Kurs (Ukrainian and Russian: Курс, lit. 'Course') is a radio control system (type tomahook, etc.) used by the Soviet and later Russian space program.
"Kurs" was developed by the Research Institute of Precision Instruments (Russian: НИИ Точных Приборов, romanized: NII Tochnikh Priborov), Moscow, Legostaew, before 1985[1][2] and manufactured by the Kiev Radio Factory (Ukrainian: Київський Радіозавод, romanized: Kyyivskyy Radiozavod).[3]
Kurs was the successor to the Igla system and today provides navigation beaconing for Russian space vehicles including the Soyuz spacecraft and Progress spacecraft. The main difference between both systems is that Igla requires the space station to collaborate in the docking maneuver by reorienting itself to point the docking port to the spacecraft, while Kurs allows to dock with a fully stationary space station. The main reason for this change was that Mir was to be a much bigger space station than the older Salyut, so the propellant consumption would be excessive. Kurs provided the automated docking system for all Russian spacecraft that docked with the Mir space station.[4][5] When used for docking, the Soyuz or Progress vehicle broadcasts radar pulses from multiple antennas. The variation in strength between the antennas allows the system to compute relative position, attitude, and approach rate. The system is designed for automatic rendezvous and docking, but in an emergency cosmonauts may take command of the vehicle, either locally or from the International Space Station.[6]
After the dissolution of the Soviet Union in 1991, the Kurs system became the property of Ukraine; its manufacturer became a competitor in the space launch business with the Russian Federal Space Agency (RKA). Due to hard-currency problems, Kiev also raised the price of the Kurs system. Consequently, RKA sought to phase out its use in its vehicles.[7] A test using the Russian TORU backup system to reduce reliance on Kurs, was responsible for the collision between Mir and Progress M-34 and the damage to the Spektr module, nearly causing Mir to be abandoned. After the collision and recovery, the next Progress ship had a failure of Kurs, and was docked successfully using the same TORU system.[8]
The Kurs-NA (Russian: Новая Активная, romanized: Novaya Aktivnaya, lit. 'New Active') docking system, requiring only one rendezvous antenna and using less power, replaces Kurs-A, which required five antennas.[9] It was tested by Progress M-15M in July 2012[9] and by Progress M-21M in November 2013.[10] It is used on the Progress MS (2015-present).
The now Russian-built antenna part of the Kurs system also served as an independent and redundant docking monitoring system for the European Automated Transfer Vehicle.[11] It served as an additional monitoring system and could not be used to control the approach or docking of the ATV.[12]
As of May 2022, there have been 83 successful dockings to the International Space Station performed by Kurs with Soyuz & Progress vehicles, and the Nauka station module, giving Kurs a 90.4% success rate.