GRAIL Probes Complete Primary Mission Ahead of Schedule

Zothecula writes with an update on NASA's lunar mapping probes. From the article: "After entering orbit around the Moon at the start of the year, NASA's twin GRAIL probes, Ebb and Flow, have completed their primary mission to study the Moon's interior structure ahead of schedule. Operating around the clock since March 8, NASA says the spacecraft have provided unprecedented detail about the interior structure and evolution of the Moon and the data they have gathered will provide insights into how Earth and its rocky neighbors in the inner solar system developed." And their extended mission? From NASA: "The extended mission goal is to take an even closer look at the moon's gravity field. To achieve this, GRAIL mission planners will halve their current operating altitude to the lowest altitude that can be safely maintained. 'Orbiting at an average altitude of 14 miles (23 kilometers) during the extended mission, the GRAIL twins will be clearing some of the moon's higher surface features by about 5 miles (8 kilometers),' said Joe Beerer of JPL, GRAIL's mission manager."

Re:Standing on the moon..

[butalearner]

Think about this: Mt. Everest is roughly 5.5 miles high. These "high surface features" are a little short of 2x that height and the satellites will fly roughly one Mt. Everest over that (equivalent to the cruising altitude of a commercial airliner). Now imagine that you will have the good fortune of standing on that surface feature watching it fly by at roughly 36,000 km/h or roughly 50x faster than a commercial airliner.

Don't forget it's the size of a washing machine. So I can definitely imagine seeing, at most, a speck of light for a brief moment if the angles between me, the spacecraft, and the sun are just right, assuming I'm looking in exactly the right direction. That would be awesome!