Apollo Science and Sites: The Sonett Report (1963)

Apollo 17 Lunar Module Pilot Harrison Schmitt, a geologist, was the only professional scientist to reach the Moon. Image credit: NASA.

The Apollo Program was driven by the perceived national need to decisively demonstrate American technological prowess in the face of early Soviet space victories. Scientific lunar exploration was a secondary concern. In fact, some engineers saw lunar science as a distraction from the already daunting task of landing a man on the Moon and returning him safely to Earth.

The community of lunar scientists was small in May 1961, when President John F. Kennedy put the U.S. on the road to the Moon. Nevertheless, lunar science had its energetic proponents. In early 1962, they saw to it that NASA's Office of Manned Space Flight (OMSF) asked NASA's Office of Space Science (OSS) to outline an Apollo science program. OSS appointed NASA physicist Charles Sonett to head up an ad hoc working group and OMSF provided the group with guidelines for its deliberations.

The Sonett group's 12 members and nine consultants included U.S. Geological Survey geologist (and aspiring astronaut) Eugene Shoemaker, astronomers Gerard Kuiper and Thomas Gold, NASA geophysicist Paul Lowman, and chemist (and Nobel Laureate) Harold Urey. They circulated their July 1962 draft report at the National Academy of Science's 10-week Iowa City meeting (17 June-31 August 1962) and within NASA, receiving, they reported, "general endorsement" for their recommendations.

The final version of the Sonett report, published in December 1963 and labeled "for internal NASA use only," was the first in a series of influential Apollo planning documents that called for ambitious scientific exploration of the Moon. Its recommendations touched on many aspects of Apollo mission planning.

The Sonett group called for all proposed Apollo landing sites to be photographed by automated Lunar Orbiter spacecraft before final site selection. Lunar Orbiter photographs would be used to make detailed geological maps of planned landing sites. This, the Sonett group's members argued, would save precious time during Apollo landing missions, because it would enable astronauts to begin geological field work without first mapping their landing site.

They urged that every two-person Apollo landing crew include a scientist-astronaut with a Ph.D. in geology and from five to 10 years of field experience. Geologists on Earth would explore the Moon vicariously through his descriptions and through real-time television transmitted from a camera mounted on his space suit.

They acknowledged that Kennedy's end-of-decade deadline for reaching the Moon meant that Apollo scientist-astronauts would probably be drawn from the community of scientists already at work in 1962-1963. They assumed, however, that Apollo would be merely the first U.S. program of piloted lunar exploration, so urged that "graduate students and young post graduate scientists. . .be brought into the field of lunar science as potential astronauts as soon as possible."

OMSF had advised the Sonett group that the Apollo lunar surface space suit would "limit the crew's ability to act, particularly in performing precise manipulations." In their final report, the group's members, undaunted by anticipated technological limitations, urged early development of surface suits that would "permit a close approximation to unsuited limb, arm, and digital [finger] movements."

Sonett working group member Eugene Shoemaker models a pressure suit proposed for advanced Apollo Extension System lunar exploration missions. He stands outside the hatch of a mockup long-range lunar rover. Image credit: U.S. Geological Survey.

OMSF also told the group that a space-suited Apollo astronaut would probably be unable to walk more than a half-mile from his lunar lander, but raised the possibility of a rover or other mobility aids. The Sonett group declared that

. . .reconnaissance beyond a one-half mile radius of the spacecraft will be a necessity. . .For example, a lunar ray, a feature of great interest, is probably a poor place to land, yet the capability of traveling to a ray area is clearly indicated. . .For scientific purposes, therefore, there should be the capability of reaching areas some 50 miles from a landing site.

In 1962-1963, OMSF considered development of an automated lander capable of delivering to the Moon up to 15 tons of equipment and supplies. In addition to a beacon for guiding an Apollo Lunar Excursion Module (LEM) piloted lander to a safe touchdown nearby, it would carry one or more rovers and expendables — for example, liquid and gaseous oxygen — for extending LEM electricity-generation and life-support capabilities. The Sonett group urged OMSF to proceed with cargo lander development, noting that the LEM as planned would carry supplies and equipment inadequate to accomplish "even the modest scientific program recommended."

The Apollo LEM lander and lunar surface space suit as envisioned in 1964. Image credit: NASA.

OMSF informed the Sonett working group that the first Apollo lunar surface mission would probably spend only four hours on the Moon. The group urged OMSF to double that stay time so the astronauts could budget four hours for operational activities (for example, checking out their LEM before departing the Moon) and four hours for exploring the lunar surface. During their lunar traverses, they would take turns moving beyond the immediate vicinity of the LEM, collect up to 100 pounds of rocks, test soil strength, and study whether solar heating caused Moon dust to flow like a highly viscous liquid, as hypothesized by Sonett group member Thomas Gold.

The group acknowledged that "an accident" might limit surface exploration during the first Apollo landing mission to one hour. In that case, a single moonwalker would hurriedly collect about 50 pounds of geological samples near the LEM.

The group's members envisioned a five-day Apollo mission with four days of uninterrupted exploration, during which the two astronauts would drive a rover up to 10 miles from their landing site. They would also drill a hole up to 20 feet deep and insert a heat probe, collect samples "for biological purposes," and emplace a seismometer, a micrometeorite detector, and other instrument packages. They expected that the instruments would be linked by cables to a "central station" containing a radio transmitter. This would use a nuclear source to generate electricity so that it could relay data from the instruments to Earth for months or years.

OMSF asked the Sonett working group to assume "more than one but less than ten" Apollo landings. Apollo landings would, OMSF explained, be limited to sites near the equator on the side of the Moon that faces Earth. The Sonett group recommended that the first Apollo piloted lander set down near Copernicus crater.

Sonett group member Eugene Shoemaker was probably behind the Copernicus site choice; he had spent a great deal of time studying the crater starting in the late 1950s as part of his effort to resolve the debate over whether lunar craters were primarily the result of volcanism or of asteroid impacts and to establish the stratigraphic sequence of the Moon's geologic units. The latter was a requirement if the history of the lunar surface would be deciphered.

Copernicus, a leading Sonett group Apollo landing site candidate, as portrayed in an early 1960s map. Moon maps in this series, based on photos from Earth-based telescopes, were the best available at the time the Sonett Group wrote its report. Image credit: Lunar and Planetary Institute. 

In keeping with their conviction that lunar exploration should continue beyond Apollo, the Sonett group scientists offered two lists with a total of 28 candidate landing sites. All sites were selected using photographs taken using Earth-based telescopes.

The first list of 15 sites, compiled in June 1962 by Eugene Shoemaker and R. E. Eggleton, another U.S. Geological Survey geologist, took into account "possible landing conditions and trafficability, and prospects of discovering natural shelter and potential water supplies."

• 9.8° North (N), 20.1° West (W), near the Copernicus central peaks
• 13.1° N, 31° W, on a "typical lunar dome" near the crater Tobias Mayer
• 20.4° N, 3° W, on the southeast edge of Mare Imbrium, near Mt. Huyghens in the Apennine Mountains
• 12.6° N, 2° W, in Alphonsus crater, site of suspected on-going lunar volcanism
• 7.7° N, 6.3° East (E), within four-mile-wide Hyginus ("one of the largest craters of likely volcanic origin"), located at a potentially significant bend in Hyginus Rille
• 37.9° N, 16.4° W, near a "possible flow" in Mare Imbrium
• 40.9° South (S), 11.1° W, on the "rubbly" north flank of the great ray crater Tycho
• 50.6° S, 60.8° W, in Wargentin, an odd lava-filled crater
• 85° S, 45° E, in the south polar crater Amundsen, where, it was believed, permanently shadowed areas might preserve ice deposits
• 12.7° S, 49.8° W, on a "very bright" plateau north of the crater Billy
• 41.7° N, 57.5° W, on Oceanus Procellarum north of the Rumker Hills
• 5.6° S, 26.6° W, near a "small irregular depression" 35 miles southeast of the crater Hortensius
• 5.1° N, 14.2° W, on dark material about 140 miles southeast of the center of Copernicus
• 35.3° N, 5.5° W, on Mare Imbrium near the "mountainous block" Spitzbergen
• 9.1° S, 16.1° W, on the north flank of crater Parry A, a natural drill hole exposing ancient dark material

The Sonett working group's second list was compiled by geochemist Duane Dugan of NASA's Ames Research Center.

• 3° S, 44° W, in the middle of the Flamsteed Ring, a mostly submerged crater north of Flamsteed crater
• 13° S, 2.3° W, in Alphonsus
• 23.4° N, 43.3° W, near bright Aristarchus crater, flat-floored Herodotus crater, and sinuous Schröter's Rille (a region of suspected on-going lunar volcanism and many apparent volcanic features)
• 23° N, 51.45° W, inside Herodotus
• 20.3° N, 3.4° W, on Mare Imbrium west of Mt. Huyghens
• 28° N, 12° E, on Mare Serenitatis near the unusual crater Linne, site of suspected on-going lunar volcanism
• 19.3° S, 40.2° W, on safe, flat ground in Mare Humorum near the south wall of dark-floored Gassendi crater
• 5.5° N, 14.3° W, in a "black" surface area east of Fauth crater
• 5° S, 28.1° W, in the Ural and Riphaeus Mountains, near "old ghost rings" (submerged craters)
• 9° S, 2° W, on the floor of Ptolemaeus crater, site of ridges, "craterlets," and a "crater cone" of "remarkable" whiteness
• 15° N, 22° E, between crater Plinius and the Haemus Mountains, a place "with access to the color discontinuity between Mare Tranquillitatis and Mare Serenitatis"
• 24.3° S, 43.4° W, in Mare Humorum east of the crater Liebig (site of "an interesting scarp" that cuts through craters)
• 4.5° S, 25.5° E, in southern Mare Tranquillitatis, at the base of Theophilus crater rim west of Torricelli crater (a "very complex" region with "shading" reminiscent of "one of the terrestrial continental shelves")

That the Shoemaker-Eggleton and Dugan lists had in common only Alphonsus, the dark region near 5.5° N, 14.3° W, and Huyghens-Appenine reflected the wide range of attractive candidate lunar landing sites. Some of the proposed sites, such as Amundsen, lay beyond the equatorial zone OMSF had said Apollo could reach. The working group asserted that "there is no question that sites of the greatest scientific interest lie outside the equatorial belt," and urged that NASA develop the "capability of landing in the equatorial belt, at the poles, and elsewhere."

Alphonsus crater made both the Shoemaker-Eggleton and Dugan lists of candidate Apollo landing sites. Image credit: Lunar and Planetary Institute.

NASA paid attention to the Sonett report and other advice it received from scientists as it planned Apollo missions, but the complex interplay of competing technical, political, and scientific requirements meant that the space agency could give scientists no more than a small fraction of what they desired. Most notably, only one scientist-astronaut reached the Moon: geologist Harrison Schmitt (image at top of post), who explored the Taurus-Littrow valley east of Mare Serenitatis with Eugene Cernan during the Apollo 17 mission (7-19 December 1972).

Schmitt and Cernan spent three days on the Moon. They wore A7LB space suits which restricted their movements, but which were an improvement over the A7L suits worn by Apollo 11, 12, and 14 moonwalkers. They collected drill cores, deployed instruments and a heat-flow probe attached by cables to a nuclear-powered central station, and drove 35.9 kilometers using a jeep-like Lunar Roving Vehicle. All of their equipment arrived stowed on board the Apollo 17 Lunar Module Challenger; NASA developed no automated cargo lander. Apollo 17 returned 110.5 kilograms of geologic samples to researchers on Earth.

Astronauts explored few of the sites Shoemaker, Eggleton, and Dugan selected. The reasons for this were manifold: the U.S. flew only six successful Apollo lunar landing missions; NASA never became capable of landing men very far beyond the Nearside equatorial belt; new knowledge of the Moon from robotic missions and orbiting Apollos made some of the sites appear less scientifically significant than had been believed or less attractive than newly found candidate sites; and no follow-on lunar landing program materialized.

The first Apollo lunar landing mission, Apollo 11 (16-24 July 1969), spent about 21 hours on Mare Tranquillitatis, not in Copernicus; in fact, Copernicus remains unvisited today. Huyghens-Apennine became Hadley-Apennine; visited by Apollo 15 (26 July-7 August 1971), it is widely considered to be the most scientifically significant Apollo site.

Robots explored Alphonsus (Ranger 9, March 1965), the Flamsteed Ring (Surveyor 1, May-July 1966), and Tycho (Surveyor 7, January 1968). The lunar south pole and Aristarchus, as yet unvisited, are frequently mentioned as candidate landing sites for NASA's eventual return to the Moon.

Source

Report of the Ad Hoc Working Group on Apollo Experiments and Training on the Scientific Aspects of the Apollo Program, 15 December 1963. 

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