The Lunar Gateway
The Lunar Orbital Platform-Gateway (LOP-G), or “the Gateway”, is a planned space station around the Moon in a particular orbit that ensures that it never enters the shadow of the Moon or the Earth, and that it can act as a relay station for telecommunications from both the lunar near and far side. Such a station forms a perfect staging point for lunar surface excursions; a lunar lander would remain docked at the Gateway.
The level of ionizing radiation at the Gateway is, however, quite large since the Gateway is outside the Earth’s protecting magnetosphere. Astronauts will therefore reside onboard for a month at a time, at most. ESA is interested in hosting scientific experiments on the Gateway to exploit its infrastructure for the rest of the time.
SP4Gateway
The Gateway could be a useful platform for space plasma physics experiments.
During most of the time the Gateway is located in interplanetary space, exposed to the solar wind. During some periods, the Gateway is inside the Earth’s magnetosphere – the region of space dominated by the Earth’s magnetic field. Therefore, solar wind and magnetospheric plasma instruments could benefit from being on the Gateway.
Since the Earth is permanently in view one can envisage UV imaging of the terrestrial environment from lunar orbit. Also cosmic ray detectors could be placed there. And clearly, some instruments that study the moon and its interaction with the solar wind would be welcome too.
BIRA-IASB was part of the “SP4Gateway team” that studied the various possibilities on ESA’s request. BIRA-IASB compiled an inventory of all possible space plasma physics instrumentation that could benefit.
Instrument accommodation
A platform such as the Gateway is much larger than a traditional satellite. This brings certain advantages: there is enough power, communication bandwidth, no strict mass limitations …
But there are also disadvantages. The Gateway environment is not chemically clean because of thruster exhaust, and sometimes the astronauts dump waste in space. It is not electrically clean either: its solar panels and ion thrusters perturb the electric field and the plasma. There are all sorts of constraints. One in particular is the Gateway orientation, which may change when an astronaut capsule or lunar lander is docking or undocking. But for most of the time the Gateway will be unoccupied.
The French team (IRAP, Toulouse, France) in this study took the lead in finding out the best locations to mount the instruments on the Gateway: on two platforms on the Logistics Module.
Perspectives
NASA, ESA and the other participating space agencies are still working out their plans. In the meantime, the first Gateway modules are built. It will take some time, but sooner or later the Gateway will become a space plasma physics observatory.
Want to know more?
European Space Agency. (2021, February). Gateway. ESA Exploration - The space Gateway is the next structure to be launched by the partners of the International Space Station
