Armstrong and Aldrin used the two-hour moon walk to deploy Early Apollo Scientific Experiment Package instruments as well as collect rock and soil samples.
Armstrong realized as they approached landing, the automatic landing system was leading them towards a rocky crater and ordered mission controllers to authorize a risky manual maneuver to address it.
Apollo 11 Mission Overview
Neil Armstrong, Buzz Aldrin and Michael Collins of Apollo 11 achieved the national goal set out by President Kennedy by using their Saturn V rocket to enter space and visit the Moon.
On July 21, the SPS stage fired for two-and-a-half minutes to conduct its initial midcourse correction during the return flight. Following this firing, astronauts then rested for 10 hours before transmitting two television broadcasts back home.
The Eagle lunar module detached itself from Columbia command module after remaining attached for its entire mission duration, with Armstrong and Aldrin embarking upon it while Collins remained inside Columbia CSM.
As Armstrong neared the Sea of Tranquility, he initiated a powered descent towards its surface. Although Armstrong reported 17 seconds of remaining propellant remaining on his fuel gauge, post-flight analysis indicated sloshing in his fuel tank had caused an error in readings.
Apollo 11 Launch
Apollo 11 launched on July 16, 1969 at 9:32 a.m. EDT from Kennedy Space Center and millions of viewers around the globe watched as five F-1 engines on its Saturn V rocket fired up to life and start orbiting around Earth.
Four days into their mission, engine burns secured both command module and lunar module into an elliptical orbit around the Moon. On July 19, a lunar orbit insertion maneuver began firing up the descent engine for the lunar module so it could begin its descent toward the Sea of Tranquility.
Armstrong and Aldrin separated the Lunar Module (LM) from Columbia and performed several checks and visual inspections before commencing their powered descent towards the lunar surface. Once there, they deployed both the Passive Seismic Experiments Package and Laser Ranging Retroreflector to gather scientific data that was later used by astronomers to ascertain its distance from Earth.
Apollo 11 Orbit
Apollo 2 used its second stage engine for six minutes to place itself into an elliptical parking orbit 175 kilometres above Earth. This enabled it to intercept lunar orbital plane and thus significantly decreases arrival time on lunar surface.
Armstrong and Aldrin carefully assessed Eagle’s systems before departing the command module to spend 21.5 hours exploring the lunar surface. While on foot they deployed seismometers for measuring moonquakes and laser reflectors that accurately measured distance between Earth and Moon as well as conducting other scientific experiments.
Once back in lunar orbit, the crew fired their service module’s engines for their return trip home. A blue contact light indicated Eagle had successfully docked with Columbia.
Apollo 11 Lunar Orbit
NASA astronauts transitioned from the command module to the lunar module (LM), a smaller spacecraft designed for landing on the Moon. Originally known as Lunar Excursion Module but later nicknamed by NASA and Grumman employees as “lem,” this smaller craft contained internal systems for life support as well as primary and backup guidance and navigation systems and rendezvous radar with a steerable parabolic dish antenna.
After three days in translunar orbit, Neil Armstrong and Buzz Aldrin separated from Michael Collins to embark on their lunar mission. Radio broadcasts followed their descent as they navigated an elliptical lunar orbit before firing Eagle’s engine for high lunar approach. Five times NASA simulations convinced Mission Control to allow the crew to continue.
Apollo 11 Landing
At 4:17 pm on 20 July, Armstrong took control of Eagle and guided it towards an effective landing site within the vast, equatorial Sea of Tranquility. For nearly an hour and a half he searched for an ideal landing spot before finally using landing rockets until their fuel ran out.
Two and a half hours later, Armstrong and Aldrin emerged from their hatch and set out across the lunar surface, conducting scientific experiments, taking photographs, reading an inscription plaque, placing an American flag, reading its inscription plaque and collecting rock samples that they would later take back home with them.
After returning to the LM, Armstrong and Aldrin fired its engine and entered lunar orbit. Three days later they returned to Columbia, jettisoned Eagle, and splashed down in the Pacific Ocean. Armstrong retired from NASA in 1971 to become a teacher, while Aldrin became a champion for space exploration.