Would it be possible to carry a spare fuel cell onboard the shuttle for emergencies?
ANSWER from Chuck Davis on May 12, 1997: One of the main reasons there are three fuel cells is redundancy. It only takes one to power the orbiter to get it home. We want two operating when coming home just in case one quits during critical re-entry maneuvers. This is why STS-83 was brought home early after one fuel cell failed. As for in-orbit replacement of a defective fuel cell, this would be an extraordinarily difficult task. The three fuel cells are located beneath the curved floor of the payload bay. On the ground, access is difficult for a technician in street-clothes and would be far worse, it even possible at all, for an astronaut in his/her spacesuit. There are no spare fuel cells carried on-board during a mission. Redundant systems are intended to provide in-place, ready-to-use spare parts for the orbiter. Return to top.
