This week’s article: Titan rockets. The first Titan rocket ever launched was in 1959 and the last launched in 2005. The Titan rocket was primarily focused on launching satellites and payloads into orbit, such as the probes of Voyager and Cassini, which helped scientists understand and capture the outer planets in much greater depth. Titan, I was the first Titan rocket made and served as a replacement for the SB-65 Atlas rocket. The Titan I used two LR-87 engines to power it (engine powered by RP-1 kerosene and LOX), and included a second stage that was powered by an LR-91 engine. The final ignition of this rocket would occur in 1965 when the ICBM model was transferred to the Titan II version. Titan II had a modified version of the LR-87 engine which contained hypergolic fuels that could be stored in liquid form in preparation for a launch. A variation known as the Titan II GLV rocket was used to launch the Gemini capsules and had the same layout of two LR-87 engines and one LR-91 on the upper stage. The first launch was on April 8th, 1964, and had 12 successful launches. Many of the Titan ICBM rockets were decommissioned, yet Titan II 23G was used for space transportation. The Titan II 23G had 13 successful launches with the first one being in September 1988 and the last being in 2003. Both The Titan I and II models were used as ICBMs developed by Glenn L. Martin company (Lockheed Martin) before being discontinued in 1987, where Titan rockets were then primarily used for satellite lifts.
Titan III added two solid rocket boosters on either side of the first stage to add more thrust while the second stage would consist of either an Agena or Centaur upper stage depending on the payload. Titan IIIA launched 4 times, the first being a failure on September 2nd, 1964. However, the next three launches were successful. This rocket model of the Titan III had the same features, yet a Transtage upper stage which was used for over 45 different launches for the Titan rockets. 1966 marked the first launch of Titan IIIB, which used an RM-81 Agena upper stage instead of the Transtage. Titan IIIC launched beforehand in 1965, consisting of the first use of strap-on rocket boosters on a Titan vehicle and a Transtage upper stage. Titan IIID followed without the Transtage, yet has 22 successful launches from 1971 to 1982 and would be used to lift satellites to low Earth orbit. The Titan IIIE used a Centaur upper stage and lifted some of the most popular-known probes into space. This rocket sent both Voyagers, as well as the Viking program, carrying space probes to study Mars. This rocket launched 7 times from 1974 to 1977 with only one failure from its first launch attempt. One separate Titan variation was the Titan 34D, which was first ignited in 1982, and would go on to feature many different upper stages including Transtage upper stage, an Inertial upper stage, or no upper stage.
Titan IV was the final variation of the Titan rocket operated by the U.S. Air Force and manufactured by Lockheed Martin and used like the Titan III: space-launch vehicles delivering payloads to space. The Titan IVA was capable of being equipped with multiple upper stages: Inertia, Centaur, or none. The rocket flew 22 times with 2 failures with its first launch on June 8th, 1990, and its last flight being August 12th, 1998. A year before the final launch of Titan IVA (February 23rd, 1997), the Titan IVB was released, with the same build as the Titan IVA. However, the solid rocket boosters attached would ignite first, and the core engines (LR-87) wouldn’t ignite until around 2 minutes when the strap-on boosters started to detach from the rocket. This rocket had hypergolic propellants on both stages and was launched on October 19th, 2005. 17 out of 17 launches of the Titan IVB were successful between 1997 and 2005 and carried probes on Centaur stages, occasionally with the Inertial upper stage. This rocket went on to be the largest expendable launch vehicle developed by the U.S. Air Force until its retirement.