NASA’s Orion spacecraft has a pressurised crew capsule where the astronauts work, with the European service module providing everything they need to fulfil their mission.
The Crew Module sits atop the service module and can hold four astronauts and cargo. This the only part of Orion designed to reenter Earth’s atmosphere: the heatshield protects it against the intense heat of reentry at 32 000 km/h.
The European Service Module (ESM) provides electricity, propulsion, air and water, and forms part of the vehicle’s structure, like a car chassis. More information about the module is given on separate pages to the left.
A Crew Module Adapter (CMA) connects the capsule to the ESM. It houses electronic equipment for communications, power and control, and includes a bridge that connects electrical, data and fluid systems between the main modules.
A number of elements are required only during launch and are discarded shortly before entering space. The Spacecraft Adapter attaches Orion to its launch vehicle. The Spacecraft Adapter Jettisonable Fairings offer aerodynamic protection during launch. When the vehicle is high enough above Earth, the fairings are jettisoned to fall into the ocean.
As Orion ferries people to space and back, safety is paramount. If anything were to go wrong during launch, an abort will propel the crew capsule up and away from the danger, returning it to the ground by parachute. The Launch Abort System forms the nose of the complete launcher and has rockets of its own that fire in an emergency. It, too, is discarded at altitude.