Project A119

During the Cold War, the Soviet Union took the lead in the Space Race with the launch of Sputnik 1 on 4 October 1957. Sputnik was the first artificial satellite in orbit around the Earth, and the surprise of its successful launch, compounded by the resounding failure of Project Vanguard to launch an American satellite after two attempts, has been dubbed the "Sputnik crisis" and was the impetus for the beginning of the Space Race. Trying to reclaim lost ground, the United States embarked on a series of new projects and studies, which eventually included the launch of Explorer 1 and the creation of the Defense Advanced Research Projects Agency (DARPA) and NASA.[1]

In 1949, the Armour Research Foundation (ARF), based at the Illinois Institute of Technology, began studying the effects of nuclear explosions on the environment. These studies continued until 1962.[2] In May 1958, ARF began covertly researching the potential consequences of a nuclear explosion on the Moon. The main objective of the program, which ran under the auspices of the United States Air Force, which had initially proposed it, was to cause a nuclear explosion that would be visible from Earth. It was hoped that such a display would boost the morale of the American people.[3]

At the time of the project's conception, newspapers were reporting a rumor that the Soviet Union was planning to detonate a hydrogen bomb on the Moon. According to press reports in late 1957, an anonymous source had divulged to a United States Secret Service agent that the Soviets planned to commemorate the anniversary of the October Revolution by causing a nuclear explosion on the Moon to coincide with a lunar eclipse on 7 November. News reports of the rumored launch included mention of targeting the dark side of the terminator—Project A119 would also consider this boundary as the target for an explosion. It was also reported that a failure to hit the Moon would likely result in the missile returning to Earth.[4]

A similar idea had been put forward by Edward Teller, the "father of the H-bomb", who, in February 1957, proposed the detonation of nuclear devices both on and some distance from the lunar surface to analyze the effects of the explosion.[5]

Research

The explosion was intended to occur along the Moon's terminator, for maximum visibility from Earth.

A ten-member team led by Leonard Reiffel was assembled at the Illinois Institute of Technology in Chicago to study the potential visibility of the explosion, benefits to science, and implications for the lunar surface. Among the members of the research team were astronomer Gerard Kuiper and his doctoral student Carl Sagan, who was responsible for the mathematical projection of the expansion of a dust cloud in space around the Moon, an essential element in determining its visibility from Earth.[3][5][6]

Scientists initially considered using a hydrogen bomb for the project, but the United States Air Force vetoed this idea due to the weight of such a device, as it would be too heavy to be propelled by the missile which would have been used.[7] It was then decided to use a W25 warhead, a small, lightweight warhead with a relatively low 1.7 kiloton yield.[5] By contrast, the Little Boy bomb dropped on the Japanese city of Hiroshima in 1945 had a yield of 13–18 kilotons.[8] The W25 would be carried by a rocket toward the shadowed side of the Moon where it would detonate on impact. The dust cloud resulting from the explosion would be lit by the Sun and therefore visible from Earth.[5][6] According to Reiffel, the Air Force's progress in the development of intercontinental ballistic missiles would have made such a launch feasible by 1959.[9]

Project A119 came to light due to research carried out for a biography of Carl Sagan.

The signing of the Partial Nuclear Test Ban Treaty in 1963 and the Outer Space Treaty in 1967 prevented future exploration of the concept of detonating a nuclear device on the Moon. By this time both the United States and the Soviet Union had performed several high-altitude nuclear explosions, including those of Operation Hardtack I, Operation Argus, Operation Dominic I and II, and The K Project.[5]

By 1969, the United States had achieved a considerable victory in the Space Race after the success of the Apollo 11 mission.[13] In December that year, Apollo scientist Gary Latham suggested detonating a "smallish" nuclear device on the Moon in order to facilitate research into its geologic make-up.[14] The idea was dismissed, as it would interfere with plans to measure the Moon's natural background radiation.[15]

The existence of Project A119 remained largely secret until the mid-1990s, when writer Keay Davidson discovered the story while researching the life of Carl Sagan for a biography. Sagan's involvement with the project was apparent from his application for an academic scholarship at the University of California, Berkeley's Miller Institute in 1959. In the application, Sagan gave details of the project research, which Davidson felt constituted a violation of national security.[16] The leak consisted of Sagan revealing the titles of two classified papers from the A119 project—the 1958 paper Possible Contribution of Lunar Nuclear Weapons Detonations to the Solution of Some Problems in Planetary Astronomy, and the 1959 paper Radiological Contamination of the Moon by Nuclear Weapons Detonations.[2] A 1958 paper titled Cosmic Radiation and Lunar Radioactivity, credited to I. Filosofo, was also named by Sagan in a 1961 paper written for the United States National Research Council.[17] These were among the eight reports created by the project, all of which were destroyed in 1987.[3]

The resulting biography—Carl Sagan: A Life—was published in 1999. Shortly after, a review published in Nature highlighted the discovery of the leaked information.[18] This led Reiffel to break his anonymity and write a letter to the journal confirming that Sagan's activity had at the time been considered a breach in the confidentiality of the project. Reiffel took the opportunity to reveal details of the studies, and his statements were later widely reported in the media.[6][19] Reiffel's public admission of the project was accompanied by his denouncement of the work carried out, with the scientist noting that he was "horrified that such a gesture to sway public opinion was ever considered".[3]

As a result of the publicity the correspondence created, a freedom of information request was lodged concerning Project A119. It was only then that A Study of Lunar Research Flights – Volume I was made public, over 40 years after its inception.[20] A search for the other volumes of documentation revealed that other reports were destroyed in the 1980s by the Illinois Institute of Technology.[5]

An illustration of the LCROSS "Centaur" impactor (the rocket's spent second stage) and shepherding spacecraft as they approached impact with the lunar south pole on 9 October 2009. The Centaur impact was expected to excavate more than 350 tonnes (390 short tons) of lunar material and create a crater about 20 metres (66 ft) in diameter to a depth of about 4 m (13 ft). Most of the material in the Centaur debris plume was expected to remain at (lunar) altitudes below 10 km (6 mi).[21]

The faint flash from the LCROSS Centaur impact. It was hoped that spectral analysis of the resulting impact plume would help to confirm preliminary findings by the Clementine and Lunar Prospector, which hinted that there may be water ice in the permanently shadowed regions on the Moon. Mission scientists expected that the Centaur impact plume would be visible through amateur-class telescopes with apertures as small as 25 to 30 centimetres (9.8 to 11.8 in).[22] But no plume was observed by such amateur telescopes. Both impacts were also monitored by Earth-based observatories and by orbital assets, such as the Hubble Space Telescope.

David Lowry, a nuclear historian from the United Kingdom, has called the project's proposals "obscene", adding: "had they gone ahead, we would never have had the romantic image of Neil Armstrong taking 'one giant leap for mankind'".[3]

A vacuum stable chemical explosive filled the seismic source mortar ammunition canisters used as part of the Apollo Lunar Active Seismic Experiments. These explosive experiments investigated the composition of the Lunar mantle during the Apollo Program, analogous to the exploration geophysics practice of mineral prospecting with chemical explosives in "deep seismic sounding" reflection seismology.[23]

The scientific objectives of Project A119 would have been the detonating of a "smallish" nuclear device (1.7+ kilotons of TNT) on the Moon in order to facilitate research into its geologic make-up".[14] This, in principle, can be attempted by non-nuclear means, for example, using the much lower impact energy released by the water prospecting Lunar Crater Observation and Sensing Satellite (LCROSS) mission, which was launched in 2009 and released the "Centaur" kinetic energy impactor, with a mass of 2,305 kilograms (5,082 lb) and an impact velocity of about 9,000 km/h (5,600 mph).[24]

The question of whether LCROSS would find water had been stated to be influential regarding whether the United States government pursues creating a Moon base.[25] On 13 November 2009, NASA confirmed that water was detected after the Centaur impacted the crater.[26] The LCROSS "Centaur" kinetic energy impactor was underpowered and therefore only partially successful, having not produced the expected earth visible flash, nor succeeding in excavating and vaporizing enough subsurface material for a complete lunar soil spectral analysis, that would identify the lunar soil composition to a great depth.[27][28]