The Stepping Stones plan for human space exploration is a series of increasingly challenging exploration missions to develop technologies and demonstrate new capabilities that enable subsequent missions to push farther into space and explore for longer durations.Step by step, at a sustained pace, astronauts will journey beyond Low Earth Orbit (LEO) to the Moon, then to distant asteroids, and finally to the outer moon of Mars. At each destination, astronauts will address key science objectives relating to the formation of the solar system and the origins of life. The Stepping Stones plan demonstrates the Orion MultiPurpose Crew Vehicle's capability beyond LEO and provides opportunities to perform and perfect telerobotic surface operations from orbit, space maneuvers near small bodies, and sample return. The missions will test and improve upon existing technologies for astronaut protection and health, forging the way for the future of human space flight.
NomenclatureAU = Astronomical Unit CM = Crew Module ECLSS = Environmental Control and Life Support System EDS = Earth Departure Stage EMU = Extra-vehicular Mobility Unit ERS = Earth Return Stage EVA = Extra-Vehicular Activity HSM = Habitat Service Module ISS = International Space Station JPL = Jet Propulsion Laboratory LAS = Launch Abort System LEO = Low Earth Orbit MMH = Monomethylhydrazine MMOD = Micrometeoroid and Orbital Debris MMU = Manned Mobility Unit MOI = Mars Orbit Injection MPCV = Multi-Purpose Crew Vehicle MTH = Mars Transfer Habitat 2 NEA = Near-Earth Asteroid OFT-1 = Orbital Flight Test 1 RCS = Reaction Control System SLS = Space Launch System SM = Service Module TEI = Trans-Earth Injection TMI = Trans-Mars Injection TPS = Thermal Protection System