Alan Shepard explosion caused the moon landing to be aborted and nearly resulted in the loss of the crew. It became a joke between Shepard and Lovell, who would offer to give Shepard back the mission each time they bumped into each other. The failure of Apollo 13 delayed Apollo 14 until 1971 so that modifications could be made to the spacecraft. The target of the Apollo 14 mission was switched to the Fra Mauro formation, the intended destination of Apollo 13. Shepard made his second space flight as Commander of Apollo 14 from January 31 to February 9, 1971. It was
Spacecraft call signs the three-man crews to name both craft for each of their missions, and these names were used as the call signs. A temporary exception to this was on the first Moon landing, Apollo 11: since the first Moon landing site was in the Sea of Tranquillity, the call sign "Tranquillity Base" was used while the LM was on the lunar surface. Before and after independent flight of the LM, the mission number was used as the call sign. The Apollo call signs were: For project Skylab, the practice returned to using the mission name as the spacecraft call sign, since