LGM-25C Titan II

The Titan II was an intercontinental ballistic missile (ICBM) and space launcher developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally used as an ICBM. It was later used as a medium-lift space launch vehicle to carry payloads for the Air Force, National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA). These payloads include the USAF Defense Meteorological Satellite Program (DMSP), the NOAA weather satellites, and NASA's Gemini manned space capsules. The modified Titan II SLVs (Space Launch Vehicles) were launched from Vandenberg AFB, California up until 2003.

Titan II missile
The Titan II ICBM was the successor to the Titan I, and carried a payload twice as heavy. It also used storable propellants, which reduced the time to launch and permitted it to be launched from its silo. Titan II carried the largest single warhead of any American ICBM.

LGM-25C Missile
The missile consists of a two-stage, rocket engine powered vehicle and a Re-entry vehicle (RV). Provisions are included for in-flight separation of Stage II from Stage I, and separation of the RV from Stage II. Stage I and Stage II vehicles each contain propellant and pressurization, rocket engine, hydraulic and electrical systems, and explosive components. In addition, Stage II contains the flight control system and missile guidance set.

Airframe
The airframe is a two-stage, aerodynamically stable structure that houses and protects the airborne missile equipment during powered flight. The missile guidance system enables the shutdown and staging enable relay to initiate Stage I separation. Each stage is 10 feet in diameter and has fuel and oxidiser tanks in tandem, with the walls of the tanks forming the skin of the missile in those areas. External conduits are attached to the outside surface of the tanks to provide passage for the wire bundles and tubing. Access doors are provided on the missile forward, aft and between-tanks structure for inspection and maintenance. A man-hole cover for tank entry is located on the forward dome of each tank.

Stage I airframe
The Stage I airframe consists of an interstage structure, oxidizer tank forward skirt, oxidizer tank, inter-tank structure, and fuel tank. The interstage structure, oxidizer tank forward skirt, and inter-tank structure are all fabricated assemblies utilizing riveted skin, stringers and frame. The oxidizer tank is a welded structure consisting of a forward dome, tank barrel, an aft dome and a feedline. The fuel tank, also a welded structure, consists of a forward dome, tank barrel an aft cone, and internal conduit.

Stage II airframe
The Stage II airframe consists of a transition section, oxidizer tank, inter-tank structure, fuel tank and aft skirt. The transition section, inter-tank structure and aft skirt are all fabricated assemblies utilizing riveted skin, stringers and frame. The oxidizer tank and fuel tank are welded structures consisting of forward and aft domes.

Missile characteristics
The following data is from publication T.O. 21M-LGM25C-1 (Dash 1)

Guidance
The first Titan II guidance system was built by AC Spark Plug. It used an IMU (inertial measurement unit, a gyroscopic sensor) made by AC Spark Plug derived from original designs from MIT Draper Labs. The missile guidance computer (MGC) was the IBM ASC-15. When spares for this system became hard to obtain, it was replaced by a more modern guidance system, the Delco Universal Space Guidance System (USGS). The USGS used a Carousel IV IMU and a Magic 352 computer.

Development
The Titan rocket family was established in October 1955, when the Air Force awarded the Glenn L. Martin Company a contract to build an intercontinental ballistic missile (ICBM). It became known as the Titan I, the nation's first two-stage ICBM and first underground silo-based ICBM. The Martin Company realized that the Titan I could be further improved and presented a proposal to the U.S. Air Force for an improved version. It would carry a larger warhead over a greater range with more accuracy and could be fired more quickly. The Martin company received a contract for the new missile, designated SM-68B Titan II, in June 1960. The Titan II was 50% heavier than the Titan I, with a longer first stage and a larger diameter second stage. The Titan II also used storable propellants, Aerozine 50 and dinitrogen tetroxide. The Titan I, whose liquid oxygen oxidizer must be loaded immediately before launching, had to be raised from its silo and fueled before launch. The use of storable propellants enabled the Titan II to be launched within 60 seconds directly from within its silo. Their hypergolic nature made them dangerous to handle; a leak could (and did) lead to explosions, and the fuel was highly toxic. However, it allowed for a much simpler and more trouble-free engine system than on cryogenically-fueled boosters.

The first flight of the Titan II was in March 1962 and the missile, now designated LGM-25C, reached initial operating capability in October 1963. The Titan II contained one W-53 nuclear warhead in a Mark 6 re-entry vehicle with a range of 9,325 miles (15,000 km). The W-53 had a yield of 9 megatons. This warhead was guided to its target using an inertial guidance unit. The 54 deployed Titan IIs formed the backbone of America's strategic deterrent force until the LGM-30 Minuteman ICBM was deployed en masse during the early to mid-1960s. Twelve Titan IIs were flown in NASA's Gemini manned space program in the mid-1960s.

The Department of Defense predicted that a Titan II missile could eventually carry a warhead with a 35 megaton yield, based on projected improvements. However, that warhead was never developed or deployed. This would have made this warhead one of the most powerful ever, and in terms of power-to-weight ratio, advantageous over the B-41 nuclear bomb by almost double.

Launch history and development
The first Titan II launch was carried out on March 16, 1962 from LC16 at Cape Canaveral and was otherwise successful but for one problem: excessive longitudinal vibrations in the first stage. While this was of little concern to the Air Force, it greatly worried NASA officials who believed that this phenomenon would be harmful to astronauts on a manned Gemini flight. Another three Titan tests were carried out during the summer, and on two of those flights, the second stage engine underperformed. In both cases, the reason for this was different and apparently unconnected. Aside from POGO (the nickname NASA engineers invented for the Titan's vibration problem since it was thought to resemble the action of a pogo stick), the Titan II was experiencing other teething problems that were expected of a new launch vehicle. The July 25 test (Vehicle N-4) had been scheduled for June 27, but was delayed by a month when the Titan's right engine experienced severe combustion instability at ignition that caused the entire thrust chamber to break off of the booster and fall down the flame deflector pit, landing about 20 feet from the pad (the Titan's onboard computer shut the engines down the moment loss of thrust occurred). The problem was traced to a bit of cleaning alcohol carelessly left in the engine. A new set of engines had to be ordered from Aerojet, after which the launch proceeded without any problems.

Although three Titan II tests during September and October met most of their objectives, the nagging POGO problem remained and the booster could not be considered man-rated until this was fixed. Martin-Marietta thus added a surge-suppressor standpipe to the oxidizer feed line in the first stage, but when the system was tested on Titan N-11 on December 6, the effect was instead to worsen POGO in the first stage, which also ended up shutting down prematurely due to the strong vibration.

Vehicle N-13 was launched 13 days later and carried no standpipes, but it did have increased pressure in the first stage propellant tanks, which did cut down on vibration. In addition, the oxidizer feedlines were made of aluminum instead of steel. On the other hand, the exact reason for POGO was still unclear and a vexing problem for NASA.

The tenth Titan II flight (Vehicle N-15) took place on January 10. While it appeared that the POGO problem was largely contained on this flight, the second stage engine again underperformed and the missile only flew half its intended trajectory. While previous second stage problems were blamed on POGO, this could not be the case for N-15. Meanwhile, combustion instability was still an issue and was confirmed by Aerojet static-firing tests which showed that the LR-91 engine had difficulty attaining smooth burning after the shock of startup.

Efforts to man-rate the Titan II also ran afoul of the fact that the Air Force and not NASA was in charge of its development. The former's primary aim was to develop a missile system, not a launch vehicle for Project Gemini, and they were only interested in technical improvements to the booster insofar as they had relevance to that program. On January 29, the Air Force Ballistic Systems Division (BSD) declared that POGO in the Titan had been reduced sufficiently enough for ICBM use and that no further improvements needed to be made. While adding more pressure to the propellant tanks had reduced vibration, it could only be done so much before putting unsafe structural loads on the Titan and in any case the results were still unsatisfactory from NASA's point of view. While BSD tried to come up with a way to help NASA out, they finally decided that it was not worth the time, resources, and risk of trying to cut down further on POGO and that the ICBM program ultimately came first.

Despite the Air Force's lack of interest in man-rating the Titan II, General Bernard Schriever assured that any problems with the booster would be fixed. BSD decided that 0.6 Gs was good enough despite NASA's goal of 0.25 Gs and they stubbornly declared that no more resources were to be expended on it. On March 29, 1963, Schriever invited Space Systems Development (SSD) and BSD officials to his headquarters at Andrews AFB in Maryland, but the meeting was not encouraging. Brig. Gen John L. McCoy (director of the Titan Systems Program Office) reaffirmed BSD's stance that the POGO and combustion instability problems in the Titan were not a serious issue to the ICBM program and it would be too difficult and risky at this point to try and improve them for NASA's sake. Meanwhile, Martin-Marietta and Aerojet both argued that most of the major development problems with the booster had been solved and it would only take a little more work to man-rate it. They proposed adding more standpipes to the first stage and using baffled injectors in the second stage.

A closed-door meeting of NASA and Air Force officials led to the former arguing that without any definitive answer to the POGO and combustion instability problems, the Titan could not safely fly human passengers. But by this point, the Air Force was taking a bigger role in the Gemini program due to proposed uses of the spacecraft for military applications (e.g. Blue Gemini). During the first week of April, a joint plan was drafted which would ensure that POGO was to be reduced to fit NASA's target and to make design improvements to both Titan stages. The program carried the conditions that the ICBM program retained first priority and was not to be delayed by Gemini, and that General McCoy would have final say on all matters.

Meanwhile, the Titan II development program faltered severely during the first half of 1963. On February 16, Vehicle N-7 was launched from a silo at Vandenberg AFB in California and malfunctioned almost immediately at liftoff. An umbilical cord failed to separate cleanly, ripping out wiring in the base of the missile and cutting off power to the guidance system. The Titan began a rapid roll and pitch downward, but due to the power loss, Range Safety was unable to destroy the errant vehicle. Launch crews were terrified that it would fly into a populated area, but finally the tumbling booster broke up when the onboard backup destruct system activated.

While N-18 flew successfully from the Cape on March 21, N-21 again suffered loss of second stage thrust after having been delayed several weeks due to another episode of the first stage thrust chambers breaking off prior to launch. The next four flights (April 27, May 9, May 13, and May 21) were mostly successful, but the last was only the tenth Titan II launch so far where all objectives were met. On May 29, Missile N-20 was launched with a new round of POGO-suppressing devices on board. Unfortunately, a fuel leak caused a fire to break out in the engine compartment soon after liftoff, leading to loss of control and vehicle breakup at T+55 seconds. No useful POGO data was obtained due to the early termination of the flight.

The next flight was a silo test from VAFB on June 20, but once again the second stage lost thrust. At this point, BSD suspended further flights for the time being. Of the 20 Titan launches so far, seven would have required the abort of a manned launch and General McCoy had to make good 12 of the 13 remaining scheduled tests. Since the ICBM program came first, POGO suppression had to be shelved.

On the other hand, only Missile N-11 suffered a malfunction due to POGO and the combustion instability issue had occurred in static firings, but not any actual flights. All Titan II failures save for N-11 were caused by hydraulics or fuel leaks or bad wiring or other problems of that nature. The trouble appeared to be with Aerojet, and a visit of MSC officials to their Sacramento, CA plant in July revealed a number of extremely careless handling and manufacturing processes.



Service history
The Titan II was in service from 1963 to 1987. There were originally 63 Titan II Strategic Air Command missiles. Nine were deployed to Vandenberg AFB training base in California. Eighteen of the missiles were on 24 hour continuous alert surrounding Davis-Monthan Air Force Base near Tucson, Arizona. The remaining missiles were deployed to Little Rock Air Force Base in Arkansas, and McConnell Air Force Base in Wichita, Kansas.

Mishaps
In August 1965, a fire and resultant loss of oxygen when a high-pressure hydraulic line was cut with a torch in a missile silo (373-4) near Searcy, Arkansas killed 53 people, mostly civilian repairmen.

On August 24, 1978, one airman, SSgt Robert Thomas, was killed at a site outside Rock, Kansas when a missile in its silo leaked propellant. Another airman, A1C Erby Hepstall, later died from lung injuries sustained in the spill.

On September 19, 1980, a major mishap occurred after a socket rolled off a platform and punctured the missile's Stage I fuel tank, subsequently causing the missile to collapse. Due to the hypergolic fuels involved, the entire missile exploded a few hours later, killing an Air Force airman, SrA David Livingston, and destroying the silo (374-7, near Damascus, Arkansas). Thanks to the warhead's built-in safety features, it did not detonate. A television movie portrays this event, "Disaster at Silo 7". Author Eric Schlosser published a book centered on the accident, Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety, in September 2013.

Retirement
It is a common misconception that the Titan IIs were decommissioned because of a weapons reduction treaty, but in fact, they were simply aging victims of a weapons modernization program. Because of the volatility of the liquid fuel and the problem with aging seals, the Titan II missiles had originally been scheduled to be retired beginning in 1971. After the two accidents in 1978 and 1980, respectively, deactivation of the Titan II ICBM system finally began in July 1982. The last Titan II missile, located at Silo 373-8 near Judsonia, Arkansas, was deactivated on May 5, 1987. With their warheads removed, the deactivated missiles were initially placed in storage at Davis-Monthan AFB, Arizona and the former Norton AFB, California, but were later broken up for salvage in 2006.

A single Titan II complex belonging to the former strategic missile wing at Davis-Monthan AFB escaped destruction after decommissioning and is open to the public as the Titan Missile Museum at Sahuarita, Arizona. The missile resting in the silo is a real Titan II, but was a training missile and never contained fuel, oxidizer or a warhead.

There is also a surviving silo complex at VAFB which is now a museum, one of three test silos used operationally.

Number of Titan II missiles in service, by year:
 * 1963 - 56
 * 1964 - 59
 * 1965 - 59
 * 1966 - 60
 * 1967 - 63
 * 1968 - 59 (3 deactivated at Vandenberg)
 * 1969 - 60
 * 1970 - 57 (3 more deactivated at Vandenberg)
 * 1971 - 58
 * 1972 - 57
 * 1973 - 57
 * 1974 - 57
 * 1975 - 57
 * 1976 - 58
 * 1977 - 57
 * 1978 - 57
 * 1979 - 57
 * 1980 - 56
 * 1981 - 56 (President Ronald Reagan announces retirement of Titan II systems)
 * 1983 - 53
 * 1984 - 43 (Davis-Monthan site closure completed)
 * 1985 - 21
 * 1986 - 9 (Little Rock closure completed in 1987)

Operational units
Each Titan II ICBM wing was equipped with eighteen missiles; nine per squadron with one each at dispersed launch silos in the general area of the assigned base. See squadron article for geographic locations and other information about the assigned launch sites.


 * 308th Strategic Missile Wing 1 April 1962-18 August 1987
 * Little Rock AFB, Arkansas
 * 373d Strategic Missile Squadron
 * 374th Strategic Missile Squadron


 * 381st Strategic Missile Wing 1 March 1962-8 August 1986
 * McConnell AFB, Kansas
 * 532d Strategic Missile Squadron
 * 533d Strategic Missile Squadron


 * 390th Strategic Missile Wing 1 January 1962-31 July 1984
 * Davis-Monthan AFB, Arizona
 * 570th Strategic Missile Squadron
 * 571st Strategic Missile Squadron


 * 1st Strategic Aerospace Division


 * Vandenberg AFB, California
 * 395th Strategic Missile Squadron, 1 February 1959-31 December 1969
 * Operated 3 silos for technical development and testing, 1963-1969

Note: In 1959, a fifth Titan II installation at the former Griffiss AFB, New York was proposed, but never constructed.

Titan II missile disposition
33 Titan-II Research Test (N-type) missiles were built and all but one were launched either at Cape Canaveral Air Force Station, Florida or Vandenberg AFB, California from March 1962 through April 1964. The surviving N-10, AF Ser. No. 61-2738/60-6817 resides in the silo at the Titan Missile Museum (ICBM Site 571-7), operated by the Pima Air and Space Museum at Green Valley, south of Tucson, Arizona on Interstate-19.

12 Titan-II Gemini Launch Vehicles (GLVs) were produced. All were launched from the then-Cape Kennedy Air Force Station from April 1964 through November 1966. The top half of GLV-5 62-12560 was recovered offshore following its launch and is on display at the U.S. Space & Rocket Center, Alabama.

108 Titan-II ICBM (B-Types) were produced. 49 were launched for testing at Vandenberg AFB from July, 1964 through June, 1976. 2 were lost in accidents within silos. One B-2, AF Ser. No. 61-2756 was given to the U.S. Space & Rocket Center in Huntsville, Alabama in the 1970s.

The 56 surviving missiles were pulled from silos and individual base stores and all transferred to the then-Norton AFB, California during the 1980s. They were stored under plastic coverings and had helium pumped into their engine components to keep them from rusting away. Two buildings at Norton AFB held the missiles, Building 942 and 945. Building 945 held 30 missiles, while Building 942 held 11 plus a single stage 1. The buildings also held extra stage engines and the interstages. 14 full missiles and one extra second stage had been transferred from Norton AFB to the manufacturer, Martin Marietta, at Martin's Denver, Colorado facility for refurbishment by the end of the decade. 13 of the 14 were launched as 23Gs. One missile, B-108, AF Ser. No. 66-4319 (23G-10 the spare for the 23G program), went to the Evergreen Aviation Museum in McMinnville, Oregon. Finally, B-34 Stage 2 was delivered from Norton AFB to Martin Marietta on 28 Apr 1986, but was not modified to a G, nor was it listed as arriving or being destroyed at AMARC at Davis-Monthan AFB, it is therefore unaccounted for within the open source public domain. 42 B-series missiles remained, 41 full and one first stage at Norton AFB, and the second stage at Martin. Of these 38 and one second stage were stored outside at the Aerospace Maintenance and Regeneration Center (AMARC), now known as the 309th Aerospace Maintenance and Regeneration Group (309 AMARG)), adjacent to Davis-Monthan AFB to await final destruction in 2004 thru 2008. Four of the 42 were saved and sent to museums (below).

Air Force Base Silo Deactivation date ranges:
 * Davis-Monthan AFB 10 Aug 82 – 28 Jun 1984
 * McConnell AFB	 31 Jul 1984 – 18 Jun 1986
 * Little Rock AFB 31 May 1985 – 27 Jun 1987

Titan II Movement Dates:
 * Titan II Bs moved to Norton AFB between - 12 Mar 1982 thru 20 Aug 1987
 * Missiles relocated to AMARC at Davis-Monthan AFB prior to Apr 1994 closure of Norton AFB due to BRAC 1989 action
 * Titan II Bs delivered to Martin Marietta/Denver between - 29 Feb 1986 thru 20 Sep 1988
 * Titan II Bs delivered to AMARC - 25 Oct 1982 thru 23 Aug 1987
 * Titan II Bs destroyed at AMARC - 7 Apr 2004 thru 15 Oct 2008
 * Titan II Bs destruction periods at AMARC - 7 Apr 2004 x2; 17 Aug 2005 x 5; 12 Jan - 17 Jan 2006 x 10; 9 Aug 2007 x 3; 7 Oct - 15 Oct 2008 x 18; 2 shipped out to museums, Aug 2009

Official Count: 108 Titan-2 'B' Series Vehicles were delivered to USAF: 49 Test launches, 2 Silo losses, 13 Space launches, 6 in museums, 37.5 destroyed at AMARC, +.5 (one second stage missing B-34) = 108.

Titan-II surviving missiles / Museum locations within the United States:
 * GLV-5, AF Ser. No. 62-12560 top half of Stage 1 was recovered offshore following its launch and is on display at the Alabama Space & Rocket Center in Huntsville, Alabama.
 * N-10 AF Ser. No. 61-2738/60-6817 in the silo at the Titan Missile Museum (ICBM Site 571-7), southwest of Davis-Monthan AFB in Green Valley, Tucson, Arizona.
 * B-2 AF Ser. No 61-2756 at the U.S. Space & Rocket Center, Huntsville, Alabama in the 1970s.
 * B-5 AF Ser. No. 61-2759 at the National Museum of the United States Air Force, Wright-Patterson AFB, Dayton, Ohio
 * B-14/20 AF Ser. No. 61-2768 at the Stafford Museum, Oklahoma
 * B-44/16 AF Ser. No. 62-0025 at the National Museum of Nuclear Science and History adjacent to Kirtland AFB, Albuquerque, New Mexico
 * B-104 AF Ser. No 66-4315 at the Spaceport USA Rocket Garden, Kennedy Space Center, Florida
 * B-108 AF Ser. No. 66-4319 (23G-10 the spare for the 23G program) at the Evergreen Aviation Museum in McMinnville, Oregon

Note: B-34 Stage 2 was delivered from Norton to Martin on 4/28/86 but was not modified to a G, nor was it listed as arriving or being destroyed at AMARC, it is therefore unaccounted for.

Titan II launch vehicle
The Titan II space-launch vehicles were purpose-built as space launchers or are decommissioned ICBMs that have been refurbished and equipped with hardware required for use as space launch vehicles. All twelve Gemini capsules, ten of which were manned, were launched by Titan II launchers. The Titan 23B was a Titan II with an Agena third stage that was used to launch reconnaissance satellites.

The Titan II space launch vehicle is a two-stage liquid fueled booster, designed to provide a small-to-medium weight class capability. It is able to lift approximately 1,900 kg into a circular polar low-Earth orbit. The first stage consists of one ground ignited Aerojet LR87 liquid propellant rocket engine (with two combustion chambers and nozzles but a single turbopump system), while the second stage consists of an Aerojet LR91 liquid propellant rocket engine.

The Martin Marietta Astronautics Group was awarded a contract in January 1986 to refurbish, integrate, and launch fourteen Titan II ICBMs for government space launch requirements. These were designated Titan 23G. The Air Force successfully launched the first Titan 23G space launch vehicle from Vandenberg AFB September 5, 1988. NASA's Clementine spacecraft was launched aboard a Titan 23G in January 1994. All Titan 23G missions were launched from Space Launch Complex 4 West (SLC-4W) on Vandenberg AFB, under the operational command of the 6595th Aerospace Test Group and its follow-on organizations of the 4th Space Launch Squadron and 2nd Space Launch Squadron.