MSC invited 11 firms to submit research and development proposals for the lunar excursion module (LEM) for the manned lunar landing mission. The firms were Lockheed Aircraft Corporation, The Boeing Airplane Company, Northrop Corporation, Ling-Temco-Vought, Inc., Grumman Aircraft Engineering Corporation, Douglas Aircraft Company, General Dynamics Corporation, Republic Aviation Corporation, Martin- Marietta Company, North American Aviation, Inc., and McDonnell Aircraft Corporation. Additional Details: here....