The Proper Course for Lunar Exploration (1965)

For a time, Thomas Evans headed up the Advanced Lunar Missions Study Program in the NASA Headquarters Office of Manned Space Flight. By the time of the 11th Annual Meeting of the American Astronautical Society (AAS) in May 1965, however, he had retired from NASA and become a farmer in Iowa. This gave him the freedom to speak his mind about what he felt were the Apollo Program's shortcomings.

Evans told assembled members of the AAS that "the idea of a manned [landing] on the moon was so spectacular. . .that [it] dominated most pronouncements and thoughts on the space program." He argued, however, that this objective had "too much the flavor of a stunt to be the final goal of a $20 billion national effort." Evans maintained that

[Our] situation today is comparable to one which might have occurred during the railroad building era in America a century ago. It is as if the federal government had invested vast sums in the construction of the first railroad spanning the North American continent, but had procurred only a single engine and caboose. . . The first crossing by that engine and caboose would have been a major milestone in man's progress and would have been greeted with enthusiasm and applause. But then those responsible for the program would have faced a major decision. . .Should the project be stopped? Should the engine-caboose be run repeatedly back and forth across the Continent to constantly remind the world of our great achievement? Or should a further modest investment be made in. . .some freight and passenger cars, to convert the system into something of practical value? Only the last solution would have been tenable then, and only a similar constructive approach would seem acceptable now.

Evans argued that the Saturn rockets and Apollo spacecraft NASA had under development would provide "an excellent base upon which to build a broad program of manned. . .lunar exploration beyond the first landing." Evans pointed to statements by President Lyndon Baines Johnson and Vice-President Hubert Humphrey which he said made clear that "the United States fully intends to explore the moon, not merely to visit it." He also noted that NASA expected to be able to launch six Saturn V rockets per year beginning in 1969.

After explaining that "most Saturn Vs will be used for lunar operations since there are only a limited number of credible missions for this vehicle in earth orbital and planetary programs during the early 1970s," Evans outlined four candidate Saturn-Apollo-based lunar exploration programs. In the first, the baseline Apollo program, a single Saturn V rocket would launch a Apollo Command and Service Module (CSM) carrying three astronauts and the Lunar Excursion Module (LEM) (as the Apollo Lunar Module - LM - was known at this time). Two astronauts would land on the moon in the LEM for a one-day stay. They would explore an area 0.2 miles in radius centered on their LEM. The crew would have at its disposal only 250 pounds of payload such as scientific instruments.

Evans's second candidate program would be based on the Apollo Extension System (AES) that NASA had begun to study as early as 1963. This option would, he explained, permit "sophisticated orbital survey. . .to gather data on the entire surface of the moon," as well as lunar surface stays lasting up to 14 days.

Two Saturn V rockets would be required for each AES lunar surface mission. The first would launch a piloted CSM and an automated cargo LEM loaded with 2500 pounds of supplies and equipment. The CSM would transport the cargo LEM to lunar orbit, then the LEM would separate and land automatically on the moon. The CSM and its crew would then return to Earth. The second Saturn V would launch three astronauts and Apollo CSM and LEM spacecraft "improved" to enable long missions. Two astronauts would land in the improved LEM near the cargo LEM, which would serve as their shelter during their 14-day surface stay. They would use a small surface rover or a pair of flying vehicles to explore an area five miles in radius.

The third candidate program, based on Apollo Logistic Support System (ALSS) studies, would also use two Saturn Vs per 14-day surface expedition, but would differ from AES in that the LEM Truck, a beefed-up LEM descent stage capable of delivering four tons of payload to the lunar surface, would replace the cargo LEM. The LEM Truck's principal payload, Evans wrote, would be the Mobile Laboratory (MOLAB), a pressurized rover that would permit two astronauts to explore an area 50 miles in radius.

Evans noted that, in spite of their impressive capabilities, the AES and ALSS cargo delivery systems would be "inherently inefficient" because astronauts would need to travel to the moon and back to deliver each automated cargo lander. This would mean that the mass of the CSM systems required for crew support and Earth-return (life support, lunar-orbit departure and course-correction propellants, reentry heat shield, and parachutes) would have to be subtracted from the mass of the payload that the AES and ALSS systems could deliver to the moon's surface.

The fourth program of lunar exploration, Lunar Exploration Systems for Apollo (LESA),would avoid this inefficiency. LESA, Evans explained, was "a family of shelters, vehicles, and other equipment. . .tailored to support not only short-term reconnaissance operations by two or three astronauts but also semi-permanent scientific stations manned by up to 12 or even 18 men." The Saturn V-launched LESA lander would need no CSM, enabling delivery of up to 14 tons of payload. Crew delivery at first would be by improved Apollo CSM and a LEM capable of landing three men on the moon. A 90-day, three-man LESA 1 expedition could explore an area 80 miles in radius; a 365-day, 12-to-18-man LESA 3 outpost with advanced manned landers for crew rotation and resupply could survey an area 200 miles in radius. The former would require a total of three Saturn V launches; the latter, 10 to 17 Saturn V launches.

Developing the AES would cost an additional $500 million over the $20 billion already committed to Apollo, Evans estimated, while ALSS would cost $1 billion. LESA 1 would cost $2 billion - just 10% of the amount already committed to Apollo, he noted - and LESA 3 would evolve from LESA 1 for an additional cost of just $800 million.

Evans then proposed a two-phase lunar program. In Phase I, which would be based on AES, ALSS, or LESA 1, astronauts would explore three areas of the moon judged to be of "major geoscientific interest" totaling up to 1800 square miles ("a meager sample," Evans noted, "of the total 10 million square miles of lunar surface"). In Phase II, which would be based on LESA 3 modified for six astronauts, NASA would maintain an outpost on the moon for four years.

Evans compared operations costs for the four programs. He determined that a combination of LESA 1 in Phase I and modified LESA 3 in Phase II would be most economical, with a total cost of less than $8 billion. ALSS/modified LESA 3, with an operations cost of $8.3 billion, would also be economically acceptable, while AES/modified LESA 3 would be "a disastrous selection" - together, the two phases would cost a total of about $20 billion.

The retired NASA manager ended his paper by assessing the state of NASA lunar planning. He noted that, of the $26 million allotted to advanced manned systems studies in the Fiscal Year 1965 NASA budget, most was budgeted for examination of inefficient and limited systems such as AES. "Only a trickle," he wrote, would be devoted to the study of "more sophisticated and efficient systems."

NASA continued studies of advanced lunar systems throughout the 1960s and on into the 1970s. It focused mainly on AES/ALSS-type missions, which it hoped to fly during the 1970s as part of its Apollo Applications Program (AAP), AES's successor. Apollo did not, however, imply a long-term commitment to lunar exploration, and, as it became increasingly obvious that the Soviet Union had not made a commitment to manned lunar missions of the same magnitude as the United States, interest in post-Apollo advanced manned lunar systems rapidly faded in the White House and in Congress.

Even more important, the 27 January 1967 Apollo 1 fire undercut NASA advanced plans. The fire killed astronauts Gus Grissom, Ed White, and Roger Chaffee during a launch rehearsal just a few weeks before the planned first manned Apollo mission. The investigation into the cause of the fire revealed engineering and management shortcomings that left Congress in no mood to "reward" the agency by funding new space projects. Apollo, which represented a $25-billion investment in national prestige, suffered almost no funding cuts in the fire's immediate aftermath, but AAP lunar missions were among the first to feel the knife.

In the 1969-1971 period, when NASA Adminstrator Thomas Paine's Integrated Program Plan held sway within NASA, the space agency and its contractors studied complex and costly lunar transportation systems (such the Nuclear Shuttle) and lunar bases. Such plans enjoyed no support within the Administration of President Richard Nixon, however, and all IPP planning ceased soon after Paine's resignation in September 1970.

The image at the top of this post illustrates the course that U.S. lunar exploration took after Evans presented his paper. It shows Apollo 17 Commander Eugene Cernan saluting Old Glory in the Taurus-Littrow valley in December 1972. The last of six missions to land on the moon, Apollo 17 left Earth atop the penultimate Saturn V rocket. The mission's jeep-like Lunar Roving Vehicle (visible behind Cernan) ranged up to 7.6 kilometers from its home base, the LM Challenger (behind flag), during three traverses spanning three days. The only professional scientist to reach the moon, Lunar Module Pilot Harrison Schmitt, snapped the picture.

Reference:

"Lunar Exploration: What is the Proper Course?" Thomas Evans, Post Apollo Space Exploration, Francis Narin, editor, 1965, pp. 647-661; paper presented at the 11th Annual Meeting of the American Astronautical Society in Chicago, Illinois, May 3-6, 1965.