"STS-121" . . . . "MPLM (STS-121)" . . . . "STS-121" . "STS\u2013121" . . . "29251" . . . . . "2006-07-17" . "launch" . "2006-07-04" . . "Space Transportation System-115" . . . . . . . . "Space Shuttle STS-121 mission" . "1103874.0" . . . "202" . "return to flight" . "Return to Flight" . . . . . . . "2006-028A" .