KVRB is essentially a single-stage booster designed to support launching various types of spacecraft.
The Khrunichev Space Center have been developing an oxygen/hydrogen upper stage (KVRB) with a view to improving the performance of the Proton M launch vehicle and broadening Proton M’s range of applications.
Its configuration enables a multi-hour space flight and multiple (up to five-fold) restarts of the main engine in flight.
In addition to integrability with Proton M, the design and properties of KVRB allow the use of this upper stage in combination with the (existing or future) medium-weight or heavy class launchers Angara, Zenit (Zenith), Energia M as well as Arian 5. This would noticeably bring up the performance of the launchers mentioned as far as injection of heavy payloads to high-energy orbit is concerned.
