Power and Propulsion Element

The Power and Propulsion Element, usually shortened to PPE, is the first building block of NASA's Gateway, a planned space station in orbit around the Moon. NASA describes it as the most powerful solar electric spacecraft ever flown. It is meant to generate 60 kilowatts of electrical power, run Gateway's systems and drive a solar electric propulsion system that keeps the station in its unusual near-rectilinear halo orbit. Two large roll-out solar arrays supply the power to ionize and accelerate xenon gas, which uses about a tenth of the propellant a chemical system would need. PPE also carries the high-rate communications links between Gateway, the lunar surface and Earth. NASA's Glenn Research Center leads the partnership with Maxar Technologies to design and build it. Plans call for PPE to be joined to the Habitation and Logistics Outpost, launched together on a SpaceX Falcon Heavy and then spend about a year in transit before reaching lunar orbit.