- Fregat
Fregat is a is a type of rocket stage developed by
NPO Lavochkin in the 1990s. Its main engine is a liquid propellant rocket that usesUDMH andN2O4 as propellants.Specifications
The dry mass of a Fregat (as of October 2006) is 924 kg; with fuel the mass is up to 5350 kg. Current modification of the main engine has a
specific impulse of 332 s and a thrust of 2018 kg.fact |date=June 2008 Thereaction control system includes 12 engines, each having 5 kg thrust, 225 s Isp, using purehydrazine , with mass up to 42 kg.Capabilities
The stage can be restarted multiple times, which has been used to place payloads such as the
GIOVE -B satellite into their planned orbits. [cite web |url=http://www.arianespace.com/site/news/releases/presrel08_04_27.html |title=Starsem successfully launches second Europe navigation satellite |publisher=Arianespace |date=2008-04-27]Uses
NPO Lavochkina created many interplanetary probes in the past, and Fregat stage follows their design traditions. The main part of the stage is six intersecting spheres placed on a single plane, four of which contain propellants. The remaining two contain the control equipment. The main engine is placed between the spheres, so Fregat is a tightly-packed stage with a diameter much larger than its height.
Fregat is a remarkably versatile spacecraft. Various versions were used by the Soviets as the landing stage for Lunar missions (e.g., Luna-16), as an escape stage to launch modern space probes into interplanetary trajectories (e.g.,
Venus Express andMars Express ) and as the braking stage to place Fobos-2 into orbit around Mars.Fregat stages are currently used as the third stage of some
Soyuz-FG launch vehicles.References
External links
* [http://www.laspace.ru/rus/fregat.php Fregat page on the manufacturer site]
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