Titan 34D

The Titan 34D was a United States expendable launch vehicle used to launch a number of satellites for military applications.

Derived from the Titan III, the Titan 34D featured Stage 1 and Stage 2 stretched with more powerful UA1206 solid motors. A variety of upper stages were available, including the Inertial Upper Stage, the Transfer Orbit Stage, and the Transtage. The Titan 34D made its maiden flight in the year of 1982 on the 30th of October with two DSCS defense communications satellites for the United States Department of Defense (DOD).

All of the launches were conducted from either LC-40 at Cape Canaveral Air Force Station or SLC-4E at Vandenberg Air Force Base. Overall, fifteen launches were carried out, of which three failed.

The first failure was the launch of a KH-11 photoreconnaissance satellite in the year 1985 on the 28th of August. The core stage suffered a propulsion system malfunction and was destroyed by Range Safety. The flight proceeded normally until the core engine starts at T+108 seconds. At T+112 seconds, an abnormal start transient occurred and Engine 2 began experiencing thrust decay. At T+212 seconds, Engine 1 shut down, causing a loss of attitude control. The onboard computer shut off Engine 2 at T+256 seconds and began a premature separation and ignition of Stage 2. With the Titan now tumbling and headed back towards land, the destruct command was issued at T+272 seconds and the KH-11 crashed into the Pacific Ocean. During Stage 1's powered flight, the oxidizer tank began leaking N₂O₄ which was thought to have resulted in the loss of lubrication to the Engine 1 turbopump and breakdown of the pinion gear. The attempts by the Navy to salvage booster debris from the ocean floor were largely unsuccessful. Investigators also complained that tracking camera coverage during the core stage burn was inadequate.

Titan 34D-7 was the first failed launch of a solid motor-equipped Titan vehicle from Vandenberg (there have been several failures from Cape Canaveral over the years) and was particularly vexing because of inadequate launch data. The Titan III's flawless West Coast launch record meant that the Air Force felt confident enough to remove several telemetry measurements from the boosters in the interest of reduced weight and complexity. There had evidently been leaks from both the fuel and oxidizer tanks, as well as suspicion hinged on clamps that held the propellant feed lines in place. However, the clamps had not failed on any previous launches so it was not clear why they would suddenly fail now. Some members of the investigative board even proposed that the SRBs had suffered an exhaust gas leak which caused damage to the core stage. As evidence, they noted that a piece of cork insulation had broken off one SRB shortly after launch. The official cause of the failure was "Leakage of oxidizer resulting in loss of turbopump lubrication and breakdown of the pinion gear." However, most of the members of the investigative team were unsatisfied with this verdict.

As a result of 34D-7, the Air Force took measures to ensure that a repeat failure would not occur. These included reinstalling some of the deleted telemetry probes on the Titan as well as improved camera coverage; the next launch would even have the aircraft flying overhead to provide additional photography.

Titan 34D-9 was launched 18 April 1986 at Vandenberg AFB. Instead of the advanced KH-11 satellite carried on 34D-7, this booster carried the older model KH-9 in what would be the final launch of that satellite and the final launch of a film capsule photoreconnaissance satellite by the United States. Lifting off at 10:45 AM Pacific Time, the Titan catastrophically exploded just above SLC-4E, showering the launch complex as well as the adjacent SLC-4W (used for Titan IIIB launches) with debris and toxic propellant.

The investigation indicated the right solid rocket motor rupturing starting at T+6 seconds with the resulting torque on the launch vehicle caused the left SRM to break away. This triggered its automatic destruct system, blowing Stage 1 to pieces and rupturing Stage 2's N₂O₄ tank. The upper stages were ejected and launched through the air until a manual destruct command was sent by the range safety officer at T+20 seconds. The KH-9 was also blown up by its internal self-destruct mechanism, which was designed to destroy the classified satellite in the event of a launch malfunction. Debris rained onto SLC-4E, badly damaging the launch complex in the process and starting numerous small fires, some of which burned for up to two days. Extracting launch personnel from the blockhouse proved difficult due to the area around the pad being filled with toxic fumes and burning debris. The casing rupture had damaged the Inadvertent Separation Destruct System (ISDS) lanyards and prevented proper destruction of the SRM, which came down largely intact onto a concrete structure near the pad, which was unoccupied at the time of launch.