There’s been a lot of talk recently about the Moon, given the recent 50th anniversary of the Moon landing. But lunar exploration is not just in our past, it's also in our future. NASA and the European Space Agency (ESA) plan to go back to the Moon and place a space station in lunar orbit.
This station is known as the Lunar Gateway and after months of analysis, the space agencies have finally announced the orbit that the station will take around our natural satellite. The teams of experts selected the “near-rectilinear halo orbit” or NRHO, which will send the Gateway in a 7-day elongated path around the Moon.
The NHRO will take the station as close as 3,000 kilometers (1,865 miles) and as far as 70,000 kilometers (43,500 miles). This orbit allows for the least number of eclipses on board (from either the Earth’s or the Moon’s shadow). It is also ideal because it offers relatively inexpensive (in term of energy) transfers from Earth, but also to the Moon’s surface, and trajectories beyond the Moon.
The station will be a way to go from Earth to the Moon and back, with less effort. For each leg, the ideal window for transfer will happen every seven days.
While there are several advantages, the NHRO has its drawbacks.
“Finding a lunar orbit for the gateway is no trivial thing,” Markus Landgraf, Architecture Analyst working with ESA’s Human and Robotic Exploration activities, said in a statement. “If you want to stay there for several years, the near rectilinear halo orbit is slightly unstable and objects in this orbit do have a tendency of drifting away.”
The gateway will be equipped with a propulsion module to help it keep on the right orbit. As it stands, the current plan is for the assembly of the vehicle to begin in the last quarter of 2022, with more modules being added over the following year by uncrewed vehicles. Then in 2024, the crewed mission to the Moon will start as part of NASA’s Artemis Program. Four successive launches will continue to bring modules, as well as providing an opportunity for astronauts to land on the Moon.
According to the plans, the space station will take until 2028 to be completed. The modules will be built by ESA, NASA, the Japanese Space Agency JAXA, and ROSCOMOS, the Russian space agency. Other space agencies are likely to get involved in the construction. The Canadian space agency, for example, is providing the robotic arm.