Being a fan of the Navy's Precision Flight Team - the Blue Angels - I have always marveled at their wing tip to wing tip flying.
In reading NASA's recent news release about Ebb and Flow (GRAIL A & B) flying formation around the Moon at 3,600 mph, I was amazed - I mean AMAZED (!) at the tolerances that the two spacecraft are capable of.
Here is what NASA says as to the twins' flying ability: "How slight a distance change can be measured by the science instrument beaming invisible microwaves back and forth between Ebb and Flow? How about one-tenth of one micron? Another way to put it is that the GRAIL twins can detect a change in their position down to one half of a human hair (0.000004 inches, or 0.00001 centimeters). For those of you who are hematologists or vampires (we are not judging here), any change in separation between the two twins greater than one half of a red corpuscle will be duly noted aboard the spacecraft's memory chips for later downlinking to Earth. Working together, Ebb and Flow will make these measurements while flying over the entirety of the lunar surface."
Why such precision? As explained by NASA: "From the data collected during these minute distance changes between spacecraft, we will be able to generate an incredibly high-resolution map of the moon's gravitational field. From that, we will be able to understand what goes on below the lunar surface in unprecedented detail, which will in turn increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today."
Ebb and Flow's precision lunar flying and the analysis of the data they return will provide a quantum leap forward in our knowledge of the Moon.
I can hardly wait to "see" what we find and learn.
Sky Guy in VA