How did NASA select the first manned moon landing site?
•How does a laser measure the distance between Earth and the Moon? Answer - During the Apollo missions (11, 14 and 15) the astronauts have been placing retroreflector arrays on the lunar surface. (Two Russian unmanned missions have deployed reflector arrays too, one failed completely probably due to being covered by dust and the other one seems to be less efficient than the Apollo reflectors). Short laser pulses are being sent to the reflectors, get reflected by the retro reflectors and then get received by the ground station. Counting the round trip travel time of the laser pulses directly gives the distance of 238, 855 miles from Earth.
•At 10:56 p.m. EST, on July 20, 1969
Neil Armstrong placed the first human foot on
another world. With more than half a billion people watching on television, he climbs down the ladder and proclaims: "That's one small step for a man, one giant leap for mankind."
•Experiment: How the craters on the moon formed. •Supplies: Clear baking pan, flour, paprika, several small stones. •Process: Fill the pan with flour and dust the top with paprika. Have a volunteer toss the stones one at a time into the pan. The results demonstrate how impact craters formed on the moon’s surface.