A spacecraft is a vehicle designed to move in space, nominally under its own power. It is often part of a launch system, although it may also be assembled in space or even built in Situ on Mars.
For the purposes of this article, a spacecraft is mainly a space vehicle designed to reach Mars, or part of a transportation system that can send payloads or crews to Mars.
SLS - Space Launch system - Orion and the support module
Spacecraft classification. For a classification by function or type of mission.