One of the questions most frequently asked at the end of Project Apollo, and even today, is What did we learn? It’s a good question. It would often be followed by other, unanswerable questions. Was the project worth the cost? Wouldn’t we have been better off spending the billions of dollars on X, Y, or Z?
Addressing the unanswerable questions first from the perspective of science, it is difficult to calculate the part of Apollo’s cost that funded scientific experiments for the Apollo flights, because the many components that made up Apollo science were carried in different parts of the NASA budget. Should it include the salaries and overhead for all the civil servants involved? Should it include the support contractors’ costs for those who worked at NASA centers and headquarters and were involved in the planning and development of the science? How about facilities such as the Lunar Receiving Laboratory? The LRL cost over $16 million to build and equip, plus additional operating expenses during the missions. Add to that sum the $19 million given to the sample analysis principal investigators, and the expenses for quarantine and sample analysis alone total over $35 million.
Considering how the post-Apollo studies contributed to Apollo science, should any of those costs be added to the total? Should all the advisory committees and summer conferences that were funded by NASA? They contributed important advice and helped us select the experiments included on the missions. And of course there were the costs associated with integrating experiments on the lunar module and the command and service module and training the astronauts in their use and deployment. Finally, there is the cost associated with experiment data reduction. Calculating an accurate sum for all these activities is probably impossible at this late date, and the items mentioned probably overlook other costs that would contribute to a grand total.
NASA bookkeeping, like that of many government agencies and cabinet departments, used a document called a program operating plan. The POPs categorized expenditures by program, and within each program the expenditures were further delineated by a work breakdown structure or, in simpler language, an item-by-item accounting. These terms are important only to show that there was great rigor in keeping track of taxpayers’ dollars. Each office and center within NASA kept these records, and they were compiled and reviewed by the NASA headquarters Office of Programing. This office not only kept track of expenditures but was also the focal point for preparing each year’s budget requests to the Bureau of the Budget and its successor, the Office of Management and Budget, and then with other senior management presenting and defending the budget before Congress. The name of this office changed through time, but the men who ran it, such as DeMarquis ‘‘Dee’’ Wyatt and William Lilly, were both feared and admired because of their power to approve or disapprove program requests.
In the Apollo era, budget control was a hallmark of NASA, and discussion of the flow of funds for all programs took up a major part of Jim Webb’s and Bob Seamans’s monthly program reviews with the associate administrators and lesser managers. Program managers were expected to keep their books up to date and in good order. Any deviations from approved schedules and budgets during an individual program’s lifetime had to be fully explained and justified, on pain of strong reprimand or even demotion or removal. Considering the uniqueness of this new frontier and the challenges it represented, only a few large overruns occurred. The Surveyor program was an example. The problems that have plagued the International Space Station in recent years, including schedule delays and large cost overruns, would not have been tolerated in the early days of NASA by either NASA management or Congress. But that is a story for another day.
My ‘‘hard’’ number for Apollo science includes estimates of the components listed above and is based on reviews of microfiche records, internal memos, and POPs, of which the last one I had access to was POP 72-1C.1 There may have been later POPs covering Apollo science, but this one showed closeout costs for the last four years of the surface and orbital science programs and contractor manpower ramping down toward zero. The total reported in POP 72-1C was $150,000,000—a nice round number, but I believe it was understated. In a memo to NASA Public Affairs, responding to a request for the costs of the Apollo 15 experiments, we made an estimate of $36 million.2 In another memo, this time to the NASA budget office in March 1972, we estimated a total expenditure of $85 million for the Apollo 16 and Apollo 17 missions, a total of $121 million for just the J missions.3 This indicates to me that the 1972 POP did not include important pieces; however, you can’t tell the basis for the number— what was included or what may have been left out. In William David Compton’s history of Apollo, Where No Man Has Gone Before, he indicates that slightly more than $218 million was spent on science payloads.4 But once again it is not completely clear what this number represents.
An estimate I made at the end of the program was $265 million, based on calculating the cost of each experiment and adding other related contractor costs available at the time. But that estimate did not include some of the items described earlier. I now believe the total would come close to $350 million in 1972 dollars, not including civil service salaries and benefits. If you accept this number, the science piece of Apollo was about 1.5 percent of the total $25 billion spent.
If we factor into the $25 billion the national prestige value of being the premier spacefaring nation, the excitement of visiting a new world, the knowledge gained about the Moon and Earth, and the advanced technologies that resulted from Apollo (some call it spin-off), we can try to answer the unanswerable. Was it a bargain, money well spent, or money wasted? My judgment: unequivocally a bargain!
What did we learn? remains an important question because as students of the Moon continue to examine material brought back during the Apollo missions, fresh results are still coming in. New information from the recently completed Clementine and Lunar Prospector missions adds to our knowledge and clarifies or extends the Apollo results. More than 1,100 abstracts were received for the Thirtieth Lunar and Planetary Science Conference held in Houston in 1999, approximately one-quarter dealing with lunar subjects, attesting to the continued interest in Moon-related studies. Programs to return to the Moon, based on a desire to learn more about our nearest celestial neighbor and perhaps begin to exploit its resources, are constantly proposed.
If, as many of us who worked on Apollo fervently hope, the United States (perhaps in concert with other nations) mounts another Apollo-type project to send astronauts back to the Moon or on to Mars, then we must be prepared to justify and explain to the American public the benefits of spending a nontrivial amount of the national budget on such undertakings. At the moment NASA management does not support going back to the Moon, on manned or unmanned missions. In spite of the interest in recent Mars missions, sustaining public support for extended Mars exploration will be difficult. To the casual observer, or the average taxpayer, one picture of a Mars landscape will look much like the last one, even if it includes an astronaut holding a rock, pointing at a mountain, or riding around on some strange-looking vehicle.
If a political objective is not the driving force at the time the debate begins, as it was at the start of the Project Apollo, then we must be able to predict scientific and economic benefits of value to those on Earth. Such predictions will be difficult to make unless we can provide a connection to what we gained from the Apollo Moon landings and extrapolate this knowledge in a rational way to these new projects. Intellectual adventures will not suffice, even if one believes that the thrill of exploring new lands still survives in our species.
Briefly, here is a summary of the findings and lessons learned from Apollo and the Lunar Orbiter missions that immediately preceded Apollo. A few of Lunar Orbiter’s contributions are discussed briefly, and the notes list references that provide details on this program. From all the missions and other programs, such as the radar studies conducted from Arecibo in Puerto Rico, by the end of Apollo we came to a new understanding of the Moon.
Lunar Orbiter’s comprehensive, high resolution coverage of the Moon’s surface allowed lunar students to expand their understanding of the Moon in significant ways.5 For example, the higher resolution pictures permitted the United States Geological Survey lunar mappers to refine the geological studies they had been making for the previous four or five years based on telescopic observations. Before Lunar Orbiter returned its magnificent photographs, geological formations mapped by USGS workers were distinguished by such characteristics as subtle differences in albedo (reflective power), surface roughness, and crater counts. With higher resolution Lunar Orbiter photographs in hand, the quality and speed of their work increased. The validity of their interpretations would have to await the additional information to be returned by Apollo missions.
In retrospect, one would have to give USGS a good grade (perhaps a B+) for its early efforts. Physical differences were no doubt present; what they represented was difficult to predict. Forced to make interpretations based on these subtle distinctions, and working under the great disadvantage of not having material in hand that represented their mapped formations, some overestimated the complexity of the Moon’s surface. Perhaps the best illustration was the view that many places on the Moon exhibited volcanic features such as cinder cones. The Apollo 16 landing site, selected in part to permit the astronauts to sample this type of feature, returned mostly breccias and no volcanic ejecta. However, the famous ‘‘orange soil’’ found at the Apollo 17 site is interpreted to mean that it was formed during lava fountaining from a volcanic vent, but almost 4 billion years ago. No traces of ‘‘recent’’ volcanism were found. Nothing significant seems to have occurred on the Moon for at least the past 50 to 100 million years except for random impacts.
Lunar Orbiter’s farside coverage allowed the USGS mappers to extrapolate their extensive nearside studies to this perpetually hidden face. Its appearance, highly cratered and without the vast, smooth maria common on the nearside, differed from the face of the Moon that had been studied for centuries. It looked much more like the nearside lunar highlands. With a few exceptions, such as the large crater named Tsiolkovsky and the Mare Moscoviense basin, the large farside impacts had not filled with marelike flows as had many of the large nearside impacts. This difference was attributed to the pull of Earth’s gravity, with the nearside being much more strongly influenced during the early history of the Moon than the farside, thus allowing lunar basalts to fill the low – lying nearside basins. This conclusion supported the belief that early in its formation the Moon had become locked into its present orbit, with its orbital rotation around its axis of twenty-eight days equaling its orbital period around the Earth.
Lunar Orbiter also permitted a more detailed analysis of the Moon’s gravitational field and the irregularities in the field. Its ability to provide this information had been proposed by Gordon McDonald. By closely tracking each spacecraft’s orbital path and calculating how it differed from the path that would be expected if the Moon’s gravity field were uniform, lunar geodesists were able to accurately plot, for the first time, the figure of the Moon. This close tracking led to the discovery of the ‘‘mascons’’ (mass concentrations) mentioned earlier. Deviations from Lunar Orbiter’s calculated flight path suggested that material denser than the surrounding terrain formed the widely scattered mascons. These data were upgraded by tracking the CSM on each Apollo mission, and more recently they have been refined by tracking the orbits of Clementine and Lunar Prospector.
Finding the mascons has important geological and geophysical implications that should contribute to deciphering the Moon’s early history. In addition, knowing the mascons’ positions will be especially useful when we return to the Moon with either manned or unmanned missions, because it will allow us to program the landers to arrive precisely at their designated landing sites. But Lunar Orbiter, Apollo, and recent missions could not tell us what the mascons are or how they were formed. Resolving these questions will have to await additional measurements made by the next generation of spacecraft.
Ranger, Surveyor, Lunar Orbiter, and Apollo put to rest for most lunar students the question of the origin of almost all lunar craters: they were formed by impacts. This knowledge has led us to look at the Earth’s history in a new light.6 Before the Apollo landings, most Earth scientists believed that in its earliest history the Earth had witnessed a period of intense infall of large and small planetesimals, meteorites, and other debris from a newly forming solar system. Little direct evidence of this epoch could be found in the geological record, and until recently only a few impacts had been positively identified and studied. The rate at which these large and small impacts bombarded the Earth was pure speculation, but those who studied these features believed large impacts were probably common.
Today some terrestrial features and events that had previously been difficult to explain are being attributed to large impacts. The most fully reported event of this type provides an explanation for the disappearance of the dinosaurs and many other species of animals and plants at the end of the Cretaceous period, some 65 million years ago. Proposed in 1980 by Luis Alvarez, his son, and several other researchers,7 the theory was based on the discovery in Italy of a thin rock formation, enriched with the element iridium, at the Cretaceous/ Tertiary geological boundary.
They concluded that the best explanation for this anomaly was that a large object composed of material containing a high percentage of iridium, a common constituent of certain types of meteorites but not common in Earth rocks, had struck the Earth at this precise time. Debris from this impact spread over a large portion of the Earth’s surface and was deposited as a thin layer that included the formation discovered in Italy. This proposal was met with great skepticism by many in the scientific community, but some, including Gene
Shoemaker and others who had been involved in Apollo science, supported the idea, knowing that large impacts had affected the Moon’s history. This Cretaceous impact has been confirmed, and through the work of many scientists, the probable impact site has now been located on the edge of the Yucatan peninsula in the Gulf of Mexico. Whether it led to the species extinctions observed at the end of the Cretaceous period is still being debated.
The Apollo program’s emphasis on understanding impact craters spurred the search for and discovery of other large Earth impacts. For example, an ancient impact crater has been found in Texas, at Sierra Madera; another underlies Chesapeake Bay; and a buried crater in southeastern Nevada is believed to have created the Alamo breccias. The identification of impact events in the geologic past has accelerated as our diagnostic techniques have improved. Australia has been especially productive for the study of impact craters because much of its surface has remained relatively undisturbed for millions of years. It was while undertaking such a study that Gene Shoemaker met his untimely death.
These discoveries have led to a related field of study, tracking objects orbiting near the Earth and crossing the Earth’s orbit (hundreds are now known) that might strike the Earth in the future. Today, if such an object took aim at Earth, it could not be avoided. If another object the size of the one that hit the Earth at the end of the Cretaceous period were to strike the planet, it would trigger a series of events with unimaginable consequences. But not much is being done to prepare for such an admittedly low-probability event. Some believe we could avoid such an impact, if it was predicted, by developing an early warning system that would track large meteors or asteroids and then deflect them with missiles. The study of impacts on the Earth and Moon has resulted in a model that predicts the frequency of impacts on the Earth. This model suggests that a large impact occurs approximately once every 50,000 to 100,000 years. Perhaps this knowledge will motivate world governments to work together for a solution that will prevent such a catastrophe.
Although a relatively small event when it occurred, the Meteor Crater impact has been dated at approximately 50,000 years ago. It undoubtedly was a devastating blow for a large region surrounding the impact point, creating ground tremors and clouds of dust and debris that would have extended over hundreds of square miles. At that time the only casualties may have been a few mastodons and other wildlife. If such an event occurred today, Flagstaff and other nearby towns would probably be destroyed, and cities as far away as Tucson and Phoenix would feel its effects. Are we due for another big impact- soon? The model suggests we may be.
By the end of the Apollo missions, the six successful landings and their predecessors had returned a wealth of new information about the Moon. Before the landing missions, Apollo 8 and Apollo 10 traveled to the Moon but did not land. Apollo 8 was the historic mission that orbited the Moon at Christmas 1968, with men being captured for the first time by the gravity field of a ‘‘planet’’ other than the Earth. Although we had in hand excellent close-up photographs from Lunar Orbiter, this was the first time men were able to view the Moon at close range.
The lunar farside especially impressed the crew of Apollo 8; Frank Borman, Jim Lovell, and William Anders reported seeing a jumble of craters on top of craters. Orbiting sixty-nine miles above the surface, they described the Moon during their Christmas Eve greeting to those back on Earth as ‘‘a vast, lonely, forbidding. . . expanse, . . . it certainly would not appear to be a very inviting place to live or work.’’8 Fortunately we were not going to try to make an Apollo landing on that ‘‘forbidding’’ farside terrain. Apollo 8 also gave us the first views of our home planet from a great distance away; the Earth was described as an oasis, isolated in the emptiness of space. Some have credited this dramatic view of Earth with imparting a new awareness of how unique our planet is and how important it is to protect its fragile environment-an unexpected bonus from the Apollo program.
Apollo 9, launched in March 1969, was the first test of all the Apollo hardware working together as it would for a Moon mission except that the crew and the equipment never left Earth orbit. It was followed two months later by Apollo 10, a dress rehearsal for the first attempt to land on the Moon. The crew of Tom Stafford, Gene Cernan, and John Young would perform all the complicated maneuvers required of a landing mission except for the most crucial-the actual landing. Stafford and Cernan would separate from the CSM in lunar orbit, descend to less than ten miles above the lunar surface, jettison the landing stage, activate the LM ascent engine, and rendezvous with the CSM. Close, but oh so far from making history. In addition to testing all the elements leading up to a landing, they proved the accuracy of Apollo targeting and the astronauts’ ability to see their landing point and observe potential hazards at a site similar to that expected for the first landing in the Sea of Tranquility. Apollo 8 and
Apollo 10’s reconnaissance also confirmed what had been seen in the Lunar Orbiter photographs: smooth landing areas were available in the ‘‘Apollo zone.’’
Cernan and Young would get another chance to perform a Moon landing; Stafford is the only man to get within ten miles of the Moon and never land. I’m sure he would gladly forgo that honor for the thrill of having kicked a little Moon dust. Two months later the first landing would take place. Many other Apollo prime and backup crew members—Walter Schirra, Donn Eisele, Walt Cunningham, Jim McDivitt, Gordon Cooper, Joe Engel, and Rusty Schweick- art—would suffer the disappointment of being selected to test the Apollo hardware but never getting to the Moon. But without their key roles and dedication the Moon landings could not have been undertaken.
By the time Apollo 11 splashed down we had developed the routine by which the science results would be processed and disseminated. The astronauts would be picked up by a navy helicopter operating from an aircraft carrier, transferred to a specially designed trailer on the carrier, and flown back to Houston to be placed in quarantine in the LRL. The samples, film, and other data would be removed from the command module and flown to the LRL in their own aircraft. Once in the LRL, the astronauts would be debriefed by a team of scientists and engineers while the samples were unpacked, examined, and cataloged and the photographs were developed. In the meantime, we would be receiving data from the instruments left on the Moon.
This routine was followed for all the missions, with the major difference that after Apollo 14 the astronauts and the samples no longer had to spend time in quarantine and the debriefings became much more relaxed and easier to carry out. Without an intervening barrier, we could question the crews much more directly as we tried to piece together all they had done. This was an important change, because the last three missions were more complex and the astronauts’ recollections more valuable in reconstructing their long traverses on the lunar roving vehicles. I will describe only how we debriefed the Apollo 11 crew and studied the first samples, but I will include results from all the missions to explain what Apollo taught us.
The Apollo 11 astronauts had their first science debriefing on August 6, 1969. Before that debriefing the Manned Spacecraft Center engineers had reviewed the nuts and bolts of the mission—the ‘‘technical debriefings’’—going over those aspects of their flight that might affect the success of the next mission. Although all spacecraft systems were carefully monitored by telemetry, with records kept of all discrepancies, the astronauts’ answers to questions would often clear up troubling inconsistencies or uncertainties in the records. Neil Armstrong’s and Buzz Aldrin’s descriptions of their landing maneuvers and their difficulties in finding a good landing site were examples of how their experience contributed to improving the landing sequence for Apollo 12 and later missions. All members of the crew of Apollo 12—Pete Conrad, Dick Gordon, and Al Bean—as well as the backup crew led by Dave Scott, were the most interested participants in these debriefings. Pete must have gained valuable knowledge, because he landed right on the money, within easy walking distance of his target, Surveyor 3.
Although I was invited to the science debriefing, I sat in one of the back rows while a few designated individuals, including Don Wise and O. B. O’Bryant from our headquarters office, were allowed to ask questions. It was a strange scene for such a momentous occasion, with the questioners and hangers-on peering at the three astronauts, who sat behind a brightly lit picture window like animals in a zoo. Unfortunately the transcript of the debriefing does not always identify the questioner, but Gordon Swann and Henry Holt of USGS and MSC’s Gene Simmons, among others, covered all the important questions relating to the astronauts’ surface observations, especially those that might affect what was planned for the next mission.9
Everyone involved in this debriefing, and in debriefings for later missions, came away with a great admiration for the astronauts’ powers of observation and recall. When these traits were added to their innate resourcefulness and doggedness in following and going beyond their ambitious timelines, every possible ounce of science was gleaned from the missions in spite of the constraints they were working under. Some might take issue with that statement, but I believe it is true; the training and simulation had paid off beyond our expectations. Explorers of all generations have been eulogized for daring to take chances beyond the imagination of the ordinary person—for the astronauts it was called ‘‘the right stuff.’’ However you wish to identify this urge to explore, it was undeniably present in these first voyagers beyond the friendly Earth who risked never returning to their home planet, a danger never before faced by explorers.
The Apollo 11 science debriefing was our first chance to talk directly to the crew after their return from the Moon. After two weeks of isolation, interrogated every day by engineers and technicians, the astronauts were in a surprisingly good mood. From time to time one could sense a little irritation at questions that were repetitive or trivial, but all in all there was great cooperation, and we gained much from listening to their firsthand observations while they were still fresh in their minds. Their photographs had been developed and were available to supplement the discussion, as was the preliminary traverse map of the landing site. When necessary, the astronauts used large pads and marker pens to illustrate their answers, and Armstrong, especially, took advantage of these aids. (Were these unique drawings preserved for future generations of historians?)
One of many exchanges was particularly interesting. While in lunar orbit, before beginning their return to Earth, the astronauts were asked to look toward the crater Aristarchus and describe it. Although Aristarchus was just on the horizon and at the limit of their view, Armstrong reported that he thought he saw fluorescence in that region. This announcement caused some stir: Was he observing some lunar transient phenomenon like that described in chapter 2? Now, during the debriefing, he went into more detail and modified his observation. Although he described the general area as the brightest spot he could see, he could not confirm that it was Aristarchus itself that was causing the bright reflection, and he did not ‘‘mean to imply that it was self-illuminated.’’ The unusually bright appearance of the Aristarchus region to the crew in orbit reinforced the belief that it might be the site of recent activity on the lunar surface. With their many other observations and much hard work, the crew of Apollo 11 had opened the door to a new era in planetary science.
The possibility of bringing some deadly unknown disease to Earth in the samples or by an infected crewman led to building the Lunar Receiving Laboratory. Strict protocols had been developed to guard against these risks. Some in the media latched on to this potential hazard, attempting to fan the public’s fears of some catastrophic invasion. One month before the Apollo 11 liftoff, a media briefing was held in Washington to describe the details of the mission and, we hoped, allay any fears that the first landing and return from the Moon’s surface posed any danger to life on Earth.10 The final portion of the briefing was conducted by Air Force colonel John Pickering, who had served on the Interagency Committee on Back Contamination and now held the title director of lunar receiving operations at the Office of Manned Space Flight. He went to great lengths to describe the procedures that would be followed, from collecting and packaging the samples on the Moon through recovery and transport of the
samples and astronauts to the LRL and eventual release of both at the end of the quarantine period. He even went so far as to include in the press handout a copy of the LRL biological certification signed by Dr. David J. Sencer of the United States Public Health Service, chairman of the Interagency Committee, to prove that all precautions had been taken. This openness and attention to detail defused this issue for most of the media, and it never surfaced again as a major public concern. However, managers of Mars missions that will return samples to Earth should head off the potential negative exploitation of this issue by being open and detailing the steps that will be taken to guard against alien organisms.
Let me illustrate how seriously the quarantine protocols were followed. During the preliminary study of the Apollo 11 samples, a technician was cataloging a sample in an isolation chamber glove box that operated under negative atmospheric pressure to avoid any leakage into the LRL when one of his gloves ruptured, exposing him to the sample. This man and another working near him were immediately placed in quarantine in the LRL with the three astronauts. One lemon-sized rock was carefully sterilized and taken out of the isolation chamber and given to the Lunar Sample Preliminary Examination Team (LSPET) so they could hold it. Cliff Frondel, a member of the team, was quoted as saying, ‘‘It was a great thing to look at this stuff that people had been
speculating about for millennia, and here it was in our hands______ It was a hell of
To determine if there were possible life-threatening forms (“replicating species’’) in the samples, ten species of animals were exposed to lunar material for twenty-eight days, either through inoculation or in their food. Four control groups were exposed in a similar fashion to nonlunar material for the same period. These animals included paramecia, planarians, shrimps, oysters, cockroaches, and houseflies. One might wonder if the testers, fourteen scientists called the Lower Animal Test Team, had any second thoughts about including cockroaches, insects that seem to be indestructible and have survived 200 million years of evolution essentially unchanged. Why would a little Moon dust hurt them, regardless of what it contained? The cockroaches and the astronauts cooped up together in the LRL became the basis of many jokes.
During the quarantine period, these ten species, living in small aquariums or jars and bowls inside the LRL, were carefully monitored for any suspicious behavior or a sudden desire to go to the special heaven reserved for them.
Nothing much unusual was observed; only the oysters, both those exposed to lunar material and the control groups, seemed to have a higher than expected death rate. This was attributed to conducting the tests during their normal spawning season, which apparently is stressful to romantic oysters. But as in all true scientific inquiry, one strange behavior was noted: planarians exposed to heat-sterilized lunar material swam at the surface of their bowl more frequently than the control groups.12 The reason was unknown.
In addition to the study of ‘‘lower animals,’’ similar tests were conducted on mice and quail. After four weeks of exposure to lunar material, 230 mice and 120 quail were autopsied by another team. Like the ‘‘lower animals,’’ the inoculated mice were found to be normal, and the quail that had lunar soil mixed in their feed showed no adverse reactions. The reports from these teams were greeted with a sigh of relief from all 142 sample PIs and the scores of coinvestigators waiting anxiously to receive their allocated portion of the returned samples and get on with their analyses. If some pathogen had been found, we might still be waiting to study Apollo 11 ’s lunar treasure. The samples were declared safe for distribution around the world and were released on September 12, 1969.
The time between the conclusion of the contamination tests on August 22, 1969, and the release of the samples twenty-one days later was spent in preliminary analyses and preparing the specific types of samples required by each of the sample PIs. On August 27 the Lunar Sample Analysis Planning Team (LSAPT), chaired by Gene Simmons, issued a final internal ‘‘summary report’’ on its findings from the study of a small selection of the samples.13 This team, consisting of scientists with differing backgrounds from MSC, USGS, and other government and university laboratories, was the first group to examine lunar samples before they were released to the sample PIs.
This final summary report and the four preceding reports were read with great interest by all of us at NASA headquarters. Each report contained some new and exciting revelation. LSAPT identified two types of rocks, crystalline and aggregates (later classified as breccias), as well as a variety of fine material from the lunar soil. Although the minerals in the rocks were similar to minerals found in the Earth’s crust, there was a major difference. They contained a larger percentage of refractory elements such as titanium and zirconium. To a mineralogist this finding was important, leading LSAPT to proclaim that this mineral assemblage provided “difficulties for the fission hypothesis,” that is, that the
Moon had been torn away from an early Earth by some cataclysmic event. If this had occurred, the minerals found in the samples should have been similar to those found on Earth.
Another, less hypothetical, conclusion was that the crystalline rocks were basalts, yet their density was greater than the average density of the Moon as a whole. This finding made it difficult to conclude that the Moon was a differentiated planetary body like the Earth, as it was thought to be, where the heavier material would be expected in the interior and the overall density of the planet should be higher than the density of rocks found at the surface. But this finding was consistent with the discovery of the “mascons,” since this dense material was found in mare basins. If one pursued this logic, then some large portion of the Moon must be made up of less dense material to account for the difference, or else the Moon’s core, if it had one, would have to be very small. It seemed clear that at some point part of the lunar surface had been molten.
After LSAPT performed its functions, it combined forces with the Lunar Sample Preliminary Examination Team to do more complete analyses and publish the results. To some degree this report skimmed the cream from the discoveries that would be announced later, but it served the important function of preparing us for the next missions. If we had had to wait for the sample PIs to report their findings we would have had little chance to modify or change the experiments and sampling procedures for Apollo 12 and the later missions. The LSPET report, published in Science two months after Apollo 11 returned, listed eighteen conclusions.14 The most important from my perspective, paraphrasing the report’s language, were that the crystalline rocks were different from any terrestrial rock and from meteorites; that the absence of hydrated minerals indicated there had been no surface water at Tranquility Base at any time since the rocks were exposed; that radioactive age dating showed they were crystallized 3 to 4 billion years ago; and that there was no evidence of biological material in the samples. Additional details and new findings would be released by the sample PIs four months later.
The Apollo 11 Lunar Science Conference was held in early January 1970 at the Rice Hotel in downtown Houston. The conference was an exciting time for all of us who had helped develop the Apollo science program. Apollo 12 had returned to Earth just a little more than a month earlier, but all of its samples were still in quarantine and unstudied. Only the Apollo 11 samples had under
gone detailed examination by January 1970. Gary Latham, the principal investigator for the passive seismic experiment, had published a short report on his findings by this date along with the LSPET report mentioned above, but the sample PIs had agreed to withhold their findings until this meeting. Those performing the detailed sample analyses were all gathering at the same place for the first time. Approximately 1,100 PIs and their collaborators, including teams from sixteen foreign countries, had spent the past three months working feverishly to have their analyses ready for this day.
The expectation was palpable the first morning as we milled around in the hotel lobby. Whose theories would be confirmed, whose relegated to the dustbin of lunar science? Would any of the LSPET findings be challenged or changed?
Gene Shoemaker, representing his team from USGS and several universities, made the first presentation. He described the geologic setting of the lunar samples collected by the Apollo 11 astronauts, coining the term ‘‘lunar regolith’’ for the surface characteristics at the landing site. The upper, regolith layer had been constantly churned and pulverized by impacts of all sizes. All the material returned had been collected from this fragmental debris layer, and the astronauts’ observations had been made within 125 feet of the landing site. No ‘‘bedrock,’’ or material in place, had been sampled. By geological standards it was not a very good collection of samples for such a large body as the Moon, but the consensus was that the samples were representative of a much larger area because of the mixing and transport of material brought in from afar as impact ejecta. Finally, he described the efforts to fix the location of each sample station. This had not been completely successful because the time limits for the EVA had restricted the number of photographs taken, but most had been located. Of the forty-seven pounds of material returned, approximately fifteen pounds had been distributed for analysis. (For the formal proceedings of the conference Shoemaker’s presentation was modified and published as ‘‘The Apollo 11 Samples: Introduction.’’)15
Four days and 180 papers later the conference ended. We now had the first comprehensive view of one spot on the Moon based on data collected on the Moon itself. Several new minerals had been found, lunar lavas and breccias were common, and many samples bore evidence of shock metamorphism caused by impacts. Science devoted its entire January 30, 1970, issue to the conference. Though it is four times the size of a normal issue, it is a much more compact reference than the three-volume Proceedings for those who want to review the results of the first analyses of the Apollo 11 samples in some detail.
The oldest samples dated gave radiogenic ages of approximately 4.7 to 4.9 billion years B. p. (before the present). Others gave dates of 4.13 to 4.22 and 3.78 billion years (some of the older dates were later disputed), in general much older than the first dates offered by LSPET. Only traces of carbon were found (one anomalous sample contained almost five hundred parts per million), and there was no evidence of any bio-organic compounds. One group of investigators (R. D. Johnson and C. C. Davis) stated that some of the high carbon readings might be attributable to contamination introduced during sample preparation or to errors in analytical techniques.16 They suggested that an upper limit of ten parts per million would be correct for indigenous lunar organic material. They thought the small amounts of carbon detected in some of the samples might have come from the solar wind or from carbonaceous chondrites that had struck the Moon in ages past.
Water was not identified in any of the minerals analyzed, nor did Luis Alvarez find any magnetic monopoles. Some samples studied for remnant magnetism seemed to indicate that the Moon once had a small magnetic field, perhaps 1,000 to 1,500 gammas, or about one-thirtieth of the current field of the Earth. The present magnetic field was much smaller, however, on the order of 10 to 30 gammas, the latter figure coming from the magnetometer at the Apollo 12 site that returned data by the time of the conference.
Preliminary results from measurements of the Laser Ranging Retro- Reflector were also reported. Accuracy in measuring the Earth-Moon distance had improved over that included in Mueller’s report to the president four months earlier. This distance was now known to a precision of approximately one foot and was predicted to improve shortly to about six inches.
The Solar Wind Composition experiment carried on Apollo 11 was not discussed at the conference. This experiment, mentioned in chapter 7, consisted of a sheet of aluminum foil hanging from a pole. After being exposed for seventy-seven minutes on the lunar surface, it was retrieved and brought back to Earth and placed in quarantine in case some lunar soil had adhered to the foil. When released from quarantine, it was carefully packed and sent to Switzerland for analysis by its PI, Johannes Geiss. He had made a quick analysis of the gases captured on the foil, finding noble gas ions as expected, and had reported his results in December in Science.17 Eventually he extended his Apollo 11 findings based on data returned from the next four missions, examination of pieces of Surveyor 3 returned by Apollo 12, and data from the Vela satellites. Compiling all this information after his last experiment returned from the Moon, he stated in 1972 that he was now able to make good approximations of the average solar wind-noble gas abundances and ratios.18 He forecast that a better understanding would evolve of the abundances of noble gases in the Sun and the atmospheres of Venus, Mars, and the major planets.
Latham’s passive seismic experiment included in the Early Apollo Scientific Experiments Package continued to operate intermittently for twenty-one days. It survived the first lunar night before succumbing to the heat of the second day. Initial data telemetered to Earth had caused some consternation in Latham and the other members of his team. The Moon, based on these early data, seemed to be highly active seismically (apparently recording many small moonquakes), contrary to what had been predicted. After the first data had been analyzed, Ed Davin remembers walking between the Mission Control Center and the press conference room at MSC with Frank Press and Maurice Ewing, two of Latham’s coinvestigators. They were trying to figure out what to tell the assembled reporters about this unexpectedly active Moon, apparently more active than the Earth. They asked Ed for his opinion, and he recalls being shocked that two of the world’s leading seismic authorities would ask a lowly civil servant such a profound question. Ed could not suggest a solution, so Press and Ewing ended up announcing that the Moon appeared to be more active than the Earth, a new and disturbing “scientific discovery.’’
Eventually the explanation for this totally unexpected finding became clear. The lunar module landing stage, left behind when the astronauts departed, was creaking and groaning under the thermal stress of the wide temperature swings between lunar day and lunar night. In addition, the LM and backpacks discarded on the surface continued to emit gas long after the astronauts departed. Each quiver and burp of gas was being detected by the extremely sensitive seismometer just sixty feet away. These disturbances appeared in the data stream as small moonquakes. No one had anticipated that such tiny movements would be measured. Thus does science advance as we try to fit new data into old theories: some mysteries are quickly resolved.
The Moon, in fact, is seismically quiet (as opposed to Earth, where large or small earthquakes are being recorded almost constantly), and this was shown again and again as we deployed four more seismometers. Once the residual effects of the SIVB and LM impacts that occurred on later missions and the astronauts’ presence had faded, the Moon stopped shaking. It was disturbed frequently by small movements believed to be caused by lunar tides (movements in the Moon’s crust as a result of Earth-Moon interactions), thermal changes at sunrise and sunset, small impacts, or what were interpreted as rockfalls on nearby crater rims or mountainsides. A few larger true moon – quakes were also recorded, with widely scattered epicenters concentrated at a depth of five hundred to six hundred miles, believed to be the base of the lunar mantle. The man-made shocks from the SIVB impacts also contributed to determining the thickness of the lunar crust.
Based on several years of data analysis, Latham and his team drew a number of conclusions. Below the thick lunar crust and mantle, constituting a “dynamically inactive outer shell,’’ was a ‘‘core’’ with ‘‘markedly different elastic properties,” and the core was very small. They believed that the core was at or near the melting point, but this did not ‘‘imply a major structural or compositional discontinuity as it does for Earth. However, the presence of a true core. . . is not precluded by present data.’’ They also believed that ‘‘the presence of a thick lunar crust suggests early, intense heating of the outer shell of the Moon.’’19 This last conclusion seemed to be validated by the visual evidence of widespread maria that filled all the low elevations on the Moon’s nearside. Recent results from the Lunar Prospector mission appear to confirm Latham’s findings and indicate that the Moon’s core probably contains less than 4 percent of its mass, whereas the Earth’s core makes up 30 percent of its total mass.
Continuing now from the findings above, where do we stand in answering the questions that had perplexed many noted scientists for centuries? Most students of the Moon would agree, I believe, that satisfactory answers are now in hand for most of those questions, although there is still no unanimous interpretation. Why should study of the Moon be different from other scientific controversies?
The burning question before the unmanned and manned missions—whether the craters observed were mostly of impact or volcanic origin—had been resolved to the satisfaction of most lunar students long before the first Apollo landing. Impacts were the answer, and Apollo data confirmed this conclusion. But the returned samples clearly showed that lava sheets or flows covered large areas of the Moon. What mechanism caused these flows is a little more debatable. Heating and melting of the lunar crust and mantle as a result of huge impacts is the favored explanation, not volcanic eruptions.
Next, where did the Moon come from? There is still some debate on this, but the possibilities have been narrowed and a preponderance of opinion favors one origin. Lunar samples show that the Moon’s composition is similar to that of Earth, yet different. The Moon is not compositionally exotic, as proposed by Harold Urey and others, thus it probably was not captured early in Earth’s history after having been formed somewhere else in the solar system. That leaves two theories: that it formed separately at about the same time as the Earth or that the Moon was split off from Earth by some event early in the Earth’s formation.
Because the mineral assemblages found in lunar samples differ somewhat from rocks that have formed on Earth, either origin is possible. However, the Moon most likely was torn from the Earth by the impact of another large body that contributed some of its material to the Moon, thus accounting for the mineralogical differences. This latter theory is gaining more and more favor in recent years as other conditions, such as the Moon’s angular momentum, become better understood and are factored into the models being used.
The next question, How old is the Moon? can now be answered with some certainty. Age dating of lunar samples has shown extremely old ages, some as high as 4.4 to 4.5 billion years B. p. This rivals the oldest ages found in meteorites, which until this point were the most ancient objects dated. This date agrees with the thinking of most solar system students about when the solar nebula began to clump and form the planets, indicating that the Moon formed almost simultaneously with the Earth at a very early point in the birth of our solar system. The ‘‘genesis rock,’’ collected on Apollo 15, is almost pure anorthosite, a type of rock formed on Earth at great depths. It is believed to represent a piece of the Moon’s early crust. Argon-argon dating found an age of crystallization of approximately 4.0 billion years b. p.20 However, this type of dating can produce lower than actual ages; thus the ‘‘genesis rock’’ may be older-closer to 4.4 to 4.5 billion years.
Whether there has ever been water on the Moon, or whether water still exists there, has been a continuing and intriguing question. None of the samples analyzed showed that water was present during the formation of the lunar crust. But in March 1971 John Freeman of Rice University, the PI for the Suprathermal Ion Detector Experiment (SIDE), reported that he had recorded
the occurrence of water vapor for three ‘‘events’’ at his instruments left at the Apollo 12 and Apollo 14 sites. These measurements had been made at the same time Gary Latham recorded a swarm of moonquakes, suggesting that the two events were connected. Earlier Freeman had recorded the LM and SIVB impacts as disturbances in the Moon’s ionosphere, but these events had a different character than those he believed indicated water vapor. This created a stir in the media that prompted us to try to put Freeman’s claim in a larger context.21
Acknowledging the importance of discovering water on the Moon, we discussed potential sources of the inferred water vapor, possibly related to material left behind by the astronauts in the LM descent stage tanks, portable life – support system tanks, and other items discarded on the lunar surface. We also pointed out that the SIDE experiment identified the mass of ions (in a gas cloud) only in a range of energy that would also include methane or neon, which could also have a lunar origin. Ultimately Freeman’s recordings were not considered conclusive in detecting water.
The recent lunar probe, Lunar Prospector, appears to support the possibility that water, in the form of ice, exists on the Moon in the permanently shadowed craters near the poles. If ice is present, it is most probably a by-product of comet impacts. Sensors on Lunar Prospector detected hydrogen, and the most likely source of the hydrogen is considered to be ice. Perhaps Freeman had detected an early whiff of water vapor from his two experiments.
To sum up the operational accomplishments of the six Apollo landing missions: almost 5,000 pounds of experimental equipment were landed on the Moon, and 840 pounds of lunar material (rocks, dirt, drill cores, etc.) were returned under carefully controlled conditions. Five ALSEPs, which included most of the total of fifty-three individual experiments deployed by the astronauts while on the lunar surface, were placed at different locations. And approximately sixty miles of traverses were recorded, both on foot and using the LRV, in support of the field geology studies and geophysical surveys. In addition, detailed data were collected on missions 15, 16, and 17 from instruments carried in the command and service module, including photographs, compositional analysis of broad areas of the Moon’s surface, mapping its magnetic and gravity fields, and analyzing its tenuous atmosphere. All of these data contributed toward deciphering the Moon’s many mysteries as well as resolving less controversial issues.
For young engineers dreaming of one day building lunar bases, the Moon will be a friendly place. Lunar bulldozers and backhoes will be able to excavate and move lunar soil just as we move soil on Earth. There will be obvious differences, but we gained sufficient data through the soil mechanics experiment and other experiments to design such machines. Structures could be covered with lunar soil to shield them from solar flares and high energy particles, thus obviating the need to bring shielding from Earth. If needed, ‘‘regolith blocks’’ could be made from the soil that would be as useful as terrestrial cinder blocks. Unlike bases built in Antarctica, the closest terrestrial analogue to lunar bases, which must be constantly refurbished or rebuilt because of damage from snow and ice, lunar bases once constructed should last for the ages. Only a direct hit or near miss from a meteorite could damage the base. And perhaps if bases are built near the Moon’s poles the Moon can be mined for water, the most valuable of all lunar resources. The Apollo program provided the shoulders to stand on—now it is up to future explorers to go beyond our ‘‘giant leap for mankind.’’
A few more words concerning the results of the Clementine and Lunar Prospector programs. Both of these programs continue to add to our knowledge of the Moon. In some instances they are expanding on what we learned from Apollo, and in other exciting ways they are providing new information. Rather than my attempting to summarize their results to date, references in the notes discuss some of the findings.22 Many other papers and reports discuss the results of these two missions.
The final maneuver for Lunar Prospector, a last-minute addition to its scientific objectives, was a controlled crash similar to those carried out by the Apollo LM ascent stages and SIVBs. This time the impact point selected was a perpetually shadowed crater near the Moon’s south pole, in the hopes that telescopes in orbit or on Earth would record the plume from the crash and confirm the presence of water. Such a cloud was not seen, repeating our experience during the Apollo missions when I asked observatories in France with large telescopes to try to observe and measure the impact of the Apollo 16 SIVB stage. This would have been a much larger event than was expected for the Lunar Prospector impact. The time of the Apollo 16 SIVB impact prevented any United States observatories from participating, since the Moon would be below the horizon. The weather was not completely cooperative when observatories at Meudon, Pic-du-Midi, and Nice attempted to observe the impact on the night of April 19, 1972, and this might have accounted for the negative report we received.23 However, the failure to see a cloud at the impact point selected for Lunar Prospector’s final act will not detract from its successes; further analysis of data recorded by the spacecraft’s sensors will without doubt continue to add to our understanding of the Moon in the years ahead.
In successfully undertaking the challenge set by President Kennedy (with emphasis on “successfully”), Apollo taught us one final lesson. Apollo’s heritage went far beyond knowledge about the Moon and Earth. Now that many of the records of the former Soviet Union have been opened to public scrutiny, it has been confirmed that we really were in a race to the Moon. It certainly seemed that way to us at the time, but you could not be sure because Soviet launches were always veiled in secrecy; the world became aware of them only after they were on their way to whatever destination, and failures were never reported. The Soviets’ long-range plans were seldom discussed, although Boris Voishol, from the Soviet Tectonic Academy, writing in the September 1968 Geotimes, stated: ‘‘The first landing of Soviet cosmonauts on our moon is scheduled in the near future.’’24
Based on information available at that time, the missing ingredient in their ability to send men to the Moon was a booster as large as the Saturn V, which would be needed for the round trip. Without such a rocket we assumed that if they were really intent on a manned lunar landing they would use their smaller, proven rockets to assemble the needed launch capability in Earth orbit before going on to the Moon-one of NASA’s original proposals. We now know that they were building a Saturn V-class rocket but that on its first test flight it crashed shortly after lift-off. On a second launch attempt a few months later, it exploded on the pad, apparently killing some of their rocket experts, and was never rebuilt.25 The Soviet failures-and there were many-were only a matter of speculation for most of us, though undoubtedly there were some who were privy to intelligence sources and knew about their difficulties. Our launches, successful or unsuccessful, were always made in full view of the world.
What if the Soviet Union had landed men on the Moon first? Several writers have discussed the effect of Project Apollo on the Soviet Union; here is another view with which you may or may not agree. My father, a civilian stationed in West Germany for the Army Signal Corps at the time of the launch of Sputnik I, remembered an unnerving encounter with one of his German contractors. When it was confirmed that the Soviets had successfully orbited the first satellite, this man came running up with fear on his face. His conclusion was that this demonstration of Soviet technological superiority spelled doom for the world. The United States failures at launching the Vanguard rocket were well known. Suddenly the Soviet Union had leapfrogged our efforts. Along with its newly demonstrated nuclear weapons, this made the man believe the bad guys had won the Cold War. We would soon have to knuckle under to this new dominant world force. He was seeking reassurance that his analysis was wrong, but with limited knowledge of how our space programs were proceeding, my father could not give it.
The point of this anecdote is to show how fragile a nation’s leadership is in a rapidly evolving world. In view of their recent history, West Germans in October 1957 might be forgiven for being pessimistic. But as I remember, this pessimism was widespread even in the United States, with finger pointing and blame all around for our inability to beat the Soviets during the early days of space flight.
What would the world look like today if the Soviets’ program had not experienced its hidden failures and they had been first to land men on the Moon? I suspect it would be different, but of course there is no way to prove it. Everyone likes a winner and gravitates toward one regardless of worthiness; second place seldom attracts much enthusiasm. Accommodation to Soviet leadership would have been rationalized, and the Soviet bloc might have become the dominant force in world politics, perhaps postponing or averting its ultimate economic collapse. Meanwhile, we would be scrambling to catch up and demonstrate that a democratic government could do as well as or better than a state-directed totalitarian government. Remember, in the 1960s many countries were experimenting with or embracing communist forms of government, and Soviet-led expansion of communist ideology was making great strides even without demonstrating the overall technological leadership that a ‘‘first’’ on the Moon would have given.
What is the lesson of Apollo that goes beyond being the first to land on the Moon and the expansion of our scientific knowledge? It seems pretty basic. Free societies can successfully undertake enormously complex actions—if they dare. Although the United States was the leader in Apollo, many other nations contributed people, technology, or facilities. Apollo was a dream that everyone could embrace, if permitted, and all could share in the sweet reward of success. The few words on the plaque carried by Apollo 11 said it all: it was an accomplishment ‘‘for all mankind.’’
Conceived primarily as a political statement, Apollo achieved much more than its original goal. Now, when faced with seemingly intractable problems, someone will be heard to say, ‘‘If we can land a man on the Moon, why can’t we [fill in the appropriate objective]?’’ And of course that is the right question to ask, because people of goodwill, working together, are capable of solving very difficult problems. Apollo proved it. Let’s not forget that dreaming big has its own rewards, even if occasionally we stub a toe. That is the essential lesson I carry away from my Apollo days, and I hope it will be remembered by those who study and follow our example in the future.