APOLLO'S LUNAR EXPLORATION PLANS

Site Selection: Ranger, Surveyor, Lunar Orbiter

The visible face of the moon offered scores of interesting sites for scientific exploration. As far back as 1961, Harold Urey, responding to a question from Homer Newell, listed five general regions of high scientific interest: high latitudes, to determine whether water might exist where temperature extremes were less marked; two maria, to determine whether they were of different composition; inside a large crater; near one of the great wrinkles in the maria; and in a mountainous area. Assuming that equatorial sites would draw the most attention anyway, Urey offered no suggestions concerning them.54 Eugene Shoemaker noted not long afterward that scientific objectives would be subordinate to operational requirements, at least on the early missions, and that the sites most operationally suitable for an Apollo landing - level, featureless maria, most likely - would be the least suited to determination of geologic relationships.55

Operations planning for the earliest Apollo missions was designed to assure the safe return of the astronauts. The spacecraft, still attached to the Saturn upper stage, would be inserted into an earth-circling "parking orbit" so that mission control could verify that all systems were working properly. Lunar landings were to be made in direct sunlight and at specific times of the lunar day chosen for optimum visibility; return to earth must take place in daylight; and allowance would be made for possible interference with communication caused by solar activity.56 These rules, along with constraints on the lunar orbit of the command module, defined a landing zone along the moon's equator within which the first mission would have to land.

Equally important for selecting a landing site was the nature of the lunar surface - how much weight it could support and how many rocks and small craters were present. For this purpose, high-resolution photographs of the lunar surface were required, which were to be supplied initially by the Ranger spacecraft [see Chapter 2]. To supplement Ranger's photographs and also to provide direct information about the surface, a second unmanned spacecraft, Surveyor, would be built. One version would soft-land on the moon and transmit scientific data and television pictures; a second version would be an orbiter that would circle the moon, photographing large portions of its surface. But when Apollo engineers specified the detail required for their purposes, the Surveyor orbiter as then defined could not meet them.57

To supply the high-resolution photographs needed to certify landing sites, both OMSF and OSSA endorsed a new lunar-orbiting spacecraft. Preliminary studies indicated that the project was feasible, and after briefly considering giving the orbiter to the Jet Propulsion Laboratory, Headquarters officials decided to assign it to Langley Research Center. By the end of August 1963 Langley had drawn up specifications for the spacecraft and camera system and called for bids. Before the year ended, project officials had selected the Boeing Company as the prime contractor. Boeing proposed a solar-powered satellite, attitude-stabilized in three axes, carrying a film camera system designed by the Eastman Kodak Company. Film was to be developed aboard the spacecraft and the images were to be transmitted to earth by an optical scanning and telemetry system. Five photographic missions were planned; the first Lunar Orbiter would be ready for flight less than three years after the contract was let.58

In Ranger and Surveyor, the two projects that contributed most to early Apollo site selection, the Manned Spacecraft Center had worked closely with the Jet Propulsion Laboratory to coordinate Apollo's requirements with mission plans [see Chapter 6].59 As late as 1964, no single organization was responsible for collecting the data needed to evaluate Apollo landing sites and recommending the final choice for each mission.60 In mid-1965, acting on a recommendation from Bellcomm, Inc.,* George Mueller formally established an Apollo Site Selection Board to evaluate and recommend landing sites for the Apollo missions. Chaired by the Apollo program manager in the Office of Manned Space Flight, the board would weigh all available scientific and operational considerations and recommend landing sites to MueIler.61

As planning for lunar science progressed during the middle 1960s, three key issues emerged: management of the returned lunar samples, selecting and training astronauts for scientific exploration, and the choice of landing sites.

* Bellcomm, Inc., was a systems-engineering organization created in 1962 by the American Telephone & Telegraph Co. at NASA's request for the' purpose of conducting independent analyses of many aspects of the Apollo program. It employed about 500 people at peak strength (1969). In 1972, its work for NASA completed, Bellcomm was merged with Bell Laboratories. J. O. Cappellari, Jr., "Where on the Moon? An Apollo Systems Engineering Problem," The Bell System Technical Journal 51 (5) (1972): 955.

54. Harold C. Urey to Newell, June 19, 1961.

55. Shoemaker, "Exploration of the Moon's Surface," American Scientist 50 (1962): 121.

56. Ted H. Skopinski to Chief, Systems Integration Div., "Selection of Lunar Landing Site for the Early Apollo Lunar Missions," Mar. 21, 1962.

57. Bruce K. Byers, Destination Moon: A History of the Lunar Orbiter Program, NASA TM X-3487 (Washington, 1977), pp. 9-15.

58. Ibid., pp. 19-47, 67-69, 75-78, 227.

59. Gilruth to Mueller, Aug. 5, 1965.

60. T. H. Thompson to G. E. Mueller and Gen. S. C. Phillips, Dec. 23, 1964.

61. Mueller to multiple addressees, "Establishment of Apollo Site Selection Board," July 1, 1965.