HGM-25A Titan I

Titan I

Launch of a Titan I ICBM from Cape Canaveral
Function	ICBM
Manufacturer	Martin Company
Country of origin	United States
Cost per launch	$1.5m (USD)
Cost per year	1962
Size
Height	31 m
Diameter	3.05 m
Mass	105,140 kg
Stages	2
Capacity
Payload to LEO	1,800 (Never used as a launch vehicle)
Launch history
Status	Retired
Launch sites	Cape Canaveral LC-15, LC-16, LC-19 & LC-20 Vandenberg AFB OSTF SLTF LC-395
Total launches	70
Success(es)	53
Failure(s)	17
First flight	6 February 1959
Last flight	5 March 1965
First stage
Engines	2 LR-87
Thrust	1 900 kN (430 000 lbf)
Specific impulse	290 seconds
Burn time	140 seconds
Propellant	RP-1/LOX
Second stage
Engines	1 LR-91
Thrust	356 kN (80 000 lbf)
Specific impulse	308 sec
Burn time	155 seconds
Propellant	RP-1/LOX

The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage ICBM (Intercontinental Ballistic Missile). 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 its 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 HGM-25A, initially called the SM-68 - originally it was the XB-68 before the Air Force began designating missiles as SM for strategic missile and TM for tactical missiles. The XB-68 designation was originally assigned to a Martin supersonic bomber concept that was canceled during the design phase.

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 thrust (1,330 kN) of thrust, the second stage 80,000 pounds thrust (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.

Operational deployment

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 1,300 feet (400 m). 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.

File:HGM-25A Titan I Missile Sites.png

HGM-25A Titan I Missile 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

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. About 90 surplus missiles remained in inventory. SM-65 Atlas missiles had already been converted to satellite launchers in the early 1960's, and the Titan I's had about the same payload capacity as an Atlas. It didn't make economic sense to refurbish the 90 remaining missiles as launch vehicles. About 20 were distributed to museums, parks and schools as static displays. Most of the remaining missiles were scrapped at Mira Loma AFS near San Bernardino, CA, the last was broken up in 1972.

During the 1980s Strategic Defense Initiative (AKA "Star Wars" program), a scrapped Titan I Second Stage was used in a Missile Defense test on 6 September 1986. 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.

Titan 1 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 development missiles built: 47. Total missiles fired: 68.
• Total production missiles built: 108. Total deployed missiles: 54.

Titan 1 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

Titan 1 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

Survivors

Below is a list of museums which have a Titan I missile in their collection:

• Air Force Space & Missile Museum, Cape Canaveral Air Force Station, Florida
• Pima Air & Space Museum, Tucson, Arizona
• NASA Ames Research Center, Mountain View, California
• Vandenberg AFB Launch Complex 395-C, Lompoc, California
• City of Lompoc, Lompoc, California
• U.S. Air Force Museum, Wright-Patterson AFB, Dayton, Ohio
• South Dakota Air & Space Museum, Ellsworth AFB, South Dakota
• Florence Regional Airport, Florence, South Carolina

While not a museum, a Titan 1 missile is on display in Cordele, Georgia, adjacent to I-75, at exit 101. It is in a parking lot between a Chevron filling station and a Krystal restaurant.
Google Street View

External links

• Tri-City Herald article by Kristin Alexander about Titan 1 complexes in Washington State
• Information on "Northern California Triad" of Titan missile bases in Lincoln, California; Chico, California and Live Oak, Sutter County, California (Sutter Buttes)

See also

Related lists

• List of military aircraft of the United States
• List of missiles