Titan 23G

Quick Facts About the Titan 23G:

- Type: Expendable launch system.

- Origin : United States.

- In service : 5 September 1988 - 18 October 2003.

- Mass : 117,020 kg (257,980 lb).

- Length/Height : 31.4 m (103 ft).

- Diameter : 3.05 m (10.0 ft).

- Payload to LEO : 3,600 kg (7,900 lb).

- Payload to HCO : 227 kg (500 lb).

- Propellant: N2O4 / Aerozine 50

- Engines: First stage: 1 LR-87 with thrust of 1,900 kN (430,000 lbf), Second stage: 1 LR-91 with thrust of 445 kN (100,000 lbf), Third stage ( Star-37XFP-ISS optional): 1 Solid with thrust of 38.03 kN (8,550 lbf).

Retired Titan II missiles were converted by Martin Marietta, into which the Glenn L. Martin Company, which built the original Titan II, had merged. It was used to carry payloads for the United States Air Force (USAF), NASA and National Oceanic and Atmospheric Administration (NOAA). Thirteen were launched from Space Launch Complex 4W (SLC-4W) at the Vandenberg Air Force Base between 1988 and 2003.

Titan 23G rockets consisted of two stages burning liquid propellant. The first stage was powered by one Aerojet LR87 engine with two combustion chambers and nozzles, and the second stage was propelled by an LR91. On some flights, the spacecraft included a kick motor, usually the Star-37XFP-ISS; however, the Star-37S was also used.

A contract to refurbish fourteen Titan II missiles to the Titan 23G configuration was awarded to Martin Marietta in January 1986. The first launch occurred on 5 September 1988, carrying a classified payload for the U.S. National Reconnaissance Office. Thirteen were launched, with the fourteenth going to the Evergreen Aviation Museum. The final flight occurred on 17 October 2003, carrying a Defense Meteorological Satellite Program (DMSP) satellite.

During refurbishment, the forward structure of the second stage was modified with the addition of a payload attachment fitting to attach the payload to the rocket, and installing a payload fairing to protect it during launch. The engines were refurbished, and the rockets' guidance and control systems were upgraded by Delco Electronics.

The former Titan IIIB pad at Vandenberg, SLC-4W, was modified to accommodate the Titan 23G, and was used for all thirteen launches.