Gemini TitanNASA Gemini Titan rocket model. NASA selected the Titan II as the launch vehicle for the Gemini spacecraft in December of 1961. This was two months after the merger between The Martin Company (who designed and built the Titan I missile) and American Marietta created Martin Marietta. One month later, a contract was drawn up and work started in Martin Marietta's plant in Baltimore. The first flight test took place on April 8th of 1964, when GLV 1 lifted