|Manufacturer||Yuzhmash, JSC "Khartron" (control system)|
|Country of origin||Ukraine|
Baikonur Site 90
Plesetsk Site 32
|First Stage - 11K69|
|Engines||1 RD-261 + RD-855 Vernier engine|
|Thrust||3,032 kilonewtons (682,000 lbf)|
|Specific impulse||301 sec|
|Burn time||120 seconds|
|Second Stage - 11S692|
|Engines||1 RD-262 + RD-856 Vernier engine|
|Thrust||941 kilonewtons (212,000 lbf)|
|Specific impulse||318 sec|
|Burn time||160 seconds|
|Specific impulse||330 sec|
|Burn time||370 sec|
The Tsyklon-4 or Cyclone-4, also known as Tsiklon-4, is a Ukrainian carrier rocket which is being developed for commercial satellite launches. Derived from the Tsyklon-3, it has a new third stage, a larger payload fairing, and a modernised flight control system compared to its predecessor. Control system has been developed by JSC Khartron.
Tsyklon-4 is a three-stage-to-orbit expendable launch system built on the successful Tsyklon-3 rocket and it uses its first two stages. The new features are mostly concentrated in the newly developed third stage:
- The third stage has a three times larger propellant capacity;
- The new rocket engine RD-861K with multiple ignition capability (3 to 5 times);
- A modern western-like control system capable of precise orbit injections;
- A new fairing derived from Ariane 4 is under development. It has a diameter of 4 meters, controlled temperature and cleanness conditions inside.
Tsyklon-4 will also improve the fueling system, allowing safe capture of toxic vapors from the Tsyklon's hypergolic propellant.
Development began in 2002, with the maiden flight aimed for 2006. Following a series of production delays, this has slipped, and is now scheduled for 2014. Alcântara Cyclone Space has been established as a launch service provider for the Tsyklon-4.
In 2008, it was reported that Brazil may pull out of the programme in favour of an alternative partnership between it and Russia to develop an Angara-derived rocket. However late 2009 Ukrainian President Viktor Yushchenko and Brazilian President Luiz Inácio Lula da Silva signed a joint declaration which included a commitment to launch the first Tsyklon-4 by the end of 2010 from Alcântara. This did not occur, and it is now to launch no earlier than 2014. 
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