Human space flight has entered the domain of private companies. Previously, large countries like the US and Russia have hired privately owned civilian companies to do specific tasks in support of their public human space flight programs.

What would it be like to drive on the Moon? You don't have to guess -- humans have actually done it. Pictured above, Apollo 16 astronauts John Young and Charles Duke recorded video during one such drive in 1972, with a digital version now available on the web.