The US space agency, the National Aeronautics and Space Administration (Nasa), has chosen renowned private-sector space company SpaceX to launch the core elements of the agency’s Moon-orbiting space station, Lunar Gateway. SpaceX was founded by South African-born engineer and entrepreneur Elon Musk in 2002. (He is also SpaceX’s chief engineer). Including mission-related costs, this will cost Nasa about $331.8-million.       

The Lunar Gateway, or just Gateway, is an essential part of the Artemis crewed space exploration programme. This will return people to the Moon, including the first women to land and walk there. 

The two core elements of the Gateway are the Power and Propulsion Element (PPE) and the Habitation and Logistics Outpost (HALO). The two will be integrated on Earth and then launched together on a Falcon Heavy rocket from Launch Complex 39A at Nasa’s Kennedy Space Centre in the US state of Florida. The launch will happen not before May 2024.

The PPE will employ solar electric propulsion and have a power capacity in the 60-kW class. It will provide Gateway with altitude control, manoeuvrability, power and high-speed communications. It will also allow Gateway to be moved into different lunar orbits, making it a cross between a space station and a spaceship. Moving Gateway from orbit to orbit will give astronauts greater access to the lunar surface than would otherwise be achievable.

The HALO is the pressurised living and working space for astronauts visiting Gateway. Often, they will be on their way to the Moon. It will also be the command and control module and the docking hub. It will distribute power, provide communications for visiting spacecraft and expeditions on the lunar surface and supplement the life support systems of visiting Orion crewed spacecraft, as well as support science experiments being conducted on Gateway itself.

Gateway will be about one-sixth the size of the International Space Station. It will be placed in a ‘near-rectilinear halo orbit’ around the Moon. This will be a highly ‘eccentric’ orbit, in which Gateway’s altitude from the lunar surface will vary from 3 000 km at the closest point to 70 000 km at the furthest point. The orbit will rotate with the Moon and, if illustrated in some manner, would appear like a halo around it. This intended orbit is ideal for long-term lunar missions, although small regular station-keeping manoeuvres will be required.