COSMOS 1681, also known as Kosmos-1681, is a reconnaissance satellite equipped for photo (film return type) missions launched by the Soviet Union on September 6, 1985, from PLMSC LC41/1 using a Soyuz-U launch vehicle. The spacecraft has dimensions of 6 meters in length and diameter of 2.2 meters, with a span of 6 meters and a dry mass of 2455 kilograms, which is also its launch mass. It uses the Zenit bus configuration and carries the Priroda-3 equipment for its mission purposes. The satellite's power source consists of batteries, and it features a shape described as a sphere with a DCone attachment. Manufactured by TSSKB, COSMOS 1681 is equipped with a Fram No. 27L payload and employs the 11D82M; S5.120 (maneuver module) motor for its propulsion needs. The satellite's ownership is listed under PRIR.