What was one major environmental factor NASA required watches to withstand during the early 1960s selection process?

Answer

Intense vibrations

NASA required watches to withstand extreme environmental variations, which explicitly included intense vibrations, along with high and low temperatures, humidity, and rapid depressurization.

What was one major environmental factor NASA required watches to withstand during the early 1960s selection process?
watchspace explorationApolloMoon landingOmega Speedmaster