Astronomy and Space
Fregat (Russian: Фрегат, lit. 'frigate') is an upper stage developed by NPO Lavochkin for universal compatibility with a wide range of medium- and heavy-lift launch vehicles. Fregat has been used primarily with Soyuz and on a few occasions with Zenit rockets, and entered operational service in February 2000. Fregat uses a liquid-propellant engine burning unsymmetrical dimethylhydrazine (UDMH) fuel and dinitrogen tetroxide (N2O4) oxidizer, a pair of hypergolic propellants that ignite on contact. With a success rate of 97.3%, including two failures and one partial failure, Fregat is among the most reliable upper stages in operation. It has deployed more than 300 payloads into a variety of orbits and is capable of placing three or more spacecraft into distinct orbits during a single mission, owing to its ability to restart up to seven times and operate for a total burn duration of up to 1,350 seconds.
Groombridge 1830.
HD 133880.
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