Mission to Mars complete the sequence to pass a test, and the crew dispatches a robotic rover to reproduce the completed signal. Following the transmission, an opening appears in the side of the structure, which Jim, Terri, and Luke enter, while Phil remains at the repaired Earth return vehicle with orders to launch, with or without them, at the agreed time. The opening seals behind them, disrupting radio communication with Phil, and a three-dimensional projection of the solar system depicts the planet Mars, covered with water, being struck by a large asteroid and rendered uninhabitable. A recreation of a Martian then reveals that
Solar System all have impact craters and tectonic surface features, such as rift valleys and volcanoes. The term "inner planet" should not be confused with "inferior planet", which designates those planets that are closer to the Sun than Earth is (i.e. Mercury and Venus). Asteroids except for the largest, Ceres, are classified as small Solar System bodies and are composed mainly of refractory rocky and metallic minerals, with some ice. They range from a few metres to hundreds of kilometres in size. Asteroids smaller than one meter are usually called meteoroids and micrometeoroids (grain-sized), depending on different, somewhat arbitrary definitions. The asteroid