Assessment of Orion Mission Capability as a Function of Driving Time and Geometry-Related Factors

The Constellation Program task to return humans to the Moon includes the development of a number of spacecraft with unique responsibilities. The Orion crew exploration vehicle must support a number of on-orbit functions including: performing a low Earth orbit (LEO) rendezvous with an awaiting Lunar Lander (also known as Altair) and Earth Departure Stage (EDS); ferrying the crew between the Earth and Moon; performing altitude maintenance while in lunar orbit; performing orbit plane changes required to allow Altair to perform an in-plane ascent and rendezvous with the Orion; performing the Trans-Earth Injection (TEI) maneuver and trajectory correction maneuvers (TCM) if needed on transit. The translational ∆V budget of Orion must successfully perform these functions under nominal and off-nominal conditions in the interest of mission success and crew safety. This report summarizes Orion’s mission performance capability for three different mission types (global sortie, polar sortie, and polar outpost) and describes how that capability varies with driving time and geometry related factors.