Apollo astronauts experienced "lunar hay fever" from Moon dust, causing sore throats, watery eyes, and respiratory symptoms that lasted days. Lunar dust contains sharp, abrasive silicate particles that can penetrate deep into lungs and remain for months, potentially causing toxic effects. Unlike Earth dust smoothed by erosion, lunar particles are spiky and electrostatically charged from solar radiation, making them levitate and more likely to enter equipment and lungs. ESA is researching the health risks using volcanic dust simulants from Germany to prepare for future lunar missions.