There has been increasing interest lately in learning more about the origin and distribution of water on the Moon. However, whenever a spacecraft descends to land on the lunar surface, it releases water vapor and other gases into the lunar environment, complicating the situation.
In this work, we use computer simulations to understand what happens to the water released by a spacecraft during a typical landing. The simulated landing creates a temporary, very thin atmosphere all around the Moon.
The behavior of this atmosphere depends on how strongly water sticks to the lunar surface, such that comparing simulations to measurements of water in the lunar environment during and after future lunar landings could help us figure out the "stickiness" of the lunar surface – something that we don't yet accurately know, but is important to understanding the past, present and future distribution of water on the Moon.
Our simulations also show that some spacecraft‐delivered water travels to regions near the poles that are cold enough to trap water for very long periods of time. If the spacecraft is heavier, or lands closer to the poles, its influence on the lunar surface and atmosphere may be more significant.