COSMOS 1129, also known as Kosmos-1129, is a satellite with the OBJECT_ID 1979-083A, launched on September 25, 1979, from PLMSC LC41/1 using a Soyuz-U launch vehicle. It was manufactured by TSSKB and owned by IMBP/TSSKB. The satellite is configured as a sphere with a diameter of 2.4 meters and includes a DCone component, measuring 6.5 meters in length and span. COSMOS 1129 has a dry mass of 2040 kg, which is also its launch mass. Its payload consists of the Bion No. 5 equipment, part of the Bion bus series, and was launched from the Soviet Union (SU). The satellite's shape is described as a sphere with a DCone addition, though specific details about its mission or purpose are not provided in the data.