 The astronauts ' widows asked that Apollo 1 be reserved for the flight their husbands never made , and on April 24 , 1967 , Associate Administrator for Manned Space Flight , Dr. George E. Mueller , announced this change officially : AS @-@ 204 would be recorded as Apollo 1 , " first manned Apollo Saturn flight – failed on ground test " . Since three unmanned Apollo missions ( AS @-@ 201 , AS @-@ 202 , and AS @-@ 203 ) had previously occurred , the next mission , the first unmanned Saturn V test flight ( AS @-@ 501 ) would be designated Apollo 4 , with all subsequent flights numbered sequentially in the order flown . The first three flights would not be renumbered , and the names Apollo 2 and Apollo 3 would go unused . 
