These great hollow globes of artificial super-metals, and artificial transparent adamant, ranged in size from the earliest and smallest structures, which were no bigger than a very small asteroid, to spheres considerably larger than the Earth. (Olaf Stapledon, STAR MAKER)
Saturday, October 12, 2013
Stairway to Mars
Alternative missions to Mars are outlined here. I like the Stairway to Mars concept, it reminds me of von Braun's space fleets to Mars.