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Steve Blattnig

Publications and source records attributed to Steve Blattnig.

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

Evaluation of Multiple Methods for Calculating Gray Equivalent

The assessment of different algorithms to determine the Gray-Equivalent as defined in NASA-STD-3001 from a source of space radiation has been evaluated in this paper. The Gray-Equivalent applies an RBE (Relative Biological Effectiveness) to the dose seen at the organ of interest in a human phantom. The current design basis solar particle event was used in the assessments along with the August 1972 event modeled by J.H. King and with idealized spheres and two vehicle designs. Three different algorithms were used and compared. One of the algorithms was the current OLTARIS algorithm. This algorithm is astronaut orientation averaged, which is not what happens in a storm shelter during a solar particle event. Two other algorithms were proposed to eliminate this issue. It is clear that either algorithm will be adequate to satisfy NASA-STD-3001 requirements. This work recommends the algorithm which applies the RBEs to the phantom points instead of at the surface of the phantom as with the current OLTARIS algorithm.

Gray Equivalent↗
NASA NTRSDate not supplied

Planned Investigations to Address Acute Central Nervous System Effects of Space Radiation Exposure with Human Performance Data

This work intends to generate evidence of acute, incremental human performance decrement similar to that due to space radiation and its impacts on the brain, to accompany ongoing human performance modeling work. The planned work will explore the boundaries of human behavioral and performance decrement after expo-sure to stress, which may be expected based in part on rodent responses found after exposure to ionizing radiation. The collection of evidence via simulation studies can characterize real human errors toward determining what stress levels lead to significantly-low levels of performance (below permissible outcome limits) which would imperil mission accomplishment. If mission-relevant yet animal-study-linked tasks are used, human and animal performance levels may be aligned to enable quantitative assignment of permissible exposure limits based on animal exposure studies. Ultimately, a transfer function between the performances of exposed rodents and humans under stress can be developed using shared impairment mechanisms.

human performance↗
NASA NTRSDate not supplied

An Approach to Quantitative Risk Assessment for Combined Spaceflight Hazards: Evaluating the Impact of Short Sleep Durations on Space Crew Cardiovascular Health

Astronauts embarking on long-duration missions will be exposed to multiple spaceflight hazards including radiation, isolation and confinement, distance from Earth, hostile closed environments, and altered gravity. These hazards pose health risks to the crew in-mission and postflight, including risks to cardiovascular health. For radiation, quantitative risk models have been developed that are based on large-scale epidemiological evidence from exposed terrestrial populations, which are extrapolated to account for the difference in radiological effectiveness between ground-based and in-flight exposures. •Cardiovascular diseases (CVD) are multifactorial, therefore multiple risk factors can influence disease risk estimates. •Astronauts with spaceflight experience is a very small population. •To overcome limitations of cohort, population data from presumed equivalent stressors on Earth can be used to quantitatively assess possible risks. •Sleep disruption and short sleep duration are known consequences of spaceflight and are also established risk factors for cardiovascular disease on earth (Pateletal.,2020). •Coronary Heart Disease (CHD), Myocardial Infarction (MI), and stroke are negative health effects due to short sleep durations and sleep disruptions (Yinetal.,2017); (Cappuccio et al., 2010). •A combined CVD risk model including spaceflight stressor such as sleep, stress, radiation, etc.) will provide more precise estimate of risks.

Spaceflight Hazards↗