[Illustration: The Titan-Centaur rocket used to launch Voyager stood as tall as a 15-story building and weighed nearly 700 tons. Here the rocket waits for launch at Kennedy Space Center, with the Voyager spacecraft enclosed in the white protective shroud at the top. [P-19471A]]
Within an hour after launch, Voyager 2’s science scan platform boom was to have been fully extended and locked. Instructions to deploy were given, and the boom moved outward; however, there was no signal to indicate that the boom was actually locked in place. Efforts to command the boom to move into the locked position were thwarted by the spacecraft. The first maneuver designed to try to lock the boom was aborted by the computer command subsystem (CCS) when the AACS erroneously indicated that it was in trouble. Three days later another maneuver was scheduled to reprogram the faulty computer in the AACS, to align the Sun sensors, and to try to lock the science boom. To provide a direct check of the boom position, the scan platform was turned so that the TV cameras could see the spacecraft. Careful measurement of these pictures verified that the boom was within ½ degree of full deployment, but still there was no indication that it was locked into place. Ultimately, it was decided that the sensor to signal actuation of the lock was at fault, and that the boom itself was almost certainly fully extended and operational.
Because of the postlaunch problems of Voyager 2, the launch of Voyager 1 was delayed twice—from September 1 to September 3 and then to September 5—in order to inspect Voyager 1’s science boom and to try to prevent a repetition of Voyager 2’s problems. An extra spring was attached to the science boom to assure its full extension. Finally, as if to make up for the troubles of the first launch, Voyager 1’s launch was both “flawless and accurate.” All launch and postlaunch events went smoothly. The launch window opened at 8:56 a.m. EDT, and Voyager took off promptly at 8:56:01. The booms and antennas deployed and locked in the first hours after launch; all instruments scheduled to be on were on and working well.
The two Voyager spacecraft were carried into space and accelerated toward Jupiter by the Titan III-E Centaur rocket, the largest launch vehicle in the NASA arsenal after the retirement of the Saturn rockets in 1975. The Titan and Centaur vehicles were originally developed separately and have been used with other rocket stages for many NASA launches. They were first combined for the two Viking launches to Mars in 1975, and this powerful four-stage launch vehicle was used again in 1977 for Voyager.