The RB-04 (Robot 04) is a long-range sea skimming[1] fire-and-forget air-to-surface, anti-ship missile.

In 1949, the Swedish government placed a request for a radar-guided, air-launched anti-ship missile.

The early versions of the missile suffered teething problems in regards to the two targeting modes, which were area attack, for striking a big group of ships (like an invasion fleet), and select targeting, where the missiles home in on a single vessel.

In the area attack the missile would only target a ship in the group if they were within 1,000 meters of another vessel, this was also in the early electronic age, and changes in this distance required hardware modifications in a workshop.

Swedish AJ37 Viggens with RB-04E's mounted under their wings, taken from top secret storage bunkers, stood on high alert for a possible Soviet incursion.