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Shielding and Mitigation

Shielding Materials​

Aluminum​

  • Usage: Common structural material in spacecraft.
  • Advantages: Provides baseline protection against electrons and protons.
  • Limitations: High atomic number (Z) can lead to secondary particle production when interacting with high-energy cosmic rays, potentially increasing radiation dose beyond the shield.

Polyethylene (PE) and Hydrogen-Rich Materials​

  • Usage: Often used in crew habitats and sensitive equipment areas.
  • Advantages:
    • High hydrogen content effectively attenuates protons and neutrons.
    • Produces fewer secondary particles compared to high-Z materials.
  • Applications: Incorporated into sleeping quarters and galley areas on the ISS to reduce crew exposure.

Composite Materials​

  • Examples: Carbon fiber reinforced plastics, boron nitride nanotubes.
  • Advantages:
    • Combine structural strength with radiation shielding properties.
    • Some composites offer up to 1.9 times the dose reduction compared to aluminum.
  • Considerations: Research is ongoing to optimize these materials for space applications.

Multi-Layer Insulation (MLI)​

  • Usage: Thermal insulation blankets with potential radiation shielding benefits.
  • Advantages:
    • When combined with materials like fiberglass and polyethylene, MLI can enhance radiation protection.
    • Used in configurations such as the "stuffed Whipple shield" to protect against micrometeoroids and radiation.

Geometric Shielding​

Strategic Component Placement​

  • Concept: Positioning sensitive electronics deep within the spacecraft or behind naturally shielding components (e.g., fuel tanks).
  • Benefits:
    • Passive reduction of radiation exposure.
    • Utilizes existing mass for dual purposes, optimizing spacecraft design.

Dedicated Shielded Compartments​

Operational Mitigation Strategies​

Mission Timing and Trajectory Planning​

  • Approach:
    • Schedule missions during solar minimum to reduce exposure to solar particle events (SPEs).
    • Design trajectories that minimize time spent in high-radiation zones like the Van Allen belts and the South Atlantic Anomaly (SAA).

Real-Time Monitoring and Response​

  • Systems:
    • Onboard dosimeters and radiation sensors to monitor exposure levels.
    • Ground-based solar activity monitoring to predict SPEs.
  • Actions:
    • Implement "storm shelters" within spacecraft for crew protection during SPEs.
    • Adjust spacecraft orientation or operations based on real-time radiation data.