Humans on Mars by 1970

[iancampbell]

There is a point here that isn't often discussed with respect to space launches. That is: Getting a craft to orbital height and getting it into orbit are by no means the same thing; the former needs MUCH less energy to do it. Which leads to the possibility of getting an Orion ship off the ground (to around 300km, perhaps) and then lighting off the main drive. I rummaged around a bit and found this, which illustrates the concept:

http://www.youtube.com/watch?feature=pla...vsbVBy-shc