A dissolvable jet vane (22/30) is a composite structure, having a support frame (38), a plug leading edge (40) connected to the forward edge (42) of the frame (38), and an insulation layer (44) on the side walls of the support frame (38). The dissolvable jet vane materials withstand the pressure and thermal loads associated with missile steering during the first few seconds of rocket boost until the missile attains sufficient speed to use conventional external aerodynamic control fins for steering control. Once control passes to the external fins, the jet vanes rapidly and uniformly dissolve in the exhaust stream. The dissolvable jet vane provides a lightweight, reliable means of removing steering jet vanes from the exhaust stream of a solid rocket motor nozzle.