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 Apollo1. 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 crewed mission was planned to launch the CSM and LM together on a SaturnV (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 Apollo1 accident occurred.