Gagarin.   The Gemini program cost $5.4 billion. Missions   There were 12 Gemini flights, including two unmanned flight tests. All were launched by   Titan II   rockets. Unmanned Mission LV  Serial N o Mission Dates Launch Time Duration Remarks Gemini 1 GLV-1 12556 8 April-12, 1964 16:01   UTC 03d 23h First