the fringes of space, that the cost of space travel will fall dramatically.
Some in the astronautics community would like to settle the Moon; others have their eyes set on Mars. Many would rather commit to the construction of solar power satellites, efforts to mine and/or divert Near Earth Asteroids (NEAs), or construct enormous cities in space such as the O’Neill Lagrange Point colonies.
But before we can begin any or all of these endeavors, we need to answer some fundamental questions regarding human life beyond the confines of our home planet. Will humans thrive under lunar or martian gravity? Can children be conceived in extraterrestrial environments? What is the safe threshold for human exposure to high-Z galactic cosmic rays (GCRs)?
http://www.centauri-dreams.org/?p=34781 [centauri-dreams.org]