The Lunar Gateway is a planned small space station in a near-rectilinear halo orbit (NRHO) around the Moon — an elongated orbit ranging from about 1,500 km at its closest to 70,000 km at its farthest from the lunar surface. It will serve as a staging point for crewed missions to the Moon and, eventually, deeper into space.
The initial configuration consists of two modules launching together on a SpaceX Falcon Heavy rocket: the Power and Propulsion Element (PPE), built by Maxar Technologies, and the Habitation and Logistics Outpost (HALO), built by Northrop Grumman. Together they provide solar electric propulsion, communications relay capability, and a small habitable volume for visiting crews.
Gateway is an international partnership involving NASA, ESA (providing the I-Hab module and ESPRIT refueling module), JAXA (life support and batteries), CSA (Canadarm3 robotic arm), and other partners. It will not be permanently crewed — rather, astronauts will visit during Artemis missions starting with Artemis IV in approximately 2028.