Moon landing: space medicine and the legacy of Project Apollo

Apollo 11 lunar module in a lunar landing configuration,
July 20, 1969 Copyright © 2019 NASA

On July 20, 1969, after a fraught 13 minutes of final descent, Apollo 11's commander Neil Armstrong and lunar module pilot Edwin “Buzz” Aldrin Jr made their historic first landing on the surface of the Moon. The US National Aeronautics and Space Administration (NASA) estimates that all-told 400 000 people were involved in that effort. The Project Apollo workforce had laboured tirelessly to achieve the goal set by US President John F Kennedy in 1961 of getting a human crew to the surface of the Moon and back before the end of the decade. Project Apollo saw state-of-the-art science, technology, and engineering applied to enable what was arguably the most ambitious feat of exploration in the history of our species. The flight of Apollo 11 had been preceded by a fierce schedule of testing, which had seen newly developed space craft and technology launched and tested in orbit around the Earth and Moon.

The protection of Apollo's human crews from the harsh environment of space was a formidable challenge. In the 1960s, human space flight was a genuine leap into the unknown and NASA flight surgeons were still unsure what hazards the space environment might present. Scientists could only guess at the likely consequences of extraterrestrial expeditions. They knew something of the nature of the physical environment: the high vacuum, its thermodynamics, the radiation and weightlessness. But precisely how this environment would interact with human physiology was unknown. Charles Berry, NASA flight surgeon and chief of medical operations for Project Apollo, once remarked on the difficulties of fulfilling the clinician's role during the project amid a programme whose core culture was driven by engineering considerations rather than medical science. The “engineering community developed 0·999 reliability figures for all of the parts of the spacecraft and launch vehicles…I had repeatedly said that I could not do that for astronauts; I had no opportunity to select the vendors, nor to have a quality assurance program developed for parts or subsystems or systems, and certainly could not test any of them to destruction”, he said. Research into human health in space presented many challenges. In this period, the flights involved only a handful of astronauts, and there was no uniformity in their flight profiles or durations. And because the number of flights was so small, it was near impossible to anonymise data acceptably. Added to that was the challenge of carrying out scientific investigations in the weightless environment of space. Nevertheless, the astronauts were willingly subjected to a battery of tests.

Pre and post flight measurements of endocrine, electrolyte, and fluid volume changes were made. Cardiovascular, musculoskeletal, and neurovestibular assessments were done, as well as haematological and biochemical analyses. In-flight heart rate and ECG telemetry were monitored. Crews took part in microbiological investigation, radiation dosimetry, and nutritional and metabolic studies. Although rudimentary, the resulting dataset formed the bedrock for all that followed.

But there was more for NASA flight surgeons to contend with than life science research. Medical events occurred throughout the Apollo programme. During the 11 Apollo flights, there were cases of everything from upper respiratory tract infections and dehydration to neurovestibular disturbance and decompression illness. Apollo astronauts would comment in later years about cramped quarters, difficulties with sleeping, spacesuit gloves that separated fingernails from finger beds during lunar excursions, the poor quality of their food, and tricky toileting arrangements. Yet from Apollo we learned how to persist in space and make it a frontier that we were capable of exploring.

More than 500 people have flown in space since Project Apollo. The past two decades have seen the International Space Station (ISS) used as a laboratory in low Earth orbit for a wide-ranging programme of scientific research, exploring everything from astrophysics and Earth science to genomics and virology. The investigation of human physiology— particularly the effects of microgravity upon the human body—has been a central feature of these expeditions.

Space life scientists now know that the space environment impacts almost all of the human body's physiological systems. Antigravity muscle groups exhibit sarcopenia during space flight and substantial osteopenia is similarly seen in load-bearing regions of the skeleton. Without effective countermeasures, mean rates of loss of bone mineral density while in space can exceed 1–2% per month. However, NASA's advanced resistive exercise device, which uses a combination of pistons and fly-wheel assemblies to mimic the inertial load of free weights and allows the crews to exercise effectively during space flight, has been successful in substantially reducing musculoskeletal losses.

Cardiovascular physiology is also altered, in the first instance by cephalad fluid shifts from the lower body to the upper torso and head, and complete unloading of the weight of tissues on vascular structures that accompany deployment in microgravity. Plasma volume is depleted and this reduction in circulating volume is accompanied by remodelling of the baroreceptor reflex arc. The resultant autonomic alterations can be viewed as an appropriate recalibration of the cardiovascular system to the weightless environment of space and the absence of orthostatic challenge. However, for some astronauts, these alterations lead to problems with orthostatic intolerance immediately after return to Earth.

The neurovestibular system and other sensory inputs that inform position and locomotion appear to exhibit a complex dependence on gravitational cues. Famously, during the 1968 flight of Apollo 8—the first human space exploration mission to leave Earth and orbit the Moon—commander Frank Borman had nausea and vomiting in what became NASA's first recorded case of space adaptation syndrome.

Astronaut Edwin E Aldrin Jr, lunar module pilot,
walks on the surface of the moon during Apollo 11
extravehicular activity on July 20, 1969,
astronaut Neil A Armstrong, commander, took this photograph,
Copyright © 2019 NASA 

The neurological system has continued to be something of an enigma in the field of space medicine. Shifts in visual acuity during space flight have been reported by astronauts since the space shuttle era. But more recently, these have been linked to a constellation of neuro-ophthalmic findings, including posterior globe flattening, disc oedema, cotton wool spots, and choroidal folds. In several returning crewmembers with disc oedema, mild elevation of intracranial pressure, as assessed by lumbar puncture, has been observed. This relatively new phenomenon gives pause for thought and requires comprehensive investigation to establish its true aetiology and operational significance.

NASA's research has focused mainly on the cardiorespiratory, musculoskeletal, and neurological systems because these have the greatest potential to impact mission operations. But broader disturbances have since been observed, including alterations in wound healing, immune function, and circadian rhythm. 50 years after the first landing on the Moon, our exploration of the effects of the space environment on the human body continues. However, while the widespread alterations in physiology remain intriguing, the experience aboard the ISS has been reassuring. Astronaut crews have been deployed regularly, for many months at a time, over the past two decades without significant operational consequences from these physiological changes.

Beyond the fascinating physiological findings, Apollo was an endeavour at the edge of possibility where risk to human life, technology, and science coincided. It is where much of modern medicine operates today, and within that similarity lie some of the most important lessons that medicine can glean from space exploration.

Apollo was a watershed in history—the point after which pushing back the frontiers of science, medicine, and exploration would take more than the heroic efforts of any individual or group of individuals. It demanded the collaborative efforts of an army of people, enmeshed with state-of-the-art science, technology, and engineering. It is often said that Armstrong, talking about the lunar landing in later years, was uncomfortable in interviews where he was lionised as the hero of Apollo 11's Moon landing, because he saw himself merely as the tip of the spear.

Acknowledging the vastness of the organisation, the need for collaboration and delegation, and the Apollo Project's dependence on technology is about more than attempting a departure from the age-old heroic narrative. It is also about appreciating the complexity of the endeavour. Like space flight, medicine depends on the complexity of a many layered system and the leveraging of technology for its capability.

But while the advantages of systems of this type are myriad, there is a price to pay. Failures in complex systems are inevitable and often difficult to predict. They arise as emergent features whose genuine root causes can be impossible to trace. In our practice and in our investigation of adverse events, health professionals often perceive medicine to be simpler in structure and operation than it truly is. The practice of medicine is—and always has been—far more complicated than rocket science. And despite the great benefits that derive from exploration and medicine, there can be no successful endeavour in these spheres without the underlying possibility of human catastrophe.

This brings us on to the subject of risk. It is tempting to think of Project Apollo as a decade-long programme of superlative performance that went from strength to strength and culminated in the successful landing of Armstrong and Aldrin. This was not the case. NASA, facing a near insurmountable challenge, found itself in difficulty for much of the first 5 years of the Apollo programme. With stretched resources and substantial production pressures, programmes progressively fell behind target. Both the construction of the lunar module in Long Island and the command module in California ran into trouble.

The whole organisation was fraught with fundamental problems, but the cadence of production and mission operations was so fierce, and the political pressure to deliver so acute, that no one was able to see it clearly. Later, after the Space Shuttle Challenger accident in 1986, this phenomenon would become understood more formally as normalised deviance—a culture in which people, operating at the limits of their resources, repeatedly tolerate events at the edges of acceptability, creating an environment where more fundamental errors of judgment go unnoticed.

It was not until February, 1967, when an accident during a ground test on the launch pad at Cape Canaveral killed astronauts Virgil “Gus” Grissom, Roger Chaffee, and Edward H White, that the parlous state of NASA's operations became fully appreciated. That incident—the Apollo 1 fire—resulted from poor design, inadequate safety culture, and a failure of leadership and managerial oversight. After that loss, NASA recalibrated its operational culture, reinvesting itself in the effort and conducting a root and branch overhaul of all of its construction lines and operational procedures. It is a remarkable case study of an organisation's recovery from catastrophic failure.

For the crews on the ground, there was more at risk besides life and limb. The pace of work was relentless. Flight controllers joked that they worked so hard, and for so little overtime, that the US Government achieved the first landing on the Moon at a fraction of its true cost. But in that is a kernel of difficult truth. From the astronauts and the flight controllers in mission control to the engineers and assembly workers on the factory line, everyone worked round the clock, through many nights and weekends. Relationships suffered and the divorce rate among NASA employees directly involved in mission operations was notoriously high.

The human impact of that relentless work rate is perhaps best captured in the words of Wally Schirra who flew as commander of Apollo 7, the first crewed mission of the Apollo programme, which launched just 21 months after the fire. Famously, the relationship between his astronaut crew and mission control became strained. None of them was assigned to later flights. Later, in an interview with Life Magazine in 1968, Schirra would make this telling remark: “The space age is very hungry. It devours people. I have been completely devoured by this business.”

The story of Apollo 11's success is one that will stand for all time, but we should be careful what lessons we choose to draw. The difficulty in understanding the causes of Apollo's success lies partly in the immense complexity of that endeavour: it was a vast sociotechnical feat that is difficult to deconvolve. But among the first lessons we might draw is this: as human as endeavours like exploration or medicine appear, these are complex pursuits in which most of the safety and reliability lie in the design and adequacy of the engineered environment. Ultimately, the system does most of the work and we, wrongly, tend to take most of the credit.

The second lesson lies in understanding that, like medicine, space flight is not and can never be an intrinsically safe endeavour. The goal of human space exploration is not safety, it is an operation in which risk is balanced against the benefits that might derive from proceeding with the mission. In the coming era, we will get no further than low Earth orbit if our politicians and society are unable to accept this. In the same vein, I've begun to wonder whether the near singular pursuit of safety in medicine is entirely correct. Perhaps we should be focusing more firmly on calibrating risk appropriately against benefit while, at the same time, improving the way we communicate the challenges involved in that balancing act.

The third lesson lies in the human costs. With burnout among clinicians reportedly at record levels in our medical workforce, that element is worth some consideration. The great unspoken truth of Project Apollo is that, like medicine, it achieved the nearly impossible, against the odds, under huge pressure, but consumed many people, lives, and relationships in the process. We should recognise that vast teams are capable of great things; Project Apollo is an example par excellence of this. But to succeed, under pressure of resource and time, NASA was forced to burn something more than rocket fuel. Nevertheless, on this 50th anniversary, we rightly celebrate Project Apollo for its legacy of discovery; the landing of the lunar module Eagle on the surface of the Moon on July 20, 1969, was a seminal moment in the history of our species. The same curiosity that first led us to look out across the stars to try and understand the universe also drew us within, to attempt to better understand ourselves. The road ahead is littered with risk and difficult questions, but the voyage of exploration continues, in all its complex wonder.


Kevin Fong is author and presenter with Andrew Luck-Baker, author and series producer, and Rami Tzabar, series editor, of 13 Minutes to the Moon, a BBC World Service podcast 

I thank NASA astronaut Dr Michael Barratt and NASA flight surgeon Dr Stevan Gilmore for their comments on an earlier version of this essay.

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