One of the best-known anecdotes in the history of science recounts how the observation of an apple falling from a tree led Isaac Newton to discover the law of gravitation. For good reason, Newton's discovery did not trigger the development of “free-fall” gravity meters and grand expeditions to the far corners of the Earth to measure gravity. Directly measuring the acceleration of a body in free fall near the surface of the Earth may be conceptually simple, but it is technologically difficult. It wasn't until more than 2 centuries later that time and length measurement techniques reached levels that motivated researchers to build free-fall absolute gravimeters. These efforts were limited to the construction of one-of-a-kind “laboratory” instruments, minus one notable exception: the construction of six identical absolute gravimeters by the Joint Institute for Laboratory Astrophysics (JILA) [Niebauer, 1987a]. Geodetic organizations worldwide used the JILA instruments to measure gravity at more than one hundred stations achieving repeatability or precision of a few microgals (1 μGal equals l×10−8ms−2).