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Radiation dose from reentrant electrons
G D Badhwar1, J Watts, T E Cleghorn
1NASA Lyndon B. Johnson Space Center, SN, 2101 NASA Road 1 Houston, TX 77058-3696, USA. gautam.d.badhwar@jsc.nasa.gov
Radiation Measurements
|February 22, 2002
Summary
Reentrant electrons, previously ignored in space radiation exposure assessments, significantly increase crew radiation dose during spacewalks (extravehicular activity). Even with added shielding, these high-energy electrons pose a substantial risk to blood-forming organs.
Area of Science:
- Space radiation physics
- Astrobiology and space exploration
Background:
- Crew exposure during extravehicular activity (EVA) is a critical concern in space missions.
- The contribution of reentrant electrons to radiation dose has been historically underestimated.
Purpose of the Study:
- To quantify the dose contribution of reentrant electrons to crew exposures during EVA.
- To evaluate the effectiveness of shielding against reentrant electron radiation.
Main Methods:
- Utilized measured reentrant electron energy spectra for dose calculations.
- Assessed dose contribution to blood-forming organs (BFO).
- Analyzed dose-depth response to shielding.
Main Results:
- Reentrant electrons contribute over 10 times more dose to BFO than trapped electrons.
- The energy spectrum of reentrant electrons extends to several GeV, far exceeding trapped electrons.
- Dose-depth response is a slowly changing function, limiting shielding effectiveness.
Conclusions:
- Reentrant electrons are a significant, previously neglected, source of radiation dose during EVA.
- Current shielding strategies may be insufficient to mitigate the risks posed by reentrant electrons.
- Further research into advanced shielding or operational strategies is warranted to protect astronauts.
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