14 CFR 1214.701: Definitions.

(a) The flight crew consists of the NASA Commander, astronaut crew members, and [any] other persons aboard the spacecraft.

(b) A mission is the period including the flight-phases from launch to landing on the surface of the Earth—a single round trip. (In the case of a forced landing, the NASA Commander's authority continues until a competent authority takes over the responsibility for the persons and property aboard).

(c) The flight-phases consist of launch, in orbit/transit, extraterrestrial mission, deorbit, entry, and landing, and post-landing back on Earth.

(d) A payload is a specific complement of instruments, space equipment, and support hardware/software carried into space to accomplish a scientific mission or discrete activity.