AS-201 February 26, 1966

Launch Vehicle: Saturn-1B

Duration: 36 minutes, 59 seconds. Suborbital

Distance: 5264 miles (8472 kilometers)

Altitude: 303 miles (488 kilometers)

The AS-201 mission demonstrated the structural integrity of the Saturn 1B rocket and the compatibility of the launch vehicle to carry Apollo loads. It successfully tested the separation of the first and second stages of the rocket and tested the operations of Saturn's propulsion, guidance and control, and electrical subsystems.

There were several malfunctions, only three were serious. First, after the service propulsion system fired, it operated correctly for only 80 seconds. Then the pressure fell 30 percent because of helium ingestion into the oxidizer chamber. Second, a fault in the electrical power system caused a loss of steering control, resulting in a rolling reentry. Third, flight measurements during reentry were distorted because of a short circuit.

AS-203 July 5,1966

Launch Vehicle: Saturn-1B

The AS-203 reached an altitude of about 113 miles (180 kilometers). The mission was flown to evaluate the performance on S-IVB instrument unit stage under orbital conditions and to obtain flight information on venting and chill-down systems, fluid dynamics and heat transfer of propellant tanks; attitude and thermal control system, launch vehicle guidance, and checkout in orbit. These goals were all achieved. The craft was not recovered.

AS-204 August 25, 1966

Launch Vehicle: Saturn-1B

Duration: 33 min, 28 seconds

Altitude: 708 miles (1,143 Kilometers)

The third test of the Saturn-Apollo configuration, AS-204 demonstrated the strength or the rocket to withstand launch and carry necessary payloads, and tested the separation of Saturn's first and second stages. It further tested the protective cover for the Command Service Module (CSM) and Lunar Module (LM). The launch further verified Saturn's propulsion, guidance and control, and electrical subsystems, and tested the reentry. All objectives were achieved.

Apollo 4 November 9, 1967

Launch Vehicle: Saturn V

Duration: 8 hours, 36 min, 59 seconds, with 4 orbits.

The first test of the Saturn V configuration which was comprised of the S-IC first-stage booster, and the S-II second stage. The first stage alone combined the firepower of five F-1 engines -- the most powerful rocket engines made -- to give the Saturn V rocket 7.5 million pounds of thrust.

The initial two stages of the Saturn rocket were used to boost the spacecraft into Earth orbit, but Apollo machines needed an extra boost to escape the planet's gravity and start toward the moon. This was the job of the third-stage Saturn-IV B (S-IVB). It could be fired several times to reach its target. During the flight, the first two stages functioned properly for the most part, separating as planned, and placing the craft into Earth orbit. Controllers then fired the S-IVB third stage to propel the Apollo vessel into a simulated translunar trajectory. The Service Propulsion System (SPS) was also successfully tested. The SPS is the rocket attached to the lunar command module -- the large bell-shaped engine that sticks out from one end of the cylinder-shaped spacecraft. It is the engine that would be used to enter and escape lunar orbit, and bring astronauts home to Earth. This rocket pushed the craft up to an altitude of 11,208 miles (18,079 kilometers).

Apollo 5 January 22, 1968

Launch Vehicle: Saturn-1B

The first launch of the Apollo Lunar Module (LM), Apollo 5 was flown to verify operation of the Lunar Module's ascent and descent propulsion systems, to evaluate the performance of the S-IVB third stage rocket. After the initial two rocket stages put the Apollo payload into orbit, the S-IVB would be fired to provide an escape from Earth orbit and send the Apollo craft to the moon. All mission objects achieved.

Apollo 6 April 4, 1968

Launch Vehicle: Saturn V

Duration: 10 hours, 22 min, 59 seconds

The second launch of a Saturn V, overall, was not considered a success by NASA planners. During the firing of the first-stage F-1 engines, there were severe oscillations resembling the bounce of a pogo-stick. Then, two second-stage J-2 engines shut down prematurely. Later, after Apollo 6 reached orbit, the third stage J-2 engine failed to re-ignite for a simulated "translunar injection." Controllers decided to use the spacecraft's Service Propulsion System (SPS) engine in its place. The SPS engine burn sent the spacecraft to an altitude of 13,769 miles (22,209 kilometers). Apollo 6 pointed out the need for several "fixes" before humans could fly on the Saturn V.

Source: NASA