| Lunar Laser Ranging Experiment |
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Information AboutLunar Laser Ranging Experiment |
| CATEGORIES ABOUT LUNAR LASER RANGING EXPERIMENT | |
| astronomy | |
| lunar science | |
| apollo program | |
| tests of general relativity | |
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The ongoing Lunar Laser Ranging Experiment measures the Distance between the Earth and the Moon using Laser Ranging . Laser s on Earth are aimed at Retroreflector s previously planted on the Moon and the time delay for the reflected light to return is determined. The distance has been measured repeatedly over a period of more than 35 years. The experiment was first made possible by a retroreflector array installed on July 21 , 1969 , by the crew of the '' Apollo 11 ''. Two more retroreflector arrays left by the '' Apollo 14 '' and '' Apollo 15 '' missions have contributed to the experiment. The unmanned Soviet '' Lunokhod 1 '' and '' Lunokhod 2 '' rovers carried smaller arrays. Reflected signals were initially received from ''Lunokhod 1'', but no return signals have been detected since 1971, at least in part due to some uncertainty in its location on the Moon. ''Lunokhod 2's'' array continues to return signals to Earth. {Link without Title} The ''Apollo 15'' array is three times the size of the arrays left by the two earlier ''Apollo'' missions. Its size made it the target of three-quarters of the sample measurements taken in the first 25 years of the experiment. Improvements in technology since then have resulted in greater use of the smaller arrays, by sites such as the McDonald Observatory and the OCA Laser-Lune Telemetry station affiliated with the Côte D'Azur Observatory . As Of 2002 work is progressing on increasing the accuracy of the Earth-Moon measurements to near millimeter accuracy. Some of the findings of this long-term experiment are:
The undeniable presence of the reflectors on the Moon's surface has been used to refute claims that the Apollo landings were Faked . SEE ALSO
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