<P> The acceleration due to gravity on the surface of the Moon is about 1.625 m / s, about 16.6% that on Earth's surface or 0.16 ɡ . Over the entire surface, the variation in gravitational acceleration is about 0.0253 m / s (1.6% of the acceleration due to gravity). Because weight is directly dependent upon gravitational acceleration, things on the Moon will weigh only 16.6% of what they weigh on the Earth . </P> <P> The gravitational field of the Moon has been measured by tracking the radio signals emitted by orbiting spacecraft . The principle used depends on the Doppler effect, whereby the line - of - sight spacecraft acceleration can be measured by small shifts in frequency of the radio signal, and the measurement of the distance from the spacecraft to a station on Earth . Since the gravitational field of the Moon affects the orbit of a spacecraft, one can use these tracking data to detect gravity anomalies . However, because of the Moon's synchronous rotation it is not possible to track spacecraft from Earth much beyond the limbs of the Moon, so until the recent GRAIL mission the far - side gravity field was not accurately known . </P> <P> A major feature of the Moon's gravitational field is the presence of mascons, which are large positive gravity anomalies associated with some of the giant impact basins . These anomalies significantly influence the orbit of spacecraft around the Moon, and an accurate gravitational model is necessary in the planning of both manned and unmanned missions . They were initially discovered by the analysis of Lunar Orbiter tracking data: navigation tests prior to the Apollo program showed positioning errors much larger than mission specifications . </P> <P> Mascons are in part due to the presence of dense mare basaltic lava flows that fill some of the impact basins . However, lava flows by themselves cannot fully explain the gravitational variations, and uplift of the crust - mantle interface is required as well . Based on Lunar Prospector gravitational models, it has been suggested that some mascons exist that do not show evidence for mare basaltic volcanism . The huge expanse of mare basaltic volcanism associated with Oceanus Procellarum does not cause a positive gravity anomaly . The center of gravity of the Moon does not coincide exactly with its geometric center, but is displaced toward the Earth by about 2 kilometers . </P>

What is the value of gravitational constant on the moon