One of the most important events in human history, the mission of Apollo 11 was the first landing by human beings on another world. Launched the morning of July 16, Apollo 11 orbited the Earth twice before firing its engines for the Moon. After an outward flight of about three days, it entered a circular lunar orbit. Neil Armstrong and Buzz Aldrin left the Command/Service Module (CSM, designated "Columbia") and entered the Lunar Module ("Eagle"). During the descent, Armstrong was dissatisfied with the boulder-stre wn landing area the computer was guiding them towards, so he took control of the craft in the last few seconds and landed manually. As the spacecraft settled into the silty lunar soil, the people of Earth heard the words; "Houston, Tranquility Base here, t he Eagle has landed." About seven hours later Armstrong became the first person to ever set foot on another planet. Great caution wa s taken by Armstrong during this procedure, as no one was sure whether the Moon's soil was strong enough to hold the weight of a hum an. A few minutes after taking his famous "one small step," Armstrong was joined by Aldrin, and the two proceeded to set up the U.S. flag and begin their explorations. (Armstrong had already secured a small lunar sample just in case they had to leave quickly.) Watched by the largest television audience to that date (some 1 billion people), the two astronauts unveiled a plaque which read "Here men from the planet Earth first set foot upon the Moon, July 1969, A.D. We came in peace for all mankind." After spending about two and 1/2 hours on the dusty floor of the Sea of Tranquillity, the astronauts re-entered the LM and l ifted off to rendezvous with Collins at an altitude of 68.4 miles (110 km). While Collins orbited above, he was able to see the Soviet automated Luna probe pass below him in a lower orbit. It was laun ched after the Apollo 11 crew in an attempt to "scoop" their mission by returning samples robotically. During their excursion Aldrin and Armstrong collected 48.5 lbs. (22 kg) of Lunar soil and rocks. Included in the 169.8 lbs. (77 kg) of experiments they set up were a laser reflector and several geological monitoring devices, including a seismometer which w ould later record the crash of the unsuccessful Luna probe and also helped confirm that the Moon was indeed a geologically "dead" world. Also left on the surface were medals from the Soviet Cosmonauts Yuri Gagarin and Vladimir Komarov, a small disk containing g reetings from dozens of world leaders, a memento of the tragic Apollo 1 crew, and a postmarked "First Men on the Moon" stamp. Also left on the surface were medals from the Soviet Cosmonauts Yuri Gagarin and Vladimir Komarov, a small disk containing g reetings from dozens of world.
