Astronomy
Designing Radiation Shielding for Long-Duration Crewed Missions
Quick fact
While a thick aluminum hull seems protective, the primary component of space radiation — galactic cosmic rays — can fragment inside aluminum and produce a shower of secondary particles, sometimes increasing the dose to astronauts beyond what they'd receive with no shielding at all.
Why this is interesting
You might think that the thicker the spacecraft walls, the safer the astronauts. But in space, adding aluminum shielding can actually make the radiation worse — so why do we still use it?