HGM-25A Titan I

The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage Intercontinental Ballistic Missile (ICBM). Incorporating the latest design technology when designed and manufactured, the Titan I provided an additional nuclear deterrent to complement the U.S. Air Force's SM-65 Atlas missile. It was the first in a series of Titan rockets, but was unique among them in that it used LOX and RP-1 as propellants, while the later Titan versions all used storeable fuels instead. Though the SM-68A was operational for only three years, it was an important step in building the Air Force's strategic nuclear forces.

Origins
The program began in January 1955 and took shape in parallel with the Atlas (SM-65/HGM-16) intercontinental ballistic missile (ICBM). The Air Force's goal in launching the Titan program was twofold: one, to serve as a backup should Atlas fail; and two, to develop a large, two-stage missile with a longer range and bigger payload that also could serve as a booster for space flights.

The Titan I was initially designated SM-68; it was later redesignated HGM-25A.

Characteristics
Produced by the Glenn L. Martin Company (which became "The Martin Company" in 1957), Titan I was a two-stage, liquid-fueled missile. The first stage delivered 300,000 pounds (1,330 kN) of thrust, the second stage 80,000 pounds (356 kN). The fact that Titan I, like Atlas, burned RP-1 and LOX meant that the oxidizer had to be loaded onto the missile just before launch from the underground storage tank, and the missile raised above ground on the enormous elevator system, exposing the missile for some time before launch. The complexity of the system combined with its relatively slow reaction time – fifteen minutes to load, raise and launch the first missile, made it a less effective weapon system.

Titan I utilized radio command guidance. The inertial guidance system originally intended for the missile was instead eventually deployed in the Atlas E missile. (The Atlas series was intended to be the first generation of American ICBMs and Titan II (as opposed to Titan I) was to be the second generation deployed). An inertial guidance system would have allowed Titan I, once launched, to guide itself independently to a pre-programmed target. It would not have relied upon continuous radio command signals from a ground location, or upon the ability to receive and react to such signals.

Titan I also was the first true multi-stage (two or more stages) design. Whereas in Atlas, all rocket engines were ignited at launch (including two small thrust vernier engines) due to the unreliable nature of the engines, Titan I’s second stage engines were reliable enough to be ignited at altitude, after separation from the first stage booster; and its fuel tanks, engines, launch interface equipment, and launch pad thrust ring. Titan I’s ability to jettison this mass prior to the ignition of the second stage, meant that Titan I  had a much greater total range (and a greater range per pound of second stage fuel) than Atlas, even if the total fuel load of Atlas had been greater.

The Titan I had an effective range of 5,500 nautical miles (10,200 km). When the first stage had finished consuming its propellant, it dropped away, thereby decreasing the mass of the vehicle. That made for a more efficient missile, which resulted in increased range and enabled a larger payload.

The warhead of the Titan I was an AVCO Mk 4 re-entry vehicle containing a W38 thermonuclear bomb with a yield of 3.75 megatons which was fuzed for either air burst or contact burst. The Mk 4 RV also deployed penetration aids in the form of mylar balloons which replicated the radar signature of the Mk 4 RV.

Research and development
The Titan-1 was tested in a comprehensive test program prior to deployment. From the first successful launch on 5 February 1959 with Titan-1 A3 through to 29 January 1962 Titan-1 M7. There were seven variants of the Titan-1 Research and Development missile: six A-types (four launched) seven B-types (two launched), six C-types (five launched), ten G-types (seven launched), 22 J-types (22 launched), four V-types (four launched), seven M-types (seven launched). 62 produced (49 launched and two exploded). They were tested and launched at Cape Canaveral Air Force Station from Launch Complexes LC15, LC16, LC19 and LC20.

Operational deployment
Titan-1 Strategic Missile (SM) production began during the final stages of the Research and Development program. In total, 101 Titan-1 SMs were produced to be tested from underground silos at Vandenberg Air Force Base and then stationed in silos in six squadrons of nine missiles each across America. Fifty-four missiles in silos in total, with one missile as a spare on standby at each squadron, bringing to 60 in service at any one time.

The Titan I was first American ICBM based in underground silos, and it gave USAF managers, contractors and missile crews valuable experience building and working in vast bunkers containing everything the missiles and crews needed for operation and survival. The complexes were composed of a control center, powerhouse, and two antenna silos for the ATHENA guidance radars.

These early silos, however, had certain drawbacks. First, the missiles took about 15 minutes to fuel, and then had to be lifted to the surface on huge elevators for launching, which slowed their reaction time. Rapid launching was crucial to avoid possible destruction by incoming missiles, even though Titan shelters were designed to withstand nuclear blasts. Second, the missiles' placement close together in groups of three—necessary because they shared a single ground-based radio guidance system—made them vulnerable to nuclear attack. All-inertial guidance, which does not depend on ground computers, was not yet perfected.

The distance between the antenna silos and the most distant missile silo was between 1,000 and 1300 ft. These were by far the most complex, extensive and expensive missile launch facilities ever deployed by the USAF. Launching a missile required fueling it in its silo, and then raising the launcher and missile out of the silo on a massive elevator. Before each launch the guidance radar had to be calibrated by acquiring a special target at a precisely known range and bearing. When the missile was launched, the guidance radar tracked the missile and supplied precise velocity range and azimuth data to the missile's guidance system. Because of this the complex could only launch and track one missile at a time.

Although Titan I's two stages gave it true intercontinental range and foreshadowed future multistage rockets, its propellants were dangerous and hard to handle. Super-chilled liquid oxygen oxidizer had to be pumped aboard the missile just before launch, and complex equipment was required to store and move this liquid. Kerosene fuel also was pumped aboard just before launch.

In its brief career, six squadrons were equipped with the Titan I. Each squadron was deployed in a 3x3 configuration, which meant a total of nine missiles were divided into three launch sites in Colorado, Idaho, California, Washington state and South Dakota. Each missile site had three Titan I ICBM missiles ready to launch at any given time. See squadron article for location of launch sites.


 * 568th Strategic Missile Squadron April 1961 – March 1965
 * Larson AFB, Washington


 * 569th Strategic Missile Squadron June 1961 – March 1965
 * Mountain Home AFB, Idaho


 * 724th Strategic Missile Squadron April 1961 – June 1965
 * Lowry AFB, Colorado


 * 725th Strategic Missile Squadron April 1961 – June 1965
 * Lowry AFB, Colorado


 * 850th Strategic Missile Squadron June 1960 – March 1965
 * Ellsworth AFB, South Dakota


 * 851st Strategic Missile Squadron February 1961 – March 1965
 * Beale AFB, California

Specifications

 * Liftoff thrust: 1,296 kN Total mass: 105,142 kg
 * Core diameter: 3.1 m. Total length: 31.0 m
 * Development cost: $1,643,300,000 in 1960 dollars.
 * Flyaway cost: $1,500,000 each, in 1962 dollars.
 * Total production missiles built: 163 Titan 1s; 62 R&D Missiles – 49 launched & 101 Strategic Missiles (SMs) – 17 launched.
 * Total deployed Strategic Missiles: 54.
 * Titan Base Cost: $170,000,000 (US$ 0 in 2024)

First Stage:
 * Gross mass: 76,203 kg
 * Empty mass: 4,000 kg
 * Thrust (vac): 1,467 kN
 * Isp (vac): 290 s (2.84 kN·s/kg)
 * Isp (sea level): 256 s (2.51 kN·s/kg)
 * Burn time: 138 s
 * Diameter: 3.1 m
 * Span: 3.1 m
 * Length: 16.0 m
 * Propellants: liquid oxygen (LOX)/kerosene
 * Number of engines: Two – Aerojet LR-87-3

Second Stage:
 * Gross mass: 28,939 kg
 * Empty mass: 1,725 kg
 * Thrust (vac):356 kN
 * Isp (vac): 308 s (3.02 kN·s/kg)
 * Isp (sea level): 210 s (2.06 kN·s/kg)
 * Burn time: 225 s
 * Diameter: 2.3 m
 * Span: 2.3 m
 * Length: 9.8 m
 * Propellants: liquid oxygen (LOX)/kerosene
 * Number of engines: One – Aerojet LR-91-3

Service history
The number of Titan I missiles in service, by year:
 * 1961 – 1
 * 1962 – 62
 * 1963 – 63
 * 1964 – 56

Retirement
When the storable-fueled Titan II and the solid-fueled Minuteman I were deployed in 1963, the Titan I and Atlas missiles became obsolete. They were retired from service as ICBMs in early 1965. The count as of 5 March 1965 (the final launch from Vandenberg Air Force Base (VAFB): 17 were launched from VAFB (September 1961 – March 1965); one was destroyed in Beale AFB Site 851-C1 silo explosion 24 May 1962; 54 were based in Silos with SAC by 20 January 1965; 29 were in storage SBAMA (three at VAFB, one at each Base, including an extra at Lowry = 9 and 20 in storage at SBAMA elsewhere), a total of 101 production SM vehicles. The 83 surplus missiles remained in inventory at Mira Loma, AFS. SM-65 Atlas missiles had already been converted to satellite launchers in the early 1960s, and the Titan I's had about the same payload capacity as an Atlas. It did not make economic sense to refurbish the 83 remaining missiles as launch vehicles.  About 33 were distributed to museums, parks and schools as static displays (see list below).  The remaining 50 missiles were scrapped at Mira Loma AFS near San Bernardino, CA, the last was broken up in 1972, in accordance with the SALT-I Treaty of 1 February 1972.

The official count is 101 Titan I Strategic Missiles produced: 17 Test launched, 1 lost, 50 destroyed Mira Loma, 33 at museum/display (some missing).

On 6 September 1985 Strategic Defense Initiative (AKA "Star Wars" program), a scrapped Titan I Second Stage was used in a Missile Defense test. The MIRACL Near Infrared Laser, at White Sands Missile Range, NM was fired at a stationary Titan I second stage that was fixed to ground. The second stage burst and was destroyed by the laser blast. The second stage did not contain any fuel or oxidizer. It was pressurized with nitrogen gas to 60-psi. A follow-up test 6 days later was conducted on a scrapped Thor IRBM, its remnants reside at the SLC-10 Museum at Vandenberg AFB.

Static displays and articles
There should be 33 Static Titan 1 Strategic Missiles and two (plus five possible) Research and Development Missiles to account for (of these 22 have been positively identified by Serial Number, eight known but need to be identified) and three are unaccounted for, missing.

Note: May have been at the 14th American Rocket Society meeting at a Wash, DC hotel on 1 Nov 59 then at Charlie Bell’s junkyard on US-1 Titusville, Fla., now Puerto Rico? (see below)
 * B2	57-2691		      Cape Canaveral Air Force Space & Missile Museum, Florida Horizontal
 * R&D (57–2743)	       Colorado State Capitol display 1959 (SN belongs to a Bomarc) Vertical
 * R&D ?			       City of Lompoc, Lompoc Park (may have been V3 or BH) see below as possible SM. was Vertical, destroyed.
 * R&D (1 of 2, poss. 6)	       Was at Patrick AFB Technical Laboratory, Satellite Beach, Florida. Vertical (destr. by Hurr. Erin 8/95)
 * R&D G-type		Science and Technology Museum, Chicago 21 June 1963	 Vertical
 * SM-5	60-3650		Was on display at VAFB Armed Forces Day 1962, is this the Lompoc static? Horizontal
 * SM-49	60-3694		Cordele, Georgia (west side of Route I-75). Vertical
 * SM-53	60-3698 Site 395-C Museum, Vandenberg AFB, Lompoc, Ca. (from March AFB) Horizontal
 * SM-54	60-3699		Strategic Air Command Museum, Bellevue, Nebraska (near Omaha).	Vertical
 * SM-61	60-3706 		Gotte Park, Kimball, NE (only first stage standing, damaged by winds in ’96?)	Vertical (damaged by winds 7/94 ?)
 * SM-63 	60-3708		In storage at Edwards AFB (still there?) Horizontal
 * SM-65	61-4492		NASA Ames Research Center, Mountain View, California. Horizontal
 * SM-67	61-4494		Titusville High School, Titusville, Florida (on Route US-1) removed was Horizontal
 * SM-70	61-4497 		Veterans Home, Quincy, IL Vertical (removed sent to DMAFB for destruction on May, 2010)
 * SM-71	61-4498		U.S. Air Force Museum, now AMARC (to go to PIMA Mus.)	Horizontal
 * SM-72	61-4499		Florence Regional Airport Air and Space Museum, Florence, South Carolina. Horizontal
 * SM-73	61-4500		former Holiday Motor Lodge, San Bernardino (now missing?). Horizontal
 * SM-79	61-4506		former Oklahoma State Fair Grounds, Oklahoma City, Oklahoma. 1960s Horizontal
 * SM-81	61-4508		Kansas Cosmosphere, Hutchinson, Kansas. In storage
 * SM-86	61-4513 		Beale AFB (not on display, was horizontal, removed 1994) Horizontal
 * SM-88	61-4515 (st. 1)	Pima Air & Space Museum, outside DM AFB, Tucson, Arizona, now WPAFB Horizontal
 * SM-89 	61-4516 (st. 2)	Pima Air Museum, outside DM AFB, Tucson, Arizona, now WPAFB Horizontal
 * SM-92	61-4519 (st. 1)	Kansas Cosmosphere, Hutchinson, Kansas.	(acq. 11/93 from MCDD) 	Vertical (st 1 mate to SM-94 st 1)
 * SM-93	61-4520 (st. 2)	SLC-10 Museum, Vandenberg AFB, Lompoc, Ca. Horizontal  (only stage 2)
 * SM-94	61-4521 (st. 1)	Kansas Cosmosphere, Hutchinson, Kansas. (acq. 6/93 from MCDD)	Vertical (st 1 mate to SM-92 st 1)
 * SM-96	61-4523		South Dakota Air and Space Museum, Ellsworth AFB, Rapid City, South Dakota. Horizontal
 * SM-101	61-4528 		Estrella Warbirds Museum, Paso Robles, CA (2nd stage damaged) Horizontal
 * SM- ?	? (full missile)	Ingram Park, town of Lompoc, Ca. (with a Nike Target Warhead) was vertical, destroyed
 * SM- ?	? (stg. 2 only)	former SDI laser test target (whereabouts?) is this 4519 & or 4521 stg 1? Horizontal  (remnants of stage 1)
 * SM- ?	? (stg. 1 only)	former Spaceport USA Rocket Garden, Kennedy Space Center, Florida.	 Vert. (stg 1 mated to stg 1 below)
 * SM- ?	? (stg. 1 only)	former Spaceport USA Rocket Garden, Kennedy Space Center, Florida. Vert. (stg 1 mated to stg 1 above)
 * SM- ?	? (stg. 1 only)	Science Museum, Bayamon, Puerto Rico (PAFB R&D/Bell’s ??) Vert. (stg 1 mated to stg 1 below)
 * SM- ?	? (stg. 1 only)	Science Museum, Bayamon, Puerto Rico  (top half from Bell’s Junkyard) Vert. (stg 1 mated to stg 1 above)
 * SM- ?	? (full missile)	former Outside main gate of White Sands Missile Range, N.M. false report?	Vertical
 * SM- ?	? (full missile)	Spacetec CCAFS Horizontal
 * SM- ?	? (full missile)	Alabama S&R Center, Huntsville (stored outside, far west corner of center) Horizontal (in trees)

Note: Two stacked Titan-1 first stages created a perfect illusion of a Titan-2 Missile for museums above.