The second Gemini mission, an unmanned suborbital flight designated Gemini-Titan 2 (GT-2), was successfully launched from complex 19 at Cape Kennedy at 9:04 a.m., e.s.t. Major objectives of this mission were to demonstrate the adequacy of the spacecraft reentry module's heat protection during a maximum-heating-rate reentry, the structural integrity of the spacecraft from liftoff through reentry, and the satisfactory performance of spacecraft systems. Secondary objectives included obtaining test results on communications, cryogenics, fuel cell and reactant supply system, and further qualification of the launch vehicle. All objectives were achieved, with one exception: no fuel cell test results were obtained because the system malfunctioned before liftoff and was deactivated. GT-2 was a suborbital ballistic flight which reached a maximum altitude of 92.4 nautical miles. Retrorockets fired 6 minutes 54 seconds after launch, and the spacecraft landed in the Atlantic Ocean 11 minutes 22 seconds later - 1848 nautical miles southeast of the launch site. Full duration of the mission was 18 minutes 16 seconds. The primary recovery ship, the aircraft carrier Lake Champlain, picked up the spacecraft at 10:52 a.m., e.s.t.

During the countdown for Gemini-Titan (GT) 2, the fuel cell hydrogen inlet valve failed to open. Efforts to correct the problem continued until it was determined that freeing the valve would delay the countdown. Work on the fuel cell ceased, and it was not activated for the flight. The fuel cell installed in spacecraft No. 2 was not a current flight design. When fuel cell design was changed in January 1964, several cells of earlier design were available. Although these cells were known to have some defects, flight testing with the reactant supply system was felt to be extremely desirable. Accordingly, it was decided to fly the entire system on GT-2, but only on a "non-interference with flight" basis. When it became clear that correcting the problem that emerged during the GT-2 countdown would cause delay, fuel cell activation for the flight was called off. References: 26 , 42 .