MILLIMETRE MOON MEASUREMENTS: 50 YEARS SINCE THE START OF THE LUNAR LASER RANGING EXPERIMENT BY APOLLO 11!
The Moon has been an object of curiosity and wonder since the dawn of world time billions of years ago, often even worshipped by some religions during the more modern epoch of that history. Determining the distance from the Earth to our only satellite has occupied the minds of some of our planet’s most notable astronomers such as Hipparchus, Eratosthenes and Aristarchus. Even within more modern times authors like Jules Verne and Star Trek creator Gene Roddenberry have sparked the imagination of the public hungry for answers about what it is like on celestial bodies other than our own terra firma, whipped into a fearful frenzy of alien invasion by radio series like War of the Worlds and the Close Encounters of the Third Kind film.
So when the seven Surveyor unmanned space modules landed on the Moon’s surface closely followed by the event of the 20th century when Neil Armstrong made his “small step for Man and Giant Leap for Mankind” onto the actual moon itself in 1969 the whole world was watching on black and white TV’s wherever they could find one. As a young 13 year old I was mesmerized but, then when I became a surveyor, I had a first-hand comprehension of measurements with laser light developing a fascination with the knowledge that “Buzz” Aldrin had set up a bank of laser retroreflectors near their Apollo 11 landing site in the Sea of Tranquility to which super powered laser rangers could shoot laser rays to the Moon and back in 2.5 seconds with an accuracy achieved to about 15 centimetres! How incredible! I have since discovered that this Moon measuring is still going on, in its 50th year, now getting sub-centimetre results from the various observatories still engaged in the experiment, one in Australia. In this paper I will show you where the reflectors are placed on the Moon, which Earth stations are monitoring them and what startling results have been extracted from these highly precise lunar distances.
About John Brock
Private land surveyor since 1973, Bachelor of Surveying (UNSW 1978), MA (Egyptology) from Macquarie Uni., Sydney (2000), Registered Surveyor NSW 1981. Now Director of Brock Surveys at Parramatta (near Sydney). Papers presented on six continents in countries such as Brunei, Nigeria, Morocco, Papua New Guinea, Hawaii, Bulgaria, Finland, Colombia, Turkey, Poland, Vietnam and all states/territories of Australia. Stalwart of FIG International Institution for the History of Surveying & Measurement awarded FIG Article of the Month March 2005, January 2012, June 2014 & April 2017. Institution of Surveyors NSW Awards – Halloran Award 1996 for Contributions to Surveying History, Fellow ISNSW 1999 & 2002 Professional Surveyor of the Year. First international Life Member of the Surveyors Historical Society (USA), Rundle Foundation for Egyptian Archaeology & Parramatta Historical Society, Foundation Member Australian National Maritime Museum & Friends of National Museum of Australia. Member of Bradman Crest, International Map Collectors Society, Royal Australian Historical Society, Hills District Historical Society, Prospect Heritage Trust, Friend of Fossils (Canowindra) and Washington (DC) Map Society, Friends of May’s Hill Cemetery, St. John’s Cemetery, State Library of NSW, George Washington’s Mt. Vernon Estate, Benjamin Banneker’s Museum (USA) and Bishop Museum (Hawaii).
4.00 PM for 4.30 PM start.
The draft program includes:
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