Mission to Mars: Health Risk Mitigation
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Transcript of Mission to Mars: Health Risk Mitigation
Mission to Mars:Health Risk Mitigation
Rich WilliamsNASA 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
49,000,000 km
22 minute 1-way communication
g
g
1 yr
1 yr
temperatureextremes
Isolation &confinement
vacuum
Isolation &confinement
temperatureextremes
vacuum
Water & food
availability
Fuel & oxygen
Reduced gravity
New geo-ecosystem
Radiation
circadian
Biorhythms?
Risks: The Space Environment
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Space Flight Experience (continuous)
Space Flight Experience (continuous)
Flights longer than 28 days (May 1973 - June 2012)Flights longer than 28 days (May 1973 - June 2012)
Flight Duration (months)
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Ex
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Most long-duration flights Most long-duration flights are 4-7 months longare 4-7 months long
Mars missions may last Mars missions may last up to 30 monthsup to 30 months
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Time Course of Physiological ChangesTime Course of Physiological Changesin Weightlessnessin Weightlessness
Mars Radiation ExposureComparing Solar Max and Solar Minimun
1 Sv = ~ 100 RemPerson at Sea level ~ 1.4 Rem/yr
ISS Crew member ~ 5.4 Rem/6 monthsMars Crew member ~20-85 Rem
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Visual Impairment/Elevated Intracranial Pressure
Background: 19 known “clinical cases” of 25 evaluated crew membersEach with different degrees of symptoms
MRI Orbital Image showing globe flattening
Normal Globe Flatten Globe
•Choroidal Folds - parallel grooves in the posterior pole
•Globe Flattening
•Optic Disc Edema (swelling)
•Altered Blood flow•“cotton wool” spots
•Hyperopic Shifts-Up to +1.75 diopters
•Increased Optic Nerve Sheath Diameter
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Martian Surface Analysis: Curiosity
Martian Dust Analysis: Curiosity
Seeing Earth through a telescope from Mars
Earth and Jupiter from the Martian surface
Behavioral Health
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 & PerformanceHHP
Component30 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 poorly-understood 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.”