COSMOS 1815 (also known as Kosmos-1815) is a radar calibration satellite launched on January 22, 1987, from the Kymash Launch Site using the Kosmos 11K65M launch vehicle. The spacecraft has dimensions of 2.5 meters in length and 1.8 meters in diameter with a span of 23 meters, indicating possible solar arrays deployment. It has a dry mass of 925 kg and was launched with a total mass of 1045 kg. Manufactured by YUZH for the Soviet Union's PVO (Air Defense), COSMOS 1815 is equipped with eight deployable fixed solar arrays and batteries, and its mission purpose is radar calibration using the Taifun-2V payload. The satellite has a bus configuration of Romb and operates in a cylindrical shape augmented by antennas. Its radar cross-section is measured at 26.6314 square meters.