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The most important moments that happened during the 8-day Apollo 11 mission

Buzz Aldrin moves toward a position to deploy two components of the Early Apollo Scientific Experiments Package (EASEP) on the surface of the moon during the Apollo 11 mission. (NASA)

HOUSTON – The Apollo 11 moon landing occurred almost 50 years ago. In honor of the 50th anniversary celebration of Apollo 11 below is a timeline as told by NASA with the most important highlights during the eight-day mission.

July 16, 1969

This was the Apollo 11 launch date out of Cape Kennedy in Florida. The launch sent Commander Neil Armstrong, Command Module Pilot Michael Collins and Lunar Module Pilot Edwin “Buzz” Aldrin into an initial Earth orbit of 114 by 116 miles. Around 650 million people watched Armstrong’s televised image during the launch. 

Additionally, the first color TV transmission occurred from Earth to Apollo 11 during the translunar coast of the command and service module/lunar module. 

July 17, 1969

A three-second burn of the service propulsion system was made to undergo the second of four scheduled midcourse corrections programmed for the flight. This turned out to be highly successful and the others were no longer needed. 

July 18, 1969

Armstrong and Aldrin put on their spacesuits and went to see the lunar module and made the second TV transmission by climbing through the docking tunnel from Columbia to Eagle. 

July 19, 1969

At this point in the mission, Apollo 11 had flown behind the moon and out of contact with Earth. At around 75 hours, 50 minutes into the flight, a retrograde firing of the SPS for 357.5 seconds put the spacecraft into an initial, elliptical-lunar orbit of 69 by 190 miles. The second burn that followed later for 17 seconds placed the docked vehicles into a lunar orbit of 62 by 70.5 miles. This calculated to change the orbit of the command and service module, piloted by Collins. The change happened due to lunar-gravity disruptions to the normal 69 miles required. Another TV transmission was made from the service of the moon before the second service propulsion system firing. 

July 20, 1969

Armstrong and Aldrin both entered the lunar module again. When the lunar module was behind the moon on its 13th orbit at 101 hours and 36 minutes, the lunar module descent engine fired for 30 seconds to provide both retrograde thrust and commence descent orbit insertion. This changed the orbit to nine by 67 miles, which was following the same trajectory as Apollo 10. Then following when Colombia and Eagle had reappeared from behind the moon, the lunar module was around 300 miles uprange and this made a powered descent with the descent engine firing for 756.3 seconds. After eight minutes, the lunar module was considered at “high” gate and 26,000 feet above the service and around five miles from the landing slide-  

The descent engine provided braking thrust until about 102 hours and 45 minutes into the mission. Partially and manually piloted by Armstrong, the Eagle landed in the Sea of Tranquility in Site 2. This happened one-and-a-half minutes earlier than scheduled and also four miles downrange from the touchdown point predicted. 

After a four-hour rest period, the activity began and Armstrong emerged from the Eagle and deployed the TV camera for transmission of this event to Earth. At 109 hours and 42 minutes after launch, Armstrong stepped on the moon. 20 minutes later, Aldrin followed him. After about 30 minutes they both spoke with President Richard Nixon through a telephone link. 

During their time on the moon, they were both around 300 feet from the Eagle and gathered and reported on lunar samples. After Aldrin spent around one hour and 33 minutes on the surface, he re-entered the lunar module. Armstrong followed around 41 minutes later. All extravehicular activity lasted two-and-a-half hours. 

Both Armstrong and Aldrin spent 21 hours and 36 minutes on the moon’s service. Following a rest stage that included seven hours of sleep, the ascent stage engine fired at 124 hours and 22 minutes. 

July 21, 1969

This was when the trans-earth injection of the command and service module began as the service propulsion system fired for two-and-a-half minutes when Columbia was behind the moon in its 59th hour of lunar orbit. The astronauts then slept for 10 hours. 

July 22, 1969

During the trans-Earth coast, two more television transmissions were made. 

July 24, 1969

Apollo 11 made its descent back into the U.S. It splashed down in the Pacific Ocean around 13 miles from the recovery ship USS Hornet. Due to bad weather, the landing point changed by 250 miles.