 In December , the second Block I flight AS @-@ 205 was canceled as unnecessary ; and Schirra , Eisele and Cunningham were reassigned as the backup crew for Apollo 1 . McDivitt 's crew was now promoted to prime crew of the Block II / LM mission , re @-@ designated AS @-@ 258 because the AS @-@ 205 launch vehicle would be used in place of AS @-@ 207 . A third manned mission was planned to launch the CSM and LM together on a Saturn V ( AS @-@ 503 ) to an elliptical medium Earth orbit ( MEO ) , to be crewed by Frank Borman , Michael Collins and William Anders . McDivitt , Scott and Schweickart had started their training for AS @-@ 258 in CM @-@ 101 at the NAA plant in Downey , California , when the Apollo 1 accident occurred . 
