RB 04

The RB 04, short for Robot 04, is a Swedish long-range, sea-skimming, fire-and-forget air-to-surface anti-ship missile that was known as the RB 304 during development and early service. Sweden asked in 1949 for a radar-guided, air-launched anti-ship missile, and the request became the Saab Robot-Byran RB 04, first test launched from a Saab 29 Tunnan fighter in early 1955. Early versions had trouble with their two targeting modes, area attack against a group of ships and select targeting of a single vessel, because changing the spacing at which the missile chose a ship required hardware changes in a workshop. The RB-04C entered service with the Swedish Air Force on the A 32A Lansen attack aircraft in 1959, the RB-04D added longer-range engines and maintenance-free thermal batteries in the late 1960s, and the RB-04E was adapted to the AJ37 Viggen with a shorter wingspan and a monopulse radar seeker that resisted jamming. The missile never saw combat; the nearest it came was the 1981 Whiskey on the Rocks incident, when Viggens armed with RB-04E missiles stood on high alert. Many of its components were reused in the later RBS-15.