The Saturn I (SA-6) launch was an unmanned vehicle development test flight. It was the first flight of a boilerplate model of the Apollo spacecraft. The primary objective was further qualification of the Saturn I launch vehicle and continued development of the technology necessary to build the more powerful Saturn IB and Saturn V launch vehicles. Spacecraft and Subsystems The Saturn 1 launch vehicle was a two-stage booster with the Apollo payload attached to the S-IV second stage. The Apollo payload was a boilerplate command and service module (BP-13) . The command module was an aluminum structure simulating the size, weight, shape, and center of gravity of a crewed Apollo command module. It was a roughly 340 cm high conical structure with a base diameter of 391 cm, and was covered with cork insulation to prevent overheating. A 305 cm high escape tower was mounted on top to support a 464 cm dummy launch escape motor. The service module was a 391 cm diameter, 315 cm long aluminum structure mounted beneath the command module. It was attached to an insert section, which was attached to an adaptor section, which remained with the instrument unit and S-IV second stage. The Apollo boilerplate had a mass of 7700 kg, the entire Apollo-instrument unit-second stage payload had a mass of 16,900 kg in orbit and was 24.4 meters long. The spacecraft was instrumented for 116 measurements such as strain, pressure, and acceleration and carried three telemetry systems. Mission Profile After launch, one of the eight first-stage H-1 engines shut off 24 seconds early, but the remaining seven engines burned an additional two seconds to compensate, and the guidance system corrected for course deviations. The final orbital parameters for the upper stage and attached Apollo spacecraft were very close to those predicted. The spacecraft spin rate of 28 degrees per second was faster than desired, caused by venting of propellant residuals. All spacecraft systems operated as planned during countdown and flight. Telemetry was obtained from 106 measurements until end of battery life on the fourth orbit. Eight movie cameras mounted on the Saturn I recorded propulsion and fuel operations, were ejected, and recovered. The spacecraft re-entered Earth's atmosphere on 1 June 1964 on its 50th orbit.