A moon landing is the arrival of an intact manned or unmanned spacecraft on the surface of a planet's natural satellite. The concept has been a goal of humankind since it was first appreciated that the Moon is Earth's closest large celestial body. One of the clearest early examples of the concept in fiction was Jules Verne's novel From the Earth to the Moon, written in 1865. Since the Soviet Union first succeeded in implementing the concept in 1966, this term referred to eighteen spacecraft landings on the Moon through 1976. Nine of these missions returned to Earth bearing samples of moon rocks.
The United States achieved the first manned landing on Earth's Moon as part of the Apollo 11 mission commanded by Neil Armstrong. On July 20, 1969, Armstrong, accompanied by Edwin 'Buzz' Aldrin, landed the lunar module Eagle on the surface of the Moon. Armstrong and Aldrin spent a day on the surface of the Moon before returning to Earth. A total of six such manned moon landings were carried out between 1969 and 1972.
The Soviet Union later achieved sample returns via the unmanned Luna 16, Luna 20 and Luna 24 moon landings. Since this was during the time of the Cold War, the contest to be the first on the Moon was one of the most visible facets of the space race.
Progress in space exploration has since broadened the phrase to include other moons in the solar system as well. The Huygens probe of the Cassini mission to Saturn performed a successful unmanned moon landing on Titan in 2005. Similarly, the Soviet probe Phobos 2 came within of performing an unmanned moon landing on Mars' moon Phobos in 1989 before radio contact with that lander was suddenly lost. There is widespread interest in performing a future moon landing on Jupiter's moon Europa to drill down and explore the possible liquid water ocean beneath its icy surface.
Upon approach of the target moon, the spacecraft must decelerate enough to land safely. The velocity to be shed from the target moon's gravitational attraction is roughly equal to the escape velocity of the target moon. For Earth's Moon, this figure is 2.4 kilometers per second or around 5,000 miles per hour. This change in velocity (referred to as the delta-v) is usually provided by a landing rocket, which must be carried into space by the original launch vehicle as part of the overall spacecraft. An exception is a moon landing on Titan such as that carried out by the Huygens probe. As the only moon with an atmosphere, landings on Titan may be accomplished by using atmospheric entry techniques that are generally lighter in weight than a rocket with equivalent capability.
Whatever method is used to slow a spacecraft as it nears a moon, the key requirement for a moon landing is to be traveling at a survivable speed upon reaching the moon's surface. Such landings may be characterized as "soft" if a human could survive them, and "hard" if only a ruggedized machine would do so. Above such speeds, the space mission ends not in a landing but a crash. Such crashes can occur because of malfunctions in a spacecraft, or they can be deliberately arranged for vehicles that do not have an onboard landing rocket. There have been many such moon crashes. For example, during the Apollo program the S-IVB third stage of the Saturn V moon rocket as well as the spent ascent stage of the lunar module were deliberately crashed on the moon several times to provide impacts registering as a moonquake on seismometers that had been left on the lunar surface. Such crashes were instrumental in mapping the internal structure of the Moon.
If a return to Earth is desired after a moon landing is accomplished, the escape velocities of the moon and Earth must again be overcome for the spacecraft to come to rest on the surface of the Earth. Rockets must be used to leave the moon and return to space. Upon reaching Earth, atmospheric entry techniques are used to absorb the kinetic energy of a returning spacecraft and reduce its speed for safe landing. These functions greatly complicate a moon landing mission and lead to many additional operational considerations. Any moon departure rocket must first be carried to the moon's surface by a moon landing rocket, increasing the latter's required size. The moon departure rocket, larger moon landing rocket and any Earth atmosphere entry equipment such as heat shields and parachutes must in turn be lifted by the original launch vehicle, greatly increasing its size by a significant and almost prohibitive degree. This necessitates optimizing the sizing of stages in the launch vehicle as well as consideration of using space rendezvous between multiple spacecraft and reaching intermediate orbits prior to landing; in particular, lunar orbit rendezvous. Thus systems engineering and logistics become major factors in the design of any moon landing mission.
On October 4, 1957, the Soviet Union launched Sputnik 1 as the first artificial satellite to orbit the Earth and so initiated the Space Age. This unexpected event was a source of pride to the Soviets and shock to the Americans. This dramatic and successful demonstration of the new R-7 Semyorka rocket on only its third test flight meant that the Soviets could use ballistic missiles carrying hydrogen bombs in a surprise attack against any target on Earth, a frightening new capability the Americans did not have. Further, the steady beeping of the radio beacon aboard Sputnik 1 as it passed overhead every 96 minutes was widely viewed on both sides as effective propaganda to Third World countries demonstrating the technological superiority of the Soviet political system compared to the American one. This perception was reinforced by a string of subsequent rapid-fire Soviet space achievements. In 1959, the R-7 rocket was used to launch the first escape from Earth's gravity into a solar orbit, the first crash impact onto the surface of the Moon and the first photography of the never-before-seen far side of the Moon. These were the Luna 1, Luna 2 and Luna 3 spacecraft, respectively.
The American response to these Soviet achievements was to greatly accelerate previously languishing space and missile projects. Military efforts were initiated to develop and produce mass quantities of intercontinental ballistic missiles (ICBMs) that would bridge the so-called missile gap and enable a policy of deterrence to nuclear war with the Soviets known as Mutually Assured Destruction or MAD. These newly-developed missiles were made available to civilians of the newly formed NASA space agency for various projects which would demonstrate the payload, guidance accuracy and reliabilities of American ICBMs to the Soviets. While NASA stressed peaceful and scientific uses for these rockets, their use in various lunar exploration efforts also had secondary goal of realistic, goal-oriented testing of the missiles themselves and development of associated infrastructure just as the Soviets were doing with their R-7. The tight schedules and lofty goals selected by NASA for lunar exploration also had an undeniable element of generating counter-propaganda to show to other countries that American technological prowess was the equal and even superior to that of the Soviets.
|U.S. Mission||Mass (kg)||Launch Vehicle||Launched||Mission Goal||Mission Result|
|Pioneer 0||38||Thor-Able||17 Aug 1958||Lunar orbit||Failure - first stage explosion; destroyed|
|Pioneer 1||34||Thor-Able||11 Oct 1958||Lunar orbit||Failure - software error; reentry|
|Pioneer 2||39||Thor-Able||08 Nov 1958||Lunar orbit||Failure - third stage misfire; reentry|
|Pioneer 3||6||Juno||06 Dec 1958||Lunar flyby||Failure - first stage misfire, reentry|
|Pioneer 4||6||Juno||03 Mar 1959||Lunar flyby||Failure - targeting error; solar orbit|
|Pioneer P-1||168||Atlas-Able||24 Sep 1959||Lunar orbit||Failure - pad explosion; destroyed|
|Pioneer P-3||168||Atlas-Able||29 Nov 1959||Lunar orbit||Failure - payload shroud; destroyed|
|Pioneer P-30||175||Atlas-Able||25 Sep 1960||Lunar orbit||Failure - second stage anomaly; reentry|
|Pioneer P-31||175||Atlas-Able||15 Dec 1960||Lunar orbit||Failure - first stage explosion; destroyed|
|Ranger 1||306||Atlas - Agena||23 Aug 1961||Prototype test||Failure - upper stage anomaly; reentry|
|Ranger 2||304||Atlas - Agena||18 Nov 1961||Prototype test||Failure - upper stage anomaly; reentry|
|Ranger 3||330||Atlas - Agena||26 Jan 1962||Moon landing||Failure - booster guidance; solar orbit|
|Ranger 4||331||Atlas - Agena||23 Apr 1962||Moon landing||Failure - spacecraft computer; crash impact|
|Ranger 5||342||Atlas - Agena||18 Oct 1962||Moon landing||Failure - spacecraft power; solar orbit|
|Ranger 6||367||Atlas - Agena||30 Jan 1964||Lunar impact||Failure - spacecraft camera; crash impact|
|Ranger 7||367||Atlas - Agena||28 Jul 1964||Lunar impact||Success - returned 4308 photos, crash impact|
|Ranger 8||367||Atlas - Agena||17 Feb 1965||Lunar impact||Success - returned 7137 photos, crash impact|
|Ranger 9||367||Atlas - Agena||21 Mar 1965||Lunar impact||Success - returned 5814 photos, crash impact|
Three different designs of Pioneer lunar probes were flown on three different modified ICBMs. Those flown on the Thor booster modified with an Able upper stage carried an infrared image scanning television system with a resolution of 1 milliradian to study the Moon's surface, an ionization chamber to measure radiation in space, a diaphragm/microphone assembly to detect micrometeorites, a magnetometer, and temperature-variable resistors to monitor spacecraft internal thermal conditions. The first, a mission managed by the United States Air Force, exploded during launch; all subsequent Pioneer lunar flights had NASA as the lead management organization. The next two returned to Earth and burned up upon reentry into the atmosphere after achieved maximum altitudes of around 70,000 and , far short of the roughly required to reach the vicinity of the Moon.
NASA then collaborated with the United States Army's Ballistic Missile Agency to fly two extremely small cone-shaped probes on the Juno ICBM, carrying only photocells which would be triggered by the light of the Moon and a lunar radiation environment experiment using a Geiger-Müller tube detector. The first of these reached an altitude of only around , serendipitously gathering data that established the presence of the Van Allen radiation belts before reentering Earth's atmosphere. The second passed by the moon at a distance of over , twice as far away as planned and too far away to trigger either of the onboard scientific instruments, yet still becoming the first American spacecraft to reach a solar orbit.
The final Pioneer lunar probe design consisted of four "paddlewheel" solar panels extending from a one-meter diameter spherical spin-stabilized spacecraft body that was equipped to take images of the lunar surface with a television-like system, estimate the Moon's mass and topography of the poles, record the distribution and velocity of micrometeorites, study radiation, measure magnetic fields, detect low frequency electromagnetic waves in space and use a sophisticated integrated propulsion system for maneuvering and orbit insertion as well. None of the four spacecraft built in this series of probes survived launch on its Atlas ICBM outfitted with an Able upper stage.
Following the unsuccessful Atlas-Able Pioneer probes, NASA's Jet Propulsion Laboratory embarked upon an unmanned spacecraft development program whose modular design could be used to support both lunar and interplanetary exploration missions. The interplanetary versions were known as Mariners; lunar versions were Rangers. JPL envisioned three versions of the Ranger lunar probes: Block I prototypes, which would carry various radiation detectors in test flights to a very high Earth orbit that came nowhere near the Moon; Block II, which would try to accomplish the first Moon landing by hard landing a seismometer package; and Block III, which would crash onto the lunar surface without any braking rockets while taking very high resolution wide-area photographs of the Moon during their descent.
The Ranger 1 and 2 Block I missions were virtually identical. Spacecraft experiments included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy-range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and scintillation counters. The goal was to place these Block I spacecraft in a very high Earth orbit with an apogee of . From that vantage point, scientists could make direct measurements of the magnetosphere over a period of many months while engineers perfected new methods to routinely track and communicate with spacecraft over such large distances. Such practice was deemed vital to be assured of capturing high-bandwidth television transmissions from the Moon during a one-shot fifteen minute time window in subsequent Block II and Block III lunar descents. Both Block I missions suffered failures of the new Agena upper stage and never left low earth parking orbit after launch; both burned up upon reentry after only a few days.
The first attempts to perform a Moon landing took place in 1962 during the Rangers 3, 4 and 5 missions flown by the United States. All three Block II missions carried a 94 pound, two-foot diameter landing sphere (made of balsa wood) designed to withstand a 150 mile per hour impact. This lander (code-named Tonto) was designed to provide impact cushioning using an exterior blanket of crushable balsa wood and an interior filled with incompressible liquid freon. A 56 pound, one-foot diameter metal payload sphere floated and was free to rotate in a liquid freon reservoir contained in the landing sphere. This payload sphere contained six silver-cadmium batteries to power a fifty milliwatt radio transmitter, a temperature sensitive voltage controlled oscillator to measure lunar surface temperatures, and a seismometer that was designed with sensitivity high enough to detect the impact of a five pound meteorite on the opposite side of the Moon. Weight was distributed in the payload sphere so it would rotate in its liquid blanket to place the seismometer into an upright and operational position no matter what the final resting orientation of the external landing sphere. After landing plugs were to be opened allowing the freon to evaporate and the payload sphere to settle into upright contact with the landing sphere. Four pounds of water were also included to provide thermal control for the lander, absorbing heat and boiling off as low-pressure steam during the hot lunar daytime and retaining sufficient heat to allow the lander electronics to avoid freezing temperatures during the cold lunar nighttime. The batteries and water supply were sized to allow up to three months of operation for the payload sphere. Various mission constraints limited the landing site to Oceanus Procellarum on the lunar equator, which the lander ideally would reach 66 hours after launch.
No cameras were carried by the Ranger landers, and no pictures were to be captured from the lunar surface during the mission. Instead, the ten-foot-high, 730 pound Ranger Block II mother ship carried a 200 scan line television camera which was to capture images from down to during the free-fall descent to the lunar surface. The 13 pound camera was designed to transmit a picture every 10 seconds. Other instruments gathering data before the mother ship crashed onto the Moon at 6,500 miles per hour were a gamma ray spectrometer to measure overall lunar chemical composition and a radar altimeter. At eight seconds before impact and above the lunar surface, the radar altimeter was to give a signal ejecting the landing capsule and its 236 pound solid-fueled braking rocket overboard from the Block II mother ship. The braking rocket was to slow the landing sphere to a dead stop at above the surface and separate, allowing the landing sphere to free fall once more and hit the surface at a survivable speed of 100 miles per hour.
On Ranger 3, failure of the Atlas guidance system and a software error aboard the Agena upper stage combined to put the spacecraft on a course that would miss the Moon. Attempts to salvage lunar photography during a flyby of the Moon were thwarted by in-flight failure of the onboard flight computer. This was probably because of prior heat sterilization of the spacecraft by keeping it above the boiling point of water for 24 hours on the ground, to protect the Moon from being contaminated by Earth organisms. Heat sterilization was also blamed for subsequent in-flight failures of the spacecraft computer on Ranger 4 and the power subsystem on Ranger 5. Only Ranger 4 reached the Moon in an uncontrolled crash impact on the far side of the Moon.
Heat sterilization was discontinued for the final four Block III Ranger probes. These replaced the Block II landing capsule and its retrorocket with a heavier, more capable television system to support landing site selection for upcoming Apollo manned moon landing missions. Six cameras weighing a total of 350 pounds were designed to take thousands of high-altitude photographs in the final twenty minute period before crashing on the lunar surface. Camera resolution was 1,132 scan lines, far higher than the 525 lines found in a typical American 1964 home television. The final pictures taken were expected to have a resolution of around two feet. While Ranger 6 suffered a failure of this camera system and returned no photographs despite an otherwise successful flight, the subsequent Ranger 7 mission to Mare Cognitum was a complete success. Breaking the six year string of failure in American attempts to photograph the moon at close range, the Ranger 7 mission was viewed as a national turning point and instrumental in allowing the key 1965 NASA budget appropriation to pass through the United States Congress intact without a reduction in funds for the Apollo manned moon landing program. Subsequent successes with Ranger 8 and Ranger 9 further buoyed American hopes.
|U.S.S.R. Mission||Mass (kg)||Launch Vehicle||Launched||Mission Goal||Mission Result|
|Semyorka - 8K72||23 Sep 1958||Lunar Impact||Failure - booster malfunction at T+ 93 sec|
|Semyorka - 8K72||12 Oct 1958||Lunar Impact||Failure - booster malfunction at T+ 104 sec|
|Semyorka - 8K72||04 Dec 1958||Lunar Impact||Failure - booster malfunction at T+ 254 sec|
|Luna-1||361||Semyorka - 8K72||02 Jan 1959||Lunar Impact||Failure - missed moon, but first spacecraft to solar orbit|
|Semyorka - 8K72||18 Jun 1959||Lunar Impact||Failure - booster malfunction at T+ 153 sec|
|Luna-2||390||Semyorka - 8K72||12 Sep 1959||Lunar Impact||Success - first lunar impact|
|Luna-3||270||Semyorka - 8K72||04 Oct 1959||Lunar Flyby||Success - first photos of lunar far side|
|Semyorka - 8K72||15 Apr 1960||Lunar Flyby||Failure - booster malfunction, failed to reach Earth orbit|
|Semyorka - 8K72||16 Apr 1960||Lunar Flyby||Failure - booster malfunction at T+ 1 sec|
|Sputnik-25||Semyorka - 8K78||04 Jan 1963||Moon landing||Failure - stranded in low Earth orbit|
|Semyorka - 8K78||03 Feb 1963||Moon landing||Failure - booster malfunction at T+ 105 sec|
|Luna-4||1422||Semyorka - 8K78||02 Apr 1963||Moon landing||Failure - lunar flyby at|
|Semyorka - 8K78||21 Mar 1964||Moon landing||Failure - booster malfunction, failed to reach Earth orbit|
|Semyorka - 8K78||20 Apr 1964||Moon landing||Failure - booster malfunction, failed to reach Earth orbit|
|Cosmos-60||Semyorka - 8K78||12 Mar 1965||Moon landing||Failure - stranded in low Earth orbit|
|Semyorka - 8K78||10 Apr 1965||Moon landing||Failure - booster malfunction, failed to reach Earth orbit|
|Luna-5||1475||Semyorka - 8K78||09 May 1965||Moon landing||Failure - lunar impact|
|Luna-6||1440||Semyorka - 8K78||08 Jun 1965||Moon landing||Failure - lunar flyby at|
|Luna-7||1504||Semyorka - 8K78||04 Oct 1965||Moon landing||Failure - lunar impact|
|Luna-8||1550||Semyorka - 8K78||03 Dec 1965||Moon landing||Failure - lunar impact during landing attempt|
|Luna-9||1580||Semyorka - 8K78||31 Jan 1966||Moon landing||Success - first lunar hard landing, numerous photos|
|Luna-13||1580||Semyorka - 8K78||21 Dec 1966||Moon landing||Success - second lunar hard landing, numerous photos|
The Luna 9 spacecraft, launched by the Soviet Union, performed the first successful Moon landing on February 3 1966 using the "hard landing" technique. Airbags protected its 200 pound ejectable capsule which survived an impact speed of over 30 miles per hour—the speed of many automobile accidents causing fatalities on Earth. Luna 13 duplicated this feat with a similar moon landing on December 24, 1966. Both returned panoramic photographs that were the first views from the lunar surface.
|U.S. Mission||Mass (kg)||Booster||Launched||Mission Goal||Mission Result||Landing Zone||Lat/Lon|
|Surveyor 1||292||Atlas - Centaur||30 May 1966||Moon landing||Success - 11,000 pictures returned, first American Moon landing||Oceanus Procellarum||002.45S 043.22W|
|Surveyor 2||292||Atlas - Centaur||20 Sep 1966||Moon landing||Failure - midcourse engine malfunction, placing vehicle in unrecoverable tumble; crashed southeast of Copernicus Crater||Sinus Medii||004.00S 011.00W|
|Surveyor 3||302||Atlas - Centaur||20 Apr 1967||Moon landing||Success - 6,000 pictures returned; trench dug to 17.5 cm depth after 18 hr of robot arm use||Oceanus Procellarum||002.94S 336.66E|
|Surveyor 4||282||Atlas - Centaur||14 Jul 1967||Moon landing||Failure - radio contact lost 2.5 minutes before touchdown; perfect automated Moon landing possible but actual outcome unknown||Sinus Medii||unknown|
|Surveyor 5||303||Atlas - Centaur||08 Sep 1967||Moon landing||Success - 19,000 photos returned, first use of alpha scatter soil composition monitor||Mare Tranquillitatis||001.41N 023.18E|
|Surveyor 6||300||Atlas - Centaur||07 Nov 1967||Moon landing||Success - 30,000 photos returned, robot arm & alpha scatter science, engine restart, second landing 2.5 m away from first||Sinus Medii||000.46N 358.63E|
|Surveyor 7||306||Atlas - Centaur||07 Jan 1968||Moon landing||Success - 21,000 photos returned; robot arm & alpha scatter science; laser beams from Earth detected||Tycho Crater||041.01S 348.59E|
Within four months of each other in early 1966 the Soviet Union and the United States had accomplished successful moon landings with unmanned spacecraft. To the general public both countries had demonstrated roughly equal technical capabilities by returning photographic images from the surface of the Moon. These pictures provided a key affirmative answer to the crucial question of whether or not lunar soil would support upcoming manned landers with their much greater weight.
However, the Luna 9 hard landing of a ruggedized sphere using airbags at a -per-hour ballistic impact speed had much more in common with the failed 1962 Ranger landing attempts and their planned -per-hour impacts than with the Surveyor 1 soft landing on three footpads using its radar-controlled, adjustable-thrust retrorocket. While Luna 9 and Surveyor 1 were both major national accomplishments, only Surveyor 1 had reached its landing site employing key technologies that would be needed for a crewed flight. Thus as of mid-1966, the United States had begun to pull ahead of the Soviet Union in the so-called Space Race to land a man on the Moon.
Advances in other areas were necessary before manned spacecraft could follow unmanned ones to the surface of the Moon. Of particular importance was developing the expertise to perform flight operations in lunar orbit. Ranger, Surveyor and initial Luna moon landing attempts all utilized flight paths from Earth that traveled directly to the lunar surface without first placing the spacecraft in a lunar orbit. Such direct ascents use a minimum amount of fuel for unmanned spacecraft on a one-way trip.
In contrast, manned vehicles need additional fuel after a lunar landing to enable a return trip back to Earth for the crew. Leaving this massive amount of required Earth-return fuel in lunar orbit until it is actually used later in the mission is far more efficient than taking such fuel down to the lunar surface in a Moon landing and then hauling it all back into space yet again, working against lunar gravity both ways. Such considerations lead logically to a lunar orbit rendezvous mission profile for a manned Moon landing. Accordingly, beginning in mid-1966 both the U.S. and U.S.S.R. naturally progressed into missions which featured lunar orbit operations as a necessary prerequisite to a manned Moon landing.
|U.S.S.R Mission||Mass (kg)||Booster||Launched||Mission Goal||Mission Result|
|Cosmos - 111||Molniya-M||01 Mar 1966||Lunar orbiter||Failure - stranded in low Earth orbit|
|Luna-10||1582||Molniya-M||31 Mar 1966||Lunar orbiter||Success - 2738 km x 2088 km x 72 deg orbit, 178 m period, 60 day science mission|
|Luna-11||1640||Molniya-M||24 Aug 1966||Lunar orbiter||Success - 2931 km x 1898 km x 27 deg orbit, 178 m period, 38 day science mission|
|Luna-12||1620||Molniya-M||22 Oct 1966||Lunar orbiter||Success - 2938 km x 1871 km x 10 deg orbit, 205 m period, 89 day science mission|
|Cosmos-159||1700||Molniya-M||17 May 1967||Prototype test||Success - high Earth orbit manned landing communications gear radio calibration test|
|Molniya-M||07 Feb 1968||Lunar orbiter||Failure - booster malfunction, failed to reach Earth orbit - attempted radio calibration test?|
|Luna-14||1700||Molniya-M||07 Apr 1968||Lunar orbiter||Success - 870 km x 160 km x 42 deg orbit, 160 m period, unstable orbit, radio calibration test?|
|Luna-19||5700||Proton||28 Sep 1971||Lunar orbiter||Success - 140 km x 140 km x 41 deg orbit, 121 m period, 388 day science mission|
|Luna-22||5700||Proton||29 May 1974||Lunar orbiter||Success - 222 km x 219 km x 19 deg orbit, 130 m period, 521 day science mission|
|U.S.S.R Mission||Mass (kg)||Booster||Launched||Mission Goal||Payload||Mission Result|
|Cosmos-146||5400||Proton||10 Mar 1967||High Earth Orbit||unmanned||Failure - stranded in elliptical high Earth orbit, unable to initiate controlled high speed atmospheric reentry test|
|Cosmos-154||5400||Proton||08 Apr 1967||High Earth Orbit||unmanned||Failure - stranded in elliptical high Earth orbit, unable to initiate controlled high speed atmospheric reentry test|
|Proton||28 Sep 1967||High Earth Orbit||unmanned||Failure - booster malfunction, failed to reach Earth orbit|
|Proton||22 Nov 1967||High Earth Orbit||unmanned||Failure - booster malfunction, failed to reach Earth orbit|
|Zond-4||5140||Proton||02 Mar 1968||High Earth Orbit||unmanned||Failure - launched successfully to 300,000 km high Earth orbit, high speed reentry test guidance malfunction, intentional self-destruct to prevent landfall outside Soviet Union|
|Proton||23 Apr 1968||Circumlunar Loop||non-human biological payload||Failure - booster malfunction, failed to reach Earth orbit; launch preparation tank explosion kills three in pad crew|
|Zond-5||5375||Proton||15 Sep 1968||Circumlunar Loop||non-human biological payload||Success - looped around Moon, returned live biological payload safely to Earth despite landing off-target outside the Soviet Union in the Indian Ocean|
|Zond-6||5375||Proton||10 Nov 1968||Circumlunar Loop||non-human biological payload||Failure - looped around Moon, successful reentry, but loss of cabin air pressure caused biological payload death, parachute system malfunction and severe vehicle damage upon landing|
|Proton||20 Jan 1969||Circumlunar Loop||non-human biological payload||Failure - booster malfunction, failed to reach Earth orbit|
|Zond-7||5979||Proton||08 Aug 1969||Circumlunar Loop||non-human biological payload||Success - looped around Moon, returned biological payload safely to Earth and landed on-target inside Soviet Union|
|Zond-8||Proton||20 Oct 1970||Circumlunar Loop||non-human biological payload||Success - looped around Moon, returned biological payload safely to Earth despite landing off-target outside Soviet Union in the Indian Ocean|
Zond 5 was the first spacecraft to carry life from Earth to the vicinity of the Moon. Believing a Soviet manned lunar flight was imminent in late 1968, NASA changed the flight plan of Apollo 8 from an Earth-orbit mission to a risky lunar orbit mission.
|U.S. Mission||Mass (kg)||Booster||Launched||Mission Goal||Mission Result|
|Lunar Orbiter 1||386||Atlas - Agena||10 Aug 1966||Lunar orbiter||Success - 1160 km X 189 km x 12 deg orbit, 208 m period, 80 day photography mission|
|Lunar Orbiter 2||386||Atlas - Agena||06 Nov 1966||Lunar orbiter||Success - 1860 km X 52 km x 12 deg orbit, 208 m period, 339 day photography mission|
|Lunar Orbiter 3||386||Atlas - Agena||05 Feb 1967||Lunar orbiter||Success - 1860 km X 52 km x 21 deg orbit, 208 m period, 246 day photography mission|
|Lunar Orbiter 4||386||Atlas - Agena||04 May 1967||Lunar orbiter||Success - 6111 km X 2706 km x 86 deg orbit, 721 m period, 180 day photography mission|
|Lunar Orbiter 5||386||Atlas - Agena||01 Aug 1967||Lunar orbiter||Success - 6023 km X 195 km x 85 deg orbit, 510 m period, 183 day photography mission|
The U.S. Moon exploration program originated during the Eisenhower administration. In a series of mid-1950s articles in Collier's magazine, Wernher von Braun had popularized the idea of a manned expedition to the Moon to establish a lunar base. A manned Moon landing posed several daunting technical challenges to the U.S. and USSR. Besides guidance and weight management, atmospheric re-entry without ablative overheating was a major hurdle. After the Soviet Union's launch of Sputnik, von Braun promoted a plan for the United States Army to establish a military lunar outpost by 1965.
After the early Soviet successes, especially Yuri Gagarin's flight, U.S. President John F. Kennedy looked for an American project that would capture the public imagination. He asked Vice President Lyndon Johnson to make recommendations on a scientific endeavor that would prove U.S. world leadership. The proposals included non-space options such as massive irrigation projects to benefit the Third World. The Soviets, at the time, had more powerful rockets than the United States, which gave them an advantage in some kinds of space missions. Advances in U.S. nuclear weapons technology had led to smaller, lighter warheads, and consequently, rockets with smaller payload capacities. By comparison, Soviet nuclear weapons were much heavier, and the powerful R-7 rocket was developed to carry them. More modest potential missions such as flying around the Moon without landing or establishing a space lab in orbit (both were proposed by Kennedy to von Braun) were determined to offer too much advantage to the Soviets, since the U.S. would have to develop a heavy rocket to match the Soviets. A Moon landing, however, would capture world imagination while functioning as propaganda.
Mindful that the Apollo Program would economically benefit most of the key states in the next election—particularly his home state of Texas because NASA's base was in Houston—Johnson championed the Apollo program. This superficially indicated action to alleviate the fictional "missile gap" between the U.S. and USSR, a campaign promise of Kennedy's in the 1960 election. The Apollo project allowed continued development of dual-use technology. Johnson also advised that for anything less than a lunar landing the USSR had a good chance of beating the U.S. For these reasons, Kennedy seized on Apollo as the ideal focus for American efforts in space. He ensured continuing funding, shielding space spending from the 1963 tax cut and diverting money from other NASA projects. This dismayed NASA's leader, James E. Webb, who urged support for other scientific work.
In conversation with Webb, Kennedy said:
The Saturn V booster was the key to U.S. moon landings. It used more efficient liquid hydrogen fuel instead of kerosene in its upper stages in order to lift heavier payloads beyond Earth orbit. The Saturn had a perfect record of zero failures in thirteen launches. By contrast, the Soviet N-1 exploded in flight during four secret test launches and never achieved operational status.
Whatever he said in private, Kennedy needed a different message to gain public support to uphold what he was saying and his views. Later in 1963, Kennedy asked Vice President Johnson to investigate the possible technological and scientific benefits of a Moon mission. Johnson concluded that the benefits were limited, but, with the help of scientists at NASA, he put together a powerful case, citing possible medical breakthroughs and interesting pictures of Earth from space. For the program to succeed, its proponents would have to defeat criticism from politicians on the left, who wanted more money spent on social programs, and on those on the right, who favored a more military project. By emphasizing the scientific payoff and playing on fears of Soviet space dominance, Kennedy and Johnson managed to swing public opinion: by 1965, 58 percent of Americans favored Apollo, up from 33 percent two years earlier. After Johnson became President in 1963, his continuing defense of the program allowed it to succeed in 1969, as Kennedy had originally hoped.
At the same time, Kennedy had suggested various joint programs, including a possible Moon landing by Soviet and American astronauts and the development of better weather-monitoring satellites. Khrushchev, sensing an attempt by Kennedy to steal Russian space technology, rejected the idea: if the USSR went to the Moon, it would go alone. Korolyov, the RSA's chief designer, had started promoting his Soyuz craft and the N-1 launcher rocket that would have the capability of carrying out a manned Moon landing. Khrushchev directed Korolyov's design bureau to arrange further space firsts by modifying the existing Vostok technology, while a second team started building a completely new launcher and craft, the Proton booster and the Zond, for a manned cislunar flight in 1966. In 1964 the new Soviet leadership gave Korolyov the backing for a Moon landing effort and brought all manned projects under his direction. With Korolyov's death and the failure of the first Soyuz flight in 1967, the co-ordination of the Soviet moon landing program quickly unraveled. The Soviets built a landing craft and selected cosmonauts for the mission that would have placed Aleksei Leonov on the Moon's surface, but with the successive launch failures of the N1 booster in 1969, plans for a manned landing suffered first delay and then cancellation.
|U.S. Mission||Booster||Launched||Mission Goal||Mission Result|
|Apollo 1 (AS-204)||Saturn 1B||(21 February 1967)||Manned Earth orbit||Failure - never launched: command module destroyed and three astronauts killed on 27 January 1967 by fire in the module during a test exercise - retroactively called Apollo 1|
|Apollo 2 (AS-203)||Saturn 1B||5 July 1966||Unmanned Earth orbit||Success - fuel tank behaviour test and booster certification - informally known as Apollo 2|
|Apollo 3 (AS-202)||Saturn 1B||25 August 1966||Unmanned suborbital||Success - command module reentry test successful, even though reentry was very uncontrolled - informally known as Apollo 3|
|Apollo 4||Saturn V||9 November 1967||Unmanned Earth orbit||Success - first test of new booster and all elements together (except lunar module), successful reentry of command module|
|Apollo 5||Saturn 1B||22 January 1968||Unmanned Earth orbit||Success - first flight of lunar module, multiple space tests of lunar module, no controlled reentry|
|Apollo 6||Saturn V||4 April 1968||Unmanned Earth orbit||Partial success - severe oscillations during orbital insertion, several engines failing during flight, successful reentry of command module (though mission parameters for a 'worst case' reentry scenario could not be achieved)|
|Apollo 7||Saturn 1B||11 October 1968||Manned Earth orbit||Success - eleven-day manned Earth orbit, command module testing (no lunar module), some minor crew issues|
|Apollo 8||Saturn V||21 December 1968||Manned lunar orbit||Success - ambitious mission profile (changed relatively shortly before launch), first human lunar orbit (no lunar module), first earthrise seen by men and major publicity success, some minor sleeping and illness issues|
|Apollo 9||Saturn V||3 March 1969||Manned Earth orbit||Success - ten-day manned Earth orbit, with EVA and successful manned flight / docking of lunar module|
|Apollo 10||Saturn V||18 May 1969||Manned lunar orbit||Success - second manned lunar orbit, test of lunar module in lunar orbit, coming as close as 8.4 nautical miles (15.6 km) to the Moon's surface|
|Apollo 11||Saturn V||16 July 1969||Manned lunar landing||Success - first manned landing on the Moon (manual landing required), exploration on foot in direct vicinity of landing site|
|Apollo 12||Saturn V||14 November 1969||Manned lunar landing||Success - mission almost aborted in-flight after lightning strike on takeoff caused telemetry loss, successful landing within walking distance (less than 200 meters) of the Surveyor 3 probe|
|Apollo 13||Saturn V||11 April 1970||Manned lunar landing||Failure - problematic oscillations on start, unrelated explosion in service module during Earth-Moon transition caused mission to be aborted - crew took temporary refuge in lunar module and eventually returned to Earth with command module after single pass around Moon|
|Apollo 14||Saturn V||31 January 1971||Manned lunar landing||Success - software and hardware problems with lunar module almost caused landing abort during lunar orbit, first color video images from the Moon, first materials science experiments in space|
|Apollo 15||Saturn V||26 July 1971||Manned lunar landing||Success - first longer (3 days) stay on Moon, first use of lunar rover to travel (total of , more extensive geology investigations|
|Apollo 16||Saturn V||16 April 1972||Manned lunar landing||Success - malfunction in a backup yaw gimbal servo loop almost aborted landing (and reduced stay duration on Moon by one day to three for safety reasons), only mission to target lunar highlands|
|Apollo 17||Saturn V||7 December 1972||Manned lunar landing||Success - last (and still most recent) manned landing on the Moon, only mission with geologist|
|Apollo 18+||Saturn V||-||Manned lunar landings||Cancelled - Several more missions (with detailed planning for up to Apollo 20) were cancelled|
In total twenty-four American astronauts have traveled to the Moon, with twelve walking on its surface and three making the trip twice. Apollo 8 was a lunar-orbit-only mission, Apollo 10 included powered descent and then an abort-mode ascent of the LM, while Apollo 13, originally scheduled as a landing, ended up as a lunar fly-by, by means of free return trajectory; thus, none of these missions made landings. Apollo 7 and Apollo 9 never left Earth orbit. Apart from the inherent dangers of manned moon expeditions as seen with Apollo 13, one reason for their cessation according to astronaut Alan Bean is the cost it imposes in government subsidies.
President Richard Nixon had speechwriter William Safire prepare a condolence speech for delivery in the event that Armstrong and Aldrin became marooned on the Moon's surface and could not be rescued.
In the 1940s writer Arthur C Clarke forecast that man would reach the Moon by 2000.
On August 16, 2006, the Associated Press reported that NASA is currently missing the original Slow-scan television tapes (which were made before the scan conversion for conventional TV) of the Apollo 11 Moon walk. Some news outlets have mistakenly reported that the SSTV tapes were found in Western Australia, but those tapes were only recordings of data from the Apollo 11 Early Apollo Surface Experiments Package.
|U.S.S.R. Mission||Mass (kg)||Booster||Launched||Mission Goal||Mission Result||Landing Zone||Lat/Lon|
|Proton||19 Feb 1969||Lunar rover||Failure - booster malfunction, failed to reach Earth orbit|
|Proton||14 Jun 1969||Sample return||Failure - booster malfunction, failed to reach Earth orbit|
|Luna-15||5700||Proton||13 Jul 1969||Sample return||Failure - lunar crash impact||Mare Crisium||unknown|
|Cosmos-300||Proton||23 Sep 1969||Sample return||Failure - stranded in low Earth orbit|
|Cosmos-305||Proton||22 Oct 1969||Sample return||Failure - stranded in low Earth orbit|
|Proton||06 Feb 1970||Sample return||Failure - booster malfunction, failed to reach Earth orbit|
|Luna-16||5600||Proton||12 Sep 1970||Sample return||Success - returned 0.10 kg of moon dust back to Earth||Mare Fecunditatis||000.68S 056.30E|
|Luna-17||5700||Proton||10 Nov 1970||Lunar rover||Success - Lunokhod-1 rover traveled 10.5 km across lunar surface||Mare Imbrium||038.28N 325.00E|
|Luna-18||5750||Proton||02 Sep 1971||Sample return||Failure - lunar crash impact||Mare Fecunditatis||003.57N 056.50E|
|Luna-20||5727||Proton||14 Feb 1972||Sample return||Success - returned 0.05 kg of moon dust back to Earth||Mare Fecunditatis||003.57N 056.50E|
|Luna-21||5950||Proton||08 Jan 1973||Lunar rover||Success - Lunokhod-2 rover traveled 37.0 km across lunar surface||LeMonnier Crater||025.85N 030.45E|
|Luna-23||5800||Proton||28 Oct 1974||Sample return||Failure - Moon landing achieved, but malfunction prevented sample return||Mare Crisium||012.00N 062.00E|
|Proton||16 Oct 1975||Sample return||Failure - booster malfunction, failed to reach Earth orbit|
|Luna-24||5800||Proton||09 Aug 1976||Sample return||Success - returned 0.17 kg of moon dust back to Earth||Mare Crisium||012.25N 062.20E|
The moon landings are often referenced by people to criticize the failure of a government project or service. A typical example being "we can land man on the moon and bring him back safely, but we can't stop a bit of floodwater."
Russia plans to send cosmonauts to the Moon by 2025 and establish a permanent manned base there in 2027-2032.
Other nations, including China, have expressed interest in pursuing human landings on the Moon, but none have currently announced formal plans.
The Google Lunar X Prize competition offers a $20 million award for the first privately-funded team to land a robotic probe on the Moon. Like the Ansari X Prize before it, the competition aims to advance the state of the art in private space exploration.
In addition, close scrutiny of film footage of the EVAs shows clearly something that could not be replicated in an Earth sound-stage. Lunar dust kicked up by the astronauts and the Lunar Rovers shoots up quite high because of the low gravity, but settles just as rapidly as there is no air resistance. Also the television show "Mythbusters" on the Discovery channel recently conducted several experiments debunking claims of conspiracy theorists. Topics included: flag waving, footprints, and movement in low gravity, ending the episode by confirming that the laser reflectors are currently on the moon.
Since the first hoax accusations were made—albeit by non-scientists pursuing the conspiracy accusations in part for monetary gain, and although they have been repeatedly debunked by many independent scientists—a small minority of the global population continues to believe the allegations, which has bothered NASA and the astronauts who flew the missions. However, it has recently become apparent from the multiple scheduled or proposed governmental and private efforts to send landers or orbiters to the Moon that it is likely that independent proof will be returned, and thus conclude any conspiracy theories. The next lunar orbiter currently scheduled for launch is NASA's Lunar Reconnaissance Orbiter mission, due to launch in November 2008. It will have the ability to photograph the historic landing sites.