Mission to Mars:
Health Risk Mitigation
Rich Williams
NASA Chief Health and Medical Officer
Societal Imperatives
• National Security Imperative
• Public Safety Imperative
• Human Exploration Imperative
Risk Mitigation in an
Occupational Environment
• Crew selection standards
– Waivers are routine
• Engineering controls
• Exposure limits standards
– In general, no waivers granted
• Personal protection, countermeasures
• Medical/environmental monitoring
Risks: The Space
Environment
temperature
extremes
vacuum
Isolation &
confinement
mg
c
i 49,000,000 km
r
c
a 22 minute 1-way
d communication
i
Biorhythms?
a
n
mg
temperature
extremes
vacuum
New geoecosystem
Isolation &
confinement
Space Flight Experience
(continuous)
Flights longer than 28 days (May 1973 - June 2012)
109
103
Most long-duration flights
are 4-7 months long
97
91
Number of
Exposures
85
79
73
67
61
55
Mars missions may last
up to 30 months
49
43
37
31
25
19
13
7
1
0
2
4
6
8
10
12
14
16
Flight Duration
(months)
30
Time Course of Physiological Changes
in Weightlessness
Mars Radiation Exposure
Comparing Solar Max and Solar Minimun
1 Sv = ~ 100 Rem
Person at Sea level ~ 1.4 Rem/yr
ISS Crew member ~ 5.4 Rem/6 months
Mars Crew member ~20-85 Rem
Visual Impairment/Elevated
Intracranial Pressure
Background:
19 known “clinical cases” of 25 evaluated crew members
Each with different degrees of symptoms
•Choroidal
Folds - parallel
•Hyperopic Shifts
-Up to +1.75 diopters
grooves in the posterior
pole
•Optic Disc Edema (swelling
•Globe Flattening
•Altered Blood flow
MRI Orbital
Image
showing
globe
flattening
Normal Globe
Flatten Globe
•“cotton wool” spots
•Increased Optic Nerve
Sheath Diameter
8
Martian Surface Analysis:
Curiosity
Martian Dust Analysis:
Curiosity
Behavioral Health
Seeing Earth through a
telescope from Mars
Earth and Jupiter from the Martian surface
NASA Health and Medical
Policies
• NASA ground workforce health and safety is regulated by
OSHA
– Executive Order 12196, February 26, 1980, Occupational Safety and
Health Programs for Federal Employees
• NASA environmental health issues are regulated by EPA
• NASA public use vehicle operations (research aircraft,
spacecraft) are controlled by NASA policy directives,
procedural requirements, standards and requirements
• NASA health and medical policies and standards “regulate”
aircrew and space flight crew selection, qualification, and
health related requirements in NASA research aircraft and
spacecraft
NASA Health Standards for
Human Spaceflight
• NASA STD-3001 Vol. 1: NASA Space Flight Human System
Standard - Volume 1: Crew Health
–
–
–
–
–
–
–
4.2.3 Fitness-for-Duty Aerobic Capacity Standard
4.2.4 Fitness-for-Duty Sensorimotor Standard
4.2.5 Fitness-for-Duty Behavioral Health and Cognition Standard
4.2.6 Fitness-for-Duty Hematology and Immunology Standard
4.2.7 Permissible Outcome Limit for Nutrition Standard
4.2.8 Permissible Outcome Limit for Muscle Strength Standard
4.2.9 Permissible Outcome Limit for Microgravity-Induced Bone
Mineral Loss Performance Standard (Baseline with Measured Tscore)
– 4.2.10 Space Permissible Exposure Limit for Space Flight Radiation
Exposure Standard
Ethical Considerations of
Exploration Class Missions
• Exceeding exposure limits is justified only if the
benefit to the population is greater than the risk to
the individual
• Examples:
– Radiation workers can exceed exposure limits to contain
nuclear power plant contingencies
• Generally defined in the radiation exposure standards
– Military members can exceed radiation dosage limits if
driven by necessity
Ethical Considerations of
Exploration Class Missions
• How do we approach increased health risks for
exploration class missions?
– Liberalize exposure limits for exploration class missions
– Waive exposure standards for exploration class missions
– Administrative risk acceptance by higher authorities
• Informed consent?
• How is health risk acceptance influenced by overall
mission risk?
National Academies:
Institute of Medicine
• Committee on Aerospace Medicine and the
Medicine of Extreme Environments (CAMMEE)
– Ethics, Principles and Guidelines for Health Standards
for Long Duration and Exploration Spaceflights
Institute of Medicine Study
• What factors should be considered in the implementation of
current health standards in exploration class missions?
• What ethical considerations are involved when exposures/risks
are uncertain and exposures may exceed current standards?
• How should informed consent be applied?
• What are appropriate modifiers for standards when
risks/exposures are uncertain?
• Should all crewmembers be protected to the same extent or
should potential individual differences be considered?
• Are there models or examples that could inform NASA
strategy?
Human Health & Performance
HHP
Component
30 months Stay total
Comments
Physiological
Countermeasures
• 0-g transit phases well within
experience base (esp. outbound)
• 3/8-g surface phase outside
experience base
• Outbound similar to 6 month ISS
missions
• How much will the 3/8 surface
phase add to human physiologic
tolerance?
• Level of Deconditioning leaving
Mars and ease of rehab on
mission home
Human Factors &
Habitability
• Access to Surface Habitat
• Atmosphere – supplies,
dependability, communications
• Replacement parts
Radiation
• Prolonged exposure to poorlyunderstood surface mixed-field
(neutrons and charged particles)
environment
• Solar max travel - lower cosmic
radiation
• Safe haven for solar flares
• Radiation protection on Mars
Behavioral Health
& Performance
• Increased risk due to longer overall
duration
• Family events
Medical
Capabilities
• Increased risk due to longer overall
duration
• Anticipation of required health
care
• Preparing for the trauma and
other unexpected illness
NASA Policy Formulation
• Federal Government Policy
– Statutes, Regulations, Executive Orders/Presidential
Directives
• NASA Agency Policy
– NASA Policy Directives
– NASA Procedural Requirements
– NASA Standards
• Plans, Requirements
– Programmatic (Space Shuttle, International Space Station)
• Project (External Tank, Shuttle Main Engines, etc)
– Mission Support
NASA Internal Regulation
• Established by the National Aeronautics and Space Act of
1958 “To provide for research into problems of flight within
and outside the earth's atmosphere, and for other purposes.”
• 51 USC 20113(a): In the performance of its functions the
Administration is authorized-– (1) to make, promulgate, issue, rescind, and amend rules and
regulations governing the manner of its operations and the exercise of
the powers vested in it by law;
• The NASA Administrator is authorized to promulgate internal
NASA policies governing operations within the Agency
• Health and medical policy formulation, promulgation, and
oversight is delegated to the Chief Health and Medical Officer
NASA Health Standards for
Human Spaceflight
• “In this document, the Office of the Chief Health and Medical
Officer establishes NASA’s space flight crew health standards
for the pre-flight, in-flight, and post-flight phases of human
space flight.”
• “Although the standards are applicable to the in-flight phase of
all space missions, it is anticipated that they will be most
relevant during long-duration lunar outpost and Mars
exploration missions, since the combined ill effects of
exposure to the space environment will be of most concern in
those mission scenarios.”