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

0 2 4 6 8 10 12 14 16

1

7

13

19

25

31

37

43

49

55

61

67

73

79

85

91

97

103

109

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)

Nu

mb

er

of

Ex

po

su

res

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

30

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

8

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

8

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.”