Apollo 11 was the firstspaceflight toland humans on theMoon, conducted byNASA from July 16 to 24, 1969. CommanderNeil Armstrong and Lunar Module PilotEdwin "Buzz" Aldrin landed theLunar ModuleEagle on July 20 at 20:17UTC, and Armstrong became the first person to step onto the surface about six hours later, at 02:56UTC on July 21. Aldrin joined him 19 minutes afterward, and together they spent about two and a half hours exploring the site they had namedTranquility Base upon landing. They collected 47.5 pounds (21.5 kg) of lunar material to bring back to Earth before re-entering the Lunar Module. In total, they were on the Moon’s surface for 21 hours, 36 minutes before returning to theCommand ModuleColumbia, which remained inlunar orbit, piloted byMichael Collins.
Apollo 11 was launched by aSaturn V rocket fromKennedy Space Center in Florida, on July 16 at 13:32UTC (9:32 am EDT, local time). It was the fifth crewed mission of theApollo program. TheApollo spacecraft consisted of three parts: thecommand module (CM), which housed the three astronauts and was the only part to return to Earth; theservice module (SM), which provided propulsion, electrical power, oxygen, and water to the command module; and theLunar Module (LM), which had two stages—a descent stage with a large engine and fuel tanks for landing on the Moon, and a lighter ascent stage containing a cabin for two astronauts and a small engine to return them to lunar orbit.
After beingsent to the Moon by the Saturn V's third stage, the astronauts separated the spacecraft from it and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved intoEagle and landed in theMare Tranquillitatis on July 20. The astronauts usedEagle's ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisonedEagle before they performed the maneuvers that propelledColumbia out of the last of its 30 lunar orbits onto a trajectory back to Earth.[9] They returned to Earth andsplashed down in the Pacific Ocean on July 24 at 16:35:35UTC after more than eight days in space.
Armstrong's first step onto the lunar surface was broadcast onlive television to a worldwide audience. He described it as "one small step for [a] man, one giant leap for mankind."[a][15] Apollo 11 provided a U.S. victory in theSpace Race against the Soviet Union, and fulfilled thenational goal set in 1961 by PresidentJohn F. Kennedy: "before this decade is out, of landing a man on the Moon and returning him safely to the Earth".[16]
Background
In the late 1950s and early 1960s, the United States was engaged in theCold War, a geopolitical rivalry with theSoviet Union.[17] On October 4, 1957, the Soviet Union launchedSputnik 1, the firstartificial satellite, surprising the world and fueling fears about Soviet technological and military capabilities. Its success demonstrated that the USSR could potentially delivernuclear weapons overintercontinental distances, challenging American claims of military, economic, and technological superiority.[18] This sparked theSputnik crisis and ignited theSpace Race, as both superpowers sought to demonstrate their superiority in spaceflight.[19] PresidentDwight D. Eisenhower responded to the challenge posed by Sputnik by creating theNational Aeronautics and Space Administration (NASA), and initiatingProject Mercury,[20] which aimed to place a man intoEarth orbit.[21] The Soviets took the lead on April 12, 1961, whencosmonautYuri Gagarin became the first person in space and the first to orbit the Earth.[22] Nearly a month later, on May 5, 1961, Alan Shepard became the first American in space; his 15-minute flight was suborbital, not a full orbit.[23]
Because the Soviet Union hadlaunch vehicles with higher lift capacity, President John F. Kennedy, Eisenhower's successor, chose a challenge that exceeded the capabilities of the existing generation of rockets, so that the U.S. and Soviet Union would be starting from a position of equality. A crewed mission to the Moon would serve this purpose.[24]
On May 25, 1961, Kennedy addressed theUnited States Congress on "Urgent National Needs" and declared:
I believe that this nation should commit itself to achieving the goal, before this decade [1960s] is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. We propose to accelerate the development of the appropriate lunar space craft. We propose to develop alternate liquid and solid fuel boosters, much larger than any now being developed, until certain which is superior. We propose additional funds for other engine development and for unmanned explorations—explorations which are particularly important for one purpose which this nation will never overlook: the survival of the man who first makes this daring flight. But in a very real sense, it will not be one man going to the Moon—if we make this judgment affirmatively, it will be an entire nation. For all of us must work to put him there.
There is no strife, no prejudice, no national conflict in outer space as yet. Its hazards are hostile to us all. Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation may never come again. But why, some say, the Moon? Why choose this as our goal? And they may well ask, why climb the highest mountain? Why, 35 years ago,fly the Atlantic? Why doesRice play Texas?We choose to go to the Moon! We choose to go to the Moon ... We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win, and the others, too.[28]
An early and crucial decision was choosinglunar orbit rendezvous over bothdirect ascent andEarth orbit rendezvous. Aspace rendezvous is anorbital maneuver in which two spacecraft navigate through space and meet up. In July 1962 NASA headJames Webb announced that lunar orbit rendezvous would be used[35][36] and that theApollo spacecraft would have three major parts: a command module (CM) with a cabin for the three astronauts, and the only part that returned to Earth; a service module (SM), which supported the command module with propulsion, electrical power, oxygen, and water; and a lunar module (LM) that had two stages—a descent stage for landing on the Moon, and an ascent stage to place the astronauts back into lunar orbit.[37] This design meant the spacecraft could be launched by a singleSaturn V rocket that was then under development.[38]
Project Apollo was abruptly halted by theApollo 1 fire on January 27, 1967, in which astronautsGus Grissom,Ed White, andRoger B. Chaffee died, and the subsequent investigation.[43] In October 1968,Apollo 7 evaluated the command module in Earth orbit,[44] and in DecemberApollo 8 tested it in lunar orbit.[45] In March 1969,Apollo 9 put the lunar module through its paces in Earth orbit,[46] and in MayApollo 10 conducted a "dress rehearsal" in lunar orbit. By July 1969, all was in readiness for Apollo 11 to take the final step onto the Moon.[47]
The Soviet Union appeared to be winning the Space Race by beating the US to firsts, but its early lead was overtaken by the USGemini program and Soviet failure to develop theN1 launcher, which would have been comparable to the Saturn V.[48] The Soviets tried to beat the US to return lunar material to the Earth by means ofuncrewed probes. On July 13, three days before Apollo 11's launch, the Soviet Union launchedLuna 15, which reached lunar orbit before Apollo 11. During descent, a malfunction caused Luna 15 to crash inMare Crisium about two hours before Armstrong and Aldrin took off from the Moon's surface to begin their voyage home. TheNuffield Radio Astronomy Laboratories radio telescope in England recorded transmissions from Luna 15 during its descent, and these were released in July 2009 for the 40th anniversary of Apollo 11.[49]
The initial crew assignment of CommanderNeil Armstrong, Command Module Pilot (CMP)Jim Lovell, and Lunar Module Pilot (LMP)Buzz Aldrin on the backup crew for Apollo 9 was officially announced on November 20, 1967.[50] Lovell and Aldrin had previously flown together as the crew ofGemini 12. Due to design and manufacturing delays in the LM, Apollo 8 and Apollo 9 swapped prime and backup crews, and Armstrong's crew became the backup for Apollo 8. Based on the normal crew rotation scheme, Armstrong was then expected to command Apollo 11.[51]
There would be one change.Michael Collins, the CMP on the Apollo 8 crew, began experiencing trouble with his legs. Doctors diagnosed a bony growth between his fifth and sixth vertebrae, requiring surgery.[52] Lovell took his place on the Apollo 8 crew, and when Collins recovered he joined Armstrong's crew as CMP. In the meantime,Fred Haise filled in as backup LMP, and Aldrin as backup CMP for Apollo 8.[53] Apollo 11 was the second American mission where all the crew members had prior spaceflight experience,[54] the first being Apollo 10.[55] The next wasSTS-26 in 1988.[54]
Deke Slayton gave Armstrong the option to replace Aldrin with Lovell, since some thought Aldrin was difficult to work with. Armstrong had no issues working with Aldrin but thought it over for a day before declining. He thought Lovell deserved to command his own mission (eventuallyApollo 13).[56]
The Apollo 11 prime crew had none of the close cheerful camaraderie characterized by that ofApollo 12. Instead, they forged an amiable working relationship. Armstrong in particular was notoriously aloof, but Collins, who considered himself a loner, confessed to rebuffing Aldrin's attempts to create a more personal relationship.[57] Aldrin and Collins described the crew as "amiable strangers".[58] Armstrong did not agree with the assessment, and said "all the crews I was on worked very well together."[58]
The backup crew consisted of Lovell as Commander,William Anders as CMP, and Haise as LMP. Anders had flown with Lovell on Apollo 8.[54] In early 1969, Anders accepted a job with theNational Aeronautics and Space Council effective August 1969, and announced he would retire as an astronaut at that time.Ken Mattingly was moved from the support crew into parallel training with Anders as backup CMP in case Apollo 11 was delayed past its intended July launch date, at which point Anders would be unavailable.[59]
Under the normal Apollo crew rotation, Lovell, Mattingly, and Haise would have been assigned toApollo 14. However, becauseAlan Shepard had only recently returned to flight status and needed additional training, NASA reassigned his crew to Apollo 14 and moved Lovell's crew up to flyApollo 13 instead. Shortly before launch, Mattingly was replaced byJack Swigert due to concerns over possible measles exposure.[59]
Support crew
During Projects Mercury and Gemini, each mission had a prime and a backup crew. For Apollo, NASA added a third group, the support crew. Their job was to maintain the flight plan, checklists, and mission rules, and to keep the prime and backup crews updated on any changes. They also developed procedures—especially for emergencies, so that by the time the prime and backup crews entered the simulators, they could focus on practicing and mastering them.[60] The support crew for Apollo 11 was Mattingly,Ronald Evans, andBill Pogue.[61]
Capsule communicators
CAPCOMCharles Duke (left), with backup crewmembers Lovell and Haise listening in during Apollo 11's descent
The Apollo 11mission emblem was designed by Collins, who wanted a symbol for "peaceful lunar landing by the United States". At Lovell's suggestion, he chose thebald eagle, thenational bird of the United States, as the symbol. Tom Wilson, a simulator instructor, suggested anolive branch in its beak to represent their peaceful mission. Collins added a lunar background with the Earth in the distance. The sunlight in the image was coming from the wrong direction; the shadow should have been in the lower part of the Earth instead of the left. Aldrin, Armstrong and Collins decided the Eagle and the Moon would be in their natural colors, and decided on a blue and gold border. Armstrong was concerned that "eleven" would not be understood by non-English speakers, so they went with "Apollo 11",[70] and they decided not to put their names on the patch, so it would "be representative ofeveryone who had worked toward a lunar landing".[71]
An illustrator at theManned Spacecraft Center (MSC) did the artwork, which was then sent off to NASA officials for approval.[70] The design was rejected.Bob Gilruth, the director of the MSC felt the talons of the eagle looked "too warlike".[72] After some discussion, the olive branch was moved to the talons.[72] When theEisenhower dollar coin was released in 1971, the patch design provided the eagle for its reverse side.[73] The design was also used for the smallerSusan B. Anthony dollar unveiled in 1979.[74]
Call signs
Original cockpit of the command module (CM) with three seats, photographed from above. It is located in theNational Air and Space Museum, the very high resolution image was produced in 2007 by theSmithsonian Institution.
After the crew of Apollo 10 named their spacecraftCharlie Brown andSnoopy, assistant manager for public affairsJulian Scheer wrote toGeorge Low, the Manager of the Apollo Spacecraft Program Office at the MSC, to suggest the Apollo 11 crew be less flippant in naming their craft. The nameSnowcone was used for the CM andHaystack was used for the LM in both internal and external communications during early mission planning.[75]
The LM was namedEagle after the motif which was featured prominently on the mission insignia. At Scheer's suggestion, the CM was namedColumbia afterColumbiad, the giant cannon that launched a spacecraft (also from Florida) inJules Verne's 1865 novelFrom the Earth to the Moon. It also referred toColumbia, a historical name of the United States.[76][77] In Collins' 1976 book, he saidColumbia was in reference toChristopher Columbus.[78]
The astronauts hadpersonal preference kits (PPKs), small bags containing personal items of significance they wanted to take with them on the mission.[79] Five 0.5-pound (0.23 kg) PPKs were carried on Apollo 11: three (one for each astronaut) were stowed onColumbia before launch, and two onEagle.[80]
Neil Armstrong's LM PPK contained a piece of wood from theWright brothers' 1903Wright Flyer's left propeller and a piece of fabric from its wing,[81] along with a diamond-studdedastronaut pin originally given to Slayton by the widows of the Apollo 1 crew. This pin had been intended to be flown on that mission and given to Slayton afterwards, but following the disastrous launch pad fire and subsequent funerals, the widows gave the pin to Slayton. Armstrong took it with him on Apollo 11.[82]
Site selection
Map of Moon showing prospective sites for Apollo 11. Site 2 was chosen.
NASA's Apollo Site Selection Board announced five potential landing sites on February 8, 1968. These were the result of two years' worth of studies based on high-resolution photography of the lunar surface by the five uncrewed probes of theLunar Orbiter program and information about surface conditions provided by theSurveyor program.[83] The best Earth-bound telescopes could not resolve features with the resolution Project Apollo required.[84] The landing site had to be close to the lunar equator to minimize the amount of propellant required, clear of obstacles to minimize maneuvering, and flat to simplify the task of the landing radar. Scientific value was not a consideration.[85]
Areas that appeared promising on photographs taken on Earth were often found to be totally unacceptable. The original requirement that the site be free of craters had to be relaxed, as no such site was found.[86] Five sites were considered: Sites 1 and 2 were in the Sea of Tranquility (Mare Tranquillitatis); Site 3 was in the Central Bay (Sinus Medii); and Sites 4 and 5 were in the Ocean of Storms (Oceanus Procellarum).[83]The final site selection was based on seven criteria:
The site needed to be smooth, with relatively few craters;
with approach paths free of large hills, tall cliffs or deep craters that might confuse the landing radar and cause it to issue incorrect readings;
reachable with a minimum amount of propellant;
allowing for delays in the launch countdown;
providing the Apollo spacecraft with a free-return trajectory, one that would allow it to coast around the Moon and safely return to Earth without requiring any engine firings should a problem arise on the way to the Moon;
with good visibility during the landing approach, meaning the Sun would be between 7 and 20 degrees behind the LM; and
a general slope of less than two degrees in the landing area.[83]
The requirement for the Sun angle was particularly restrictive, limiting the launch date to one day per month.[83] A landing just after dawn was chosen to limit the temperature extremes the astronauts would experience.[87] The Apollo Site Selection Board selected Site 2, with Sites 3 and 5 as backups in the event of the launch being delayed. In May 1969, Apollo 10's lunar module flew to within 15 kilometers (9.3 mi) of Site 2, and reported it was acceptable.[88][89]
First-step decision
During the first press conference after the Apollo 11 crew was announced, the first question was, "Which one of you gentlemen will be the first man to step onto the lunar surface?"[90][91] Slayton told the reporter it had not been decided, and Armstrong added that it was "not based on individual desire".[90]
One of the first versions of the egress checklist had the lunar module pilot exit the spacecraft before the commander, which matched what had been done on Gemini missions,[92] where the commander had never performed the spacewalk.[93] Reporters wrote in early 1969 that Aldrin would be the first man to walk on the Moon, and Associate AdministratorGeorge Mueller told reporters he would be first as well. Aldrin heard that Armstrong would be the first because Armstrong was a civilian, which made Aldrin livid. Aldrin attempted to persuade other Lunar Module pilots he should be first, but they responded cynically about what they perceived as a lobbying campaign. Attempting to stem interdepartmental conflict, Slayton told Aldrin that Armstrong would be first since he was the commander. The decision was announced in a press conference on April 14, 1969.[94]
For decades, Aldrin believed the final decision was largely driven by the Lunar Module's hatch location. Because the astronauts had their spacesuits on and the spacecraft was so small, maneuvering to exit the spacecraft was difficult. The crew tried a simulation in which Aldrin left the spacecraft first, but he damaged the simulator while attempting to egress. While this was enough for mission planners to make their decision, Aldrin and Armstrong were left in the dark on the decision until late spring.[95] Slayton told Armstrong the plan was to have him leave the spacecraft first, if he agreed. Armstrong said, "Yes, that's the way to do it."[96]
The media accused Armstrong of exercising his commander's prerogative to exit the spacecraft first.[97]Chris Kraft revealed in his 2001 autobiography that a meeting occurred between Gilruth, Slayton, Low, and himself to make sure Aldrin would not be the first to walk on the Moon. They argued that the first person to walk on the Moon should be likeCharles Lindbergh, a calm and quiet person. They made the decision to change the flight plan so the commander was the first to egress from the spacecraft.[98]
The ascent stage ofLM-5Eagle arrived at theKennedy Space Center on January 8, 1969, followed by the descent stage four days later, andCSM-107Columbia on January 23.[6] There were several differences betweenEagle and Apollo 10's LM-4Snoopy;Eagle had a VHF radio antenna to facilitate communication with the astronauts during their EVA on the lunar surface; a lighter ascent engine; more thermal protection on the landing gear; and a package of scientific experiments known as theEarly Apollo Scientific Experiments Package (EASEP). The only change in the configuration of the command module was the removal of some insulation from the forward hatch.[99][100] The CSM was mated on January 29, and moved from theOperations and Checkout Building to theVehicle Assembly Building on April 14.[6]
TheS-IVB third stage of Saturn V AS-506 had arrived on January 18, followed by theS-II second stage on February 6,S-IC first stage on February 20, and theSaturn V Instrument Unit on February 27. At 12:30 on May 20, the 5,443-tonne (5,357-long-ton; 6,000-short-ton) assembly departed the Vehicle Assembly Building atop thecrawler-transporter, bound for Launch Pad 39A, part ofLaunch Complex 39, while Apollo 10 was still on its way to the Moon. A countdown test commenced on June 26, and concluded on July 2. The launch complex was floodlit on the night of July 15, when the crawler-transporter carried themobile service structure back to its parking area.[6] In the early hours of the morning, the fuel tanks of the S-II and S-IVB stages were filled withliquid hydrogen.[101] Fueling was completed by three hours before launch.[102] Launch operations were partly automated, with 43 programs written in theATOLL programming language.[103]
Slayton roused the crew shortly after 04:00, and they showered, shaved, and had the traditional pre-flight breakfast of steak and eggs with Slayton and the backup crew. They then donned their space suits and began breathing pure oxygen. At 06:30, they headed out to Launch Complex 39.[104] Haise enteredColumbia about three hours and ten minutes before launch time. Along with a technician, he helped Armstrong into the left-hand couch at 06:54. Five minutes later, Collins joined him, taking up his position on the right-hand couch. Finally, Aldrin entered, taking the center couch.[102] Haise left around two hours and ten minutes before launch.[105] The closeout crew sealed the hatch, and the cabin was purged and pressurized. The closeout crew then left the launch complex about an hour before launch time. The countdown became automated at three minutes and twenty seconds before launch time.[102] Over 450 personnel were at the consoles in thefiring room.[101]
Mission
Launch and flight to lunar orbit
The Apollo 11 Saturn V space vehicle lifts off with astronauts Neil A. Armstrong, Michael Collins and Edwin E. Aldrin Jr. at 9:32 am. EDT July 16, 1969, from Kennedy Space Center's Launch Complex 39A.
An estimated one million spectators watched the launch of Apollo 11 from the highways and beaches in the vicinity of the launch site. Dignitaries included theChief of Staff of the United States Army,GeneralWilliam Westmoreland, fourcabinet members, 19state governors, 40mayors, 60 ambassadors and 200congressmen. Vice PresidentSpiro Agnew viewed the launch with former presidentLyndon B. Johnson and his wifeLady Bird Johnson.[101][106] Around 3,500 media representatives were present.[107] About two-thirds were from the United States; the rest came from 55 other countries. The launch was televised live in 33 countries, with an estimated 25 million viewers in the United States alone. Millions more around the world listened to radio broadcasts.[106][101] PresidentRichard Nixon viewed the launch from his office in theWhite House with his NASA liaison officer, Apollo astronautFrank Borman.[108] Lodging near Cape Canaveral was reported as being booked months ahead in advance for the launch by a Florida newspaper.[109]
Saturn V AS-506 launched Apollo 11 on July 16, 1969, at 13:32:00UTC (9:32:00EDT).[6] At 13.2 seconds into the flight, the launch vehicle began toroll into itsflight azimuth of 72.058°. Full shutdown of the first-stage engines occurred about 2 minutes and 42 seconds into the mission, followed by separation of the S-IC and ignition of the S-II engines. The second stage engines then cut off and separated at about 9 minutes and 8 seconds, allowing the first ignition of the S-IVB engine a few seconds later.[8]
Apollo 11 entered anear-circular Earth orbit at an altitude of 100.4 nautical miles (185.9 km) by 98.9 nautical miles (183.2 km), twelve minutes into its flight. After one and a half orbits, a second ignition of the S-IVB engine pushed the spacecraft onto its trajectory toward the Moon with thetrans-lunar injection (TLI) burn at 16:22:13 UTC. About 30 minutes later, with Collins in the left seat and at the controls, thetransposition, docking, and extraction maneuver was performed. This involved separatingColumbia from the spent S-IVB stage, turning around, and docking withEagle still attached to the stage. After the LM was extracted, the combined spacecraft headed for the Moon, while the rocket stage flew on a trajectory past the Moon.[110][8] This was done to avoid the third stage colliding with the spacecraft, the Earth, or the Moon. Aslingshot effect from passing around the Moon threw it into anorbit around the Sun.[111]
On July 19 at 17:21:50 UTC, Apollo 11 passed behind the Moon and fired its service propulsion engine to enterlunar orbit.[8][112] In the thirty orbits that followed, the crew saw passing views of their landing site in the southern Sea of Tranquility about 12 miles (19 km) southwest of the craterSabine D. The site was selected in part because it had been characterized as relatively flat and smooth by the automatedRanger 8 andSurveyor 5 landers and the Lunar Orbiter mapping spacecraft, and because it was unlikely to present major landing or EVA challenges.[113] It lay about 25 kilometers (16 mi) southeast of the Surveyor 5 landing site, and 68 kilometers (42 mi) southwest of Ranger 8's crash site.[114]
At 12:52:00 UTC on July 20, Aldrin and Armstrong enteredEagle, and began the final preparations for lunar descent.[8] At 17:44:00Eagle separated fromColumbia.[13] Collins, alone aboardColumbia, inspectedEagle as it pirouetted before him to ensure the craft was not damaged, and that the landing gear was correctly deployed.[115][116] Armstrong exclaimed: "TheEagle has wings!"[116]
As the descent began, Armstrong and Aldrin found themselves passing landmarks on the surface two or three seconds early, and reported that they were "long"; they would land miles west of their target point.Eagle was traveling too fast. The problem could have beenmascons—concentrations of high mass in a region or regions of the Moon's crust that contains agravitational anomaly, potentially alteringEagle's trajectory. Flight Director Gene Kranz speculated that it could have resulted from extra air pressure in the docking tunnel, or a result ofEagle's pirouette maneuver.[117][118]
Five minutes into the descent burn, and 6,000 feet (1,800 m) above the surface of the Moon, theLM guidance computer (LGC) distracted the crew with the first of several unexpected 1201 and 1202 program alarms. Inside Mission Control Center, computer engineerJack Garman toldGuidance OfficerSteve Bales it was safe to continue the descent, and this was relayed to the crew. The program alarms indicated "executive overflows", meaning the guidance computer could not complete all its tasks in real-time and had to postpone some of them.[119][120]Margaret Hamilton, the Director of Apollo Flight Computer Programming at theMITCharles Stark Draper Laboratory later recalled:
To blame the computer for the Apollo 11 problems is like blaming the person who spots a fire and calls the fire department. Actually, the computer was programmed to do more than recognize error conditions. A complete set of recovery programs was incorporated into the software. The software's action, in this case, was to eliminate lower priority tasks and re-establish the more important ones. The computer, rather than almost forcing an abort, prevented an abort. If the computer hadn't recognized this problem and taken recovery action, I doubt if Apollo 11 would have been the successful Moon landing it was.[121]
During the mission, the cause was diagnosed as the rendezvous radar switch being in the wrong position, causing the computer to process data from both the rendezvous and landing radars at the same time.[122][123] Software engineerDon Eyles concluded in a 2005 Guidance and Control Conference paper that the problem was due to a hardware design bug previously seen during testing of the first uncrewed LM inApollo 5. Having the rendezvous radar on (so it was warmed up in case of an emergency landing abort) should have been irrelevant to the computer, but an electrical phasing mismatch between two parts of the rendezvous radar system could cause the stationary antenna to appear to the computer as dithering back and forth between two positions, depending upon how the hardware randomly powered up. The extra spuriouscycle stealing, as the rendezvous radar updated an involuntary counter, caused the computer alarms.[124]
Landing
Armstrong pilotsEagle to its landing on the Moon, July 20, 1969.
When Armstrong again looked outside, he saw that the computer's landing target was in a boulder-strewn area just north and east of a 300-foot-diameter (91 m) crater (later determined to beWest crater), so he took semi-automatic control.[125][126] Armstrong considered landing short of the boulder field so they could collect geological samples from it, but could not since their horizontal velocity was too high. Throughout the descent, Aldrin called out navigation data to Armstrong, who was busy pilotingEagle. Now 107 feet (33 m) above the surface, Armstrong knew their propellant supply was dwindling and was determined to land at the first possible landing site.[127]
Armstrong found a clear patch of ground and maneuvered the spacecraft towards it. As he got closer, now 250 feet (76 m) above the surface, he discovered his new landing site had a crater in it. He cleared the crater and found another patch of level ground. They were now 100 feet (30 m) from the surface, with only 90 seconds of propellant remaining. Lunar dust kicked up by the LM's engine began to impair his ability to determine the spacecraft's motion. Some large rocks jutted out of the dust cloud, and Armstrong focused on them during his descent so he could determine the spacecraft's speed.[128]
A light informed Aldrin that at least one of the 67-inch (170 cm) probes hanging fromEagle's footpads had touched the surface a few moments before the landing and he said: "Contact light!" Armstrong was supposed to immediately shut the engine down, as the engineers suspected the pressure caused by the engine's own exhaust reflecting off the lunar surface could make it explode, but he forgot. Three seconds later,Eagle landed and Armstrong shut the engine down.[129] Aldrin immediately said "Okay, engine stop. ACA—out ofdetent." Armstrong acknowledged: "Out of detent. Auto." Aldrin continued: "Mode control—both auto. Descent engine command override off. Engine arm—off. 413 is in."[130]
ACA was theAttitude Control Assembly—the LM's control stick. Output went to the LGC to command thereaction control system (RCS) jets to fire. "Out of Detent" meant the stick had moved away from its centered position; it was spring-centered like the turn indicator in a car. Address 413 of theAbort Guidance System (AGS) contained the variable that indicated the LM had landed.[10]
Eagle landed at 20:17:40 UTC on Sunday July 20 with 216 pounds (98 kg) of usable fuel remaining. Information available to the crew and mission controllers during the landing showed the LM had enough fuel for another 25 seconds of powered flight before an abort without touchdown would have become unsafe,[10][131] but post-mission analysis showed that the real figure was probably closer to 50 seconds.[132] Apollo 11 landed with less fuel than most subsequent missions, and the astronauts encountered a premature low fuel warning. This was later found to be the result of the propellantsloshing more than expected, uncovering a fuel sensor. On subsequent missions, extraanti-slosh baffles were added to the tanks to prevent this.[10]
Armstrong acknowledged Aldrin's completion of the post-landing checklist with "Engine arm is off", before responding to the CAPCOM, Charles Duke, with the words, "Houston,Tranquility Base here. TheEagle has landed." Armstrong's unrehearsed change of call sign from "Eagle" to "Tranquility Base" emphasized to listeners that landing was complete and successful.[133] Duke expressed the relief at Mission Control: "Roger, Twan—Tranquility, we copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."[10][134]
Two and a half hours after landing, before preparations began for the EVA, Aldrin radioed to Earth:
This is the LM pilot. I'd like to take this opportunity to ask every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours and to give thanks in his or her own way.[135]
He then tookcommunion privately. At this time NASA was still fighting a lawsuit brought by atheistMadalyn Murray O'Hair (who had objected to theApollo 8 crew reading from the Book of Genesis) demanding that their astronauts refrain from broadcasting religious activities while in space. For this reason, Aldrin chose to refrain from directly mentioning taking communion on the Moon. Aldrin was an elder at theWebsterPresbyterian Church, and his communion kit was prepared by the pastor of the church, Dean Woodruff. Webster Presbyterian possesses the chalice used on the Moon and commemorates the event each year on the Sunday closest to July 20.[136] The schedule for the mission called for the astronauts to follow the landing with a five-hour sleep period, but they chose to begin preparations for the EVA early, thinking they would be unable to sleep.[137]
Lunar surface operations
Preparations forNeil Armstrong andBuzz Aldrin to walk on the Moon began at 23:43 UTC.[13] These took longer than expected; three and a half hours instead of two.[138] During training on Earth, everything required had been neatly laid out in advance, but on the Moon the cabin contained a large number of other items as well, such as checklists, food packets, and tools.[139] Six hours and thirty-nine minutes after landing, Armstrong and Aldrin were ready to go outside, andEagle was depressurized.[140]
Eagle's hatch was opened at 02:39:33.[13] Armstrong initially had some difficulties squeezing through the hatch with hisportable life support system (PLSS).[138] Some of the highest heart rates recorded from Apollo astronauts occurred during LM egress and ingress.[141] At 02:51 Armstrong began his descent to the lunar surface. The remote-control unit on his chest kept him from seeing his feet. Climbing down the nine-rung ladder, Armstrong pulled a D-ring to deploy the modular equipment stowage assembly (MESA) folded againstEagle's side and activate the TV camera.[142][15]
Apollo 11 usedslow-scan television (TV) incompatible with broadcast TV, so it was displayed on a special monitor and a conventional TV camera viewed this monitor (thus, a broadcast of a broadcast), significantly reducing the quality of the picture.[143] The signal was received atGoldstone in the United States, but with better fidelity byHoneysuckle Creek Tracking Station nearCanberra in Australia. Minutes later the feed was switched to the more sensitiveParkes radio telescope in Australia.[144] Despite some technical and weather difficulties, black and white images of the first lunar EVA were received and broadcast to at least 600 million people on Earth.[144] Copies of this video in broadcast format were saved and are widely available, butrecordings of the original slow scan source transmission from the lunar surface were likely destroyed during routine magnetic tape re-use at NASA.[143]
Video of Neil Armstrong and the first step on the Moon
After describing the surface dust as "very fine-grained" and "almost like a powder",[15] at 02:56:15,[145] six and a half hours after landing, Armstrong stepped offEagle's landing pad and declared: "That's one small step for [a] man, one giant leap for mankind."[a][146][147]
Armstrong intended to say "That's one small step for a man", but the word "a" is not audible in the transmission, and thus was not initially reported by most observers of the live broadcast. When later asked about his quote, Armstrong said he believed he said "for a man", and subsequent printed versions of the quote included the "a" in square brackets. One explanation for the absence may be that his accent caused him to slur the words "for a" together; another is the intermittent nature of the audio and video links to Earth, partly because of storms near Parkes Observatory. A more recent digital analysis of the tape claims to reveal the "a" may have been spoken but obscured by static. Other analysis points to the claims of static and slurring as "face-saving fabrication", and that Armstrong himself later admitted to misspeaking the line.[148][149][150]
About seven minutes after stepping onto the Moon's surface, Armstrong collected a contingency soil sample using a sample bag on a stick. He then folded the bag and tucked it into a pocket on his right thigh. This was to guarantee there would be some lunar soil brought back in case an emergency required the astronauts to abandon the EVA and return to the LM.[151] Twelve minutes after the sample was collected,[146] he removed the TV camera from the MESA and made a panoramic sweep, then mounted it on a tripod.[138] The TV camera cable remained partly coiled and presented a tripping hazard throughout the EVA. Still photography was accomplished with aHasselblad camera that could be operated hand-held or mounted on Armstrong'sApollo space suit.[152] Aldrin joined Armstrong on the surface. He described the view with the simple phrase: "Magnificent desolation."[15]
Armstrong said moving in thelunar gravity, one-sixth of Earth's, was "even perhaps easier than the simulations ... It's absolutely no trouble to walk around."[15] Aldrin joined him on the surface and tested methods for moving around, including two-footed kangaroo hops. The PLSS backpack created a tendency to tip backward, but neither astronaut had serious problems maintaining balance. Loping became the preferred method of movement. The astronauts reported that they needed to plan their movements six or seven steps ahead. The fine soil was quite slippery. Aldrin remarked that moving from sunlight intoEagle's shadow produced no temperature change inside the suit, but the helmet was warmer in sunlight, so he felt cooler in shadow.[15] The MESA failed to provide a stable work platform and was in shadow, slowing work somewhat. As they worked, the moonwalkers kicked up gray dust, which soiled the outer part of their suits.[152]
Aldrin salutes the deployed United States flag on thelunar surface.
The astronauts planted theLunar Flag Assembly containing aflag of the United States on the lunar surface, in clear view of the TV camera. Aldrin remembered, "Of all the jobs I had to do on the Moon the one I wanted to go the smoothest was the flag raising."[153] But the astronauts struggled with the telescoping rod and could only insert the pole about 2 inches (5 cm) into the hard lunar surface. Aldrin was afraid it might topple in front of TV viewers, but gave "a crisp West Point salute".[153] Before Aldrin could take a photo of Armstrong with the flag, President Richard Nixon spoke to them through a telephone-radio transmission, which Nixon called "the most historic phone call ever made from the White House."[154] Nixon originally had a long speech prepared to read during the phone call, but Frank Borman, who was at the White House as a NASA liaison during Apollo 11, convinced Nixon to keep his words brief.[155]
Nixon: Hello, Neil and Buzz. I'm talking to you by telephone from the Oval Room at the White House. And this certainly has to be the most historic telephone call ever made from the White House. I just can't tell you how proud we all are of what you have done. For every American, this has to be the proudest day of our lives. And for people all over the world, I am sure that they too join with Americans in recognizing what an immense feat this is. Because of what you have done, the heavens have become a part of man's world. And as you talk to us from the Sea of Tranquility, it inspires us to redouble our efforts to bring peace and tranquility to Earth. For one priceless moment in the whole history of man, all the people on this Earth are truly one: one in their pride in what you have done, and one in our prayers that you will return safely to Earth.
Armstrong: Thank you, Mr. President. It's a great honor and privilege for us to be here, representing not only the United States, but men of peace of all nations, and with interest and a curiosity, and men with a vision for the future. It's an honor for us to be able to participate here today.
Nixon: Thank you very much, and I look forward, all of us look forward, to seeing you on the Hornet on Thursday.[156][157]
Aldrin's bootprint; part of an experiment to test the properties of the lunarregolith
They deployed theEASEP, which included aPassive Seismic Experiment Package used to measuremoonquakes and aretroreflector array used for thelunar laser ranging experiment.[158] Then Armstrong walked 196 feet (60 m) from the LM to take photographs at the rim ofLittle West Crater while Aldrin collected twocore samples. He used thegeologist's hammer to pound in the tubes—the only time the hammer was used on Apollo 11—but was unable to penetrate more than 6 inches (15 cm) deep. The astronauts then collected rock samples using scoops and tongs on extension handles. Many of the surface activities took longer than expected, so they had to stop documenting sample collection halfway through the allotted 34 minutes. Aldrin shoveled 6 kilograms (13 lb) of soil into the box of rocks to pack them in tightly.[159] Two types of rocks were found in the geological samples:basalt andbreccia.[160] Three new minerals were discovered in the rock samples collected by the astronauts:armalcolite,tranquillityite, andpyroxferroite. Armalcolite was named after Armstrong, Aldrin, and Collins. All have subsequently been found on Earth.[161]
While on the surface, Armstrong uncovered aplaque mounted on the LM ladder, bearing two drawings of Earth (of the Western and Eastern Hemispheres), an inscription, and signatures of the astronauts and President Nixon. The inscription read:
Here men from the planet Earth first set foot upon the Moon July 1969, A. D. We came in peace for all mankind.[15]
At the behest of theNixon administration to add a reference to God, NASA included the vague date as a reason to include A.D., which stands forAnno Domini ("in the year of our Lord").[162]
Mission Control used a coded phrase to warn Armstrong his metabolic rates were high, and that he should slow down. He was moving rapidly from task to task as time ran out. As metabolic rates remained generally lower than expected for both astronauts throughout the walk, Mission Control granted the astronauts a 15-minute extension.[158] In a 2010 interview, Armstrong explained that NASA limited the first moonwalk's time and distance because there was no empirical proof of how much cooling water the astronauts' PLSS backpacks would consume to handle their body heat generation while working on the Moon.[163]
Lunar ascent
Aldrin enteredEagle first. With some difficulty the astronauts lifted film and two sample boxes containing 21.55 kilograms (47.5 lb) of lunar surface material to the LM hatch using a flat cable pulley device called the Lunar Equipment Conveyor (LEC). This proved to be an inefficient tool, and later missions preferred to carry equipment and samples up to the LM by hand.[138] Armstrong reminded Aldrin of a bag of memorial items in his sleeve pocket, and Aldrin tossed the bag down. Armstrong then jumped onto the ladder's third rung, and climbed into the LM. After transferring to LMlife support, the explorers lightened the ascent stage for the return to lunar orbit by tossing out their PLSS backpacks, lunar overshoes, an empty Hasselblad camera, and other equipment. The hatch was closed again at 05:11:13. They then pressurized the LM and settled down to sleep.[164]
Aldrin next to the Passive Seismic Experiment Package with theLunar ModuleEagle in the background
Presidential speech writerWilliam Safire had prepared anIn Event of Moon Disaster announcement for Nixon to read in the event the Apollo 11 astronauts were stranded on the Moon.[165] The remarks were in a memo from Safire to Nixon'sWhite House Chief of StaffH. R. Haldeman, in which Safire suggested a protocol the administration might follow in reaction to such a disaster.[166][167] According to the plan, Mission Control would "close down communications" with the LM, and a clergyman would "commend their souls to the deepest of the deep" in a public ritual likened toburial at sea. The last line of the prepared text contained an allusion toRupert Brooke's World War I poem "The Soldier".[167] The script for the speech does not make reference to Collins; as he remained onboardColumbia in orbit around the Moon, it was expected that he would be able to return the module to Earth in the event of a mission failure.[168]
While moving inside the cabin, Aldrin accidentally damaged thecircuit breaker that would arm the main engine for liftoff from the Moon. There was a concern this would prevent firing the engine, stranding them on the Moon. The nonconductive tip of a Durofelt-tip pen[169] was sufficient to activate the switch.[164]
After more than21+1⁄2 hours on the lunar surface, in addition to the scientific instruments, the astronauts left behind: anApollo 1 mission patch in memory of astronauts Roger Chaffee,Gus Grissom, andEdward White, who died when their command module caught fire during a test in January 1967; two memorial medals of Soviet cosmonautsVladimir Komarov andYuri Gagarin, who died in 1967 and 1968 respectively; a memorial bag containing a gold replica of an olive branch as a traditional symbol of peace; and a silicon message disk carrying thegoodwill statements by presidents Eisenhower, Kennedy, Johnson, and Nixon along with messages from leaders of 73 countries around the world.[170] The disk also carries a listing of the leadership of the US Congress, a listing of members of the four committees of the House and Senate responsible for the NASA legislation, and the names of NASA's past and then-current top management.[171]
Map showing landing site and photos taken
After about seven hours of rest, the crew was awakened by Houston to prepare for the return flight. At that time, unknown to them, some hundred kilometers away from them the Soviet probeLuna 15 was about to descend and impact. Despite having been known to be orbiting the Moon at the same time, through a ground-breaking precautious goodwill exchange of data, the mission control of Luna 15 unexpectedly hastened its roboticsample-return mission, initiating descent, in an attempt to return before Apollo 11.[172] Just two hours before Apollo 11's launch Luna 15 crashed at 15:50 UTC, with British astronomers monitoring Luna 15 and recording the situation one commented: "I say, this has really been drama of the highest order",[173] bringing theSpace Race to a culmination.[174]
Roughly two hours later, at 17:54:00 UTC, the Apollo 11 crew on the surface safely lifted off inEagle's ascent stage to rejoin Collins aboardColumbia in lunar orbit.[146] Film taken from the LM ascent stage upon liftoff from the Moon reveals the American flag, planted some 25 feet (8 m) from the descent stage, whipping violently in the exhaust of the ascent stage engine. Aldrin looked up in time to witness the flag topple: "The ascent stage of the LM separated ... I was concentrating on the computers, and Neil was studying theattitude indicator, but I looked up long enough to see the flag fall over."[175] Subsequent Apollo missions planted their flags farther from the LM.[176]
Columbia in lunar orbit
During his day flying solo around the Moon, Collins never felt lonely. Although it has been said "not sinceAdam has any human known such solitude",[177] Collins felt very much a part of the mission. In his autobiography he wrote: "this venture has been structured for three men, and I consider my third to be as necessary as either of the other two".[177] In the 48 minutes of each orbit when he was out of radio contact with the Earth whileColumbia passed round the far side of the Moon, the feeling he reported was not fear or loneliness, but rather "awareness, anticipation, satisfaction, confidence, almost exultation".[177]
One of Collins' first tasks was to identify the Lunar Module on the ground. To give Collins an idea where to look, Mission Control radioed that they believed the Lunar Module landed about 4 miles (6.4 km) off target. Each time he passed over the suspected lunar landing site, he tried in vain to find the module. On his first orbits on the back side of the Moon, Collins performed maintenance activities such as dumping excess water produced by thefuel cells and preparing the cabin for Armstrong and Aldrin to return.[178]
Just before he reached the dark side on the third orbit, Mission Control informed Collins there was a problem with the temperature of the coolant. If it became too cold, parts ofColumbia might freeze. Mission Control advised him to assume manual control and implement Environmental Control System Malfunction Procedure 17. Instead, Collins flicked the switch on the system from automatic to manual and back to automatic again, and carried on with normal housekeeping chores, while keeping an eye on the temperature. WhenColumbia came back around to the near side of the Moon again, he was able to report that the problem had been resolved. For the next couple of orbits, he described his time on the back side of the Moon as "relaxing". After Aldrin and Armstrong completed their EVA, Collins slept so he could be rested for the rendezvous. While the flight plan called forEagle to meet up withColumbia, Collins was prepared for a contingency in which he would flyColumbia down to meetEagle.[179]
Eagle rendezvoused withColumbia at 21:24 UTC on July 21, and the two docked at 21:35.Eagle's ascent stage was jettisoned into lunar orbit at 23:41.[9] Just before theApollo 12 flight, it was noted thatEagle was still likely to be orbiting the Moon. Later NASA reports mentioned thatEagle's orbit had decayed, resulting in it impacting in an "uncertain location" on the lunar surface.[180] In 2021, however, some calculations show that the lander may still be in orbit.[181]
On July 23, the last night before splashdown, the three astronauts made a television broadcast in which Collins commented: "All this is possible only through the blood, sweat, and tears of a number of people ... All you see is the three of us, but beneath the surface are thousands and thousands of others, and to all of those, I would like to say, 'Thank you very much'."[182] Aldrin added: "This has been far more than three men on a mission to the Moon; more, still, than the efforts of a government and industry team; more, even, than the efforts of one nation. We feel that this stands as a symbol of the insatiable curiosity of all mankind to explore the unknown ..."[182]
Armstrong concluded:
The responsibility for this flight lies first with history and with the giants of science who have preceded this effort; next with the American people, who have, through their will, indicated their desire; next with four administrations and their Congresses, for implementing that will; and then, with the agency and industry teams that built our spacecraft, the Saturn, the Columbia, the Eagle, and the littleEMU, the spacesuit and backpack that was our small spacecraft out on the lunar surface. We would like to give special thanks to all those Americans who built the spacecraft; who did the construction, design, the tests, and put their hearts and all their abilities into those craft. To those people tonight, we give a special thank you, and to all the other people that are listening and watching tonight, God bless you. Good night from Apollo 11.[182]
On the return to Earth, a bearing at the Guam tracking station failed, potentially preventing communication on the last segment of the Earth return. A regular repair was not possible in the available time but the station director, Charles Force, had his ten-year-old son Greg use his small hands to reach into the housing and pack it with grease. Greg was later thanked by Armstrong.[183]
Splashdown and quarantine
Columbia floats on the ocean as Navy divers assist in retrieving the astronauts.
Theaircraft carrierUSS Hornet, under the command ofCaptainCarl J. Seiberlich,[184] was selected as the primary recovery ship (PRS) for Apollo 11 on June 5, replacing her sister ship, theLPHUSS Princeton, which had recovered Apollo 10 on May 26.Hornet was then at her home port ofLong Beach, California.[185] On reachingPearl Harbor on July 5,Hornetembarked theSikorsky SH-3 Sea King helicopters ofHS-4, a unit which specialized in recovery of Apollo spacecraft, specialized divers ofUDT Detachment Apollo, a 35-man NASA recovery team, and about 120 media representatives. To make room, most ofHornet's air wing was left behind in Long Beach. Special recovery equipment was also loaded, including aboilerplate command module used for training.[186]
Weather satellites were not yet common, but US Air ForceCaptain Hank Brandli had access to top-secretspy satellite images. He realized that a storm front was headed for the Apollo recovery area. Poor visibility which could make locating the capsule difficult, and strong upper-level winds which "would have ripped their parachutes to shreds" according to Brandli, posed a serious threat to the safety of the mission.[190] Brandli alerted Navy Captain Willard S. Houston Jr., the commander of theFleet Weather Center at Pearl Harbor, who had the required security clearance. On their recommendation,Rear AdmiralDonald C. Davis, commander of Manned Spaceflight Recovery Forces, Pacific, advised NASA to change the recovery area, each man risking his career. A new location was selected 215 nautical miles (398 km) northeast.[191][192]
This altered the flight plan. A different sequence of computer programs was used, one never before attempted. In a conventional entry, trajectory event P64 was followed by P67. For a skip-out re-entry, P65 and P66 were employed to handle the exit and entry parts of the skip. In this case, because they were extending the re-entry but not actually skipping out, P66 was not invoked and instead, P65 led directly to P67. The crew were also warned they would not be in a full-lift (heads-down) attitude when they entered P67.[191] The first program's acceleration subjected the astronauts to 6.5 standard gravities (64 m/s2); the second, to 6.0 standard gravities (59 m/s2).[193]
Before dawn on July 24,Hornet launched four Sea King helicopters and threeGrumman E-1 Tracers. Two of the E-1s were designated as "air boss" while the third acted as a communications relay aircraft. Two of the Sea Kings carried divers and recovery equipment. The third carried photographic equipment, and the fourth carried the decontamination swimmer and the flight surgeon.[194] At 16:44 UTC (05:44 local time)Columbia'sdrogue parachutes were deployed. This was observed by the helicopters. Seven minutes laterColumbia struck the water forcefully 2,660 km (1,440 nmi) east ofWake Island, 380 km (210 nmi) south of Johnston Atoll, and 24 km (13 nmi) fromHornet,[9][191] at13°19′N169°9′W / 13.317°N 169.150°W /13.317; -169.150.[195] 82 °F (28 °C) with 6 feet (1.8 m) seas and winds at 17 knots (31 km/h; 20 mph) from the east were reported under broken clouds at 1,500 feet (460 m) with visibility of 10 nautical miles (19 km; 12 mi) at the recovery site.[196] Reconnaissance aircraft flying to the original splashdown location reported the conditions Brandli and Houston had predicted.[197]
Duringsplashdown,Columbia landed upside down but was righted within ten minutes by flotation bags activated by the astronauts.[198] A diver from the Navy helicopter hovering above attached asea anchor to prevent it from drifting.[199] More divers attached flotation collars to stabilize the module and positioned rafts for astronaut extraction.[200]
Crew of Apollo 11 inquarantine after returning to Earth, visited by Richard Nixon
The divers then passed biological isolation garments (BIGs) to the astronauts, and assisted them into the life raft. The possibility of bringing backpathogens from the lunar surface was considered remote, but NASA took precautions at the recovery site. The astronauts were rubbed down with asodium hypochlorite solution andColumbia wiped withPovidone-iodine to remove any lunar dust that might be present. The astronauts were winched on board the recovery helicopter. BIGs were worn until they reached isolation facilities on boardHornet. The raft containing decontamination materials was intentionally sunk.[198]
After touchdown onHornet at 17:53 UTC, the helicopter was lowered by the elevator into the hangar bay, where the astronauts walked the 30 feet (9.1 m) to themobile quarantine facility (MQF), where they would begin the Earth-based portion of their 21 days of quarantine.[201] This practice would continue for two more Apollo missions, Apollo 12 andApollo 14, before the Moon was proven to be barren of life, and the quarantine process dropped.[202][203] Nixon welcomed the astronauts back to Earth. He told them: "[A]s a result of what you've done, the world has never been closer together before."[204]
After Nixon departed,Hornet was brought alongside the 5-short-ton (4.5 t)Columbia, which was lifted aboard by the ship's crane, placed on adolly and moved next to the MQF. It was then attached to the MQF with a flexible tunnel, allowing the lunar samples, film, data tapes and other items to be removed.Hornet returned to Pearl Harbor, where the MQF was loaded onto aLockheed C-141 Starlifter and airlifted to the Manned Spacecraft Center. The astronauts arrived at theLunar Receiving Laboratory at 10:00 UTC on July 28.Columbia was taken toFord Island for deactivation, and its pyrotechnics made safe. It was then taken toHickham Air Force Base, from whence it was flown to Houston in aDouglas C-133 Cargomaster, reaching the Lunar Receiving Laboratory on July 30.[205]
In accordance with theExtra-Terrestrial Exposure Law, a set of regulations promulgated by NASA on July 16 to codify its quarantine protocol,[206] the astronauts continued in quarantine. After three weeks in confinement (first in the Apollo spacecraft, then in their trailer onHornet, and finally in the Lunar Receiving Laboratory), the astronauts were given a clean bill of health.[207] On August 10, 1969, the Interagency Committee on Back Contamination met in Atlanta and lifted the quarantine on the astronauts, on those who had joined them in quarantine (NASA physicianWilliam Carpentier and MQF project engineerJohn Hirasaki),[208] and onColumbia itself. Loose equipment from the spacecraft remained in isolation until the lunar samples were released for study.[209]
Numerous countries and organizations honored the Moon landing by issuing special commemorative items. These included postage stamps, coins, medals, plaques, and magazine features.TIME,National Geographic,LIFE, and dozens of international publications featured the astronauts on their covers. Many of these commemoratives are now held in public and private collections, and some were placed aboard later Apollo missions in symbolic tribute.[217]
Additionally, the success of Apollo 11 contributed to a brief spike in interest in science and technology education, often referred to as the “Apollo effect,” influencing a generation of engineers and scientists.[218]
8-Day NASA Mission timeline [9-Days]
Date & Mission Day
Summary & Milestones
Launch and Translunar Flight
July 16, 1969 (Day 1)
Mission Day 1 (Launch from Earth) Summary
(All times are in Earth-based Eastern Standard Time (EST)
A girl holdingThe Washington Post newspaper stating "'The Eagle Has Landed' – Two Men Walk on the Moon"
Humans walking on the Moon and returning safely to Earth accomplished Kennedy's goal set eight years earlier. In Mission Control during the Apollo 11 landing, Kennedy's speech flashed on the screen, followed by the words "TASK ACCOMPLISHED, July 1969".[219] The success of Apollo 11 demonstrated the United States' technological superiority;[219] and with the success of Apollo 11, America had won theSpace Race.[220][221]
New phrases permeated into the English language. "If they can send a man to the Moon, why can't they ...?" became a common saying following Apollo 11.[222] Armstrong's words on the lunar surface also spun off various parodies.[220]
While most people celebrated the accomplishment, disenfranchised Americans saw it as a symbol of the divide in America, evidenced by protesters led byRalph Abernathy outside of Kennedy Space Center the day before Apollo 11 launched.[223] NASA AdministratorThomas Paine met with Abernathy at the occasion, both hoping that the space program can spur progress also in other regards, such as poverty in the US.[224] Paine was then asked, and agreed, to host protesters as spectators at the launch,[224] and Abernathy, awestruck by the spectacle,[107] prayed for the astronauts.[224] Racial and financial inequalities frustrated citizens who wondered why money spent on the Apollo program was not spent taking care of humans on Earth. A poem byGil Scott-Heron called "Whitey on the Moon" (1970) illustrated theracial inequality in the United States that was highlighted by the Space Race.[220][225][226] The poem starts with:
A rat done bit my sister Nell. (with Whitey on the moon) Her face and arms began to swell. (and Whitey's on the moon) I can't pay no doctor bill. (but Whitey's on the moon) Ten years from now I'll be paying still. (while Whitey's on the moon) [...][226]
Twenty percent of the world's population watched humans walk on the Moon for the first time.[227] While Apollo 11 sparked the interest of the world, the follow-on Apollo missions did not hold the interest of the nation.[219] One possible explanation was the shift in complexity. Landing someone on the Moon was an easy goal to understand; lunar geology was too abstract for the average person. Another is that Kennedy's goal of landing humans on the Moon had already been accomplished.[228] A well-defined objective helped Project Apollo accomplish its goal, but after it was completed it was hard to justify continuing the lunar missions.[229][230]
While most Americans were proud of their nation's achievements in space exploration, only once during the late 1960s did theGallup Poll indicate that a majority of Americans favored "doing more" in space as opposed to "doing less". By 1973, 59 percent of those polled favored cutting spending on space exploration. The Space Race had been won, and Cold War tensions were easing as the US and Soviet Union entered the era ofdétente. This was also a time when inflation was rising, which put pressure on the government to reduce spending. The space program was saved due to the perception that it was one of the few government programs that had achieved something great. Drastic cuts, warnedCaspar Weinberger, the deputy director of theOffice of Management and Budget, might send a signal that "our best years are behind us".[231]
After the Apollo 11 mission, officials from the Soviet Union said landing humans on the Moon was dangerous and unnecessary. At the time the Soviet Union was attempting to retrieve lunar samples robotically. The Soviets publicly denied there was a race to the Moon, and indicated they were not making an attempt.[232]Mstislav Keldysh said in July 1969, "We are concentrating wholly on the creation of large satellite systems." It was revealed in 1989 that the Soviets had tried to send people to the Moon, but were unable due to technological difficulties.[233] The public's reaction in the Soviet Union was mixed. The Soviet government limited the release of information about the lunar landing, which affected the reaction. A portion of the populace did not give it any attention, and another portion was angered by it.[234]
Columbia was moved in 2017 to the NASM Mary Baker Engen Restoration Hangar at theSteven F. Udvar-Hazy Center in Chantilly, Virginia, to be readied for a four-city tour titledDestination Moon: The Apollo 11 Mission. This includedSpace Center Houston from October 14, 2017, to March 18, 2018, theSaint Louis Science Center from April 14 to September 3, 2018, the Senator JohnHeinz History Center inPittsburgh from September 29, 2018, to February 18, 2019, and its last location atMuseum of Flight inSeattle from March 16 to September 2, 2019.[236][238] Continued renovations at the Smithsonian allowed time for an additional stop for the capsule, and it was moved to theCincinnati Museum Center. The ribbon cutting ceremony was on September 29, 2019.[239]
For 40 years Armstrong's and Aldrin's space suits were displayed in the museum'sApollo to the Moon exhibit,[240] until it permanently closed on December 3, 2018, to be replaced by a new gallery which was scheduled to open in 2022. A special display of Armstrong's suit was unveiled for the 50th anniversary of Apollo 11 in July 2019.[241][242] The quarantine trailer, the flotation collar and the flotation bags are in the Smithsonian'sSteven F. Udvar-Hazy Center annex nearWashington Dulles International Airport in Chantilly, Virginia, where they are on display along with a test lunar module.[243][244][245]
The descent stage of the LMEagle remains on the Moon. In 2009, theLunar Reconnaissance Orbiter (LRO) imaged the various Apollo landing sites on the surface of the Moon, for the first time with sufficient resolution to see the descent stages of the lunar modules, scientific instruments, and foot trails made by the astronauts.[246]
The remains of the ascent stage are assumed to lie at an unknown location on the lunar surface. The ascent stage,Eagle, was not tracked after it was jettisoned. The lunar gravity field is sufficiently non-uniform to make low Moon orbits unstable after a short time, leading the orbiting object to impact the surface.[247] However, using a program developed by NASA, and high-resolution lunar gravity data, a paper was published, in 2021, indicating thatEagle might still be in orbit as late as 2020. Using the orbital elements published by NASA, aMonte Carlo method was used to generate parameter sets that bracket the uncertainties in these elements. All simulations, of the orbit, predicted thatEagle would never impact the lunar surface.[248]
In March 2012 a team of specialists financed byAmazon founderJeff Bezos located theF-1 engines from the S-IC stage that launched Apollo 11 into space. They were found on the Atlantic seabed using advanced sonar scanning.[249] His team brought parts of two of the five engines to the surface. In July 2013, a conservator discovered a serial number under the rust on one of the engines raised from the Atlantic, which NASA confirmed was from Apollo 11.[250][251] The S-IVB third stage which performed Apollo 11's trans-lunar injection remains in a solar orbit near to that of Earth.[252]
The main repository for the Apollo Moon rocks is theLunar Sample Laboratory Facility at the Lyndon B. Johnson Space Center inHouston, Texas. For safekeeping, there is also a smaller collection stored atWhite Sands Test Facility nearLas Cruces, New Mexico. Most of the rocks are stored in nitrogen to keep them free of moisture. They are handled only indirectly, using special tools. Over 100 research laboratories worldwide conduct studies of the samples; approximately 500 samples are prepared and sent to investigators every year.[253][254]
In November 1969, Nixon asked NASA to make up about 250 presentationApollo 11 lunar sample displays for 135 nations, the fifty states of the United States and its possessions, and the United Nations. Each display included Moon dust from Apollo 11 and flags, including one of the Soviet Union, taken along by Apollo 11. The rice-sized particles were four small pieces of Moon soil weighing about 50 mg and were enveloped in a clear acrylic button about as big as aUnited States half-dollar coin. This acrylic button magnified the grains of lunar dust. Nixon gave the Apollo 11 lunar sample displays as goodwill gifts in 1970.[255][256]
Experiment results
The Passive Seismic Experiment ran until the command uplink failed on August 25, 1969. The downlink failed on December 14, 1969.[257] As of 2018[update], theLunar Laser Ranging experiment remains operational.[258]
Moonwalk camera
The Hasselblad camera used during the moonwalk was thought to be lost or left on the Moon surface.[259]
Lunar ModuleEagle memorabilia
In 2015, after Armstrong died in 2012, his widow contacted theNational Air and Space Museum to inform them she had found a white cloth bag in one of Armstrong's closets. The bag contained various items, which should have been left behind in theLunar ModuleEagle, including the 16mm Data Acquisition Camera that had been used to capture images of the first Moon landing.[260][261] The camera is currently on display at the National Air and Space Museum.[262]
Columbia at the Mary Baker Engen Restoration Hangar
On July 15, 2009,Life.com released a photo gallery of previously unpublished photos of the astronauts taken byLife photographerRalph Morse prior to the Apollo 11 launch.[263] From July 16 to 24, 2009, NASA streamed the original mission audio on its website in real time 40 years to the minute after the events occurred.[264] It is in the process of restoring the video footage and has released a preview of key moments.[265] In July 2010, air-to-ground voice recordings and film footage shot in Mission Control during the Apollo 11 powered descent and landing was re-synchronized and released for the first time.[266] TheJohn F. Kennedy Presidential Library and Museum set up anAdobe Flash website that rebroadcasts the transmissions of Apollo 11 from launch to landing on the Moon.[267]
On July 20, 2009, Armstrong, Aldrin, and Collins met with PresidentBarack Obama at the White House.[268] "We expect that there is, as we speak, another generation of kids out there who are looking up at the sky and are going to be the next Armstrong, Collins, and Aldrin", Obama said. "We want to make sure that NASA is going to be there for them when they want to take their journey."[269] On August 7, 2009, an act of Congress awarded the three astronauts aCongressional Gold Medal, the highest civilian award in the United States. The bill was sponsored by Florida SenatorBill Nelson and Florida RepresentativeAlan Grayson.[270][271]
A group of British scientists interviewed as part of the anniversary events reflected on the significance of the Moon landing:
It was carried out in a technically brilliant way with risks taken ... that would be inconceivable in the risk-averse world of today ... The Apollo programme is arguably the greatest technical achievement of mankind to date ... nothing since Apollo has come close [to] the excitement that was generated by those astronauts—Armstrong, Aldrin and the 10 others who followed them.[272]
A documentary film,Apollo 11, with restored footage of the 1969 event, premiered inIMAX on March 1, 2019, and broadly in theaters on March 8.[275][276]
The Smithsonian Institute'sNational Air and Space Museum andNASA sponsored the "Apollo 50 Festival" on theNational Mall in Washington DC. The three-day (July 18 to 20, 2019) outdoor festival featured hands-on exhibits and activities, live performances, and speakers such asAdam Savage and NASA scientists.[277]
Saturn V rocket projected onto theWashington Monument during the Apollo 11 50th anniversary show
As part of the festival, a projection of the 363-foot (111 m) tallSaturn V rocket was displayed on the east face of the 555-foot (169 m) tallWashington Monument from July 16 through the 20th from 9:30 pm until 11:30 pm (EDT). The program also included a 17-minute show that combined full-motion video projected on the Washington Monument to recreate the assembly and launch of theSaturn V rocket. The projection was joined by a 40-foot (12 m) wide recreation of theKennedy Space Center countdown clock and two large video screens showing archival footage to recreate the time leading up to the moon landing. There were three shows per night on July 19–20, with the last show on Saturday, delayed slightly so the portion where Armstrong first set foot on the Moon would happen exactly 50 years to the second after the actual event.[278]
On July 19, 2019, theGoogle Doodle paid tribute to the Apollo 11 Moon landing, complete with a link to an animated YouTube video with voiceover by astronautMichael Collins.[279][280]
Aldrin, Collins, and Armstrong's sons were hosted by PresidentDonald Trump in the Oval Office.[281][282]
Apollo 11, a 2019 documentary film by Todd Douglas Miller with restored footage of the 1969 event[286][287]
Chasing the Moon, a July 2019PBS three-night six-hour documentary, directed byRobert Stone, examined the events leading up to the mission. An accompanying book of the same name was also released.[288]
8 Days: To the Moon and Back, aPBS andBBC Studios 2019 documentary film by Anthony Philipson re-enacting major portions of the mission using mission audio recordings, new studio footage, NASA and news archives, and computer-generated imagery.[289]
^abEric Jones of theApollo Lunar Surface Journal explains that the indefinite article "a" was intended, whether or not it was said; the intention was to contrasta man (an individual's action) andmankind (as a species).[14]
Citations
In some of the following sources, times are shown in the formathours:minutes:seconds (e.g. 109:24:15), referring to the mission's Ground Elapsed Time (GET),[290] based on the official launch time of July 16, 1969, 13:32:00UTC (000:00:00 GET).[105][6]
^Byrne., Dave (July 8, 2019)."Apollo 11 Image Library".hq.nasa.gov.Archived from the original on February 24, 2020. RetrievedJune 10, 2021.
^abcdeJones, Eric M., ed. (1995)."The First Lunar Landing".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on December 27, 2016. RetrievedJune 13, 2013.
^Williams, David R. (December 11, 2003)."Apollo Landing Site Coordinates".NASA Space Science Data Coordinated Archive. NASA.Archived from the original on December 25, 2018. RetrievedOctober 18, 2021.
^Jones, Eric (April 8, 2018)."One Small Step".Apollo 11 Lunar Surface Journal.Archived from the original on September 3, 2019. RetrievedSeptember 6, 2019.
^abcdefgJones, Eric M., ed. (1995)."One Small Step".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on August 8, 2019. RetrievedJune 13, 2013.
^Glen E. Swanson, ed. (August 5, 2004).SP-4223: Before This Decade is Out—Personal Reflections on the Apollo Program—Chapter 9—Glynn S. Lunney.NASA. p. 211.ISBN978-0-16-050139-5.Archived from the original on February 27, 2021. RetrievedJune 21, 2019.Apollo 11 flight directors pose for a group photo in the Mission Control Center. Pictured left to right, and the shifts that they served during the mission, are (in front and sitting) Clifford E. Charlesworth (Shift 1), Gerald D. Griffin (Shift 1), Eugene F. Kranz (Shift 2), Milton L. Windler (Shift 4), and Glynn S. Lunney (Shift 3). (NASA Photo S-69-39192.)
^Woods, David; MacTaggart, Ken; O'Brien, Frank (May 18, 2019)."Day 4, part 4: Checking Out Eagle". Apollo Flight Journal.Archived from the original on February 24, 2021. RetrievedJune 21, 2019 – viaNASA.
^abWoods, W. David; MacTaggart, Kenneth D.; O'Brien, Frank (June 6, 2019)."Day 1, Part 1: Launch". Apollo Flight Journal.Archived from the original on December 5, 2020. RetrievedOctober 11, 2018 – via NASA.
^Woods, W. David; MacTaggart, Kenneth D.; O'Brien, Frank (February 10, 2017)."Day 4, part 1: Entering Lunar Orbit". Apollo Flight Journal.Archived from the original on February 27, 2021. RetrievedJuly 14, 2019 – via NASA.
^"Apollo 11 Lunar Landing Mission"(PDF) (Press kit). Washington, D.C.: NASA. July 6, 1969. Release No: 69-83K.Archived(PDF) from the original on August 11, 2013. RetrievedJune 13, 2013.
^Martin, Fred H. (July 1994)."Apollo 11: 25 Years Later".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on May 27, 2013. RetrievedJune 13, 2013.
^Jones, Eric M., ed. (1995)."Post-landing Activities".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on May 10, 2013. RetrievedJune 13, 2013.
^abcdJones, Eric M.; Glover, Ken, eds. (1995)."First Steps".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on October 9, 2006. RetrievedSeptember 23, 2006.
^Canright, Shelley, ed. (July 15, 2004)."Apollo Moon Landing—35th Anniversary".NASA Education. NASA.Archived from the original on July 4, 2013. RetrievedJune 13, 2013. Includes the "a" article as intended.
^abJones, Eric M., ed. (1995)."EASEP Deployment and Closeout".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on February 25, 2014. RetrievedJune 13, 2013.
^abJones, Eric M., ed. (1995)."Trying to Rest".Apollo 11 Lunar Surface Journal. NASA.Archived from the original on May 10, 2013. RetrievedJune 13, 2013.
^"Apollo 11 Goodwill Messages"(PDF) (Press release). Washington, D.C.: NASA. July 13, 1969. Release No: 69-83F.Archived(PDF) from the original on September 3, 2019. RetrievedJune 14, 2013.
^Richelson, Jeffrey T. (October 2013)."Weather or Not".Air Force Magazine.Archived from the original on July 22, 2019. RetrievedJuly 22, 2019.
^abcWoods, W. David; MacTaggart, Kenneth D.; O'Brien, Frank."Day 9: Re-entry and Splashdown". Apollo Flight Journal.Archived from the original on November 12, 2020. RetrievedSeptember 27, 2018 – via NASA.
^Johnston, Richard S.; Dietlein, Lawrence F.; Berry, Charles A.; James f. Parker, Jr; West, Vita; Jones, Walton L. (January 1975)."The Lunar Quarantine Program".Biomedical Results of Apollo. NASA-SP-368. SP-368.Archived from the original on July 14, 2019. RetrievedSeptember 6, 2019.
^"Mobile Quarantine Facility".Smithsonian Air and Space Museum. March 20, 2016.Archived from the original on August 10, 2018. RetrievedSeptember 30, 2018.
^"Apollo 11 Flotation Collar".Smithsonian Air and Space Museum. March 20, 2016.Archived from the original on August 9, 2018. RetrievedSeptember 30, 2018.
^"Apollo 11 engine find confirmed".Albuquerque Journal. Albuquerque, New Mexico. July 21, 2013. p. 5.Archived from the original on April 7, 2019. RetrievedDecember 23, 2018 – via Newspapers.com.
^"Moon Landing Film Coming to Theaters".Pittsburgh Post-Gazette. Pittsburgh, Pennsylvania. September 1, 1969. p. 69.Archived from the original on September 5, 2019. RetrievedSeptember 5, 2019 – via Newspapers.com.
^"Space Specials at a Glance".Florida Today. Cocoa, Florida. July 17, 1994. p. 115.Archived from the original on September 27, 2021. RetrievedSeptember 14, 2019 – via Newspapers.com.
Bates, James R.; Lauderdale, W. W.; Kernaghan, Harold (April 1979).ALSEP Termination Report(PDF) (Report). Washington, D.C.: NASA. RP-1036.Archived(PDF) from the original on February 27, 2021. RetrievedSeptember 27, 2018.
Carmichael, Scott W. (2010).Moon Men Return: USSHornet and the Recovery of the Apollo 11 Astronauts. Annapolis, Maryland: Naval Institute Press.ISBN978-1-59114-110-5.OCLC562772897.
Chaikin, Andrew (2007). "Live from the Moon: The Societal Impact of Apollo". In Dick, Steven J.; Launius, Roger D. (eds.).Societal Impact of Spaceflight(PDF). Washington, D.C.: NASA.OCLC175218028. SP-4801.Archived(PDF) from the original on February 25, 2021. RetrievedJanuary 4, 2019.
Johnston, Richard S.; Dietlein, Lawrence F.; Berry, Charles A., eds. (1975).Biomedical Results of Apollo(PDF). Vol. NASA-SP-368. Washington, D.C.: NASA. SP-368.Archived(PDF) from the original on November 2, 2019. RetrievedNovember 2, 2019.
Swenson, Loyd S. Jr.; Grimwood, James M.; Alexander, Charles C. (1966).This New Ocean: A History of Project Mercury. The NASA History Series. Washington, D.C.: National Aeronautics and Space Administration.OCLC569889. SP-4201.Archived from the original on June 17, 2010. RetrievedJune 28, 2007.
"Coverage of the Flight of Apollo 11" as aired on CBS Radio and WCCO Radio (Minneapolis/St. Paul) for RadioTapes.com. Radio station recordings (airchecks) covering the flight of Apollo 11.
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated inunderline. Uncatalogued launch failures are listed initalics. Payloads deployed from other spacecraft are denoted in (brackets).
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