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 TITAN/CENTAUR LAUNCH VEHICLE 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. The Titan/Centaur stands nearly 50 meters tall, about the height of a fifteen-story building. Fully fueled, it weighs nearly 700 tons. At takeoff, the thrust of the two solid-propellant Stage-0 motors is about 10.7 million newtons. These motors, which burn for 122 seconds, use powdered aluminum as fuel and ammonium perchlorate as oxidizer. Together, they have a mass of 500 tons. The first stage of the liquid propellant core of the Titan rocket ignites about 112 seconds after takeoff. The propellant is hydrazine as fuel and nitrogen tetroxide as oxidizer. The first stage is 3 meters in diameter and 20 meters tall. Fueled, it has a mass of 130 tons. The motor provides a thrust of 2.5 million newtons for a duration of 146 seconds. About 4.3 minutes after takeoff the Titan Stage II liquid propellant motor begins to fire, and the first stage is separated and falls back into the Atlantic. The second stage is 3 meters in diameter and more than 7 meters long, with a fueled mass of 35 tons. The single liquid fuel motor burns for 210 seconds with a thrust of half a million newtons. During the second stage burn, the shroud covering the Voyager spacecraft is jettisoned.