National Aeronautics and Space Administration

Glenn Research Center

Harkirat Sohi Research Project

Validation of the Software Backbone of the NASA Digital Astronaut Project.

Research Associate: Harkirat Sohi

Principal Investigator: Beth Lewandowski

Background: The health and well-being of astronauts during spaceflight missions is critical to the success of the missions. From previous missions it has been learned that astronauts experience physiological changes and challenges as a result of being in space, such as motion sickness and weight loss early in the mission; muscle atrophy, bone loss, increased risk of kidney stones and high levels of radiation exposure during long duration missions; and loss of balance and orthostatic intolerance upon return to Earth. Since experimental data on these physiological phenomena resulting from space travel is scarce, computational models are used to predict the physiological responses of the body for a given set of parameters representing space conditions.

The Quantitative Human Physiology (QHP) software is a comprehensive computational model of systemic human physiology. The software has been under continuous development for over 20 years at the University of Mississippi Medical Center. QHP has been primarily used during this time as a teaching tool for medical students and validation efforts to date have been qualitative. The Digital Astronaut Project at NASA is using QHP as the software backbone of a computational model that is capable of making predictions about the physiological changes astronauts experience in space under a given set of conditions. However, before the software can be used to make any predictions, it must be quantitatively validated in order to ensure that the results obtained from the simulations in the QHP software are accurate and reliable.

Goal: To perform a validation study of the QHP software by quantitatively comparing experimental data to the output of the software resulting from a simulation using the conditions with which the experimental data was collected. Once validated, the QHP software will serve as the software backbone of the Digital Astronaut Project at NASA.

Future Implications: Once the QHP Software has been validated as reliable software for running simulations of human health responses to different environmental and physiological conditions, the software will be used to predict the physiological responses that the astronauts may have under the space conditions. Such predictions will help provide information for mission planning and decision making.

Specific Goals:

  1. Become familiar with the QHP Software environment so that simulations can be performed effectively and efficiently.
  2. Extract the experimental protocol and resulting data from several published studies on human physiology responses to various conditions, including some with space flight conditions. This involves reading several journal articles in which these studies are described, digitizing the data and developing a step by step guide for simulating the experiment in the QHP software.
  3. Quantitatively compare the results obtained from the QHP software to the experimental data, using a validation metric and uncertainty quantification. The quantitative comparison will follow the methods outlined in: Oberkampf WL, Barone MF, Measures of agreement between computation and experiment: Validation metrics, Journal of Computational Physics, 217, pp. 5-36, 2006.

Suit Impact Load Attenuation Study (SILAS)

Goal: To assess the efficiency of the space suit material in protecting against impacts that astronauts may experience during their time in space.
Specific Goals:

  1. I will be assisting in setting up and running the experiments to measure the attenuation of the space suit material.