All seemed set fair for the Cosmos 2511 ocean, weather and wave monitoring satellite (also known as Kanopus ST-1) after its launch by the second operational flight of the small-to-medium class Soyuz 2-1v launch vehicle at 1409 GMT on 5 December 2015, from the Plesetsk launch site in Northern Russia. However, Russian Aerospace Defence Forces subsequently confirmed that during the latter stages of the flight the spacecraft failed to separate from the rocket’s Volga upper stage. The spacecraft was subsequently lost as it re-entered the Earth’s atmosphere with the Volga upper stage.
Somewhat more fortunate was a smaller co-payload aboard the flight. The Cosmos 2512 spacecraft aka KYuA-1, is a very basic 15.8kg radar calibration satellite that was released as planned into the correct orbit from the Soyuz upper stage.
An initial investigation has found that one of four pyrotechnic triggered locks holding the spacecraft to the Volga upper stage apparently failed to open. The rocket stage was later automatically lowered to re-enter as per its programme, although with its extra mass attached, it could not lower its perigee enough to ensure immediate re-entry. The Volga stage, with Kanopus-ST attached, eventually re-entered over the South Atlantic (at 35S, 1W) at approximately 0543 GMT on 8 December with the surviving debris falling into the sea.
The Russian-built 350kg Kanopus ST (Cosmos 2511) spacecraft had been built as a ocean and weather monitoring satellite but one that was thought to have a military application. The spacecraft carries microwave radiometer with a swath of 2,300km and a resolution of 12-160km, and a multispectral camera with a swath of 1000km and a resolution of 30-50m. The satellite instrumentation was aksi to monitor wave heights and has been suggested that this also has a military application in being able to detect and track submarines travelling underwater by using wave height monitoring to track their wakes.