A study of thin‐film penetration by micrometeoroids on Gemini 9 and 12

A thin copper surface was flown on the Gemini 9 capsule, June 3–6, 1966, with a sampling area of 3.23 × 10−4 m² and an exposure time of 17 hours and 47 minutes. Two thin surfaces, one of gold and one of aluminum, were flown on the Gemini 12 capsule, November 11–14, 1966, each with sampling areas of 7.06 × 10−4 m² and exposure times of 6 hours and 24 minutes. There was no evidence of impact with extraterrestrial particles on any of the surfaces. Early sounding rocket and satellite data would lead to the prediction that 10 particles 5 µ or larger would have impacted the sampling surface on the Gemini 9 capsule during exposure, and 16 particles would have impacted each sampling surface on Gemini 12. This prediction has not been supported.