Kris and the crew of the Pioneer discover a solar system with a planet covered in giant flowers, a planet where the inhabitants move in slow motion, and a planet where giant robots fight the population's wars.; To save the earth from collision with a runaway planet, scientists use giant rocket motors to move the earth.; An air force officer, riding in an experimental rocket capsule, is captured by extraterrestrials who fear human violence.; A pacifist from the future urges a modern-day peace proponent to work to save mankind from endless war.; The possible effects on humanity of another ice age.; The possible impacts on mankind of robotics.