|astronautix.com||Two Apollo CSM fuel cells failed qualification testing|
Two CSM fuel cells failed qualification testing, the first failing after 101.75 hrs of the vacuum endurance test. Pratt and Whitney Aircraft determined that the failure was caused by a cleaning fluid which contaminated and plugged the oxygen lines and contaminated the oxygen gas at the electrodes.
The fuel cell would be rebuilt for qualification testing and test preparation procedures were to be revised.
An internal short circuit occurred in the second fuel cell 16 hrs before the end of the 400-hour qualification test. In spite of the failure the fuel cell met the current Block I mission specification and did not need to be redesigned. References: 16 .