NASA is designing and building the capabilities to send humans to explore the solar system, working toward a goal of landing humans on Mars. It is planned to build the Multi-Purpose Crew Vehicle, based on the design for the Orion capsule, with a capacity to take four astronauts on 21-day missions.
The Orion MPCV (Multi-Purpose Crew Vehicle) is based on the Orion design requirements for traveling beyond low Earth orbit (LEO). Orion will serve as the exploration vehicle that will carry the crew to space, provide emergency abort capability, sustain the crew during the space travel, and provide safe re-entry from deep space return velocities.
This are the main features of the MPCV:
Launch Abort System
The launch abort system (LAS), positioned on a tower atop the crew module, activates within milliseconds to propel the crew module to safety in the event of an emergency during launch or climb to orbit. The system also protects the crew module from dangerous atmospheric loads and heating, then jettisons after the Multi Purpose Crew Vehicle (MPCV) is through the initial mission phase of ascent to orbit.
The crew module is the transportation capsule that provides a safe habitat for the crew, provides storage for consumables and research instruments, and serves as the docking port for crew transfers. The crew module is the only part of the MPCV that returns to Earth after each mission.
The service module supports the crew module from launch through separation prior to reentry. It provides in-space propulsion capability for orbital transfer, attitude control, and high altitude ascent aborts. When mated with the crew module, it provides the water, oxygen and nitrogen needed for a habitable environment, generates and stores electrical power while on-orbit, and maintains the temperature of the vehicle's systems and components. This module can also transport unpressurized cargo and scientific payloads.