In this article the authors discuss how the adaptation of ideas from robotic planetary exploration would enable astronauts, as part of the U.S. National Aeronautics & Space Administration’s (NASA’s) human space program, to travel to asteroids and the planet Mars cheaply and quickly. They argue that NASA engineers need to make plans to address the unpredictability of the U.S. political system by designing mission options that can be revised when circumstances change and discuss the deep space vehicles propelled by ion drives that are capable of mounting progressively complicated expeditions to lunar orbit, near-Earth asteroids, and Mars. INSET: More Than One Way to Reach into Space.