Rusty Schweickart Orbit Quotations

Asteroids are deep-space bodies orbiting the Sun, not the Earth, and traveling to one would mean sending humans into solar orbit for the very first time. Facing those challenges of radiation, navigation and life support on a months-long trip millions of miles from home would be a perfect learning journey before a Mars trip.

The nice thing about asteroids is that once you've found them, and once you have a good solid orbit on them, you can predict a hundred years ahead of time whether there is a likelihood of an impact with Earth.