Physiology: Integrative gravitational physiology

Human Physiology

57th ESA Parabolic Flight Campaign

23 October 2012

U. Walter ⁽¹⁾, T. Dirlich ⁽¹⁾, C. Plank ⁽¹⁾, S. Diehl ⁽¹⁾, B. Werner ⁽¹⁾, M. Kollmar ⁽¹⁾

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This experiment was performed by the Hydronauts2Fly team within ESA's educational programme: "Fly Your Thesis! - An Astronaut Experience". The Fly Your Thesis! programme gives university students the possibility to fly their scientific experiment in microgravity, as part of their Masters thesis, PhD thesis or research programme, by participating in a series of parabolic flights. In total, three teams of postgraduate students were flying their experiments during the 2012 'Fly Your Thesis!' campaign.

Prime goal of the Hydronauts2Fly Team and their experiment is the investigation and definition of the human neutral body posture. The aerospace students from the Technische Universität München want to find out which position the human body adopts while relaxing under zero gravity environment, what is called the Neutral Body Posture - NBP. Due to neutralization of the gravity force in space and onboard parabolic flights, the human body does not have to make any efforts working against it. As a result its muscles and body limbs will rest in a different posture in space than on earth, similar to the posture of embryos.
With this experiment the Hydronauts2Fly team is studying the neutral body posture of different persons in order to find out whether or not there is a mutual position for test subjects with different body masses and sizes. And if so, is it predictable?

Prior to the parabolic flight each test subject had to undergo a procedure of underwater tests, similar to the one on flight.
The gathered data is then inputted into a self-made mathematical software algorithm which helps us to make better assumptions of how the human body will rest in weightlessness.
The parabolic flight campaign with data from real microgravity will help us to verify the software code and our NBP-predictions. This will help us to improve the software in order to be able to use underwater data as a true alternative to expensive parabolic flights in the future. Our research may also be used to develop the next generation of space suits.
During the Parabolic Flight, the test subject is located in the center of our experiment surrounded by three cameras, recording its movement for post-flight analyses. The persons will be suited to a harness which is then fixed to the experimental rack on the floor of the plane in order to prevent them from uncontrollably floating through the aircraft during micro gravity so they will not leave the designated zone detected by our sensors and cameras. They will be wearing a harness system which is fixed by magnets to a linear sliding system equipped with springs. This will allow them to lie on the padded floor during 1G and 1.8G periods and to be lifted up to about 40cm above floor level during 0G. The springs are designed to lift our heaviest subject in microgravity and to allow our lightest to lie during the rest. Our subject will be blindfolded and wearing headphones to prevent distractions from sight and noise since the brain would automatically react to these disturbances which will lead to contraction of the muscles and therefore will no longer be in a truly relaxed state. At the beginning of each low G period the subject will be asked to perform little efforts like a stretch or a crunch and then to relax. This relaxed state will be monitored by our cameras, one from above and two from the side with a 90 degree angle. After the flight the data will be put into a multi-body-simulation software to compare the results to the ones gathered during underwater testing.

APPLICATIONS OF THE RESEARCH
Our research will be used to detect the quality of underwater tests as means to predict the human body’s behavior in low gravity and will help make alterations to the multi body simulation program to improve the results. It will also help making improvements to space suits since designers will have a better understanding of the body’s posture in space.

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