The RIM-7 Sea Sparrow is a U.S. ship-borne short-range anti-aircraft and anti-missile weapon system, primarily intended for defense against anti-ship missiles.

Fifty years after its development, the Sea Sparrow remains an important part of a layered air defense system, providing a short/medium-range component especially useful against sea-skimming missiles.

The advantage was so great that when the Royal Navy was faced by the threat of the new Soviet Sverdlov-class cruiser, they responded in a non-linear fashion by introducing the Blackburn Buccaneer aircraft to attack them.

US Navy doctrine stressed long-range air cover to counter both high-speed aircraft and missiles, and development of newer short range defenses had been largely ignored.

Unlike the earlier generation of anti-ship missiles (ASMs), sea-skimmers approached at low level, like an attack aircraft, hiding themselves until the last moment.

To successfully counter this threat, ships needed new weapons able to attack these targets as soon as they appeared, accurately enough to give them a high first-attempt kill probability - there would be little time for a second attempt.

[2] The Navy's confidence in Mauler proved misplaced; by 1963 the program had been downgraded to a pure technology development effort due to continued problems, and was canceled outright in 1965.

While the British took a longer-term approach and developed the new Rapier missile, the US Army and Navy scrambled to find a system that could be deployed as quickly as possible.

[2] Quickly organizing the "Basic Point Defense Missile System", BPDMS, the then-current AIM-7E from the F-4 Phantom was adapted to shipboard use with surprising speed.

Its rocket engine was designed with the assumption that it would be launched at high speed from an aircraft, and therefore is optimized for a long cruise at relatively low power.

These were used on the Sparrow because they required less energy for basic maneuvers during cruise, but this made the missile less maneuverable overall, which was not well suited to the quick-reaction weapon.

Although the Sea Sparrow was meant as a small missile system that could be fit to a wide variety of ships, the launcher was relatively large and was deployed only to larger frigates, destroyers and aircraft carriers.

Finally, the manually aimed illuminator was of limited use at night or in bad weather, which was hardly encouraging for a ship-borne weapon where fog was a common occurrence.

In 1968, Denmark, Italy, and Norway signed an agreement with the US Navy to use the Sea Sparrow on their ships, and collaborate on improved versions.

Over the next few years a number of other countries joined the NATO SEASPARROW Project Office (NSPO), and today it includes 12 member nations.

[4] Under this umbrella group, the "Improved Basic Point Defense Missile System" (IBPDMS) program started even while the original version was being deployed.

[5] This was done in a fashion similar to carrier-based aircraft; the wings were hinged at a point about 50% along the span, with the outer portions rotated back toward the body of the missile.

The other major change was to allow the seeker to work with a variety of illumination radars, including those being used with existing European missile systems.

The guidance system was much smaller, which allowed the warhead to be moved from its former rear-mounted position to one in front of the mid-mounted wings, and increased in weight to 86 lb (39 kg).

The RIM-7F enhanced the performances, but also the proximity fuse versus low flying targets, as the minimum altitude was reduced to 15 metres (49 ft) or less.

A final upgrade to the Sparrow was the AIM-7P, which replaced the M's guidance system with an improved model that allowed mid-course updates to be sent from the launching platform via new rear-mounted antennas.

[14] FrankenSAM was confirmed to be in use in December 2023,[15] and was first used successfully in combat to bring down a Russian Shahed drone on 17 January 2024 from 9 km distance.

[14][16] Although the Navy and Air Force initially planned additional upgrades for the Sparrow, notably the AIM-7R with a combination radar/infrared seeker, these were canceled in favor of the much more advanced AIM-120 AMRAAM in December 1996.