Space radiation dosimetry in low-Earth orbit and beyond

Area of Science:

• Space radiation
• Radiation protection
• Dosimetry

Background:

• Space radiation environments in Low-Earth Orbit (LEO) and interplanetary space are complex and pose significant challenges for astronaut safety.
• Instrument design constraints in spaceflight further complicate accurate radiation dosimetry.
• Decades of spaceflight have yielded valuable, yet incomplete, dosimetric data.

Purpose of the Study:

• To review the sources and composition of space radiation environments.
• To present a review of dosimetric data gathered over four decades of human spaceflight.
• To emphasize factors affecting astronaut radiation exposure, particularly on the International Space Station (ISS).

Main Methods:

• Review of existing literature and dosimetric data from human spaceflight.
• Analysis of factors influencing crew dose and dose equivalent on the ISS.
• Examination of secondary particle production and shielding effects within spacecraft.

Main Results:

• Approximately 50% of the ISS dose originates from trapped protons, with the other 50% from galactic cosmic rays (GCRs).
• Secondary particle production and spacecraft shielding significantly impact crew dose.
• Significant uncertainties exist in neutron measurements, crucial for dose equivalent estimations.
• Limited crew dosimetry data exists beyond Earth's magnetosphere, necessitating reliance on models for interplanetary missions.

Conclusions:

• Accurate space radiation dosimetry remains a significant challenge, impacting radiation protection strategies.
• Interplanetary missions, such as to Mars, may expose astronauts to dose equivalents approaching recommended limits.
• Further advancements in dosimetry and modeling are essential for ensuring crew safety on future deep space missions.