MISSION AND SCIENCE PLANNING
Site Selection:
Throughout 1965, site selection was one of Apollo's biggest concerns. Early in the year the ill-starred Ranger project flew its second consecutive successful mission (in seven tries). Its photographs had enabled the Manned Spacecraft Center to draw some generally encouraging conclusions about lunar topography, but MSC's Space Environment Division concluded that Ranger photographs would never enable them to certify lunar landing sites. They would, perhaps, allow Apollo planners to rule out unsuitable areas, but picking a suitable landing site by eliminating the unsuitable ones could take years.16 Besides, Ranger provided no information about the physical characteristics of the surface, which designers of the lunar landing craft needed.17 Surveyor was expected to soft-land on the moon within a few months, and MSC was offering advice to Surveyor mission planners at the Jet Propulsion Laboratory as to where the missions should land to be of maximum use to Apollo. The Houston center was also working closely with Langley's Lunar Orbiter program office in planning for optimum use of its high-resolution cameras to locate sites for the lunar landing mission.
In efforts to satisfy the sometimes conflicting aims of lunar science and Apollo, the Ranger project had been subjected to a great deal of pulling and hauling. [see Chapter 2] The result was that neither side was completely satisfied, and the lunar scientists were particularly upset when Apollo preempted their experiments. Intending to forestall similar problems with Surveyor and Lunar Orbiter, Homer Newell established an ad hoc Surveyor/Orbiter Utilization Committee in the spring of 1965, after the last Ranger mission (Ranger 9) successfully concluded that project. Newel! appointed his deputy, Edgar M. Cortright, chairman of the committee, whose other members were chosen from Headquarters and center project Offices.* 18
Mueller, meanwhile, had discovered that no single organization was responsible for coordinating lunar data and evaluating candidate landing sites. Shortly after Newell created the Surveyor/Orbiter Utilization Committee, Mueller established an Apollo Site Selection Board in the Office of Manned Space Flight. Its primary responsibility was to select and recommend candidate sites after considering all data required to ensure the success of the lunar landing. If the board could not unanimously agree on a site, majority rule did not apply; Mueller wanted all dissenting opinions recorded, and as he had done when he created the Manned Space Flight Experiments Board, [see Chapter 2] he reserved for himself the authority to make the final choice. Chaired by OMSF's Apollo program director, Air Force Major General Samuel C. Phillips, the board included members from the Office of Space Science and Applications and the three manned space flight field centers. ** 19
The overlapping membership of these two boards was yet another way of making sure that all interested parties were sufficiently involved in decisions when scientific concerns and manned space flight objectives converged (and sometimes conflicted) in a single program - which, some felt, had not been the case during Ranger. MSC Director Bob Gilruth expressed satisfaction with this arrangement and selected two of his engineers to serve on both boards.20
Since Surveyor and Lunar Orbiter were expected to fly their first missions within a year, the Surveyor/ Orbiter Utilization Committee began work early. From late August 1965 until the first launches in mid-1966 the committee met as frequently as necessary to evaluate sites and set priorities. Lunar Orbiter project officials initially outlined four types of missions, from a general survey of the moon to photography of specific sites within the Apollo zone. Surveyor representatives presented 40 possible landing sites for their first spacecraft, chosen on the basis of independent evaluations by the Jet Propulsion Laboratory and the Geological Survey based on the best available geologic maps and telescopic observations. With little discussion the committee recommended that Lunar Orbiter's first mission give priority to Apollo site photographs. Surveyor, like Lunar Orbiter, had objectives independent of its usefulness to Apollo, but its project managers seemed less willing to allow their science goals to be subordinated to those of the lunar landing program. After some discussion, the committee agreed on a set of ground rules for selecting Surveyor landing sites. It was more important to have well-lit photographs of some part of the lunar surface as soon as possible than to have photographs within the Apollo zone; however, if a daylight landing was possible within that zone as well as outside it, the committee gave priority to an Apollo site. If the first Surveyor could not land in sunlight at all, it should be put down within the Apollo zone. The committee approved 14 of the 40 sites proposed for the first Surveyor mission, then sent its recommendations to the project offices, which would plan specific missions in more detail for review by the committee and by OSSA's Space Sciences Steering Committee.21
Lunar Orbiter project officials set about making detailed plans for the first mission that would satisfy Apollo's requirements. Surveyor managers, however, were reluctant to comply with the committee's recommendations. They pointed out that the ground rules required landing at a less-suitable site even though a better one was available - a significant threat to mission success, JPL believed. They would target the first Surveyor in compliance with the committee's ground rules, but if the spacecraft had any trouble at an inferior site, JPL intended to recommend strongly that the next mission be sent to a better one.22
America's first unmanned lunar explorer,*** Surveyor I, launched on May 30, 1966, landed 63 hours later approximately 90 kilometers north of the crater Flamsteed in Oceanus Procellarum, at the extreme western fringe of the Apollo landing zone.23 Its first television pictures were encouraging to Apollo engineers: the surface was firm enough to support a lunar landing module and the surrounding area was reasonably level. But beyond the immediate landing area the TV images showed more than a few large boulders and craters. The pictures served to demolish some hypotheses about the lunar surface, notably Gold's idea that the maria were covered with deep layers of dust. The surface was composed of fine particles, firmly packed and cohesive.24
Less than three months later, on August 10, Lunar Orbiter I roared off the pad at Cape Canaveral; four days later the spacecraft was in orbit around the moon, and by the end of the month it had photographed all nine of its assigned sites in the Apollo landing zone. After completing its photography, Orbiter remained in orbit, transmitting electronic data on gravity, meteoroids, and radiation around the moon - another aspect of its service to Apollo and to lunar science.25
Malfunctions of the spacecraft and photographic system resulted in fewer
good photographs than project officials would have liked; but
preliminary photographic analysis began in late August and produced
recommendations for the second Surveyor and Lunar Orbiter missions by
the end of September. On the basis of crater density and regional
slopes, 10 of 23 areas selected for detailed study seemed satisfactory;
8 potential sites were recommended for detailed analysis.26 On September 29 the Surveyor/Orbiter
Utilization Committee reviewed these results and outlined the
requirements for the second Orbiter mission.**** Again Apollo sites were stressed,
particularly those types of terrain shown by to
be the most promising - landing areas smooth enough to land on, having
little enough slope in the approach path to avoid confusing the lunar
module's landing radar system. Lighting conditions for photography would
be chosen so that slopes of 7 degrees, and surface protuberances 6 feet
(2 meters) in diameter and 1.5 feet (0.5 meter) high, could be detected
in an area 20 feet (7 meters) square.27
Lunar Orbiter II, modified to correct the problems
encountered by its predecessor, was launched November 6, 1966, and its
results far surpassed those of the first mission. All of the 30
preplanned sites were photographed at medium and high resolution, giving
geologists and cartographers excellent material with which to work.# 28
The mapmakers believed that with more stereo photographs of the quality
returned by Lunar Orbiter II they could produce terrain-maps with two-
to three- meter contours. MSC's Apollo project office representatives
were pleased with the second mission's results and believed that one
more flight would satisfy their requirements for the first one or two
lunar landings. Apart from some additional site photography, Apollo
wanted one or more Orbiter spacecraft to stay in lunar orbit long enough
to allow precision tracking by earth-based radar. All navigational
calculations for the lunar module were to be made by ground-based
computers using data from the Manned Space Flight Network, Apollo's
communication and tracking system, and early certification of this
system was essential.29
In mid-December 1966 the Apollo Site Selection Board met to review the
status of site selection. In general the process was going well.
Geologic interpretation of the Orbiter photographs had already yielded
some general conclusions about the nature of the lunar surface and where
the best landing sites were likely to be found. Cartographers could not
accurately determine slopes in the landing area without stereoscopic
photography, but MSC gave higher priority to finding a landing site with
a minimum of rocks and craters; the slope of the terrain leading to a
suitable site could be evaluated some other way. No serious problems in
site selection were apparent, and the board could only await the results
of Lunar Orbiter III and more detailed analysis of the available data.30
As 1967 began Apollo planners did not want much more from the unmanned
lunar investigation projects. They would use whatever additional data
became available, but priorities were changing. Three more Lunar
Orbiters and four Surveyors would be sent to the moon during the next 13
months, but after the third orbiter they would do more for lunar science
generally than for Apollo specifically.31
* Other members were: Everett E.
Christensen, mission operations dir., OMSF; Victor C. Clarke, Surveyor
project office, JPL; Willis B. Foster, dir., Manned Space Science Div.,
OSSA; William A. Lee, asst. mgr., Apollo spacecraft program office, MSC;
Urner Liddell, chmn., Planetology Subcommittee of the Space Sciences
Steering Committee, OSSA; Benjamin Milwitzky, Surveyor project dir.,
OSSA; Oran W. Nicks, lunar and planetary programs dir., OSSA; Samuel C.
Phillips, Apollo program dir., OMSF; Lee R. Scherer, Lunar Orbiter
project dir., OSSA; and William E. Stoney, Space Environment Div., MSC;
and Israel Taback, Lunar Orbiter project office, Langley Research
Center,
** Other members were: Cortright,
Lee, Stoney, and Christensen, all members of the Surveyor/Orbiter
Utilization Committee; Ernst Stuhlinger, Research Projects Office dir.,
MSFC; and John P. Claybourne, Future Studies Office, Design Engineering
Branch, KSC.
*** But not the world's first; on
Feb. 3, 1966, the Soviet Union, apparently intent on establishing space
"firsts," had logged another by landing Luna IX
on the moon several hundred kilometers northwest of Surveyor
I's landing site. Similarly the Russian Luna X
became the first moon-orbiting satellite on Apt. 3, 1966, four months
before the U.5.'s Lunar Orbiter I. Luna X did
not relay photographs to earth, however.
**** A small thruster failed on
Surveyor II (launched on Sept. 20, 1966) after its
midcourse correction maneuver, causing the spacecraft to spin at one
revolution per second. All attempts to correct the malfunction failed
and the lander crashed 250-300 km southeast of crater Copernicus.
# A famous by-product of the Lunar
Orbiter II mission resulted from the need to advance film periodically
even if no picture was taken. To avoid wasting that film, mission
controllers were given a limited choice of targets for these exposures.
One was used to take an oblique picture of crater Copernicus under
almost ideal lighting conditions, showing hitherto invisible surface
details. News media called this "one of the greatest pictures of
the century."
16. John M. Eggleston to Dr. W. A. Lee,
"Target Selection for Future Ranger Flights," Feb. 4, 1965.
17. C. J. Byrne, "Ranger VII Photo
Analysis - Preliminary Measurements of Apollo Landing Hazards,"
Bellcomm, Inc., Tech. Memo. TM-65-1012-2, Mar. 17, 1965.
18. Newel] to multiple addressees,
"Establishment of Ad Hoc Surveyor/Orbiter Utilization
Committee," June 22, 1965.
19. George E. Mueller to multiple
addressees, "Establishment of Apollo Site Selection Board,"
Management Instruction (NMI) 1152.20, Aug. 6, 1965.
20. John P. Mayer to Chief, Mission
Planning and Analysis Div., MSC, "Lunar landing site
selection," Oct. 6, 1964; Robert R. Gilruth to Mueller,
"Establishment of Apollo Site Selection Board," July 29, 1965;
Gilruth to Newell, "Members of Ad Hoc Surveyor/Orbiter Utilization
Committee," July 29, 1965.
21. OSSA, "Ad Hoc Surveyor/Orbiter
Utilization Committee, Minutes First Meeting, Washington, D.C., August
20, 1965," Sept. 16, 1965; I. M. Ross (Bellcomm, Inc.) to Maj. Gen.
S. C. Phillips, "MSF Position for Surveyor/Orbiter Utilization
Committee Meeting August 20, 1965," Aug. 20, 1965. For a more
detailed description of Lunar Orbiter mission planning, especially in
support of Apollo, see Bruce K. Byers, Destination Moon: A
History of the Lunar Orbiter Program, NASA TM X-3487 (Washington,
1977), pp. 177-99, 248-53, 261; Orbiter's contributions to Apollo site
selection are summarized on pp. 308-14. No useful single source for
Surveyor mission planning and its relation to Apollo is available; the
project's results (almost entirely scientific) are summarized in
Surveyor Program Results, NASA SP-184 (Washington, 1969).
22. Willis E. Foster, "Draft
Minutes of Second Meeting of Ad Hoc Surveyor/Orbiter Utilization
Committee," Oct. 1, 1965, with encl., ltr., R. J. Parks to Benjamin
Milwitzky, subj.: Surveyor Mission A Landing Site Selection, Sept. 28,
1965.
23. Albert Sehlstedt, Jr.,
"Surveyor Makes Soft Landing On Moon," Baltimore
Sun, June 2, 1966.
24. William Hines, "Man Could
Explore the Moon on Foot," Washington Evening Star,
June 17, 1966; Evert Clark, "Surveyor Found 'Gritty' Moon That Can
Support a Spacecraft," New York Times, June 17, 1966.
25. Byers, Destination
Moon, pp. 228-45.
26. Lunar Orbiter Photo Data Screening
Group, "Preliminary Terrain Evaluation and Apollo Landing Site
Analysis Based on Lunar Orbiter I Photography," Langley Working
Paper LWP-323, Nov. 1966.
27. Foster, "Minutes of the
Surveyor/Orbiter Utilization Committee, Washington, D.C., September 29,
1966"; Byers, Destination Moon, p. 251.
28. Byers, Destination
Moon, p. 258. See L. J. Kosofsky and Farouk El-Baz, The
Moon as Viewed by Lunar Orbiter, NASA SP-200 (Washington, 1970),
for an annotated collection of many of the best photographs from the
Lunar Orbiter missions, along with brief descriptions of the spacecraft
and its systems and a complete listing of the sites photographed on each
of the five missions. The detail in these photographs, even in halftone
reproduction, must be seen to be believed. Much of the geologic
interpretation of the moon has been accomplished using Lunar Orbiter
photographs and the information they contain is far from exhausted,
according to Eugene Shoemaker (interview, Mar. 17, 1984).
29. Foster, "Minutes of the
Surveyor/Orbiter Utilization Committee, Washington, D.C., January 5,
1967."
30. S. C. Phillips to multiple
addressees, "Minutes of the Apollo Site Selection Board Meeting,
December 15, 1966," Mar. 3, 1967.
31. John M. Eggleston to Dir., MSC,
"Utilization of Orbiter and Surveyor in Support of Apollo and
Apollo Applications Program Objectives," Jan. 18, 1967; Byers,
Destination Moon, pp. 312-26, 329-30.
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