Evidence Evidence
Human Research Program Evidence
The NASA Human Research Program (HRP) Evidence is a collection of evidence-based risk reports or cited journal articles for each individual risk contained within the HRP Program Requirements Document (PRD). Thus, this set of reports provides the current record of the state of knowledge from research and operations for each of the defined human health and performance risks for future NASA exploration missions. The Evidence Reports provide a brief review article containing the evidence related to a specified risk, written at a level appropriate for the scientifically-educated, non-specialist reader. (For more information regarding the overview and evolution of the evidence, see Evidence Book Overview.)
As an adjunct to these HRP-approved Evidence Reports, a Wiki site has been developed as an online collaborative environment that was developed to enable authors internal and external to NASA to update the evidence base for the HRP risks. This collaboration site provides the opportunity to generate more timely updates to the evidence base, and a peer review process is employed to ensure quality and validity of information.
Behavioral Health and Performance
Risk of Adverse Behavioral Conditions and Psychiatric Disorders
Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team
Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload
Exploration Medical Capability
Risk of Unacceptable Health and Mission Outcomes Due to Limitations of In-flight Medical Capabilities
Human Health Countermeasures
Concern of Clinically Relevant Unpredicted Effects of Medication
Risk Factor of Inadequate Nutrition
Risk of Bone Fracture
Risk of Cardiac Rhythm Problems
Risk of Crew Adverse Health Event Due to Altered Immune Response
Risk of Decompression Sickness
Risk Of Early Onset Osteoporosis Due To Spaceflight
Risk of Impaired Control of Spacecraft, Associated Systems and Immediate Vehicle Egress Due to Vestibular/Sensorimotor Alterations Associated with Space Flight
Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance
Risk of Ineffective or Toxic Medications Due to Long Term Storage
Risk of Injury and Compromised Performance due to EVA Operations
Risk of Injury from Dynamic Loads
Risk of Intervertebral Disc Damage
Risk of Orthostatic Intolerance During Re-Exposure to Gravity
Risk of Reduced Physical Performance Capabilities Due to Reduced Aerobic Capacity
Risk of Renal Stone Formation
Risk of Spaceflight-Induced Intracranial Hypertension/Vision Alterations
Space Human Factors and Habitability
Risk of Adverse Health Effects Due to Alterations in Host-Microorganism Interactions
Risk of Adverse Health Effects of Exposure to Dust and Volatiles During Exploration of Celestial Bodies
Risk of an Incompatible Vehicle/Habitat Design
Risk of Inadequate Critical Task Design
Risk of Inadequate Design of Human and Automation/Robotic Integration
Risk of Inadequate Human-Computer Interaction
Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System
Risk of Performance Errors Due to Training Deficiencies
Space Radiation
Risk of Acute and Late Central Nervous System Effects from Radiation Exposure
Risk of Acute Radiation Syndromes Due to Solar Particle Events (SPEs)
Risk Of Cardiovascular Disease and Other Degenerative Tissue Effects From Radiation Exposure
Risk of Radiation Carcinogenesis

EVIDENCE BOOK OVERVIEW

A. Evolution of the Evidence Book

The original Evidence Book is a collection of Evidence Reports created from the information presented verbally and discussed within the NASA HRP in 2006. In April of 2008, the 2008 Evidence Book was reviewed by the members of the Committee on NASA's Research on Human Health Risks, established by the Institute of Medicine (IOM). The resulting thorough Review of NASA's Human Research Program Evidence Books: A Letter Report (2008) provided guidance for both the revision of the current risk evidence reports and for the development of future versions. It is publicly available via the National Academies Press website.

Per the recommendations of the IOM Review, the Evidence Report information was made publicly available. The method was either to publish the content of selected reports in multiple specialized journals or to publish a subset of the reports in a collection, forming a NASA Special Publication entitled the HRP Evidence Book 2008. The specialized journal publications containing the Evidence Report information were revised and reviewed per the specifications of the particular journals in which they were published.

Since this original publication, the HRP Elements have continued to update each risk Evidence Report given results from ongoing research and technology development (R&TD) tasks. The HRR contains the most up-to-date Evidence Reports in the above table.

HRP Evidence Book
An archived publication entitled The Human Health and Performance Risks for Space Exploration Missions, issued in 2009, is available for reference. Download a copy by clicking this link.

B. Spaceflight and Ground-Based Evidence

Each risk Evidence Report contains a narrative discussion of the risk and its supporting evidence. All cited publicly-available references are listed at the end of the report. In addition, data that are significant or pivotal are summarized in text, tables, and charts in sufficient detail to allow the reader to critique and draw conclusions. The authors also indicate whether the data are from human, animal, or tissue, cellular, or molecular studies. The reports discuss evidence from both spaceflight (including biomedical research, Medical Requirements Integration Document [MRID] data, and operational performance or clinical observations) and ground (including space analog research and non-space analog biomedical or clinical research) research. When providing evidence from ground-based studies, authors discuss why these results are likely to be applicable in the space environment, offering any available validation information for the use of these ground-based systems.

C. Categories of Evidence

To help characterize the type of evidence provided in the reports, authors are encouraged to label evidence according to the "NASA Categories of Evidence". These categories indicate whether data are from two possible types of controlled experiments, are observational, or are expert opinion. As shown below, the NASA categories are compared with a more familiar version of a scale for levels of evidence. The use of a coordinated data categorization system is new to many NASA life scientists, but authors are encouraged to use such a system to help clarify the type of evidence presented and thus provide some additional information about the strength of interpretations derived from those data. They are not required to use the categorization system hierarchically.

Broad "Experimental" Design Type Silagy & Haines Levels of Evidence* (for comparison only) NASA Categories of Evidence
Controlled Ia. Meta-analysis of randomized trials I. At least one randomized, controlled trial
Ib. At least one randomized trial
IIa. At least one controlled study without randomization II. At least one controlled study without randomization, including cohort, case-control, or subject operating as own control
IIb. At least one other type quasi-experimental study
Observational III. Non-experimental descriptive studies, e.g. comparative correlation, or case studies III. Non-experimental observations or comparative, correlation, and case or case-series studies
Opinion IV. Expert committee reports or opinions or clinical experiences of respected authorities IV. Expert committee reports or opinions of respected authorities based on clinical experiences bench research, or "first principles"

*Source: Silagy C, Haines A. Evidence Based Practice in Primary Care, 2nd ed., London: BMJ Books, 2001.

D. Computer-Based Simulation Information

Mathematical modeling and computer simulation provide another type of information distinct from experimental evidence, observation, and expert opinion that can support decision making, including the identification of risks. In the Evidence Reports, authors present the results of simulations, the types of models used, and the reasoning that supports the acceptance of the modeling and simulation results as valid and appropriate in the situation of interest. Appropriate references to papers or reports describing the types of verification to which models were subjected and the validation methods used are also provided.