Apollo 11

Apollo 11 was NASA's first crewed Moon landing, flown from 16 to 24 July 1969.¹ On 20 July 1969 humans walked on the Moon for the first time.² Neil Armstrong and Buzz Aldrin landed in the lunar module Eagle while Michael Collins orbited overhead in the command module Columbia.²

Apollo 11's objective was the national goal President John Kennedy had set on 25 May 1961: to perform a crewed lunar landing and return the crew safely to Earth.¹ The mission completed that goal with five months to spare in the decade, and all three astronauts returned safely.¹

On 12 April 1961 the Soviet Union launched Yuri Gagarin, the first human in space.² Within days, President Kennedy asked Vice President Lyndon Johnson to find a space program in which the United States could win.² On 25 May 1961 Kennedy set the national goal that Apollo 11 would complete: a crewed lunar landing and a safe return to Earth.¹

The vehicle for the attempt was the Saturn V, a three-stage rocket.⁵ The flight control team had only about 40 hours of total training in the simulators, essentially one week's worth.⁶ In the final training runs the team met computer program alarms it had never seen or studied, and guidance officer Steve Bales decided to abort.⁶ The simulator supervisor told them they should not have aborted over those alarms: they should have checked that guidance, navigation and thrusters were still working.⁶ When a controller checked overnight, he told Kranz that the simulator supervisor had been right.⁶ Michael Collins later summed up the sequence: Apollo 8 had been about leaving, and Apollo 11 was about arriving.⁷

Armstrong had joined NASA's predecessor NACA in 1955 as an aeronautical research scientist and pilot, and he flew on the Gemini 8 mission in 1966 before being assigned to Apollo 11.¹ The backup crew was James Lovell as commander, William Anders as command module pilot and Fred Haise as lunar module pilot.² While Armstrong and Aldrin worked on the surface, Michael Collins remained in lunar orbit in Columbia.² After the others docked with Columbia, Collins said that for the first time he really felt they were going to carry the thing off.⁵

The day before the launch, Ralph Abernathy led a protest to the gates of the Kennedy Space Center drawing attention to economic and racial inequality.² Apollo 11 lifted off from Cape Kennedy on 16 July 1969 carrying Neil Armstrong, Michael Collins and Buzz Aldrin, and entered an initial Earth orbit of 114 by 116 miles.³ The engines fired at 9:32 a.m., and Apollo 11 cleared the launch tower.⁵ More than a million spectators came to watch the liftoff, among them Vice President Spiro Agnew and former President Lyndon Johnson.² The rocket was the three-stage Saturn V, 363 feet tall, producing 7.5 million pounds of thrust.⁵

Two hours 44 minutes after launch, the S-IVB stage reignited for a burn of five minutes 48 seconds, placing Apollo 11 on a translunar trajectory.³ It was the last Apollo mission to fly a free-return trajectory, which would enable a return to Earth with no engine firing and a ready abort at any time before lunar orbit insertion.³ The launch had a literary precedent: Jules Verne's 1865 novel From the Earth to the Moon placed its fictional Moon shot in Florida, where one solitary town, Tampa Town, staked its claim on the launch site.⁸

Columbia, the command module, was the living quarters for the three-person crew during most of the mission.⁹ The flight plan was a minute-by-minute timeline of activities for the crew and Mission Control in Houston.¹⁰ A midcourse correction came on 17 July, and the crew checked out the lunar module on 18 July.³ Lunar orbit insertion followed on 19 July, after Apollo 11 had flown behind the Moon out of contact with Earth.³ At about 75 hours 50 minutes into the flight, a retrograde firing of the service propulsion system for 357.5 seconds placed the spacecraft into an initial elliptical lunar orbit of 69 by 190 miles.³

Eagle undocked from Columbia at 100 hours 12 minutes into the flight so that the lunar module could be inspected visually.³ From a descent orbit of 9 by 67 miles, powered descent began at 102 hours 33 minutes, with the descent engine burning for 756.3 seconds.³ After eight minutes the module passed through high gate, about 26,000 feet above the surface and about five miles from the landing site.³

The final approach was a running conversation with Mission Control, preserved word by word in the mission transcripts.⁴

The alarms were symptoms rather than failures: the 1202 came from data overflow in the lunar module's guidance computer.⁴ Armstrong said afterwards that in the real flight the crew were spring-loaded to the land position rather than to abort.⁴ He also said that if he had run out of fuel he would have put the module down right there, but that with any choice of a more promising spot he was going to take it.¹¹ The lunar module touched down with only about 30 seconds of fuel remaining.⁵ Aldrin's call of contact light came at 20:17:40 GMT, the moment the landing was announced.⁴ The National Archives record touchdown as scheduled on 20 July, 102 hours 47 minutes and 11 seconds after launch.¹⁰

Touchdown came about four miles downrange of the predicted point and almost one and a half minutes earlier than scheduled.³ The powered descent ran only a nominal 40 seconds longer than planned, because Armstrong had to translate the module to avoid a crater in the final phase.³ In the last minutes he flew the module manually to avoid a sharp-rimmed crater about 180 meters across and 30 meters deep known as West.² Eagle landed about 6 km from the originally intended site, roughly 400 meters west of West crater.² Shortly after landing, Houston confirmed that all the crew's consumables were solid and that they looked good in every respect.¹² Flight director Gene Kranz has said that for the flight controller failure is not an option.⁶

At about 109 hours 42 minutes after launch, Armstrong stepped onto the Moon.³ More than half a billion people were watching on television as he prepared to plant the first human foot on another world.⁵

At the foot of the ladder, Armstrong reported that the footpads sank only about 1 or 2 inches into a surface that was very fine grained and looked almost like a powder up close.¹³ He was surprised that kicking the surface raised no cloud of dust: each particle simply followed its own ballistic arc.⁴ He was also surprised by the apparent closeness of the lunar horizon.⁴

In the United States, 93% of televisions were tuned in to see Armstrong walk on the Moon.² An estimated 650 million people watched Armstrong's televised image and heard his voice during the landing.³ Armstrong and Aldrin spent 21 hours and 36 minutes on the Moon's surface.³ Aldrin re-entered the module after spending one hour 33 minutes on the surface, and Armstrong followed him 41 minutes later.³ The entire spacewalk lasted more than two and a half hours, ending at 111 hours 39 minutes into the mission.³

During the spacewalk the two astronauts ranged up to 300 feet from Eagle, and Aldrin deployed the Early Apollo Scientific Experiments Package while both men gathered and described lunar samples.³ They left behind an American flag, a patch honoring the fallen Apollo 1 crew, and a plaque on one of Eagle's legs.⁵ Commemorative medallions bearing the names of the three Apollo 1 astronauts who lost their lives in a launch pad fire, and two cosmonauts who also died in accidents, were left on the surface.³ A one-and-a-half inch silicon disk containing micro-miniaturized goodwill messages from 73 countries, and the names of congressional and NASA leaders, stayed behind as well.³ Reading the plaque on Eagle's landing gear, Armstrong reported that it carried the signatures of the three crew members and of the President of the United States.¹³ The plaque stated that the crew came in peace for all mankind.⁵

President Richard Nixon spoke to the astronauts by telephone from the Oval Room of the White House, and called it the most historic telephone call ever made.¹⁶ Armstrong replied that it was a great honor and privilege to represent not only the United States but men of peace of all nations.¹⁶

After a rest period that included seven hours of sleep, the ascent stage engine fired at 124 hours 22 minutes.³ It shut down 435 seconds later with Eagle in an initial orbit of 11 by 55 miles, while Columbia was on its 25th revolution.³ Eagle docked with Columbia on the command module's 27th revolution, 128 hours and three minutes into the mission.³ Trans-Earth injection began on 21 July, when the service propulsion system fired for two and a half minutes while Columbia was behind the Moon.³ A single 11.2-second burn of the service propulsion system was the only midcourse correction needed on the return flight.³

After a flight of 195 hours 18 minutes 35 seconds, about 36 minutes longer than planned, Apollo 11 splashed down in the Pacific Ocean, 13 miles from the recovery ship USS Hornet.³ The splashdown point was 13 degrees 19 minutes north latitude and 169 degrees nine minutes west longitude.³ The splashdown was near Hawaii.² Once aboard USS Hornet, the astronauts walked ten steps from the recovery helicopter to the Mobile Quarantine Facility, wearing Biological Isolation Garments.¹⁷ They completed their 21-day quarantine in the Lunar Receiving Laboratory at what is now NASA's Johnson Space Center in Houston.¹⁴ Scientists began examining the first Moon rocks two days after splashdown, while the astronauts were still inside their quarantine.¹⁷

Scientists in the Lunar Receiving Laboratory examined the 48 pounds of lunar material the Apollo 11 astronauts returned from the Sea of Tranquility.¹⁴ In total, the returned material weighed 22 kg: 11 kg of rock fragments more than 1 cm across and 11 kg of smaller particulate material.¹⁸

The first box of Moon rocks reached the Lunar Receiving Laboratory, and less than 48 hours after splashdown the first lunar rock was documented.¹⁷ The preliminary science report described the surface at the site as relatively soft to depths ranging from 5 to 20 cm.¹⁸ The soil could be scooped easily, offered low resistance to penetration and gave low lateral support for staffs, poles or core tubes.¹⁸ Because spoken observations are far easier to study from a written record than from the spoken description alone, the Lunar Geology Experiment team prepared a transcript of all communication between the lunar module and the Capcom, from descent through the end of the spacewalk.¹⁹

The crew's 21-day quarantine ended on 10 August 1969.¹⁴ New York's ticker-tape parade drew an estimated four million people, and Chicago's drew two million.¹⁴ The homecoming brought together 44 governors and 83 ambassadors.¹⁴ The parade day ended with a state dinner hosted by President Nixon in Los Angeles.¹⁴ Collins left an inscription inside Columbia calling it the best ship to come down the line.¹⁴

Apollo 12 was announced on 29 July 1969 for a launch in November.¹⁴ Collins judged that everything worked on Apollo 11 so extraordinarily well that there were no embarrassments to explain away afterwards.⁷ For the 50th anniversary of the mission, the National Archives highlighted its records about NASA and the space program.²⁰ It presented events and exhibits in Washington, DC, and at Presidential Libraries.²⁰

Apollo 11 left instruments that were still in use decades later.¹⁴ The command module was the only portion of the spacecraft to return to Earth.⁹ Columbia was physically transferred to the Smithsonian in 1971, following a NASA-sponsored tour of American cities.⁹