I am not sure if they are hiding something or simply don't understand what they have done. This is a link to GRAIL, but I am absolutely certain that there is a side effect that is far more important than moon dust. Unless somebody has changed the laws of the universe while I was asleep, there is no doubt that a specific effect is observed only when there is a communicating binocular gravity sensor. I don't see any reason why they might conceal their secondary intent, but I am not them. Perhaps they don't really know what they have done. Perhaps they will get some funny readings and then try to figure out why. I already know the why, but do they? That makes me a bit sad if they aren't at least suspicious of what is about to happen. I suppose there are so many thing in the universe that everybody is bound to miss some of them. It is said that physics is not just hard, but NP-hard.