The Eagle Has Landed
On July 16th, 1969, the Apollo 11 crew and their Saturn V launched from LC-39A at 13:32:00 UTC en route to the surface of 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 which we intend to win"
President John F. Kennedy, 1962
Pictured: The mighty Saturn V rocket as she passes through Max Q. The max q condition is the point when an aerospace vehicle's atmospheric flight reaches maximum dynamic pressure. After the Saturn V's seven and a half million pounds of thrust pushes her through Max Q, it's all downhill from there, and the opposite becomes true. The dynamic pressure acting against the craft decreases as the air density decreases, ultimately reaching 0
Next stop, Tranquillity Base...
July 19th, 1969, at precisely 17:21:50 UTC, Apollo 11 passed behind the Moon and fired its service propulsion engine to enter lunar orbit. In the thirty orbits that followed, the crew saw passing views of their landing site in the southern Sea of Tranquillity (Mare Tranquillitatis) about 12 miles southwest of the crater Sabine D (0.67408N, 23.47297E). The landing site was selected in part because it had been characterized as relatively flat and smooth by the automated Ranger 8 and Surveyor 5 landers along with the Lunar Orbiter mapping spacecraft, and was unlikely to present major landing or extra-vehicular activity (EVA) challenges.
July 20th, 1969, the Apollo 11 Lunar Module Eagle separated from the Command Module Columbia. Collins, alone aboard Columbia, inspected Eagle as it pirouetted before him to ensure the craft was not damaged.
As the descent began, Armstrong and Aldrin found they were passing landmarks on the surface 4 seconds early and reported that they were "long"; they would land miles west of their target point.
Five minutes into the descent burn, and 6,000 feet above the surface of the Moon, the LM navigation and guidance computer distracted the crew with the first of several unexpected "1202" and "1201" program alarms. Inside Mission Control Center in Houston, Texas, computer engineer Jack Garman told guidance officer Steve Bales it was safe to continue the descent, which was relayed to the crew.
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 980 ft diameter crater (later determined to be "West crater," named for its location in the western part of the originally planned landing ellipse). Armstrong took semi-automatic control and, with Aldrin calling out altitude and velocity data, landed at 20:17 UTC on July 20 with about 25 seconds of fuel left.
25 SECONDS OF FUEL LEFT!
Apollo 11 landed with less fuel than other missions, and the astronauts also encountered a premature low-fuel warning. This was later found to have been due to greater propellant 'slosh' than expected, uncovering a fuel sensor. On subsequent missions, extra baffles were added to the tanks to prevent this.
Throughout the descent, Aldrin had called out navigation data to Armstrong, who was busy piloting the LM. A few moments before the landing, a light informed Aldrin that at least one of the 67-inch probes hanging from Eagle's footpads had touched the surface, and he said, "Contact light!" Three seconds later, Eagle landed, and Armstrong called, "Shutdown."
Aldrin immediately responded, "Okay, engine stop. ACA - out of detent." Armstrong acknowledged "Out of detent. Auto," and Aldrin continued "Mode control - both auto. Descent engine command override off.
Engine arm - off. 413 is in."
Charles Duke, acting as CAPCOM during the landing phase, acknowledged their landing by saying, "We copy you down, Eagle."
Armstrong acknowledged Aldrin's completion of the post-landing checklist with "Engine arm is off" before responding to Duke with the words, "Houston, Tranquillity Base here. The Eagle has landed."
Armstrong's change of call sign from "Eagle" to "Tranquillity Base" confirmed that the landing was complete and successful, and Duke mispronounced his reply as he expressed the relief at Mission Control: "Roger, Twan-- Tranquillity, we copy you on the ground. You've got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."
As the descent began, Armstrong and Aldrin found they were passing landmarks on the surface 4 seconds early and reported that they were "long"; they would land miles west of their target point.
Five minutes into the descent burn, and 6,000 feet above the surface of the Moon, the LM navigation and guidance computer distracted the crew with the first of several unexpected "1202" and "1201" program alarms. Inside Mission Control Center in Houston, Texas, computer engineer Jack Garman told guidance officer Steve Bales it was safe to continue the descent, which was relayed to the crew.
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 980 ft diameter crater (later determined to be "West crater," named for its location in the western part of the originally planned landing ellipse). Armstrong took semi-automatic control and, with Aldrin calling out altitude and velocity data, landed at 20:17 UTC on July 20 with about 25 seconds of fuel left.
25 SECONDS OF FUEL LEFT!
Apollo 11 landed with less fuel than other missions, and the astronauts also encountered a premature low-fuel warning. This was later found to have been due to greater propellant 'slosh' than expected, uncovering a fuel sensor. On subsequent missions, extra baffles were added to the tanks to prevent this.
Throughout the descent, Aldrin had called out navigation data to Armstrong, who was busy piloting the LM. A few moments before the landing, a light informed Aldrin that at least one of the 67-inch probes hanging from Eagle's footpads had touched the surface, and he said, "Contact light!" Three seconds later, Eagle landed, and Armstrong called, "Shutdown."
Aldrin immediately responded, "Okay, engine stop. ACA - out of detent." Armstrong acknowledged "Out of detent. Auto," and Aldrin continued "Mode control - both auto. Descent engine command override off.
Engine arm - off. 413 is in."
Charles Duke, acting as CAPCOM during the landing phase, acknowledged their landing by saying, "We copy you down, Eagle."
Armstrong acknowledged Aldrin's completion of the post-landing checklist with "Engine arm is off" before responding to Duke with the words, "Houston, Tranquillity Base here. The Eagle has landed."
Armstrong's change of call sign from "Eagle" to "Tranquillity Base" confirmed that the landing was complete and successful, and Duke mispronounced his reply as he expressed the relief at Mission Control: "Roger, Twan-- Tranquillity, we copy you on the ground. You've got a bunch of guys about to turn blue. We're breathing again. Thanks a lot."
Pictured: Shortly after touching down, this is the very picture of the view through the LM window by astronaut Neil Armstrong from the surface of our moon.
02:39 UTC - July 21, 1969, Commander Neil Armstrong opened the hatch of the Lunar Lander "Eagle", and at 02:51 UTC began his descent to the lunar surface. The Remote Control Unit controls 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 against Eagle's side and activate the TV camera, and at 02:56:15 UTC he set his left foot on the surface.
After describing the surface dust as "very fine-grained" and "almost like a powder," Armstrong stepped off Eagle's footpad and uttered his famous line, "That's one small step for [a] man, one giant leap for mankind"
Despite some technical and weather difficulties, ghostly black-and-white images of the first lunar EVA were received and broadcast to at least 600 million people on Earth.
After describing the surface dust as "very fine-grained" and "almost like a powder," Armstrong stepped off Eagle's footpad and uttered his famous line, "That's one small step for [a] man, one giant leap for mankind"
Despite some technical and weather difficulties, ghostly black-and-white images of the first lunar EVA were received and broadcast to at least 600 million people on Earth.
During the Apollo 11 lunar surface EVA, three new minerals were discovered in the rock samples collected by the astronauts: armalcolite, tranquillityite, and pyroxferroite. Armalcolite was named after Armstrong, Aldrin, and Collins.
A little-known fact about Apollo 11 is that a simple felt-tip pen saved the lives of both astronauts and salvaged the entire moon mission.
As the mission was coming to a close, Aldrin, while moving within the LM, accidentally broke the circuit breaker that would arm the main engine for lift off from the Moon. There was a major concern since this would prevent firing the main engine, stranding on the surface of the Moon. Fortunately, a felt-tip pen was sufficient to activate the switch.
At 17:54 UTC, they lifted off in Eagle's ascent stage, carrying 21.5 kilograms of lunar samples with them, to rejoin CMP Michael Collins aboard Columbia in lunar orbit. Sadly, during the launch, Aldrin looked up in time to see the exhaust from the ascent module's engine knock over the American flag they had planted.
Buzz Aldrin was quoted as saying: "The ascent stage of the LM separated ... I was concentrating on the computers, and Neil was studying the attitude indicator, but I looked up long enough to see the flag fall over." Subsequent Apollo missions usually planted the American flags at least 100 feet from the LM to prevent its being blown over by the ascent engine exhaust.
Before their departure, the crew of Apollo 11 left some items, including Soviet medals commemorating Cosmonauts Vladimir Komarov and Yuri Gagarin.
A single Apollo 1 mission patch was also left in honour of her crew, Gus Grissom, Roger B. Chaffee and Edward White, who, on January 27, 1967, were killed at Cape Kennedy, Florida, during early testing of the Apollo I rocket. Many say that had that accident not occurred, Gus Grissom might very well have been the first man to walk on the moon.
A little-known fact about Apollo 11 is that a simple felt-tip pen saved the lives of both astronauts and salvaged the entire moon mission.
As the mission was coming to a close, Aldrin, while moving within the LM, accidentally broke the circuit breaker that would arm the main engine for lift off from the Moon. There was a major concern since this would prevent firing the main engine, stranding on the surface of the Moon. Fortunately, a felt-tip pen was sufficient to activate the switch.
At 17:54 UTC, they lifted off in Eagle's ascent stage, carrying 21.5 kilograms of lunar samples with them, to rejoin CMP Michael Collins aboard Columbia in lunar orbit. Sadly, during the launch, Aldrin looked up in time to see the exhaust from the ascent module's engine knock over the American flag they had planted.
Buzz Aldrin was quoted as saying: "The ascent stage of the LM separated ... I was concentrating on the computers, and Neil was studying the attitude indicator, but I looked up long enough to see the flag fall over." Subsequent Apollo missions usually planted the American flags at least 100 feet from the LM to prevent its being blown over by the ascent engine exhaust.
Before their departure, the crew of Apollo 11 left some items, including Soviet medals commemorating Cosmonauts Vladimir Komarov and Yuri Gagarin.
A single Apollo 1 mission patch was also left in honour of her crew, Gus Grissom, Roger B. Chaffee and Edward White, who, on January 27, 1967, were killed at Cape Kennedy, Florida, during early testing of the Apollo I rocket. Many say that had that accident not occurred, Gus Grissom might very well have been the first man to walk on the moon.
As the mission was coming to a close, and the crew of Apollo 11 watched the Earth grow as they approached their home planet...July 22nd, 1969, the last night before the Apollo 11 splashdown, the three astronauts made a television broadcast in which Collins commented,
"... The Saturn V rocket, which put us in orbit, is an incredibly complicated piece of machinery, every piece of which worked flawlessly ... We have always had confidence that this equipment will work properly. 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.'"
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 ... Personally, in reflecting on the events of the past several days, a verse from Psalms comes to mind. 'When I consider the heavens, the work of Thy fingers, the Moon and the stars, which Thou hast ordained; What is man that Thou art mindful of him?'"
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 little EMU, 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."
"... The Saturn V rocket, which put us in orbit, is an incredibly complicated piece of machinery, every piece of which worked flawlessly ... We have always had confidence that this equipment will work properly. 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.'"
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 ... Personally, in reflecting on the events of the past several days, a verse from Psalms comes to mind. 'When I consider the heavens, the work of Thy fingers, the Moon and the stars, which Thou hast ordained; What is man that Thou art mindful of him?'"
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 little EMU, 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."
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