During and after World War I several engineers made experimental cruise missiles.
In World War II the Germans made the first working weapon, the V-1.
This was propelled by a pulsejet engine and used a set of gyroscopes for navigation.
It flew at a speed of 640 kilometers per hour, as fast as the fastest fighter airplanes and had a range 250 kilometers.
It carried a 850 kilogram warhead.
Accuracy was poor: it could miss its target by up to 10 kilometers.
Only three months later the V-1 was joined by the rocket-powered V-2, the first guided ballistic missile.
A ballistics missile is different from a cruise missile, as it cannot fly a level trajectory, only a ballistic one.
Flying at supersonic speeds, this weapon was unstoppable by contemporary air defenses, though it was very expensive and less effective than the V-1.
At the start of the Cold War other countries immediately picked up where the German engineers had been stopped.
They tried to improve on the pioneering weapons, but encountered many difficulties on the way.
Early cruise missiles had a number of disadvantages compared to conventional bombers:
once committed, they could not be rerouted or recalled; they could not defend themselves and were inaccurate.
Technological advances during the 1960's CE, like radar altimeters, inertial systems and flight computers, dramatically improved accuracy.
These technologies also allowed the missiles to fly very low, 'hugging the ground' ducking under enemy radar.
The jet engines that powered cruise missiles were changed from turbojets to turbofans.
These are more fuel efficient, increasing range; also they generate less heat, making the missiles harder to detect.
All these developments changed cruise missiles from cumbersome, unreliable weapons to elusive, far-ranging precision strikers and provided their breakthrough in the 1970's CE.
Since then several countries have developed a great variety of cruise missiles.
They can be launched from the ground, from ships or from aircraft.
In 1953 CE the first one was fired from a submarine.
Some are subsonic, others supersonic or even hypersonic, flying more than 5x the speed of sound.
Some try to home in on their targets slow and stealthy, while others surge ahead with supersonic or even hypersonic speeds.
Sophisticated models approach their target subsonically and accelerate to supersonic speeds on the last stretch of their trajectory.
The most advanced cruise missiles can turn around obstacles and achieve accuracies of just a few meters.
Cruise missiles can be equipped with explosive, chemical or even nuclear warheads.
All in all, roughly three categories can be discerned:
- Strategic: Capable of ranges of 1,000 - 3,000 kilometers, often armed with nuclear warheads. These rival intercontinental ballistic missiles.
- Tactical land-based: Ranging several hundred kilometers, aimed at land targets.
- Anti-ship: Ranging from a few tens to about 500 kilometers, aimed at ships.
Cruise missiles are relatively expensive weapons, yet hard to detect and even harder to stop, because they are small and fly fast. Their versatility means that their popularity with the military is still increasing.