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Wednesday, 16 October 2019 
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Physical Sciences

Introduction
Physical sciences are any of the sciences, such as physics, chemistry, astronomy and geology that analyze the nature and properties of energy and nonliving matter.  

The risks of exposure to space radiation are the most significant factor limiting humans ability to participate in long-duration space missions. Learning from experiments in space and developing a better understanding of the effects of space radiation on human is an important element in space exploration.


Radiation
Physical sciences are any of the sciences, such as physics, chemistry, astronomy and geology that analyze the nature and properties of energy and nonliving matter. The risks of exposure to space radiation are the most significant factor limiting humans' ability to participate in long-duration space missions. 

Learning from experiments in space and developing a better understanding of the effects of space radiation on human is an important element in space exploration.

Background
The primary radiation risk to astronauts arises due to induced cancer for which organ level dose equivalent measurements are required. The issue in assessing radiation risk in manned spaceflight is related to the estimation of organ level dose-equivalent. Currently, both experimental and operational methods are limited to the measurement of surface (skin) dose.

Organ level dose is conservatively estimated by calculations using the radiation environment model and the appropriate radiation transport models. If the accuracy of these models were refined, the more experienced astronauts would be less flight limited by measured, accrued skin dose. 

Objectives
The overall goal of the Torso experiment is to develop the capability to accurately calculate organ-absorbed dose and dose equivalent in humans exposed to ionizing space radiation. This experiment proposes using a fully instrumented phantom torso (with head) to provide the necessary depth-dose-equivalent measurements. 

Depth-dose-equivalent measurements will be taken as a function of spacecraft altitude, attitude, location and time.  Measurements internal to the phantom torso will be supported by other radiation measurements from the Tissue Equivalent Proportional Counter and the Charged Particle Direction Spectrometer. The hardware for this experiment consists of three major pieces Similar equipment was flown on earlier shuttle missions.

a) The Phantom Torso itself is a tissue-muscle plastic equivalent anatomical model of a male head and torso comprised of 35 sliced "sections" housed in a Nomex suit.  Each section is connected via a system of pins and holes.  Voids within the phantom are used for active and passive radiation detectors. 

The five small active dosimeters are located at strategic radiobiological points of interest (head, neck, heart, stomach and colon) within the phantom and will provide real time measurements.    
   
b) A Tissue Equivalent Proportional Counter (TEPC) will be placed near the phantom to measure external dose.  This instrument provides an efficient method of determining radiation dose and dose-equivalent in complex (mixed) radiation fields.  It records the linear energy spectra for determining dose-equivalent exposures. 

c) A Charged Particle Direction Spectrometer (CPDS) will be placed near the phantom to measure particle energy and direction in the same general environment as the TEPC.  Since the interactions of heavy ions and their secondaries with tissue are not at all well understood, proton and heavy ion spectra both incident upon and inside the spacecraft will be measured. 

 

Media


Radiation Suite


Radiation Suite


Radiation Suite

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