In a letter to Datamation, March 1, 1971, Margaret H. Hamilton, Director of Apollo Flight Computer Programming MIT Draper Laboratory, Cambridge, Massachusetts, stated: “Due to an error in the checklist manual, the rendezvous radar switch was placed in the wrong position.
This caused it to send erroneous signals to the computer. The result was that the computer was being asked to perform all of its normal functions for landing while receiving an extra load of spurious data which used up 15% of its time. |
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The computer (or rather the software in it) was smart enough to recognize that it was being asked to perform more tasks than it should be performing. It then sent out an alarm, which meant to the astronaut, I'm overloaded with more tasks than I should be doing at this time and I'm going to keep only the more important tasks; i.e., the ones needed for landing...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...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”.
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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 metres (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.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.
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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 (170 cm) probes hanging from Eagle's footpads had touched the surface, and he said "Contact light!". Three seconds later, Eagle landed and Armstrong said "Shutdown". Aldrin immediately said "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."
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Armstrong acknowledged Aldrin's completion of the post landing checklist with "Engine arm is off." before responding to Duke with the words, "Houston, Tranquility Base here. The Eagle has landed." Armstrong's change of call sign from "Eagle" to "Tranquility Base" confirmed that landing was complete and successful, and Duke mispronounced his reply as he 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 |
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On August 13, they rode in parades in their honor in New York, Chicago, and Los Angeles. On the same evening in Los Angeles there was an official State Dinner to celebrate the flight, attended by members of Congress, 44 governors, the Chief Justice of the United States, and ambassadors from 83 nations at the Century Plaza Hotel. President Richard Nixon and Vice President Spiro T. Agnew honored each astronaut with a presentation of the Presidential Medal of Freedom. This celebration was the beginning of a 45-day "Giant Leap" tour that brought the astronauts to 25 foreign countries and included visits with prominent leaders such as Queen Elizabeth II of the United Kingdom. Many nations would honor the first manned Moon landing by issuing Apollo 11 commemorative postage stamps or coins.On September 16, 1969, the three astronauts spoke before a joint session of Congress on Capitol Hill. They presented two U.S. flags, one to the House of Representatives and the other to the Senate, that had been carried to the surface of the Moon with them.
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The Soviet Union was secretly attempting to compete with the US in landing a man on the Moon, but had been hampered by repeated failures in development of a launcher comparable to the Saturn V. Meanwhile, they tried to beat the US to return lunar material to the Earth, by means of unmanned probes. On July 13, three days before Apollo 11's launch, they launched Luna 15 which reached lunar orbit before Apollo 11. During descent, a malfunction caused Luna 15 to crash in Mare Crisium, about two hours before Armstrong and Aldrin took off from the surface. The Jodrell Bank Observatory radio telescope in England was later discovered to have recorded transmissions from Luna 15 during its descent, and this was published in July 2009 on the 40th anniversary of Apollo 11 |
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The command module is displayed at the National Air and Space Museum, Washington, D.C. It is in the central Milestones of Flight exhibition hall in front of the Jefferson Drive entrance, sharing the main hall with other pioneering flight vehicles such as the Wright Flyer, the Spirit of St. Louis, the Bell X-1, the North American X-15, Mercury spacecraft Friendship 7, and Gemini 4. Armstrong's and Aldrin's space suits are displayed in the museum's Apollo to the Moon exhibit. The quarantine trailer, the flotation collar, and the righting spheres are displayed at the Smithsonian's Udvar-Hazy Center annex near Washington Dulles International Airport in Virginia.
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In 2009 the Lunar Reconnaissance Orbiter imaged the various Apollo landing sites on the surface of the Moon with sufficient resolution to see the descent stages of the lunar modules, scientific instruments, and foot trails made by the astronauts.In March 2012 Amazon founder Jeff Bezos located the F-1 engines that launched Apollo 11 into space. The engines were found below the Atlantic Ocean's surface through the use of advanced sonar scanning. His team plans to bring at least one of the five engines to the surface
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On July 15, 2009, Life.com released a photo gallery of previously unpublished photos of the astronauts taken by Life photographer Ralph Morse prior to the Apollo 11 launch.From July 16–24, 2009 NASA streamed the original mission audio on its website in real time 40 years to the minute after the events occurred. In addition, it is in the process of restoring the video footage and has released a preview of key moments.The John F. Kennedy Library set up a Flash website that rebroadcasts the transmissions of Apollo 11 from launch to landing on the Moon.
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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.
On August 7, 2009, an act of Congress awarded the three astronauts a Congressional Gold Medal, the highest civilian award in the United States. The bill was sponsored by Florida Sen. Bill Nelson and Florida Rep. Alan Grayson.
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-synchronised and released for the first time
There have been six manned moon landings -
- Apollo 11 landed 20 July 1969
- Apollo 12 landed 19 November 1969
- Apollo 14 landed 5 February 1971
- Apollo 15 landed 30 July 1971
- Apollo 16 landed 20 April 1972
- Apollo 17 landed 11 December 1972
The NASA Apollo missions also included 3 manned missions that only orbited the Moon : Apollo 8, 10, and 13 (the Apollo 13 landing mission was canceled after damage from an explosion).
There have been numerous unmanned moon landings, 13 soft landings are listed as well as 26 crash landings. Crash landings listed include retired satellites and orbiters, impactors, as well as failed soft landings.
USSR probes
- Luna 2 crashed 13 September 1959
- Luna 5 crashed 12 May 1965
- Luna 7 crashed 7 October 1965
- Luna 8 crashed 6 December 1965
- Luna 9 landed 3 February 1966
- Luna 13 landed 24 December 1966
- Luna 15 crashed 21 July 1969
- Luna 16 landed 20 September 1970
- Luna 17 landed 17 November 1970
- Luna 18 crashed 11 September 1971
- Luna 20 landed 21 February 1972
- Luna 21 landed 15 January 1973
- Luna 23 landed 6 November 1974
- Luna 24 landed 18 August 1976
NASA / US probes
- Ranger 4 crashed 26 April 1962
- Ranger 6 crashed 2 February 1964
- Ranger 7 crashed 31 July 1964
- Ranger 8 crashed 20 February 1965
- Ranger 9 crashed 24 March 1965
- Surveyor 1 landed 2 June 1966
- Surveyor 2 crashed 23 September 1966
- Surveyor 3 landed 20 April 1967
- Surveyor 4 crashed (or possibly exploded just above surface) 17 July 1967
- Surveyor 5 landed 11 September 1967
- Surveyor 6 landed 10 November 1967
- Surveyor 7 landed 10 January 1968
- Lunar Orbiter 1 crashed 29 October 1966
- Lunar Orbiter 2 crashed 11 October 1967
- Lunar Orbiter 3 crashed 9 October 1967
- Lunar Orbiter 4 crashed 31 October 1967
- Lunar Orbiter 5 crashed 31 January 1968
- Lunar Prospector crashed 31 July 1999
- LCROSS crashed 9 October 2009
Other Space Agency Probes
- Hiten (Japan) crashed 10 April 1993
- SMART 1 (ESA) crashed 3 September 2006
- MIP (India) crashed 14 November 2008
- Okina (Japan) crashed 12 February 2009
- Chang'e 1 (China) crashed 1 March 2009
- Kaguya (Japan) crashed 10 June 2009
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