Adding more shielding to a spacecraft can actually increase the radiation dose for astronauts
Science
Thick spacecraft walls can inadvertently increase radiation exposure by triggering nuclear spallation, where high-energy cosmic rays strike dense shielding and shatter into a cascade of dangerous secondary particles.
Excessive shielding on spacecraft creates a hazardous paradox where adding mass actually increases the biological dose of radiation for astronauts. When high-energy galactic cosmic rays strike dense materials like lead or aluminum, they trigger nuclear spallation—a process that shatters atomic nuclei into a secondary shower of neutrons and protons. This secondary radiation is often more biologically damaging than the original primary particles.