was the original raison d'être for the Titan IIIB's existence, as well as its primary payload, the booster was also used for Jumpseat SIGINT satellites and military comsats. It also lived up to its promise of greater reliability than the Thor and Atlas, with only a few failures over its run. Primary function: Launch vehicle used to lift medium class satellites into space: Builder: The Martin Company Launch site: Vandenberg AFB, Calif. First stage: Length: Diameter: 10 feet (3.05 m) Engine thrust: vacuum Weight: Fueled Empty weight: Second stage: Length: Diameter: Engine Thrust: vacuum Weight: Fueled Empty weight: Third stage: Length: Diameter: Engine thrust: vacuum Weight: – fueled Empty Weight: Guidance: Radio Subcontractor: GE Payload fairing: Diameter: Length: Skin and Stringer ConstructionTri-Sector Design Subcontractor: Boeing Date deployed: July 1966 Titan 23B Titan 23B used the basic Titan 3A core (including its Transtage) with an Agena D upper stage, though without the all-inertial guidance system, malfunction detection equipment, and redundant systems required for man-rating the 3A. The Titan 23B was launched from SLC-4W at Vandenberg AFB, Calif. Its main payload was the GAMBIT (KH-8 reconnaissance) satellites, in 9 flights from 1969 through 1971. Titan 24B The Titan 24B differed from the Titan 23B in that the Titan IIIM core with extended propellant tanks was used in place of the original Titan II core. The payload remained attached to the Agena stage. 23 flights took place from 1971 to 1984, with two failures. Titan 33B The Titan 33B was a Titan 23B with the entire Agena and payload completely enclosed in a shroud. It flew only three times (1971–73) with one failure and was used to launch Jumpseat satellites. Titan 34B The Titan 34B was a Titan 24B, modified by the addition of the larger fairing used on the Titan 33B. 23 were launched in 1971–87 with two failures. All launches consisted of KH-8 satellites. Failures Titan IIIB rockets suffered four outright failures, and two partial failures. The first failure occurred on 26 April 1967 during the launch of a Gambit 3 satellite when the second stage suffered a sudden thrust decay which left it unable to achieve orbital velocity, sending the Agena and GAMBIT into the Pacific Ocean some 400 miles (644 km) downrange. It was not possible to determine the cause of the malfunction with certainty, but a fuel line obstruction was believed to be the most likely explanation. Martin-Marietta