In September 1943, the Italian battleship Roma was steaming toward Malta to surrender to the Allies when a pair of German Dornier Do 217 bombers appeared overhead. The planes released two Fritz X glide bombs—each fitted with radio control and fins that allowed a bombardier to steer it midair. One of the weapons punched through the Roma’s deck and detonated her magazines, splitting the ship in half and killing more than 1,300 sailors.
It was the first time in history that a battleship, or a major military target, had been destroyed by a precision-guided weapon. The world took notice, but American planners were already developing their own guided weapons.
America’s Early Guided Weapons
While the attack shocked Allied commanders, American engineers had already successfully tested their own guided munitions. The U.S. military recognized early in the war that accuracy, not explosive power, was the future of aerial warfare and invested heavily in anti-ship and infrastructure weapons that could be controlled remotely.
Teams from the Navy’s Bureau of Ordnance, the Army Air Forces, and several universities developed a range of experimental weapons that combined radio, radar, and even television guidance in an effort to hit targets that traditional bombs could not.
- Navy ASM-N-2 “Bat” - The world’s first fully automatic, radar-homing bomb. Developed by the National Bureau of Standards and put into service in 1945, the Bat could detect ships on its own radar and adjust its flight path without human control. In the war’s final months, PB4Y-2 Privateer patrol bombers used Bat bombs to sink several Japanese freighters and coastal vessels in the South China Sea—years before the first true anti-ship missiles entered service.
- GB-4 Glide Bomb - A 2,000-pound television-guided glide bomb that transmitted live images from a nose-mounted camera to an operator in the launching aircraft. Tested in 1944, it was one of the earliest uses of real-time video guidance. Though combat results were limited and unsatisfactory, the GB-4 proved that remote targeting was possible decades before laser designators or GPS.
- Bomb Mark 55/ SWOD Mark 7 “Pelican” - A radar-guided predecessor to the Bat. The Pelican possessed a semi-active radar seeker in the front of the weapon, which allowed it to home on radar reflections from a target illuminated by the launching aircraft’s radar. The project was cancelled before operational use, but it led to the development of the Bat.
- VB-1 “Azon” - Short for “azimuth only,” it was a 1,000-pound bomb fitted with a radio-controlled tail kit that allowed an operator to steer the weapon left or right after release. Used in 1944–45 against bridges and other narrow targets in Europe and the China-Burma-India theater, Azon could not alter range, only azimuth, but it proved an early, practical step toward converting unguided bombs into precision weapons.
- Project Aphrodite - Converted worn-out B-17 and PB4Y (B-24) bombers into radio-controlled “flying bombs,” packing them with tens of thousands of pounds of explosives, fitting them with television cameras and remote-control gear, and having crews take off, arm the payload, then parachute out while a mother ship guided the drone to the target. Missions launched in August–September 1944 aimed at targets such as U-boat pens and oil facilities, but control problems, enemy fire, and technical limits made results uneven and costly—most famously the death of Lt. Joseph P. Kennedy Jr. when his PB4Y exploded prematurely. It was America’s first test of drones as weapons.
Although America’s guided weapons of World War II weren’t decisive on the battlefield, they marked the beginning of remote warfare and introduced technologies that still define modern weapons today.
The Cold War
World War II’s guided bombs directly influenced the missile and space programs of the Cold War. The same technologies—radio control, gyroscopes, and radar homing—that guided the Bat and Azon were expanded into the guidance and control systems of early missiles.
When German scientists and engineers arrived in the United States under Operation Paperclip, they joined existing American teams studying those wartime tests. Their experience in developing V-2 rockets, combined with wartime U.S. research, led to the Navy’s “Lark” surface-to-air missile and the Army’s “Redstone” rocket, both advancements of the previous drive for guided munitions.
The Redstone and its successors, including the “Atlas” and “Thor,” became the foundation of America’s space launch program. The same guidance and propulsion technologies developed for WWII weapons were repurposed to carry nuclear warheads and, later, astronauts.
The first U.S. crewed spaceflights launched on modified ballistic missiles built by teams whose experience traced back to the guided weapon projects of the 1940s. Those early American experiments—once aimed at hitting ships and bridges—ultimately helped send humans to the Moon.
Many of these same principles led to the development of the Joint Direct Attack Munition (JDAM) and other weapons that were put to great effect in the Gulf War and recent conflicts.
Drone Warfare
The principles behind America’s early guided bombs—remote control, onboard guidance, and precision targeting—are the same ones driving today’s drone warfare. Modern drones use miniature cameras, GPS, and digital signal links instead of the analog radios and primitive radar of 1940s glide bombs, but their purpose is identical: to deliver explosives accurately from a safe distance.
In Ukraine, both sides now field small, inexpensive drones that act as modern descendants of those early guided weapons. Pilots steer them with handheld controllers, relay video to operators, and adjust course midflight much like bomber crews once did with a radio-guided bomb. Some loitering munitions and “kamikaze” drones even use autonomous guidance to strike without human input, similar to the fully automatic radar homing used by the Navy’s Bat bomb in 1945.
The result is a return to the kind of precision once considered revolutionary in World War II—but now available at a much smaller cost. As adversaries adapt faster than the U.S. anticipated, the Pentagon faces the same challenge it did when the Fritz X sank the Roma: catching up to a new era of precision weapons before it’s too late.
