Following a recent thread on dive watches - here is some information relating to NASA specifications. The rest (as they say) is history.

The first qualification program for the NASA watches was conducted in 1965. To be “flight-qualified by NASA for all manned space missions”, a wrist chronograph must pass all of the following tests numerous times without failure of any kind:

  1. High Temperature – 48 hours at a temperature of 160°F (71°C) followed by 30 minutes at 200°F (93°C). For the high temperature tests, atmospheric pressure shall be 5.5 psi (0.35 atm) and the relative humidity shall not exceed 15%.
  2. Low Temperature – Four hours at a temperature of 0°F (-18° C)
  3. Temperature Pressure Chamber – pressure maximum of 1.47 x 10exp-5 psi (10exp-6 atm) with temperature raised to 160°F (71°C). The temperature shall then be lowered to 0°F (-18°C) in 45 minutes and raised again to 160°F in 45 minutes. Fifteen more such cycles shall be completed.
  4. Relative Humidity – A total time of 240 hours at temperatures varying between 68°F and 160°F (20°C and 71°C, respectively) in a relative humidity of at least 95%. The steam used shall have a pH value between 6.5 and 7.5.
  5. Pure Oxygen Atmosphere – The test item shall be placed in an atmosphere of 100% oxygen at a pressure of 5.5 psi (0.35 atm) for 48 hours. Performance outside of specification tolerance, visible burning, creation of toxic gases, obnoxious odors, or deterioration of seals or lubricants shall constitute a failure. The ambient temperature shall be maintained at 160°F (71°C).
  6. Shock – Six shocks of 40g each, in six different directions, with each shock lasting 11 milliseconds.
  7. Acceleration – The test item shall be accelerated linearly from 1g to 7.25g within 333 seconds, along an axis parallel to the longitudinal spacecraft axis.
  8. Decompression – 90 minutes in a vacuum of 1.47 x 10E-5 psi (10 E-6 atm) at a temperature of 160° F (71° C), and 30 minutes at a 200° F (93°C).
  9. High Pressure – The test item shall be subjected to a pressure of 23.5 psi (1.6 atm) for a minimum period of one hour.
  10. Vibration – Three cycles of 30 minutes (lateral, horizontal, vertical, the frequency varying from 5 to 2000 cps and back to 5 cps in 15 minutes. Average acceleration per impulse must be at least 8.8g.
  11. Acoustic Noise – 130dB over a frequency range from 40 to 10,000 HZ, for a duration of 30 minutes.