OBJECTIVES:
Currently, US astronauts return to Earth aboard the Soyuz spacecraft. Recent evidence has shown that the occurrence of injuries in crewmembers landing in the Soyuz spacecraft is higher than predicted by current models. There are several possible explanations for this trend: the landing impacts are harder than predicted, current models do not accurately capture the true injury risk, space flight deconditioning decreases the crewmembers’ tolerance to impact, or some combination of the three. In addition, NASA and commercial companies are developing three new capsule-type spacecraft in which crewmembers will be subjected to a landing impact at the end of the mission. To improve the understanding of Soyuz crewmember injury risk, as well as risk to future crew onboard the Orion, SpaceX Dragon2, and Boeing CST-100, the researchers propose a computational study, which will assess the injury risk to Soyuz crewmembers in a direct and relative sense.
Soyuz landings with midsize male human body finite element (FE) models will be simulated, and injury risk predictions will be correlated with actual injury outcomes observed from the HRP-funded Soyuz Landing
Injury Risk Characterization Study (Soyuz_Impact_Risk). Afterwards, relative risk between the different
vehicles will be determined by comparing outcome data from new simulations of Soyuz landings
to previous mid-size male human body FE results from the HRP-funded ATD Injury Metric
Sensitivity and Extensibility Study (ATD_Sensitivity_Study).
This study has the following specific aims:
1) Identify expected injury risks associated with Soyuz nominal and off-nominal landing scenarios.
2) Examine differences in injury risk to crew as a function of seat / restraint and loading combinations between Soyuz and modern vehicle designs.
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APPROACH:
A FE model of the Soyuz seat will be developed from CAD or 3D scans and appropriate material models. The Global Human Body Models Consortium 50th percentile male simplified (M50-OS) and detailed (M50-O) occupant models will be positioned in the seat. Acceleration pulses from previously conducted drop tests of the Soyuz vehicle will be used as boundary conditions. Head, neck, spine, chest, pelvis, and extremity injury risks will be assessed using established metrics. The researchers will leverage previous work on injury risk to crew in the seats of the three modern vehicles. Data from that study which describes the impact event will be the basis of 140 new simulations with the Soyuz seat model to create a robust set of comparative data in various impact scenarios. Differences in response between the simplified and detailed male models will be quantified. Matched simulation comparisons will be conducted using polynomial regression. Differences in predicted injury risk between the Soyuz and modern vehicles will be statistically determined using a students’ matched t-test.
RESULTS:
The project will yield novel scientific knowledge on crewmember injury risk associated with landing events in the Soyuz, Orion, Dragon2, and CTS-100 vehicles. The work will also produce validated analytical tools including a Soyuz seat FE model with mid-size male human body FE models which can be used to verify occupant safety of crewmembers in impact conditions. By achieving the aims of the work, the study will advance the overall understanding of crewmember injury risk due to dynamic loads encountered in spacecraft landings, and produce validated computational models which can be used to predict the associated occupant injury risk when the Soyuz and modern spacecraft vehicle designs are subjected to various dynamic loading events.
Crew health and performance is critical to successful human exploration beyond low Earth orbit.
The Human Research Program (HRP) investigates and mitigates the highest risks to human health
and performance, providing essential countermeasures and technologies for human space exploration.
Risks include physiological and performance effects from hazards such as radiation, altered gravity,
and hostile environments, as well as unique challenges in medical support, human factors,
and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify
the approach and research activities planned to address these risks, which are assigned to specific
Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.
The Human Research Roadmap is located at:
https://humanresearchroadmap.nasa.gov/
+ Click here for information of how this experiment is contributing to the HRP's path for risk reduction.
