Buzz
Submarine-launched Tomahawk cruise missile.
Photo courtesy of the U.S. Department of DefenseTomahawk cruise missiles often make headlines as they are the U.S.'s weapon of choice for numerous rapid-response missions. With so many other missile types available in the U.S. arsenal, have you ever wondered why cruise missiles are so frequently used?
In this edition of Mytour, we will explore cruise missiles, giving you a comprehensive understanding of their design, how they function, and why they are perfectly suited for specific operational needs.
The Fundamentals
A cruise missile is essentially a small, unmanned aircraft. With a wingspan of 8.5 feet (2.61 meters), powered by turbofan engines, it has a range of 500 to 1,000 miles (805 to 1,610 km) depending on its design.
The primary function of a cruise missile is to deliver a 1,000-pound (450-kg) high-explosive warhead to a pinpoint target. Upon impact, the missile is destroyed along with its payload. Considering that cruise missiles cost between $500,000 and $1,000,000 each, this method of delivering a 1,000-pound bomb is quite costly.
Cruise missiles are available in several variants (see the links at the end of the article for further details), and they can be launched from submarines, destroyers, or aircraft.
Left: AGM Tomahawk air-launched cruise missile mounted on a B-52 Stratofortress. Right: Ground Launch Cruise Missile (GLCM) system
Photo courtesy of the U.S. Department of Defense
Left: Tomahawk cruise missile launched from the USS Merrill. Right: Tomahawk cruise missile launched from the nuclear submarine USS La Jolla
Photo courtesy of the U.S. Department of DefenseWhen reports mention hundreds of cruise missiles being launched at targets, they are typically referring to Tomahawk missiles fired from destroyers.
Specifications
Cruise Missile
Photo courtesy of the U.S. Department of DefenseCruise missiles measure 20 feet (6.25 meters) in length and 21 inches (0.52 meters) in diameter. At launch, they are equipped with a 550-pound (250-kg) solid rocket booster and have a total weight of 3,200 pounds (1450 kg).
Once the booster has expended its fuel, it detaches. The missile's wings, tail fins, and air intake deploy, and the turbofan engine takes over propulsion.
This engine weighs a mere 145 pounds (65 kg) and generates 600 pounds of thrust by burning RJ4 fuel. The missile's fuel load at launch is between 800 and 1,000 pounds (approximately 450 kg), or around 150 gallons (600 liters). It cruises at a speed of 550 mph (880 kph).
Navigation
Tomahawk cruise missile escorted by an F-14
Photo courtesy of the U.S. NavyThe defining feature of a cruise missile is its remarkable precision. A well-known phrase describing the cruise missile is, "It can travel 1,000 miles and strike a target the size of a single-car garage." Cruise missiles also excel at avoiding detection by the enemy, as they fly at very low altitudes, staying beneath the radar coverage of most radar systems.
There are four distinct systems that guide a cruise missile to its target:
- IGS - Inertial Guidance System
- Tercom - Terrain Contour Matching
- GPS - Global Positioning System
- DSMAC - Digital Scene Matching Area Correlation
The IGS is a basic system that measures acceleration to track the missile's position by detecting motion-related changes. Tercom, on the other hand, utilizes a detailed 3-D map of the terrain over which the missile flies. It uses radar to compare real-time terrain data with the stored map, ensuring the missile can maintain low altitude, known as "hugging the ground." The GPS system relies on military satellites and an onboard receiver to precisely calculate the missile's location, ensuring high accuracy.
As the missile nears its target, it shifts to a "terminal guidance system" to select the impact point, which may be pre-set by either the GPS or Tercom. The DSMAC system comes into play here, using a camera and an image correlator to lock onto the target, particularly effective for moving targets. In addition, cruise missiles may carry thermal imaging or illumination sensors, often utilized by smart bombs for enhanced targeting accuracy.
