However , Alan Shepard , then number 2 at the Astronaut office , gave himself the Apollo 13 command slot instead .
By the normal rotation in place during Apollo , the backup crew would have been scheduled to fly on Apollo 13 .
Alan Shepard , then number 2 at the Astronaut office , gave himself the Apollo 13 command slot instead .
By the normal rotation in place during Apollo , the backup crew would have been scheduled to fly on Apollo 13 .