Luna 2 Becomes the First Human-Made Object to Impact on the Moon Summary

  • Last updated on November 10, 2022

The Soviet space probe Luna 2 became the first human-made object to make contact with the surface of another celestial body.

Summary of Event

Less than two years separated the launching of the first artificial satellite and the first human contact with the Moon. The principal obstacle to be overcome in reaching the Moon, in comparison to reaching Earth orbit, was reaching Earth’s escape velocity, 11 kilometers per second, as opposed to 8 kilometers per second required to send a satellite into orbit around the earth. Luna program Space program, Soviet;Luna program Lunar exploration [kw]Luna 2 Becomes the First Human-Made Object to Impact on the Moon (Sept. 14, 1959)[Luna 02] [kw]First Human-Made Object to Impact on the Moon, Luna 2 Becomes the (Sept. 14, 1959) [kw]Human-Made Object to Impact on the Moon, Luna 2 Becomes the First (Sept. 14, 1959)[Human Made] [kw]Moon, Luna 2 Becomes the First Human-Made Object to Impact on the (Sept. 14, 1959)[Moon, Luna 02] Luna program Space program, Soviet;Luna program Lunar exploration [g]Europe;Sept. 14, 1959: Luna 2 Becomes the First Human-Made Object to Impact on the Moon[06190] [g]Soviet Union;Sept. 14, 1959: Luna 2 Becomes the First Human-Made Object to Impact on the Moon[06190] [c]Space and aviation;Sept. 14, 1959: Luna 2 Becomes the First Human-Made Object to Impact on the Moon[06190] [c]Science and technology;Sept. 14, 1959: Luna 2 Becomes the First Human-Made Object to Impact on the Moon[06190] Vernov, Sergei Chudakov, Aleksandr Lovell, Bernard

The first attempt to reach the Moon by spacecraft came on October 11, 1958, when the United States launched Pioneer 1 Pioneer program Space program, U.S.;Pioneer program . Pioneer 1 did not quite achieve escape velocity; it fell about 350 meters per second short of the required 10,800 needed to escape and fell back to Earth after reaching a maximum altitude of 115,000 kilometers. Pioneer 1 had been equipped with a retrorocket to slow it so that it could be captured into a lunar orbit, and when it became clear that Pioneer 1 would not reach the Moon, attempts were made to fire the rocket to put the probe into an elongated orbit around the earth. These attempts failed, and the probe was destroyed on reentry into Earth’s atmosphere. The next probe, Pioneer 2, reached an altitude of less than 2,000 kilometers. Pioneer 3, launched on December 6, also fell short of its goal, reaching a maximum altitude of 107,000 kilometers.

The Soviet Union inaugurated its lunar exploration program on January 2, 1959, with the launch of the Soviet probe Luna 1, also called Mechta (“dream”). The official name for the Soviet lunar spacecraft series is Luna (“moon”), but with the memory of the first Sputnik Earth satellites still vivid, the American press nicknamed the Soviet probes “Lunik,” a name still found in many histories. The word “Lunik” does not exist in Russian; in fact, early Russian scientific reports on Soviet lunar missions did not even refer to the probes by name. Instead, they were simply called by generic terms such as Space Rocket 1.

Luna 1 carried instruments to measure cosmic rays, charged particles from the Sun, interplanetary gases and magnetic fields, and meteor impacts. On January 3, at a distance of 113,000 kilometers, Luna 1 released a cloud of sodium vapor as part of an experiment to study the earth’s magnetic field. The next day, Luna 1 passed about 5,000 kilometers from the Moon and became the first space probe to orbit the Sun. The final weight of Luna 1 and its booster stage was 1,472 kilograms, with Luna 1 itself weighing 361 kilograms. The U.S. probe Pioneer 4 was launched two months later, on March 3. The goal of Pioneer 4 had been to pass close by the Moon and enter an orbit around the Moon, but the probe actually missed it by 60,000 kilometers and went on to orbit the Sun.

Luna 2 was launched on September 13. It was similar in instrumentation and appearance to Luna 1, a sphere about 120 centimeters in diameter. After a flight of thirty-six hours, it impacted on the Moon at 9:02:23 p.m. Greenwich mean time, or 4:02:23 p.m. eastern standard time, on September 14. Impact occurred at about 3 kilometers per second, about a minute and a half later than scheduled. The point of impact was 435 kilometers north of the visible center of the Moon, near the craters Archimedes, Aristillus, and Autolycus.

Luna 2 was tracked by the British radio telescope at the Nuffield Radio Astronomy Laboratories Nuffield Radio Astronomy Laboratories at Jodrell Bank Jodrell Bank radio telescope , under the direction of Bernard Lovell. At the time of impact, the Moon was below the horizon for most of the United States, though it was later learned that one military tracking facility in the eastern United States also detected the last minutes of data transmission before impact. As was usual for that time, there had been no prior announcement of the launch, but a teletype message from Moscow arrived at Jodrell Bank less than an hour after launch with precise information on transmission frequencies and the position of the spacecraft. In his account of the history of Jodrell Bank, Lovell expressed a conviction that the information must have been prepared before launch specifically for that tracking facility, and sent once the launch had gone successfully.

The sudden cessation of signals from Luna 2 did not persuade all observers that the probe had hit the Moon. In the suspicious political climate of the time, some Americans suspected that the probe might have missed the Moon and that its transmitter might have failed or been turned off. A crucial set of Jodrell Bank observations provided unambiguous proof that Luna 2 had, in fact, impacted on the Moon. As the probe neared the Moon, it accelerated under the influence of the Moon’s gravity. As its speed increased, the frequency of its transmissions decreased because of the Doppler effect. The observations matched exactly the expected acceleration because of the Moon’s gravity and showed that there had been no attempt to change the spacecraft’s course before impact.

Data transmitted by Luna 2 were analyzed by Sergei Vernov, Aleksandr Chudakov, and other Soviet scientists. These data showed that the Moon lacked an appreciable magnetic field; nor were there any radiation belts around the Moon, as there were around the earth. Luna 2 also encountered unexpected differences in the earth’s Van Allen radiation belts Van Allen radiation belts[Vanallen radiation belts] compared to the findings of Luna 1. Luna 1 had found that the earth’s outer radiation belt was strongest about 27,000 kilometers from the earth. Luna 2 found that the outer belt was strongest 17,000 kilometers from Earth, and the peak radiation intensity was about five times stronger than that measured by Luna 1. Both spacecraft traveled similar paths with respect to the earth’s magnetic field, Earth, magnetic field of Magnetic field of Earth except that the path of Luna 2 took it through a more sunward part of the earth’s magnetic field. Luna 2 scientists suspected that the earth’s magnetic field was being distorted by the flow of charged atomic particles from the Sun, a hypothesis that was confirmed by later investigations by other space probes.

The micrometeorite detectors of Luna 2 were modified from those on Luna 1. In the 1950’s, scientists tended to overestimate the hazard from meteorites. The detectors on Luna 1 recorded micrometeorites in three ranges, with the coarsest detector set to register objects heavier than one-tenth of a microgram. Also, the spacecraft was designed to transmit data only after the detectors had accumulated a certain number of impacts. The detection threshold of Luna 1 was so high that no data were transmitted. Luna 2 was designed to register every impact, and its coarsest detection range was sensitive to particles only one-sixth as heavy as that of Luna 1. Luna 2 recorded two impacts in thirty hours of data transmission. The detection limits on Luna 3 were reduced by an additional one-half, so that the coarsest particle detector was sensitive to particles weighing less than one hundredth of a microgram, and Luna 3 recorded seven impacts in six and one-half hours. Some of the observed difference was caused by variations in meteorite abundance as the earth swept through streams of meteor debris, but the Luna data showed that the hazard from micrometeorites was extremely small.

Significance

The effects of Luna 2 were more symbolic—political and emotional—than scientific. The symbolic importance of Luna 2 was that it marked the first human contact with another celestial body. The political and emotional impact was a product of the rivalry between the United States and the Soviet Union. The launch of Sputnik 1 in 1957 had been a profound shock to Americans. In the early years of space exploration, there was great anxiety in the United States over an apparent Soviet superiority in space technology. The Soviet Union achieved major space objectives and launched heavier spacecraft one to two years before the United States matched the same accomplishments. The ability to send a 390-kilogram probe to the Moon was a striking demonstration of Soviet space capability, and its dramatic effect was heightened by the timing of the launch shortly before a visit to the United States by Soviet premier Nikita S. Khrushchev.

The complexion of the early space age was colored by military decisions made some years before the first satellites were launched. The fundamental decision was the way the United States and Soviet Union chose to deliver nuclear weapons, which at that time were extremely bulky. The United States, which had access to bases close to Soviet territory, chose to defer development of intercontinental ballistic missiles Missiles;intercontinental ballistic (ICBM’s) and rely on piloted bombers until the weight and size of nuclear weapons decreased. The Soviet Union, with no bases close to U.S. territory, chose to develop ICBM’s powerful enough to carry the heavy warheads then in use. As a result, when military missiles were applied to launching space probes, the Soviet Union had a significant advantage in launch capability. Early U.S. space probes, in contrast, were launched by upgraded medium-range missiles, and were therefore small.

The scientific achievements of Luna 2 were modest and largely overshadowed by the dramatic Luna 3 mission only three weeks later (it impacted the Moon on October 4), which transmitted the first photographs of the far side of the Moon. From a technological standpoint, the major achievement of Luna 2 was the development of the ability to aim and navigate spacecraft accurately enough to hit a moving celestial target. At that time, space technology was rudimentary by contemporary standards, as demonstrated by the failures of the early Pioneer probes, and “hitting” the Moon was a considerable achievement.

Luna 2 confirmed that the Moon lacked a magnetic field and provided hints of the complexity of solar interactions with the earth’s magnetic field. Finally, the use of Doppler-shifted radio transmissions pioneered by Jodrell Bank later became a powerful tool in spacecraft navigation and a means of determining accurately the masses of planets visited by spacecraft. Luna program Space program, Soviet;Luna program Lunar exploration

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Braun, Wernher von, Frederick Ordway, and David Dooling. Space Travel: A History. Rev. ed. New York: Harper & Row, 1985. A comprehensive history of space exploration, with lengthy coverage of the early history of rocketry. The emphasis is on human spaceflight, but there is a good summary of planetary missions.
  • citation-type="booksimple"

    xlink:type="simple">Cadbury, Deborah. Space Race: The Epic Battle Between America and the Soviet Union for Dominion of Space. New York: HarperCollins, 2006. A 384-page account of American and Soviet efforts to launch the first satellite and to send humans to the Moon.
  • citation-type="booksimple"

    xlink:type="simple">Canby, Thomas Y. “Are the Soviets Ahead in Space?” National Geographic, October, 1986, 420-459. A well-illustrated examination of the Soviet space program with numerous diagrams and photographs of Soviet launch vehicles and spacecraft.
  • citation-type="booksimple"

    xlink:type="simple">Ley, Willy. Rockets, Missiles, and Men in Space. Rev. ed. New York: Viking Press, 1968. A history of the early years of space exploration by one of its key participants. Useful for its descriptions of the political impact of early space events.
  • citation-type="booksimple"

    xlink:type="simple">Lovell, Bernard. The Story of Jodrell Bank. New York: Oxford University Press, 1968. A history of the great Jodrell Bank radio telescope, by its founder and first director. Its chapters on the early years of space probe tracking provide some of the best available historical insights into these events.
  • citation-type="booksimple"

    xlink:type="simple">McDougall, Walter A. The Heavens and the Earth: A Political History of the Space Age. 2d ed. Baltimore: Johns Hopkins University Press, 1997. An excellent study of the military and political history of the space age. McDougall also discusses the dangers of aerospace technocracy, both Soviet and American—a welcome change from the nonanalytical enthusiasm of most histories of spaceflight. Analyzes the connections between the space race and the Cold War.
  • citation-type="booksimple"

    xlink:type="simple">Oberg, James E. Red Star in Orbit. New York: Random House, 1981. A detailed account of Soviet space exploration that attempts to penetrate the secrecy that surrounded the Soviet space program. The primary emphasis is on human space exploration.
  • citation-type="booksimple"

    xlink:type="simple">Scott, David, and Alexei Leonov. Two Sides of the Moon: Our Story of the Cold War Space Race. New York: Simon & Schuster, 2004. A personal account of the space race between the Soviet Union and the United States by two major players in the programs of their respective countries.
  • citation-type="booksimple"

    xlink:type="simple">Siddiqi, Asif A. Sputnik and the Soviet Space Challenge. Gainesville: University Press of Florida, 2003. An award-winning book that offers a comprehensive and detailed history of the Soviet space program, from its earliest days. An essential resource.
  • citation-type="booksimple"

    xlink:type="simple">Wukelic, George E., ed. Handbook of Soviet Space-Science Research. New York: Gordon & Breach, 1968. Although superseded by many references with regard to recent space developments, this book contains photographs, diagrams, and technical data on most early Soviet spacecraft.

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