The Apollo Lunar Surface Experiments Package. and Associated Experiments

By 1964 the growing fraternity of space and lunar scientists began to see the Apollo missions as an opportunity to address many age-old questions. These questions related not only to the Moon itself but to the Earth, the entire solar system, and to some degree the whole universe. The Moon would provide the equivalent of a spacecraft on which to conduct experiments never before possi­ble. The Sonett Report, along with advisory panels from the Office of Space Science and Applications, the Office of Manned Space Flight, and the National Academy of Sciences’ Space Science Board, guided us in soliciting experiments to be associated with a permanent science station such as we studied for post – Apollo missions under contract at Marshall Space Flight Center (these studies became the basis for the Apollo Lunar Surface Experiments Package, or ALSEP, developed for Apollo missions). We also solicited additional experiments that could be conducted on the Moon’s surface independent of a geophysical ground station. At this time a few of the scientists who were thinking about experi­ments on the Moon were also considering how to conduct experiments in lunar orbit. Aside from Lunar Orbiter, however, there were no ‘‘approved’’ plans to provide a platform for lunar orbit experiments in the Apollo missions. I em­phasize ‘‘approved,’’ for though planning for such experiments was going on, no specific spacecraft had been designated to carry them. Experiments as well as cameras had been solicited for the Lunar Orbiter program, but the proposals were on the shelf until a program was approved.

Will Foster’s February 13, 1964, memorandum, in addition to recommend­ing a Field Geology Team that would help plan for sample collection, listed four geophysics teams, selected to recommend and design lunar seismic, magnetic, heat flow, and gravity experiments.1

The seismology experiment was divided into two parts, passive and active (each requiring different instrumentation), to monitor the Moon’s internal activity (moonquakes) and determine its shallow and deep structure. The team consisted of Frank Press, then at California Institute of Technology, and Mau­rice Ewing and George Sutton of Columbia University. The memo proposed additional investigators for the active experiment, but they were unnamed.

A third type of seismic experiment, engineering seismology, was also listed, to provide data that would be used for post-Apollo mission planning. Although considered a nonscientific experiment, it was designed to measure the Moon’s surface characteristics to a depth of fifty feet. For this team Foster suggested personnel from the Manned Spacecraft Center and the United States Geological Survey at Flagstaff, since USGS had begun to study the data needed for design­ing lunar bases and mobility devices under my office’s contract with Gene Shoemaker. The engineering seismology experiment was finally designated the active seismic experiment, and Robert Kovach at Stanford University became the principal investigator (PI), supported by coinvestigators Thomas Landers, also from Stanford, and Joel Watkins, who had moved from USGS at Flagstaff to the University of North Carolina. Kovach never selected anyone from MSC to join his team.

The magnetic measurements team consisted of James R. Balsley of Wesleyan University, Richard R. Doell from USGS, Norman Ness of NASA Goddard Space Flight Center, Chuck Sonett from NASA Ames Research Center, and Victor Vaquier from the University of California, San Diego. This team was to specify the magnetic measurements needed to determine the lunar magnetic field (if any) in the presence of solar and interplanetary magnetic fields and the methods for measuring any remnant magnetic field in lunar rocks. All previous attempts to measure a lunar magnetic field from a distance had failed to find any significant field; thus these measurements would be critical in unraveling the Moon’s early history.

The heat flow measurement team consisted of Francis Birch from Harvard, Sydney P. Clark from Yale, Arthur H. Lachenbruch of USGS, Mark Langseth from Columbia, and Richard Von Herzen from the University of California, San Diego. In addition to designing the heat flow instrumentation, the PI for this experiment would become closely involved with the design of the Apollo lunar drill, because the heat flow sensors would be lowered into two holes made by the drill.

The final team listed in the memo was to make gravity measurements. It consisted of Gordon MacDonald from the University of California, Los An­geles, and Joseph Weber from the University of Maryland. This experiment, it was hoped, would provide some of the more exotic measurements to be made on the Moon; not only would it measure the deformation of the Moon created by the pull of the Earth’s mass, but it might detect gravity waves, predicted by Einstein but never unequivocally measured. This experiment was truly unique to the Moon, since to have any hope of recording gravity waves the instrument, a sensitive gravimeter, had to be on an extremely quiet body, as many believed the Moon to be.

These teams, like the field geology, geochemistry, petrography, and miner­alogy teams, were also approved by the Space Science Steering Committee (SSSC). My purpose for listing the team members is twofold. First, it shows for the record that their members included many of the leading scientists of the day in the identified fields. Thus this obviated the need to make the usual formal solicitation to the scientific community as a whole, since it would undoubtedly have resulted in teams similar to those proposed. Some might take issue, but I believe that is true, since only a few leading scientists in these fields were considering lunar experiments. This procedure shortened the time it took to get the key players in place, probably by six months or more—not an insignificant consideration. Second, the makeup of the teams changed with time, especially the important position of PI for each experiment. This position, of course, was the key to future scientific fame, for the PI’s name would appear first in the final reports and citations.

Each team was to design and build its experiment through the prototype stage, training the astronauts in its use or deployment and, finally, reducing and reporting on the data returned. This opportunity was extremely important, because Apollo promised long-term data collection for experiments attached to the lunar ground station (one year or perhaps longer) and exciting data trans­mission (bandwidth) capability. Weight and power allowances were expected to be generous compared with a typical unmanned spacecraft experiment, and having an astronaut set up the experiment or return some or all of the data would add to the value. Some people in the unmanned science camp argued that using the astronauts for those types of experiments was an unnecessary complication, but in general their involvement was considered a real plus. Before this date in 1964 we had little experience deploying unmanned payloads either in space or on the Moon, and those that had been deployed were rela­tively unsophisticated. Using astronauts to set up or operate an experiment had only occasionally been factored into an experiment’s design for the Gemini program, so this would be a new challenge to the scientific community.

After SSSC approved Foster’s recommendations, contracts were negotiated with the team members, and OSSA began to fund and manage their efforts. As promised in Foster’s memo, other experiments and investigators were brought on board later to cover important areas of science not included in the initial teams. Experiments added during this time were the Solar Wind Spectrometer (SWS) to measure the solar plasma striking the lunar surface; the Suprathermal Ion Detector Experiment (SIDE), which could measure a variety of interactions with the solar wind and complement the SWS measurements; and the Cold Cathode Gauge (CCG) to measure the composition of the lunar atmosphere. These experiments would also be attached to the ground station for their power, housekeeping, and data transmission needs.

Another experiment that would operate independently of any ground sta­tion, the Solar Wind Composition experiment, was also approved for the first missions. It was proposed by a Swiss team headed by Johannes Geiss from the University of Bern. Its purpose was to collect and return solar wind ions, such as helium and neon, to help us understand the composition of the solar wind. This experiment was funded in part by the Swiss government.

With the initial suite of experiments and experimenters under contract, in early 1965 our efforts turned to the design and development of the station that would support the experiments. By this time the MSFC Emplaced Scientific Station (ESS) contractors, Bendix and Westinghouse, had progressed to a pre­liminary design of a geophysical station for post-Apollo missions. It had all the characteristics we wanted for an Apollo station; the major differences were in overall size, the ESS being larger than we could expect for the first Apollo landings.

On May 10, 1965, Foster sent Ernst Stuhlinger at MSFC a request to submit a work statement for an Apollo scientific station.2 At the same time he also asked Max Faget at MSC to submit a similar work statement. Much to our chagrin, George Mueller’s office, led by James Turnock and Leonard Reiffel, thought MSC should be the lead center in managing this complex payload. I was lobby­ing hard for MSFC and had convinced E. Z. Gray and Will Foster that, based on all the work MSFC had done for our post-Apollo mission studies, it was the best qualified. MSC had nowhere near as much experience with lunar science payloads, and it lacked qualified staff to oversee such a contract.

This controversy came to a head at a Saturday meeting with George Mueller, on May 24.3 (Remember the best day to get his undivided attention?) Also at the meeting (besides me) were Sam Phillips, Edgar Cortright (Mueller’s deputy), E. Z. Gray, Will Foster, Dick Allenby, Jim Turnock, Len Reiffel, Benjamin Milwitzky, and Jack Trombka. The major issue was deciding who would man­age the Apollo science station. We reviewed the two work statement proposals from MSC and MSFC and weighed the strengths and weaknesses of each. We described the problems we had working with MSC on matters dealing with science and the much better relationship we, and the scientists we had brought into the post-Apollo studies, had with MSFC.

After about two hours of discussing the pros and cons, the MSFC work statement was judged superior to MSC’s and likely to elicit the best proposals. I thought we had carried the day and that MSFC would be assigned this impor­tant task. But Phillips finally weighed in with his opinion—that in spite of its deficiencies MSC should become NASA’s ‘‘lunar expert.’’ Mueller agreed and also expressed his unwillingness to have Stuhlinger manage the Apollo science program. Why he was uncomfortable with Stuhlinger he never explained. He did agree that the MSFC work statement should be the basis of the request for proposals and asked that three companies be selected in the initial study to ensure some competition.

The anointing of MSC as our lunar expert was a devastating blow to many of us in attendance and presaged the at times bitter disagreements we and the PIs would have with the MSC managers in the years ahead. As a gesture to assuage our disappointment, Mueller asked us to prepare a history of our past year’s negotiations with MSC so that he could understand the situation. Perhaps Mueller’s review of our tales of past disagreements was a factor in the decision to transfer Bill Hess to MSC at the end of 1966 to lead the science activities there.

The MSFC’s Apollo work statement, based on the ESS study, in essence called for a junior ESS. Because extended periods of data collection were needed for many of the experiments selected, it was decided that the station would be powered by a radioisotope thermoelectric generator, the same power source proposed for the ESS. RTGs, already under development for planetary space­craft that would fly too far from the sun to collect sufficient solar energy, generate electric power through the decay of radioactive elements, in this case plutonium. This decay produces heat, which is in turn converted by thermo­couples to electric power. RTGs were an ideal power source for lunar-based experiments, because for fourteen consecutive Earth days of every day/night lunar month cycle, the station would be in darkness and very cold. Batteries alone could not do the job; they would be far too heavy to accommodate the required duty cycles. A solar-powered station would have required a large solar array, would be difficult to deploy on the lunar surface, and would still re­quire a large, heavy battery pack to sustain it during the fourteen-day lunar night. When the solar array and the batteries were studied, it became evident that RTGs provided not only a distinct savings in weight but also greater reliability and simplicity, because among their other advantages they have no moving parts.

The Atomic Energy Commission (AEC), the agency responsible for oversee­ing the manufacture of RTGs, had several well-tested designs to choose from that could provide various amounts of power depending on how much weight one could allocate to the power source. The RTGs were manufactured by Gen­eral Electric’s Valley Forge, Pennsylvania, plant, with the plutonium supplied by the AEC. Safety considerations were the primary arguments against using an RTG. First was the question of how an astronaut could safely deploy the RTG. It would be ‘‘hot,’’ both in temperature and in radioactivity. Second was the chance of a mission abort in which the plutonium 238 fuel source might be released into the atmosphere. Plutonium is highly toxic if inhaled. AEC and General Electric believed they could solve both problems, and later ground handling tests and destructive tests exposing the system to high-energy impact and heat loads proved them correct.

The RTG power source (system for nuclear auxiliary power, SNAP) selected to provide power for a year or longer was designated SNAP-27. It consisted of a fuel capsule and generator. The fuel capsule would be carried to the Moon on the lunar module descent stage in a special graphite container, and after the as­tronauts removed it and inserted it in the generator, it would provide 63.5 watts of electrical power to the central station. With a fuel half-life of almost ninety years, it more than filled the need for a long-term power source.

(The RTG on the Apollo 13 mission, still attached to the LM lifeboat that sustained the astronauts during that harrowing, nearly fatal experience, reen­tered at a speed far beyond that anticipated for a typical Earth orbit failure, but it is believed to have survived intact, as designed. If the cask protecting the plutonium heat element had failed, the sensitive instruments on the aircraft sent to sample the air at the reentry point over the Pacific Ocean would have detected plutonium in the atmosphere.)

Once the power source had been decided, the next critical step was selecting a design for the communication and data relay subsystem. Commands would be transmitted from Earth to control the station and its experiments, and data would be relayed back from the lunar surface. NASA’s Manned Space Flight Network (later incorporated into the Space Tracking and Data Network) would provide round-the-clock monitoring, eliminating the need to provide data storage at the station as we had envisioned for some of the ESS experiments. Raw or processed data would then be given to the PIs for reduction and inter­pretation. A difficult question was, How much data should the station be capa­ble of handling? No matter how much was made available, PIs would always be hungry for more. Until specific instruments were designed, this would remain an open question. At the Falmouth conference, attended by some of the proba­ble experiment PIs, it was recommended that the station be designed to accept various types of experiments so that the instrument complement could be easily changed, depending on the landing site and the experiments required to answer site-specific questions. All in all, it would be a tough design challenge, but based on the work we had done for our post-Apollo studies, we felt con­fident it could be met.

In June, using the MSFC work statement as its model, MSC released the request for proposal (RFP) for the geophysical ground station that came to be known as the Apollo Lunar Surface Experiments Package. Max Faget’s Engi­neering and Development Directorate’s new Experiments Program Office was named MSC program manager, reporting to Robert Piland, recently appointed to head the office. Nine companies submitted proposals, and as Mueller had requested, three were selected to provide a preliminary design. In August, Bendix Systems Division, Space General Corporation, and the TRW Systems Group were each awarded a contract for $500,000. Each company would pro­vide a preliminary design and mock-ups, to be delivered to MSC and Grum­man at the end of the six months.4

The RFP requested that each design include a seismometer, heat flow sen­sors, magnetometer, a suite of atmospheric and radiation sensors, and a device to measure the micrometeorite flux at the lunar surface. (This last device,

proposed by MSC and rejected by the Planetology Subcommittee four months earlier as not relevant to lunar science, had found its way back into consider­ation. MSC used its position as NASA’s ‘‘lunar expert’’ to push one of its pet ideas.) The weight allowance for the entire package was not to exceed 150 pounds. After a review and evaluation of each contractor’s design and perfor­mance during the six months, we planned to select one contractor to provide the flight hardware.

After the mock-ups were delivered, we convened a selection committee to decide which of the three teams would build the flight hardware. Bendix had obviously profited from its part in our post-Apollo studies of the ESS. Its pre­liminary ALSEP design was judged the most responsive to our requirements, and a contract was awarded in March 1966. With an initial value of $17 million, the contract finally grew to $58 million through increases in the number of flight and test units required and the added job of building four ALSEP experi­ments for the PIs and integrating more experiments than originally projected.

The contract and its subsequent modifications called for the manufacture of six flight-qualified ALSEPs, a ‘‘dummy’’ unit to fly to the Moon in the storage bay of the Apollo 10 lunar module, prototype and qualification units, two training units, and one unit dubbed the ‘‘shop queen,’’ which was modified and cannibalized and was generally available to test ideas. Joseph Clayton, later promoted to division general manager, was the initial Bendix program manager and was succeeded by Chuck Weatherred at the time ALSEP progressed to the prototype phase. Chuck, who had been closely involved with many of our post – Apollo studies, then continued as program manager through the missions.

Some additional details now about ALSEP, the attached experiments, and the other experiments that were deployed at the landing sites but were not dependent on ALSEP for their operation. First the ALSEP central station. The central station was the control center for the many instruments that were so carefully crafted by the experiment teams, some designed to record sensitivity levels unachievable for similar Earth measurements. The central station data subsystem would receive and decode the uplink commands for each experi­ment and collect the scientific and housekeeping data and transmit them back to Earth. A small helical S-band antenna would be mounted on top of the station and pointed by the astronauts to provide the data link to Earth.

Most of the experimenters were interested in collecting data over a long period, in most cases the longer the better. The ALSEP design goal was to survive for a minimum of one year, providing power, housekeeping functions, data collection, and transmission. This was no mean task, given the extreme temperature fluctuations (over 500°F) experienced on the Moon every twenty- eight days. At the same time that instruments or devices would be experiencing these temperature changes, they and the central station would be operating in a high vacuum. Lacking the normal methods of regulating experiment tempera­tures on Earth, their design would have to include novel ways to both heat and cool all the components.

Keeping the experiments warm was not as hard as keeping them cool; heat could be supplied by small electrical heating elements of various designs. But since liquid coolants could not be used, radiators, thermal blankets, and shield­ing were employed, utilizing new materials. In addition, the central station and the experiments would have to be carefully oriented to provide selective shad­owing and reflection of the sun’s rays.

Thirteen experiments were ultimately selected to operate with the five ALSEPs deployed on the Moon. (Some were on the ALSEP carried on the Apollo 13 mission, and their remains are at the bottom of the Pacific Ocean.) Each ALSEP had a unique combination of experiments, ranging from four to seven, and some experiments were carried several times. The eight listed at the begin­ning of this chapter were considered of highest priority. Four more would be added over the next few years, plus a dust detector to help monitor ALSEP’s health if dust or dirt on thermal surfaces caused a problem.

One of the four new experiments, Seismic Profiling, had an objective similar to the active seismic experiment but would provide additional information on the Moon’s shallow structure. The other three were the Lunar Ejecta and Mete­orites Experiment to measure the direction of travel, speed, and mass of mi­crometeorites arriving at the lunar surface (not the MSC proposal mentioned earlier); the Charged Particle Lunar Environment Experiment for measuring a wide range of charged particles caused by the interaction of the solar wind on the lunar surface; and the Lunar Atmosphere Composition Experiment, a spec­trometer that would measure the composition and density of whatever gas molecules might be found in the tenuous lunar atmosphere. Some of the experimenters did their own contracting and built their experiments, deliver­ing them to Bendix for integration, and some used Bendix as their contractor.

Nine other experiments, not dependent on ALSEP and not including those discussed in chapter 5, were to be deployed by the astronauts either in the

vicinity of the LM or during their traverses. They fell into two categories: those used for studying the Moon and those that used the Moon as a convenient platform from which to make measurements.

As I mentioned earlier, one could think of the Moon as a spacecraft circling the Sun, on which you could place instruments to measure phenomena occur­ring within or outside our solar system. In our post-Apollo studies we had examined using the Moon as a site for astronomical observations, and this preliminary study elicited some interest from the astronomy community dur­ing the Falmouth and Santa Cruz conferences.

On later missions, when larger payloads became available, we had the op­portunity to test this idea. An ultraviolet camera-spectrograph was proposed and carried on Apollo 16, the second J mission. The objective of the experiment was to evaluate the Moon as an astronomy base and to take pictures of targets in the far ultraviolet portion of the electromagnetic spectrum, a frequency that could not be studied from the Earth’s surface because of our intervening atmo­sphere. The experiment was proposed by George Carruthers of the Naval Re­search Laboratory, and the instrument was designed and fabricated at his lab.

A second experiment in the category of using the Moon as an observation post was the Cosmic Ray Experiment, a multipart experiment proposed by three teams, one at the General Electric Research and Development Center, a second at the University of California at Berkeley, and a third led by Caltech. Its objective was to detect high and low energy particles emanating from the Sun and from outside the solar system. It had the potential to record particles that had not been detected on Earth, again because of interactions with our protec­tive magnetic fields and atmosphere. It would go to the Moon mounted on the LM descent stage, where it would be exposed just after translunar injection, then folded and retrieved at the end of the third EVA. A related part of the experiment was a detector carried inside the astronauts’ helmets to determine their exposure to cosmic rays during their transit and stay on the Moon or while in lunar orbit. This was important information because it concerned the astronauts’ health, especially if a solar flare or some other major event that occurred somewhere in the universe at an earlier date would expose them to high energy particles during the mission. It was also important for planning longer-duration, manned missions to Mars.

Five of the nine experiments fell into the category of studying the Moon

through various measurements. These were the Lunar Neutron Probe, the Laser Ranging Retro-Reflector (LRRR), the Lunar Portable Magnetometer, the Lunar Traverse Gravimeter, and the Surface Electrical Properties (SEP) experiments. By the time the last three were proposed, it was known that a small vehicle would be available to the astronauts, so the magnetometer, gravimeter, and SEP were designed to be carried on the lunar roving vehicle (LRV), with measure­ments taken either at the astronauts’ discretion or at planned points. The magnetometer and gravimeter would measure the Moon’s gravity and magnetic fields to determine if these values changed as the astronauts moved away from the LM. The SEP used radio waves to penetrate the lunar surface to look for layering in the Moon’s crust. If there was no moisture in the upper layers, it might be able to penetrate deeper than the Seismic Profiling experiment. If water or ice occurred below the surface, the signals received would reveal their presence. The neutron probe would be lowered into the drill hole after the core was extracted to measure the rate of neutron capture below the lunar surface. This measurement would help us understand the physical processes that pro­duced the lunar soil. After remaining in the drill hole for some time, the probe would be recovered and brought back to Earth for study.

The LRRR was a late addition to the roster of Apollo experiments and deserves further description. A laser beam, originating at an observatory on Earth, would be reflected from the Moon back to the observatory and thus provide an accurate determination of the Earth-Moon distance (within a few inches). It was proposed by Carl Alley from the University of Maryland and was built in time to be carried on Apollo 11. Alley was supported by a host of coinvestigators; one of them, James Faller from Wesleyan University, became the PI for the Apollo 14 and Apollo 15 missions. The experiment was designed and developed by the A. D. Little Company of Cambridge, Massachusetts, and built by Bendix. The experiment carried on the Apollo 11 and Apollo 14 mis­sions consisted of one hundred reflectors, each about an inch and a half in diameter, arranged in a ten by ten square. They were mounted on an adjustable support that could be tilted and aimed at the appropriate angle for each landing site to best reflect the laser beams coming from Earth. The astronauts aimed the device using a sun compass and a bubble level, pointing the array at the center of the Earth. Individual corner-cube reflectors were manufactured under a separate contract by the Perkin Elmer Company. Because of difficulties in locating the LRRR at Tranquility Base and the Fra Mauro landing sites, the array carried on Apollo 15 was increased to three hundred reflectors, and it proved much easier to locate and reflect laser beams from Earth.

A network of three LRRRs was to be placed on the Moon, separated as far as possible in latitude and longitude. By sending laser beams from the Earth to the LRRRs and bouncing them back, it was anticipated that the Earth-Moon dis­tance could be calculated within approximately six centimeters. Such precise measurements would permit the study of many physical properties of the Earth and the Moon, including fluctuations in the Earth’s rotation rate, the wobble about its axis, the shape of the Moon’s orbit, and the Moon’s wobble about its axis. Ultimately, if enough stations on Earth were capable of sending laser beams to the Moon, small movements in the Earth’s crust might be measured. (Crustal movements are no longer measured this way. Instead, accurate laser ranging measurements are made from Earth to orbiting satellites. The LRRR, however, is the only experiment carried to the Moon by the Apollo astronauts that is still used for other types of measurements.)

Headquarters management of ALSEP was initially under the direction of OSSA in the Lunar and Planetary Programs office managed by Oran Nicks, and OSSA provided the funds to get ALSEP started. (The vast majority of ALSEP funding eventually came from OMSF.) William ‘‘O. B.’’ O’Bryant, a retired navy captain, was named program manager, and Dick Green, a retired air force officer returning to NASA after a recall, was named program engineer. Ed Davin, still reporting to Will Foster, was named program scientist. I also main­tained an oversight of ALSEP because of its close relationship to other programs I was managing, such as the lunar drill. Relations between headquarters staffers and MSC soured almost immediately. MSC continued its practice of not notify­ing headquarters when important reviews were to be held at Bendix or MSC. This caused a great deal of heartburn at headquarters. This attitude and way of doing business eventually led to the appointment of John ‘‘Jack’’ Small, who proved easier to work with; but the atmosphere had already deteriorated, and an uneasy relationship continued even when Small was replaced toward the end of the program by Donald Wiseman. Fortunately from our perspective, Bendix proved to be a cooperative contractor and recognized the importance of main­taining good relations with headquarters. This was a wise move, for in the ensuing six years there were a number of times when obstacles and difficult decisions arose that required the intervention of headquarters.

In some small defense of MSC’s reluctance to keep headquarters apprised of ALSEP’s progress, a careful line was always drawn between NASA’s contract offices and its contractors in order to avoid any misunderstanding about who was in charge. MSC had the sole authority to control the ALSEP contractor’s actions, and any changes to the contract scope could occur only with written direction from the MSC program manager. Probably all NASA centers had experienced instances when a contractor had used a conversation with someone from NASA headquarters to attempt to modify the scope of its contract, a surefire way to screw up the contract and make the center in charge see red. O. B., with his navy background, was a no-nonsense manager, and never to my knowledge did he create this kind of problem. But he never backed down from exercising his management prerogatives, which included the right to suggest changes to the program manager if he or his staff saw trouble developing and to keep a tight rein on the funding. O. B., Green, and Davin also felt that they were often the only ones sticking up for the experimenters when trade-offs were required, and they didn’t hesitate to make their concerns known.

Toward the end of summer 1968, with ALSEP development in its final stages, NASA management began to reevaluate the first landing mission’s lunar surface activities. Concern was growing about how well the astronauts would function on the Moon and, more important, how the LM would perform. Several ways to alleviate these concerns were explored. First the number and length of EVAs could be reduced. But if only one EVA was allowed, then ALSEP could not be deployed and still leave time for the astronauts to carry out their other important tasks, including sample collection. Not carrying ALSEP would reduce the astronauts’ workload and the weight of the LM for the first mis – sion—a partial solution to both concerns. Removing weight would also add a few seconds of hover time. ALSEP became a prime target for removal.

When rumors spread that the scientific experiments on the first landing would be drastically reduced, Charles Townes, chairman of the Science and Technology Advisory Committee, went to NASA senior management and ar­gued for keeping as much science as possible on the first mission. Our office, Bill Hess at MSC, and others in the scientific community were also lobbying hard to keep ALSEP on the first landing mission and to maintain two EVAs. Our office was fighting for more than just the science. ALSEP and the geological tasks the astronauts were scheduled to carry out represented years of planning and hard work, not to mention suffering through many a contentious meeting

with those in NASA who did not embrace the need to include science on Apollo. We were not prepared to accept such a defeat.

In September and October, in response to this outcry, our office and MSC studied an alternative to dropping the full ALSEP and presented it to the NASA Senior Management Council. A new, much smaller, and more easily deployed science payload was proposed and approved and given the name Early Apollo Experiments Scientific Package (EASEP). EASEP would comprise just three experiments, the passive seismometer, packaged with the dust detector, and the LRRR. Another self-contained, easily deployed experiment, Solar Wind Com­position, along with the equipment for the field geology experiment, would constitute the rest of the science payload. EASEP would be much lighter than ALSEP and require less time to deploy. By including these experiments on the first mission, NASA hoped to divert the criticism that was sure to come its way and show that its heart was in the right place regarding science. The astronauts would leave the highest priority experiment, the seismometer, at the landing site and still have time to conduct a limited geological study, collecting fewer samples than originally planned.

Instead of being powered by an RTG, the EASEP seismometer would get its power from solar panels and batteries charged by the solar array, the power source rejected for ALSEP but now acceptable because of the short lifetime expected for this substitute. The seismometer would have to operate only through the rest of the lunar day in which it was deployed, although we hoped it might survive longer. It would contain several small isotope heaters to help it survive the lunar night and, with luck, continue to function during a second lunar day. Like ALSEP, it would also have a self-contained telemetry system to transmit to Earth the seismometer and dust detector readings.

EASEP’s design was developed through close cooperation between MSC and Bendix, working under the ground rule that as much as possible of the hard­ware and subsystems would be based on ALSEP. Donald Gerke led the MSC team in the design phase and became the program manager for this hurry-up ALSEP substitute. In November 1968 NASA and Bendix agreed to a $3.7 mil­lion contract for the design and manufacture of the EASEP as well as the LRRR. By this time, with the Apollo flight program rapidly moving ahead, the date of the first landing was becoming obvious—sometime in the summer of 1969. Only three more Apollo test flights were scheduled before the first landing attempt. EASEP would have to be built in five months if it was to meet a May 1 delivery date at Kennedy Space Center for a subsequent June or July flight date. In contrast to some of the difficulties we encountered with MSC’s ALSEP managers, Gerke was easy to work with, especially for us at NASA headquarters. EASEP proceeded without a hitch and was delivered to KSC one day ahead of schedule.5

At the beginning of the chapter I listed the prominent scientists who were identified in Foster’s memo, along with the highest priority ALSEP experi­ments. In the months after the SSSC approved their selection to develop the experiments for Apollo, and before the ALSEP contract was signed, some ma­neuvering took place—at times a little indelicate—to determine who would be named principal investigators. This title conferred an important imprimatur because the PI would be the primary contact in the years ahead as we built the instrument and also would be responsible for interpreting the returned data and publishing the results. As a reward for all this effort, the PI would receive the largest amount of NASA funding allocated to the experiment and in some cases would be in charge of distributing funds to other members of the team. Remember the golden rule: ‘‘He who has the gold rules.’’ This was certainly the case for the PIs. In addition to the gold, they also got the publicity and all the other notoriety that went with this high-profile position. Most prominent sci­entists are not shrinking violets; being identified as Apollo PIs enhanced their reputations, and the exposure certainly helped advance their careers. How many scientists could look forward to saying they had designed an experiment that was placed on the Moon by the astronauts? Everyone knew only a lucky handful would have this claim to fame.

An example of the competition for this honor was the naming of the PI for the passive seismic experiment. Frank Press, while at Caltech, had developed the first lunar seismometer (which never flew) for Ranger. Maurice Ewing and George Sutton, at Columbia University’s Lamont-Doherty Laboratory, had de­veloped a seismometer (which likewise never flew) for Surveyor, and it was this very experience, plus their overall reputations, that led to their inclusion on the passive seismometer team. Ed Davin recalls a meeting at NASA headquarters to select the passive seismometer PI. Press and Ewing were present along with one of Ewing’s graduate students, Gary Latham. Ewing, being the senior scientist present, led the discussion and declared that Latham should be the PI be­cause this role would require that someone devote full time to the job and he thought—taking the liberty to speak for himself and Press—that they would not be able to do this. He volunteered that he, Press, and Sutton should remain as coinvestigators. Press, having studied under Ewing at Columbia University, graciously acquiesced, but after the meeting he remarked to Ed, ‘‘What Papa Doc wants, Papa Doc gets.’’ He was obviously disappointed at not being named PI by ‘‘Papa Doc,’’ a somewhat affectionate name given Ewing by his former students. Soon after, several others would be added to the team, but with Latham at Lamont-Doherty, Ewing’s laboratory reaped the public acclaim. Latham went on to do an outstanding job as PI.

I have not had the opportunity to talk to Press about this incident, but I imagine that in hindsight he might think it was not a bad decision. Soon after that meeting he became chairman of the Department of Earth and Planetary Sciences at MIT, certainly a full-time job. His reputation certainly did not suffer from not being an Apollo PI, for among other important jobs he held in later years, he was named president of the National Academy of Sciences, one of the most prestigious scientific positions in the nation.

There are some other interesting anecdotes concerning the experiments. Perhaps the most star-crossed was the Lunar Surface Gravimeter. Its tale of woe has been partially told before, but it deserves further discussion, perhaps with some new insights. I met the PI, Joseph Weber, early in his struggle to get his experiment accepted by NASA. His laboratory was only twenty minutes from our office in downtown Washington, on the campus of the University of Mary­land. Dick Allenby, Ed Davin, and I visited Weber in his basement laboratory sometime in early 1964. He had been building and modifying gravimeters in his lab for several years, hoping to arrive at a design sensitive enough to detect gravity waves. Gravity waves were predicted by Einstein’s general theory of relativity, and it was believed they could be generated by the collapse of some distant star or perhaps might emanate from an ancient supernova. It was believed that gravity waves would propagate outward from such events at the speed of light and that if one had a sensitive enough gravimeter they could be detected on Earth. Further, it was believed that analyzing them would provide new insights into the structure and evolution of the universe.

A secondary objective of his proposed experiment was to measure the defor­mation of the Moon by the tidal pull of the Earth. Weber showed us his latest model, and it was indeed a sensitive instrument—so sensitive that it was detect­ing large trucks and trains passing in the distance. Therein lay the snag that led

him to propose his experiment for an Apollo mission. The Earth was subject to so many events that would disturb its gravity field that some thought it would never be possible to make the delicate gravity measurements he wanted. The Moon offered a location without a lot of extraneous gravity sources—certainly no trains and trucks would mask gravity waves. Simultaneous measurements by similar instruments on the Earth and the Moon might identify movements that would be associated only with a passing gravity wave.

Weber’s experiment was eventually approved for Apollo, and he was given a contract to build a new gravimeter with the highest sensitivity possible based on the technology of the day (nominal sensitivity one part in 1011 of lunar gravity). He in turn contracted with Bendix to build his instrument with a subcontract to LaCoste and Romberg, world-famous builders of gravimeters, to design and supply the sensor. Because of the late approval to include the experiment on Apollo 17 and the complexity of the design, MSC questioned in August 1970 whether the experiment could achieve delivery in July 1972. We suggested shortcutting some of the normal procedures and, if necessary, integrating the flight hardware with ALSEP at KSC instead of Bendix.6 Development pro­ceeded on this new schedule with just the usual problems one encountered in such a program, and the flight instrument was delivered on time for integration with the Apollo 17 ALSEP, the last opportunity to get it to the Moon on an Apollo flight. Because its objective was so unusual, it was billed as the star experiment of the Apollo 17 mission. Weber and his coinvestigators, John J. Giganti, J. V. Larson, and Jean Paul Richard, all from the University of Mary­land, eagerly anticipated being the first to unequivocally detect the elusive gravity waves. Gordon MacDonald, originally on the team with Weber, had dropped out, for reasons I don’t recall.

Astronauts Eugene Cernan and Jack Schmitt, aware of its scientific signifi­cance, practiced diligently with the training model to be sure they would not foul up its deployment. In his pamphlet On the Moon with Apollo 17, printed just before the mission, Gene Simmons, MSC’s chief scientist, went so far as to predict that ‘‘the practical utilization of gravitational waves may lead to benefits that far exceed those gained from the practical utilization of electromagnetic waves’’ (italics in the original). That would be a hard prediction to live up to, but his pronouncement reflected the enthusiasm and anticipation that accom­panied the gravimeter to the Moon. An article in Science in August 1972 reported that a race was on at a number of laboratories around the world to be the first to confirm the measurement of gravity waves, labeled an ‘‘exotic problem.’’7

On the Apollo 17 mission ALSEP and the gravimeter were deployed on the first EVA by Jack Schmitt, approximately six hundred feet west-northwest of the LM. When commands were sent to the gravimeter to turn on the experiment, readings were received almost immediately back in the Science Support Room. The readings didn’t look right to those monitoring ALSEP, but this was the first time the instrument had operated in the reduced gravity of the Moon, so no one was quite sure how the signal should look. Jack completed the ALSEP deployment and activation and went about his other tasks. Meanwhile the Bendix engineers and Weber tried to figure out how to get the instrument to operate more to their liking. They tried to rebalance the beam (the part of the sensor that responded to the pull of gravity) by sending commands to add or subtract mass on the beam, but the signal coming back didn’t change signifi­cantly with these commands.

A ‘‘tiger team’’ was appointed to come up with a solution while the astro­nauts were still on the Moon and might be able to help resolve the difficulty, although at the time it still wasn’t clear what the problem was or how serious it might be. Perhaps just a little rap by one of the astronauts might clear up what appeared to be a minor discrepancy in the instrument’s readings. Schmitt went back to the gravimeter several times during later EVAs to jiggle it a little, but the instrument still did not respond as expected. The beam seemed to be resting on the upper stop and not swinging free. Jack’s comments reflected his concern that perhaps he had made some mistake during the deployment, but he had done nothing wrong.

When the Apollo 17 astronauts left the Moon, Weber and the Bendix engi­neers were still unhappy with the gravimeter’s readings but could not find the cause. Perhaps operating the instrument through one or more lunar day/night cycles might help clear up the signal; so it was monitored for the next several months, but there was no change in the response. The Preliminary Science Report for Apollo 17 came out almost a year later still promising that the gravimeter would return useful information. But it wasn’t to be.

Back at Bendix, in Ann Arbor, a second team delved into the mystery. The instrument had been checked out at Bendix before shipment and had worked satisfactorily. What had gone wrong? Then it occurred to LaCoste what had happened. To test the gravimeter on Earth a set of weights were dropped on the balance beam, correctly calculated for Earth’s gravity. After the test these weights were recalculated to compensate for the Moon’s gravity, which is much less than the Earth’s (1/81), and installed by LaCoste. Because of a faulty calculation, those installed were not the proper weights for the Moon.8 Thus this experiment, on which so much hope for a major discovery had been riding, never returned much useful data. Joe Weber and his team of coinvestigators never forgave LaCoste for the mistake. Perhaps accelerating the schedule con­tributed to this miscalculation, but at the time it seemed a reasonable risk to get the instrument on the final mission.

At this time, to my knowledge, no one has directly detected gravity waves, and new efforts are under way to build a gravity wave experiment called LIGO.9 LIGO’s announced objective is to detect gravity waves originating from black holes or supernova events. Sound familiar? Designed by scientists at several universities and funded by the National Science Foundation, two identical instruments have been built. One has been installed at the Department of Energy’s Hanford, Washington, laboratory and another at Livingston, Loui­siana. The two instruments will permit simultaneous measurements at distant points, thus removing the possibility that, rather than signaling the passage of a gravity wave, the mirrors used to bounce a laser beam back and forth in a tunnel two and a half miles long would be misaligned by some local disturbance (such as the trucks and trains observed in Weber’s earlier experiments). A difficult quest, but perhaps this time it will succeed.

Another experiment that caused a problem was the lunar surface magne­tometer (not to be confused with the Lunar Portable Magnetometer). In this case Chuck Sonett, the PI, chose to have the instrument built by Philco-Ford and then integrated by Bendix. (The PI on the Apollo 15 and Apollo 16 missions was Palmer Dyal, also from the NASA Ames Research Center.) The sensor electronics for the instrument contained thirteen hundred active components, eighteen hundred passive components, and thirty-three hundred memory core locations. It included thousands of tiny diodes supplied by Fairchild. Scheduled to fly on the first ALSEP, with the first landing fast approaching, all the ALSEP experiments were under pressure to meet the schedules for delivery, test, and integration at Bendix. Prototype instruments were always tested before build­ing the actual flight hardware to ensure that the design would perform as advertised, and the tests were closely monitored by MSC and headquarters.

When the prototype magnetometer was tested it failed miserably. Short circuits were noted at many places in the circuitry. Trouble. Was there a major flaw in the experiment design? And if so, would there be time to redesign to meet the schedule and have a new instrument ready for this high priority experiment?

The prototype was torn down and subjected to a careful analysis that re­vealed the problem. To meet the tight schedule, the circuits had not been properly cured, or ‘‘burned in,’’ and in addition many of the diodes were contaminated by fine particulate matter embedded in the potting compound. Fixing the curing time was easily solved, but how did the contamination occur?

A team from headquarters and MSC went to Fairchild to review its man­ufacturing techniques, and the contamination mystery was solved. After the diodes were manufactured, they were placed on shelves—not in a clean room— to cure. Dust and other airborne contaminants circulated in the air and stuck to the potting compound, and these minute particles were enough to permit arcing across the circuits. But could Fairchild come up with a new batch of clean diodes in time to meet the schedule? With the first ALSEP deployment postponed until Apollo 12, Fairchild pulled out all the stops and made the delivery, saving the magnetometer’s assignment. The instrument operated suc­cessfully for many months, with only a few minor discrepancies that were corrected as it continued sending information back to Earth.

Five years after the last Apollo mission, at the end of September 1977, Noel Hinners, who had left Bellcomm and later had been appointed NASA associate administrator, Office of Space Science, decided to save the $1 million per year spent monitoring the five ALSEPs and sending the data to the PIs. Few data were being recorded by this time. It was not expected that the passive seismic experiment, probably the most interesting experiment still operating, would provide much new information because there were no more man-made im­pacts on the horizon, and naturally occurring major meteor impacts and large moonquakes were uncommon.

During the years they were operating, before being put in a standby condi­tion, all the ALSEPs were still functioning long past their design goals, though occasional glitches and data dropouts were observed. Before NASA terminated support for the ALSEPs, several engineering tests were conducted on the central stations and some of the experiments. These tests were devised to answer questions raised during their operational lives but that had not been allowed to be asked for fear of damaging the ALSEPs and the experiments. The test results were then filed away for possible use if another ALSEP-like station was sent to the Moon. After these tests, commands were sent to the ALSEPs, with each of the PIs sorrowfully taking part in the ceremony, to place their experiments and central stations in a standby mode in case someone wanted to turn them back on later. In the meantime, no data would be collected or transmitted.

In October 1994 the Department of Energy (the successor to the AEC, which had provided the RTGs) wanted to determine if the RTGs had survived over the intervening eighteen years. Ground controllers at the Johnson Space Center tried to reactivate the stations. They hoped the ALSEPs would still be receiving power, as predicted by the plutonium half-life, waiting to spring back to action when Earth called. They made two attempts to turn on each of the ALSEPs, but none of them responded. Although the RTGs were probably still generating electric power, it seems likely that as the RTGs aged and power levels dropped, the ALSEPs turned themselves off, as designed, when a minimum operating power level was reached.10 The next time they are revisited will probably be when some intrepid lunar explorer or entrepreneur lands near an Apollo land­ing site and drives over to recover pieces, as we did for Surveyor 3 during the Apollo 12 mission, bringing them back to be put in a museum or someone’s private collection of space memorabilia.