NASA/TP–2011-216159

Impact of Medical Training Level on Medical 

Autonomy for Long-Duration Space Flight

Laura M. Bridge, M.D.

Georgetown University School of Medicine

Sharmi Watkins, M.D., M.P.H.

Element Scientist, Exploration Medical Capability

The University of Texas Medical Branch

NASA Johnson Space Center Bioastronautics Contract

January 2012
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NASA/TP–2011-216159

Impact of Medical Training Level on Medical 

Autonomy for Long-Duration Space Flight

Laura M. Bridge, M.D.

Georgetown University School of Medicine

Sharmi Watkins, M.D., M.P.H.

Element Scientist, Exploration Medical Capability

The University of Texas Medical Branch

NASA Johnson Space Center Bioastronautics Contract

January 2012
Available from:

NASA Center for AeroSpace Information National Technical Information Service

7115 Standard Drive 5285 Port Royal Road

Hanover, MD 21076-1320 Springfield, VA 22161

301-621-0390 703-605-6000

This report is also available in electronic form at http://ston.jsc.nasa.gov/collections/TRS/
i

ABSTRACT

As the National Aeronautics and Space Administration (NASA) and its international partners 

plan for manned interplanetary space exploration missions, the question of how to provide 

optimum medical care during a long-duration space flight becomes increasingly relevant. A 

mission beyond low-Earth orbit, especially an expedition to Mars, demands a level of medical 

autonomy unprecedented for manned space flight.

1

 Mission planners must consider that in all

the history of human exploration, it has been disease, injury, and the limitations of human 

physiology that have accounted for more losses than any other factors, including technological

failures.

2

 Most of the published literature on the subject of the medical requirements for a 

manned expedition to Mars assumes at least one, if not two, physician-astronaut crewmembers. 

However, a 2008 NASA ad hoc committee of flight surgeons and space medicine experts 

observed, “Any additional capability in one area (the medical care system) will require decreased 

capability in another area.”3Flying a physician crewmember to Mars implies the exclusion of a 

crewmember who may possess a greater depth of knowledge or skill in another field such as 

engineering, geology, or astrophysics. Despite assumptions in the field of space medicine, no 

study presently exists that quantifies the capabilities of physicians and compares them to the 

capabilities of persons with lesser levels of medical training with respect to maximizing crew 

health and well-being on a long-duration, exploration space flight. This paper attempts to answer 

the following question: what benefits does a mission to Mars gain by including a physician in 

the crew, and are those benefits essential for crew health and mission success? Is there a medical 

training level below that of a physician that can meet the needs of the crew while 

accommodating greater knowledge and skill in another area of expertise?
ii

Table of Contents

1.0 INTRODUCTION..................................................................................................................... 1

2.0 APPROACH ............................................................................................................................ 2

3.0 HISTORY OF MEDICAL EVENTS DURING MANNED SPACE FLIGHT........................................ 3

4.0 CHALLENGES TO MEDICAL CARE DURING MARS EXPLORATION MISSIONS......................... 4

5.0 MEDICAL TRAINING LEVELS .................................................................................................. 8

6.0 DEFINING MEDICAL TASKS BY TRAINING LEVEL ................................................................. 12

7.0 ADDITIONAL BENEFITS OF PHYSICIAN TRAINING ............................................................... 14

8.0 STUDY LIMITATIONS............................................................................................................ 16

9.0 CONCLUSIONS ..................................................................................................................... 17

10.0 BIBLIOGRAPHICAL REFERENCES........................................................................................ 18

Tables

Table 1 Incidence of Musculoskeletal Injuries in the U.S. Space Program................................. 4

Table 2 Exploration Medical Condition List. ............................................................................ 12

Table 3 Expanded Exploration Medical Condition List. ............................................................ 13

Table 4 Summary of Training Level Required to Meet Mars Expedition Medical Needs ........ 14
1

1.0 INTRODUCTION

The Exploration Medical Capability (ExMC) project at NASA’s Johnson Space Center falls 

under the umbrella of NASA’s Human Research Program (HRP). The overarching purpose of 

the HRP is to provide for the health and safety of all astronauts, both current and former, not 

only during space flight but also during training and after mission completion. The specific task 

of ExMC is the promotion of crewmember health on long-duration space flights, such as to the 

moon or Mars. To accomplish this charge, ExMC is responsible for advancing current medical 

technology, informatics, and clinical capabilities to fulfill the needs of an exploration mission. 

The members of the ExMC project identify potential risks to crew health, determine which

resources are necessary to address those risks, and assess the present capacity to meet those 

needs. Through this process, the scientists, physicians, and engineers of ExMC describe gaps in 

current technology, informatics, and clinical capabilities that they must find a way to close

before the undertaking of an exploration mission.4

To determine current medical capabilities and identify areas to target for future development, 

ExMC created the Exploration Medical Condition List. This list is a dynamic document 

produced through analysis of medical incidents over the history of manned space flight, studies 

of human beings in analogous environments, modeling of projected missions, and expert 

consensus. The list details 77 medical conditions that could occur during an exploration mission 

and explains why each condition is of concern, the likelihood of an occurrence, and the potential 

impact of each event on crew health and mission success. The condition list also catalogues the 

equipment required to diagnose and treat an affected crewmember. 

In 2009, ExMC underwent evaluation by the Standing Review Panel (SRP), a committee 

chartered by HRP to appraise HRP projects. The 2009 ExMC SRP members included

physicians, physician astronauts, and scientists. They assessed the gaps identified by ExMC as 

well as the tasks outlined by ExMC to fill those gaps. The final report of the panel expressed its 

opinion that a physician crewmember would be necessary on exploration class missions, but 

conceded that no quantifiable assessment of the benefit provided by a physician crewmember 
2

existed. Therefore, the panel suggested a new gap, “Define impact of inadequate assessment of 

value of a physician on board,” to quantify the risk to crew health and mission success of each of 

the identified medical conditions with and without a physician.5

 

The task levied by the SRP raises questions about the level of medical training that allows for 

maximization of crew autonomy. Medical care for a Mars exploration mission requires a 

paradigm shift. The contingency for potential medical events in low-Earth orbit involves return 

to Earth and definitive care. The current approach on the International Space Station (ISS) is 

patient stabilization and transport back to fully equipped terrestrial medical facilities as soon as 

possible. Providing for crew health on a long-duration mission beyond the moon dictates a 

transition toward autonomous treatment in space. Although complete care on board the 

spacecraft is the goal, exploration mission planners must accept that current capacity falls short 

of this ideal. As such, planners must agree on an acceptable level of risk.1,6 This paper describes 

an effort to assess the impact of medical training on crew health outcomes and addresses the 

issue of which level of medical training best minimizes the health risks of long-duration space 

flight.

2.0 APPROACH

The current Exploration Medical Condition List6is derived in part from the 45-year history of 

medical events during manned space flight. Revisiting the literature describing and analyzing 

those events provided a better appreciation for the medical problems already experienced by 

humans in space. More importantly, a literature review of the medical and health challenges 

anticipated for a Mars expedition yielded information about the capabilities necessary for an 

exploration mission. The results of these reviews, in combination with the Exploration Medical 

Condition List, served as a basis to identify a medical skill set necessary for the accurate 

diagnosis and appropriate treatment of each foreseeable medical event.

 

Training guidelines and analogous studies, mostly from military and trauma literature, offered

information regarding the competencies of persons with three different medical training 

backgrounds, namely: crew medical officer, paramedic, and physician. Additionally, these 
3

studies supplied evidence regarding the effects of medical training level on patient outcomes. 

Each task extrapolated from the condition list was categorized by minimum training level 

required. Those categories were then applied to the condition over all, depending on the tasks 

needed for diagnosis and treatment.

3.0 HISTORY OF MEDICAL EVENTS DURING MANNED SPACE FLIGHT

In the approximately 50 years since humans first traveled beyond Earth, about 400 men and 

women have flown in space.2 While several serious medical incidents have occurred over the 

course of space exploration, such as the widely publicized case of urosepsis affecting astronaut 

Fred Haise during the Apollo 13 mission, the most common medical events were self-limited 

illnesses or exacerbations of chronic conditions requiring only an ambulatory level of care.1,2 

Despite the low acuity of medical events in space, they are quite frequent. Seventy-five percent 

of shuttle astronauts utilized medication to treat a non-emergent problem.2 Common ailments 

included minor trauma to the skin and mucous membranes, exercise-induced overuse injuries, 

space motion sickness, sleep disturbances, and extravehicular activity (EVA)-associated injuries. 

Cardiovascular abnormalities, predominantly manifested as dysrhythmias detected on EKG, did 

not occur infrequently. In fact, on the NASA-Mir missions from 1995 to 1998, EKG monitoring 

revealed physiologic dysrhythmias in 10 crewmembers, all of whom had a history of at least one

abnormal preflight EKG, and only one of whom was symptomatic.

7

 Other medical events during

manned space flight spanned a variety of ailments and etiologies, including headaches from 

carbon dioxide exposure, fatigue or other environmental factors, rashes ranging from atopic 

dermatitis to folliculitis, and even cellulitis, urinary retention, renal stones, pneumonitis, dental 

caries, behavioral health problems, and medical reactions to human experiments.2,8

Minor injuries during space flight are common and encompass mainly abrasions, contusions, and 

strains. More serious injuries such as dislocations and sprains are exceedingly rare, and despite 

documented bone density loss, there is no history of a skeletal fracture occurring in space. The 

following table shows the incidence of overall musculoskeletal injury in comparison to hours of 

manned space flight through December 2006.8
4

Male Female

 Total Hours of Manned Space Flight 198,275.5 33,449.4

 Injury Incidence (injury/day) 0.021 0.015

 Total Hours of EVA 1,087.8

 Injuries Associated with EVA (injuries/day) 1.21

 

Table 1. Incidence of Musculoskeletal Injuries in the U.S. Space Program through December 2006. Injuries 

among astronauts during space flight are common, but are usually mild and are most frequently abrasions, 

contusions, or strains. The most common causes of crewmember injury are crew activity, such as impacting 

structures, stowing equipment, or transiting through the spacecraft, the EVA suit, and exercise. These data exclude 

injuries for which a mechanism could not be determined or which were thought to be an exacerbation of a chronic 

injury that occurred preflight.

9

As can be seen from this table, EVA results in a much higher incidence of injury compared to the 

risk of space flight in general. This becomes relevant for any exploration mission, as the 

frequency and total number of EVAs is anticipated to exceed current operations. 

There are several limitations to using a historical review of medical events during space missions 

to predict future medical challenges. Methods of data collection and the type of data collected 

are inconsistent over the history of manned space flight, even within the U.S. program. 

Furthermore, the data that do exist are stored in multiple formats across many repositories 

located at a variety of institutions in different countries. The total number of subjects available 

for analysis is very small, and there is a possibility of underreporting among space program

participants. Finally, there is a lack of adequate controls to confirm the validity and significance

of the data collected.9

4.0 CHALLENGES TO MEDICAL CARE DURING MARS EXPLORATION MISSIONS

Any plans for a long-duration, interplanetary exploration mission must address many conditions 

not previously encountered during manned space flight. These conditions, which include the 

logistics of traveling such a great distance away from Earth and the environment faced by 

astronauts living and working in interplanetary space and on the Martian surface for an extended 
5

period of time, impose novel challenges to the delivery of health care to exploration 

crewmembers.

The technical requirements for a mission to Mars necessitate an expedition of two to three years 

in duration. No human has yet spent such a consecutive length of time in space. This extended 

stay in an inhospitable environment increases the likelihood of medical events occurring, both 

minor and severe. These events may include, but are not limited to, disease, trauma, 

decompression sickness, burns, toxic exposures, overheating or overcooling, life support failure, 

depressurization, and meteorite impacts. The distance imposes additional challenges for a Mars 

exploration mission. As the spacecraft travels away from Earth, there will be increased

lengthening of the time needed for a communication signal to travel from Earth to the crew and 

back. With current technology, it could take as long as 45 minutes to complete a communication 

loop between mission control on Earth and a crew on the Martian surface, depending on the 

orbital positions of both planets. Additionally, in the event of a serious medical incident that

compelled evacuation of an ill or injured crewmember, Earth and definitive care are four to six 

months away.

10

 The distance renders not only medical evacuation but timely resupply 

impossible, meaning that the crew must bring with them all of the medical equipment and 

disposables required for the duration of the mission.

It is difficult to anticipate all of the medical equipment the crew needs to carry for a two- to 

three-year mission, particularly because of the lack of precedent for such an undertaking. Some 

variables with potential repercussions for human health during a Mars expedition relate to the 

impact of the known physiologic changes resulting from space flight over an extended period of 

time, such as loss of muscle and bone mass, neurovestibular changes, immune suppression, 

plasma volume loss, reduction in cardiac volume and mass, and effects on metabolism and the 

endocrine system.1,3,6,11 Other factors with possible health implications include radiation 

exposure, multiple gravity transitions, and psychological stressors.1,7,12 Likewise, Mars surface 

conditions present distinct challenges for sustaining human life and maintaining the equipment 

that the astronauts will depend on for their health and safety. The surface of Mars is treacherous 

and inhospitable, with frequent dust storms and below freezing temperatures. There is a reduced 
6

atmospheric pressure of 6.1 mbar compared to Earth’s atmospheric pressure of 1,013 mbar, and 

the lack of a magnetic field places astronauts at continued risk of radiation exposure.7,10

Crewmembers of a Mars expedition will face a level and duration of radiation exposure never 

before encountered in the history of space flight. Multiple authors identify radiation as a 

principal risk to crew health on an exploration mission.1,3,7,13 During the six-month journey 

between planets, there will be nothing to protect the crew but their own spacecraft. As described 

by Davis in 1999,13 with exposure models available at the time and assuming an aluminum 

spacecraft wall 0.75 cm thick (2 g/cm2), a Mars mission would exceed the 0.5 sievert radiation 

exposure limits adopted by NASA. Adding thicker shielding to the spacecraft will result in 

greater mass, thus increasing the amount of thrust necessary to propel the aircraft and, therefore,

mission cost. Once on the Martian surface, the planet itself will offer some shielding, but 

without a magnetic field there will be nothing to dampen incoming radiation.7

Complicating the issue of radiation exposure, there remains no reliable way to forecast large 

radiation events. Approximately 75% of the radiation total dose equivalent the crew will receive 

will be in the form of galactic cosmic rays (GCR). This radiation originates outside of Earth’s 

solar system and is not well understood. Even radiation emitted from Earth’s own sun, called 

solar particulate radiation, is unpredictable. Current technology enables less than 30 minutes of 

warning before a solar particle event.7 Assuming a 180-day surface stay and 65 EVAs, among 

the lower estimates encountered in the literature, Hamilton et al,1describe a 0.2-0.3% risk of a 

very large solar particle event delivering up to 1 Gray of radiation to blood-forming organs. 

While the likelihood of acute radiation sickness is low, they estimate a 10% risk of prodromal 

symptoms, primarily nausea and vomiting.

1

 Though these percentages are small, there remains a 

significant risk of radiation-induced illness. Furthermore, the late effects of radiation exposure, 

likely to result from GCR, occur months to years after exposure and manifest as an increased 

incidence of certain tumors, skin cancer, and hematologic cancers, cataracts, and tissue damage 

or mutations, among other symptoms.7 Given a multi-year expedition, it is possible that 

astronauts may begin to show these late effects, with potential mission impact.
7

Radiation is not the only long-term exposure with which the crew must contend. After six 

months transiting to Mars in a microgravity environment, it is not clear how the crew will adapt 

to functioning in the 0.38 gravity of Mars. Even more uncertain is how the crew will tolerate the 

forces of lift off from the planetary surface following roughly two years of living and working in 

reduced gravity.11 The deconditioning of the crew, coupled with the increased demand of 

multiple, frequent EVAs, may precipitate a variety of musculoskeletal injuries. 

While the long-term effects of reduced gravity may have a substantial impact on crew 

physiology and predispose crewmembers to injury, the long-term effects of the mission itself 

may have a substantial impact on crew psychology and, in turn, the outcome of the expedition. 

Space medicine literature contains many descriptions of psychological stressors. Russian 

literature uses the term “asthenia” to describe a combination of depressive and dissociative 

symptoms occurring in cosmonauts and defines three stages of psychological adaptation to space 

flight.

12

 These stages include an acute phase of up to two months duration while cosmonauts 

adapt to their new environment, an intermediate phase characterized by physical and mental 

tiredness, irritability, and declining motivation, and a long-duration phase during which 

psychological and somatic symptoms worsen with potential effects on inter-crew relationships 

and performance.13 The pressure of the mission, its associated workload and compressed 

timeline, the lack of privacy, confined living and working area, reduced sensory stimulation, loss

of traditional social support, prolonged isolation, and the unique challenges arising from the 

interactions of a multicultural crew are all factors that can influence behavioral health.7,11 These 

stressors will be more severe and of longer duration on an expedition to Mars, worsened by the 

inability to communicate with physicians, friends, and family in real time, and necessitating

additional training for the on-board medical crewmember in psychiatric diagnosis, counseling, 

and pharmacotherapy.3,13 Behavioral health is a perceivable threat to crew health and mission 

success, as it has resulted in substantial mission impact in the past, both in space and in 

analogous environments. Psychiatric issues likely contributed to three Russian cosmonaut

evacuations, and even among the prescreened population of U.S. Navy submarines, psychiatric 

and behavioral health problems are the third leading reason for emergency evacuation (after 

trauma and surgical necessity).

7
8

With consideration of all possible events, both U.S. and Russian models predict one medical 

emergency per year for a six-person crew.10 Therefore, as Kozlovskaya and colleagues observe 

in a 2003 paper10 on the subject, the crew of a Mars exploration mission must possess the

“resources to enable medical prevention, diagnostics, and care without assistance from the 

outside.”11 These resources may be any combination of a medically trained crewmember, 

medical equipment, diagnostic and treatment aids, and decision making tools. However, many 

authors assume a benefit with greater degrees of medical training. Pool and Davis identify

knowledge, skill, and proficiency as the three “critical elements” upon which medical capability 

depends.

11

 The remainder of this paper attempts to address in detail the impact of medical 

training level on capability and the effect that medical training level may have on an exploration 

mission to Mars.

5.0 MEDICAL TRAINING LEVELS

Analysis of a combination of published articles, accreditation guidelines, and training flow sheets 

enables a comparison of the clinical capabilities and technical skills of the following three levels 

of practitioners: 

1) Astronaut crew medical officers, 

2) Civilian paramedics, and 

3) Physicians. 

While many training paths exist within the health care fields, such as emergency medical 

technician, medical assistant, nurse, nurse practitioner, and physician assistant, choosing three 

distinct levels of training permits a more quantifiable distinction in competencies. Although 

paramedic and physician education is not standardized, a review of the literature provides 

sufficient background to generalize the abilities of each practitioner. 

The crew medical officer (CMO) is any astronaut chosen by a mission commander to serve as 

the person that manages medical care for other crewmembers during a given mission. The crew 

medical officer usually lacks previous medical training or experience. On board the ISS, there 

are currently two CMOs for each six-person crew.

1

 Before launch, each CMO undergoes an 
9

additional 40 hours of instruction in the use of the medical equipment on station and basic 

recognition and treatment of a variety of common conditions. The CMO training flow includes 

four hours of lecture and practical lessons on medical diagnostics, five hours devoted to medical 

therapeutics, and 10.5 hours of basic life support (BLS) and advanced cardiac life support 

(ACLS) training to American Heart Association standards. There is an additional optional 

clinical component consisting of emergency department shadowing or an ambulance ride-along, 

for example.14 Additional resources are available on board ISS to offset the limitations in CMO 

knowledge and skill. These resources include real-time telemedicine support from flight 

surgeons in mission control and just-in-time training, which utilizes computer-based tutorials that 

CMOs access by topic at point of care. Just-in-time training with telemedicine guidance resulted 

in the acquisition of good quality ultrasonographic images when CMOs without experience in 

ultrasonography performed examinations on fellow astronauts on board the ISS in 2004.10 

Further attempts at telemedicine-guided ultrasonography and ophthalmoscopy, in addition to 

other diagnostic and therapeutic procedures over the past several years, also met with success.

In contrast to CMOs, who undergo a standard course of instruction administered by NASA and 

its partners, the training of paramedics is variable. Much of the literature regarding the skills of 

paramedics and health outcomes of their patients in comparison to other providers originates

outside the country. Even within the United States, certification requirements for paramedics 

differ by jurisdiction. However, the National Highway Traffic Safety Administration (NHTSA), 

an element of the U.S. Department of Transportation, produces a curriculum designed to 

establish minimum requirements for paramedic training, and there is some consensus in the 

literature and among health care providers regarding the expectations of paramedic performance 

and their capabilities.15 The tasks that paramedics generally perform include pharmacotherapy, 

placing peripheral intravenous catheters and administering intravenous fluids and medications, 

BLS and ACLS, laryngeal airway and endotracheal tube placement, and needle thoracostomy, in 

addition to more basic skills such as physical examination and vital sign monitoring. For the 

most part, paramedics are not able to perform a rapid sequence induction before intubation of

conscious patients, and they are not capable of advanced airway procedures, such as a 

cricothyrotomy. Additionally, paramedics do not perform invasive monitoring, which requires 

techniques such as placement of arterial or central lines.

16 The focus of paramedic training is 
10

short-term, pre-hospital emergency care, and the scope of paramedic practice is limited and 

specialized. Paramedics are more likely to regularly perform lifesaving interventions, such as 

intubation, than a general physician but they lack the depth and breadth of knowledge possessed 

by the average physician.17

For the most part, physicians possess all of the skills and capabilities of paramedics, with 

additional competencies born of their advanced education. However, physician training is even 

less standardized than that of a paramedic, and a physician’s abilities depend largely on his field 

of specialty, experience, and personal interest.17 The guidelines and objectives set forth by the 

Accreditation Council for Graduate Medical Education (ACGME), which accredits all residency 

and fellowship programs for physicians in the United States, are frequently vague. Nonetheless, 

examples of training expectations do exist. Emergency medicine is one specialty for which the 

ACGME maintains specific requirements for types and numbers of procedures necessary for 

completion of residency training. A selection of those skills includes adult medical and trauma 

resuscitation, bedside ultrasound, cardiac pacing, central line placement, chest tube placement, 

conscious sedation, cricothyrotomy, dislocation reduction, intubation, lumbar puncture, and 

pericardiocentesis.

18

 As this list demonstrates, many of the clinical competencies of a physician 

fall beyond the range of a paramedic’s ability.

Despite variability in physician skills and the possibility, as Pool purports,7“that physicians who 

provide care on missions to the Moon and Mars require a breadth of training that does not 

currently exist in any single physician training program or residency,” there are many benefits to 

flying a crewmember with a physician background on an exploration mission as compared to 

other levels of medical training.11 A physician crewmember is an already maximally educated 

medical provider, and therefore lessens the demands on limited mission preparation time. An 

increase in the independent functioning of the crew medical provider may decrease the 

requirements of the medical equipment flown on board the spacecraft, particularly in terms of 

complexity, automaticity, and redundancy, thereby reducing mass, volume, power, and cost.

 

In relation to a physician’s higher level of autonomy, numerous studies, predominantly in trauma 

and emergency response literature, demonstrate improved patient outcomes when a physician
11

provided treatment as opposed to a paramedic. A review of studies examining primary 

helicopter retrieval of trauma patients found in 10 of 12 publications that mortality rates were 

lower for physician teams compared to paramedic teams, even when a nurse practitioner with the 

same pharmacotherapy and procedural skills as a physician accompanied the paramedics.19 The 

authors attributed this finding to the superior wealth of knowledge and clinical judgment of a 

physician. Whereas CMOs and paramedics depend heavily on algorithms for patient 

management, physicians use a different decision making process. Physicians obtain data through 

history taking and physical examination, then synthesize and interpret that data to determine a 

diagnosis and formulate a plan of care. Physicians also have a unique perspective and more 

complete understanding of health care delivery, as they care for patients not only in the 

immediate and short-term setting, but through the intermediate and long-term stages of an illness 

or injury, as well as in times of good health.17,20 This scope of practice is essential for 

maximizing the health and well-being of astronauts on a long-duration mission. In fact, a group 

working with the Israeli armed forces found physicians superior to paramedics for military 

ground operations, with the most pronounced benefit occurring on long-duration missions with 

limited resources far from definitive treatment.17 Finally, the perception of a physician as the 

most highly trained of medical providers cannot be discounted. Physicians are thought of by 

many as able to deliver the highest standard of care, and this may impact the morale of not only 

the crew, but their friends and family, and favorably influence public opinion.17 This reasoning 

may be why most of the Russian and American papers published assume a physician 

crewmember on any Mars exploration mission.1,3,7,11,13 
12

6.0 DEFINING MEDICAL TASKS BY TRAINING LEVEL

To quantify the impact of flying a physician compared to a crewmember with a lesser level of 

medical training, analysis was performed based on the current Exploration Medical Condition 

List, a sample of which appears in Table 2.6

Priority Rationale Incidence Data Likelihood

Kidney Stone 2 – Shall An untreated kidney 

stone...can result in 

severe pain, and may lead 

to infection, sepsis, and 

the need for EVAC. 

0.002555 

events per 

person-year 

2 – Low 

Consequence 

Data

Consequence Mitigation Diagnosis Treatment

Kidney Stone An untreated 

kidney stone could 

become serious 

enough to require 

evacuation... 

3 – Moderate ...80 to 85% of 

kidney stones will 

respond to 

conservative 

treatment... 

Vital signs

Imaging 

Modality

Stethoscope

Urinalysis

Crew Medical Restraint 

System

Lithotripsy 

Surgical Treatment

Antiemetic

Carpuject Injector

BZK Wipes

Gauze Pads

Non-sterile Gloves 

(pair)

Sharps Container

Narcotic Analgesic

Tape 

IV Fluid

Y-type Catheter

Lever Lock Cannula

IV Pressure Infusor

IV Administration Set

Iodine Pads

Tourniquet

CMRS 

Table 2. Exploration Medical Condition List. The entries in this table are an abridged example of a condition 

from the Exploration Medical Condition List. Prioritization is on a scale of 0 to 2, with 0 indicating that mission 

planners currently do not expect to carry the capacity to diagnose and treat the condition on board the spacecraft 

during an exploration mission, 1 signifying that the capacity should be manifest if possible, and 2 being the highest 

level of priority and a condition that the crew will be able to diagnose and treat during the mission. Likelihood and 

consequence are both rated on a scale of 1 to 5, or very low to very high.

Specific medical tasks necessary to diagnose and treat each condition were identified and 

described based on the information already in the database. These tasks included the knowledge 

and skill necessary to properly use the equipment associated with each condition or perform the 
13

procedures listed. The medical tasks were added to the condition list in a new column entitled 

“Skill/Capability,” as shown in Table 3.

Diagnosis Treatment Skill/Capability Training Level

Kidney 

Stone

Vital Signs 

Measurement 

Capability 

Imaging Modality 

(Ultrasound, CT, MRI, 

IV Pyelography or 

Urography)

Stethoscope

Urinalysis 

Crew Medical 

Restraint System

Lithotripsy 

Surgical Treatment

Antiemetic

Carpuject Injector

BZK Wipes

Gauze Pads

Non-sterile Gloves 

(pair)

Sharps Container

Narcotic Analgesic

Tape 

IV Fluid

Y-type Catheter

Lever Lock Cannula

IV Pressure Infusor

IV Administration Set

Iodine Pads

Tourniquet

CMRS 

Vital signs

Diagnostic ultrasound

Urine dipstick

Urinalysis

Urine microscopy

Urine culture and 

sensitivity

Administer PO

Venipuncture

Assess fluid status

IV fluid administration 

Surgical capability 

Physician

Table 3. Expanded Exploration Medical Condition List. The changes made to the condition list for the purposes 

of this analysis included the creation of two new fields or columns. The first new column, “Skill/Capability,” 

inventories the various tasks a medical provider must complete to diagnose and treat the condition. These 

capabilities are not all inclusive, but are based on the information already in the condition list. Each individual task 

was described further, and a determination of medical training level necessary for performance of that task was 

made through best clinical judgment with expert agreement. With the second new column, “Training Level”, a, 

either a crew medical officer (CMO), paramedic, or physician, was assigned to each condition based on the lowest 

level of training required to complete all of the tasks ascribed to that condition.

Each skill/capability identified in the expanded condition list was described further, and a 

training level was assigned to the task, based on the lowest level of medical training deemed 

necessary for task completion, by the best clinical judgment of a group of physicians and 

scientists with a background in aerospace medicine experienced in the delivery of medical care 

in space. For example, “Vital Signs,” was defined as, “Assessment of pulse rate, respiratory rate, 

blood pressure by manual or automatic sphygmomanometry, temperature, and pulse oximetry,”

and was determined to be a CMO-level capability. Some tasks mandated further explication, 

particularly capabilities that CMOs performed on ISS but that were assigned a higher level of 

medical training in this exercise. The reason such increases in necessary level of training 

occurred is related to the novel challenges of traveling to Mars as already delineated. For many 
14

medical skills, there was a substantial difference in the degree of training required to complete a 

task with basic telemedicine support in contrast to the training that would enable independent, 

autonomous, immediate performance of that task. 

The expanded condition list assumes current technology, including current image storage and 

forwarding capability and telemedicine limitations with, at most, a 25-minute one-way 

communication delay between Mars and Earth. While telemedicine will undoubtedly become 

more advanced before the undertaking of an exploration of Mars, by assuming no forward 

development, the Exploration Medical Condition List portrays the worst-case scenario for the 

management of medical events beyond Earth’s orbit. Of the 77 conditions on the Exploration 

Medical Condition List, 64 (83.1%) are prioritized as “shall” or “should.” These are the 

conditions for which the appropriate diagnostic and therapeutic equipment and supplies will 

likely fly on a mission to Mars. Thus, the medical provider on that mission must possess the 

ability to manage a wide spectrum of health problems. According to the new classification of 

conditions by training level, most anticipated events require a physician for optimum diagnosis 

and treatment. Table 4 summarizes these conclusions.

Number Percent of Total (77)

Shall and should conditions 64 83.1

CMO-level conditions 30 39.0

Paramedic-level conditions 12 18.8

Physician-level conditions 47 54.7

Table 4. Summary of Training Level Required to Meet Mars Expedition Medical Needs. Of the 77 conditions 

described by the Exploration Medical Condition List, 64 are priority 1 or 2, necessitating on-board capability for 

diagnosis and treatment. Of these 64 conditions, 47 (54.7%) require skills that a consensus of space medicine 

experts consider physician-level tasks. Only 12 conditions require skills above the training level of CMO but not yet 

at the level of a physician. A CMO can successfully manage the remaining 30 conditions with a sufficient degree of 

autonomy, despite the difficulties in telemedicine guidance imposed by long-duration space flight.

7.0 ADDITIONAL BENEFITS OF PHYSICIAN TRAINING

While this analysis attempts to define a discreet skill set for three levels of medical training to 

quantify the impact of a physician crewmember on an exploration mission to Mars, physicians 
15

generally possess qualities that are difficult to enumerate or measure. These are attributes that 

one cannot learn in medical texts but that physicians develop through years of training and 

experience. For example, a substantial part of physician training emphasizes cultural 

competency and interpersonal relationships, which are essential in the comprehensive and 

compassionate delivery of health care and have a potential impact on crew well-being during an 

exploration mission.21 Delay in communication during a journey to Mars and while living on the 

Martian surface will prevent direct conversation with flight surgeons, and as the 2008 NASA ad 

hoc committee observes, “will render the interpersonal human interaction and give and take of 

any needed counseling...useless.”3 This impairment in communication and counseling has 

possible drastic implications for the behavioral health of the crew that will already be under 

threat from the many psychological stressors of the mission. However, a physician with 

sufficient counseling skills can ameliorate the potential negative outcomes for the crew.

The issue of behavioral health is closely intertwined with the general concepts of preventive 

health and health maintenance. Maximizing crew health for long-duration missions will require 

more than management of acute or even chronic illnesses or injuries. According to ACGME 

guidelines, all physician training incorporates elements of preventive medicine, making 

physicians ideal providers for a healthy crew during an extended mission. Furthermore, 

physicians receive exposure to health systems and training in the recognition of ways in which 

systematic improvements can better promote patient health.21 A physician crewmember is best 

suited to observe crew habits and performance, identify risks to crew health and well-being, 

innovate and implement interventions, and monitor the effectiveness of those interventions. 

Such insights may result in systematic improvements of benefits for future exploration missions 

to Mars or beyond. In a similar vein, physician crewmembers can facilitate discussions 

regarding issues relevant to crew health that may better identify problems for which the 

physician can then implement solutions. In a prospective study of injuries in the neutral 

buoyancy lab at Johnson Space Center where astronauts train for EVAs, Strauss and colleagues 

report that involving astronauts in the documenting of injuries precipitates enhanced joint 

decision making and more thorough discussion of treatment and prevention strategies, leading to 

better use of countermeasures and reduced symptoms.22 
16

A physician’s flexibility extends beyond prevention to treatment scenarios. A logical 

assumption is that a physician’s clinical judgment and breadth and depth of knowledge allows a 

greater level of independence and provides the physician with more advanced real-time problemsolving abilities. No amount of preflight screening will ever preclude every medical event.10

 

Even in a prescreened population at McMurdo Station in Antarctica, 0.036 medical emergencies

occur per person per year. Excluding those events that are unlikely to occur in microgravity, 

such as trauma, which accounts for 48% of the injuries at McMurdo, the rate of medical 

emergencies is 0.02 per person per year.23 Assuming a crew of six on a three-year mission 

results in a 36% risk of a serious medical event. While this analogy is imperfect, and the crew 

may never need to rely on the flexibility and problem-solving of a physician during a two- to

three-year mission, in a worst-case scenario, including a physician in the crew could prove to be 

life or mission saving. 

8.0 STUDY LIMITATIONS

There are many limitations to the work presented here, including the basis of this study on 

modern technology. There is no way to fully anticipate the developments that will occur in 

medical decision making tools, diagnostic aids, and therapeutic equipment over the decade or 

more before a long-duration exploration mission is undertaken. As technology becomes more 

sophisticated and reliable, the level of medical training necessary to attain a given degree of crew 

autonomy may decrease. Another shortfall of this study is the variability in medical training for 

paramedics and physicians already described. This variability is not well categorized, and many 

of the studies assessing differences in the care delivered by physicians compared to paramedics 

took place outside of the United States and under conditions not entirely analogous to space 

flight, such as in combat or trauma situations. That variability may increase depending on 

recency of training. Traditionally, when physician astronauts enter the astronaut training flow, 

they cease clinical practice. Increasing time since last training and a lack of clinical practice 

possibly results in a decline in clinical skill. Given these factors, the classification of tasks by 

training level must still undergo vetting and validation, though it is currently based on the best 

clinical judgment of several experts in the field of space medicine. The next step in this vetting 

process is to present the classification to the ExMC advisory group, comprised of physicians, 
17

astronauts, and scientists. Additionally, many avenues of medical training were purposefully 

excluded from this analysis. It is possible that some other training background, such as that of a 

nurse practitioner or physician assistant, provides the essential autonomy while maximizing crew 

and mission resources. Another type of independent practitioner may prove valuable during a 

long-duration mission, but physicians remain the gold standard, particularly in depth and breadth 

of knowledge and those intangible qualities mentioned above.

9.0 CONCLUSIONS

The medical providers on a long-duration space flight to Mars must be prepared to manage a 

wide range of clinical quandaries. There are many variables that may affect crew health during 

an exploration mission, and there is no way to accurately predict or prepare for every eventuality. 

Literature on the topic of the medical requirements for exploration space flight assumes at least 

one physician crewmember, a recommendation that is supported by this analysis of the 

Exploration Medical Condition List. Additional quantification of the impact of a physician on 

crew health would require more complex modeling or a clinical trial comprised of real-time 

scenarios and simulations performed by individuals with differing medical training backgrounds. 
18

 

10.0 BIBLIOGRAPHICAL REFERENCES

1 Hamilton D, Smart K, Melton S, Polk JD, Johnson-Throop K. Autonomous medical care for 

exploration class space missions. J Trauma. 2008; 64: S354-63.

2

Summers RL, Johnston SL, Marshburn TH, Williams DR. Emergencies in space. Ann Emerg 

Med. 2005; 46: 177-84.

3 Baisden DL, Beven GE, Campbell MR, Charles JB, Dervay JP, Foster E, Gray GW, Hamilton 

DR, Holland DA, Jennings RT, Johnston SL, Jones JA, Kerwin JP, Locke J, Polk JD, Scarpa PJ, 

Sipes W, Stepanek J, Webb JT, Ad Hoc Committee of Members of the Space Medicine 

Association, Society of NASA Flight Surgeons. Human health and performance for longduration space flight. Aviat Space Environ Med. 2008; 79: 629-35.

4 National Aeronautics and Space Administration, Human Research Program. (2008, Nov 3). 

Exploration medical capability. Retrieved from 

http://humanresearch.jsc.nasa.gov/elements/exmc.asp.

5 Human research program (HRP) exploration medical capability (ExMC) standing review panel 

(SRP) final report. Dec 2009.

6 Watkins, SD. “Space Medicine Exploration Medical Condition List,” NASA TP 2010-216118, 

2010.

7 Gontcharov IB, Kovachevich IV, Pool SL, Navinkov OL, Barratt MR, Bogomolov VV, House 

N. In-flight medical incidents in the NASA-Mir program. Aviat Space Environ Med. 2005; 76: 

692-6.

8

Scheuring RA, Mathers CH, Jones JA, Wear ML. Musculoskeletal injuries and minor trauma 

in space: incidence and injury mechanisms in U.S. astronauts. Aviat Space Environ Med. 2009; 

80:117-124.

9 Cermack M. Monitoring and telemedicine support in remote environments and in human space 

flight. Br J Anaesth. 2006; 97: 101-14.

10 Kozlovskaya IB, Egorov AD. Some approaches to medical support for Martian expedition. 

Acta Astronaut. 2003; 53: 269-75.

11 Pool SL, Davis JR. Space medicine roots: a historical perspective for the current direction. 

Aviat Space Environ Med. 2007; 78: A3-4.

12 Grigoriev AI, Kozlovskaya IB, Potapov AN. Goals of biomedical support of a mission to 

Mars and possible approaches to achieving them. Aviat Space Environ Med. 2002; 73: 379-84.
19

 

13 Davis JR. Medical issues for a mission to Mars. Aviat Space Environ Med. 1999; 70:162-8.

14 CMO Training Flow, Wyle Laboratories, April 2010.

15 United States Department of Transportation, National Highway Traffic Safety Administration. 

(1998). EMT-Paramedic: National Standard Curriculum. Retrieved from 

http://www.nhtsa.gov/people/injury/ems/EMT-P/disk_1%5B1%5D/Intro.pdf. 

16 Cameron S, Pereira P, Mulcahy R, Seymour J. Helicopter primary retrieval: tasking who 

should do it? Emerg Med Australas. 2005; 17: 387-91.

17 Levy G, Goldstein L, Erez Y, Levite R, Bar U, Marmor M, Linn G, Onn E, Levi Y, Bar-Dayan 

Y. Physician versus paramedic in the setting of ground forces operations: are they 

interchangeable? Mil Med. 2007; 172: 301-305.

18 Accreditation Council for Graduate Medical Education. Emergency Medicine Guidelines. 

(2010, Apr 29). Retrieved from http://www.acgme.org/acWebsite/RRC_110/110_guidelines.asp.

19 Garner AA. The role of physician staffing of helicopter emergency medical services in 

prehospital trauma response. Emerg Med Australas. 2004; 16: 318-23.

20 Kilner T. Triage decisions of prehospital emergency health care providers, using a multiple 

casualty scenario paper exercise. Emerg Med J. 2002; 19: 348-53.

21 Accreditation Council for Graduate Medical Education. Common Program Requirements. 

(2007, Jul 1). Retrieved from 

http://www.acgme.org/acWebsite/dutyHours/dh_dutyhoursCommonPR07012007.pdf.

22 Strauss S, Krog RL, Feiveson AH. Extravehicular mobility unit training and astronaut 

injuries. Aviat Space Environ Med. 2005; 76: 469-74.

23 Summers RL, Johnston SL, Marshburn TH, Williams DR. Emergencies in space. Ann Emerg 

Med. 2005; 46: 177-84.
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January 2012 NASA Technical Paper

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Impact of Medical Training Level on Medical Autonomy for Long-Duration Space Flight

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Laura M. Bridge, M.D., Georgetown University School of Medicine

Sharmi Watkins, M.D., M.P.H., NASA Johnson Space Center

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13. ABSTRACT (Maximum 200 words)

As NASA and its international partners plan for manned interplanetary space exploration missions, the question of how to provide 

optimum medical care during long-duration space flight becomes increasingly relevant. In the history of human exploration, disease, 

injury, and the limitations of human physiology have accounted for more losses than other factors, including technological failures. 

Most published literature on the subject of the medical requirements for a manned expedition to Mars assumes at least one, if not two, 

physician-astronaut crewmembers. However, a 2008 NASA ad hoc committee of flight surgeons and space medicine experts 

observed, “Any additional capability in one area (the medical care system) will require decreased capability in another area.” Flying a 

physician crewmember to Mars implies the exclusion of a crewmember who may possess a greater depth of knowledge or skill in 

another field. This paper attempts to answer the following question: what benefits does a mission to Mars gain by including a 

physician in the crew, and are those benefits essential for crew health and mission success? Is there a medical training level below that 

of a physician that can meet the needs of the crew while accommodating greater knowledge and skill in another area of expertise?long14. SUBJECT TERMS 15. NUMBER OF 

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long duration space flight; medical personnel; physicians; flight surgeons; manned Mars 

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