TLV-5304 was removed from storage and began modification to serve as the launch vehicle for the ATDA. The standard mission of the Atlas standard launch vehicle (SLV-3) was to place an Agena into a specified coast ellipse. The ATDA mission, however, required the SLV-3 to place the target into a direct-ascent Earth orbit. This called for numerous modifications. The necessity for such modifications had been anticipated when the ATDA program was initiated after the Agena failure on October 25, 1965. By March 1, 1966, there were ATDA kits ready at the Cape to modify any SLV-3 for an ATDA mission to be launched within 18 days from go-ahead. In fact, it took only 14 days. Modification was complete May 20, TLV-5304 was erected at complex 14 on May 21, TLV and ATDA were mated May 25, and all launch preparations were completed by May 30. The launch took place on June 1, the 15th day following the TLV-5303 failure.