KVTK to give hydrogen power to Angara

A new powerful space tug designated KVTK 372RB01 and powered by cryogenic propellant promised to greately improve the performance of Angara rockets.

Bookmark and Share


The KVTK hydrogen-powered upper stage. Copyright © 2011 Anatoly Zak

Although first stage boosters of the Angara launcher would be fueled by a traditional combination of liquid oxygen and kerosene, GKNPTs Khrunichev promised to equip upper stages of the rocket with engines burning two cryogenically cooled components -- liquid oxygen and liquid hydrogen. Previously, the company built a similar stage designated 12KRB for the Indian GSLV rocket, which was launched for the first time on April 18, 2001.

The KVTK upper stage sporting the hydrogen-oxygen RD-0146D engine was expected to fly onboard the Angara-A5 (Angara-5) rocket. The project apparently designated 372RB01 officially started in 2009. (556) For the purpose of this program, NITs RKP test center was to revive its hydrogen-production infrastructure, including capabilities to supply this fuel to Plesetsk. As of 2011, firings of RD-0146D for the benefit of the Angara-A5 project were to be conducted during 2012-2014. This work would also prepare a foundation for the next-generation Rus-M rocket, before the program was cancelled in 2011.

In April 2011, Roskosmos announced a formal tender for the development of the hydrogen-fueled upper stage during June-December of that year at a price tag of 500 million rubles ($18 million). Bids would be accepted until May 27 and the winner was to be picked on June 3, 2011. Naturally, GKNPTs Khrunichev was expected to conduct the work. In August 2012, Roskosmos announced a tender for a new phase of the KVTK stage development extending all the way to Nov. 25, 2018, with a price tug of 4.35 billion rubles. Technical requirements for the stage included the capability to deliver 4.5 and 5 tons to the geostationary orbit, when launched from Plesetsk and Vostochny, respectively. It obviously implied that the stage would fly on top of the Angara rocket. The same combination would have to be able to place 7.5 and 8 tons into the geostationary transfer orbit from same launch sites, the agency required. The stage would also have to be able to transmit its telemetry to ground control via Luch relay satellites.

As of 2013, NPTs AP development center was working on the inertial flight control system for the KVTK, however, according to multiple unofficial reports, the KVTK stage was still several years away from the completion of its development. In 2014, the project still remained largely on paper.

On December 10, 2020, Roskosmos published details of a 20.6-billion-ruble ($280 million) contract awarded to KB Salyut, the development arm at GKNPTs Khrunichev in Moscow for the work on the KVTK stage. The hydrogen-powered KVTK could serve as the fourth stage for Angara-5/KVTK variant and Angara-5V.

The contract called for the completion of the key development milestones, including the manufacturing and testing of prototypes, by the end of 2025. By then, the KVTK stage was not expected to fly until the second half of the 2020s.


Bookmark and Share

Known specifications of the KVTK stage and its deriviatives as of 2011:

Base launch vehicle
Payload mass to geostationary orbit, GSO
2.0 tons
4.5 tons
7.6 tons
Payload mass to geostationary transfer orbit, GTO
3.6 tons
7.5 tons
12.5 tons
Number of engine firings
up to 5
up to 5
up to 5
Maximum duration in autonomous flight
up to 9 hours
up to 9 hours
up to 9 hours
Promised launch date



This page is maintained by Anatoly Zak

Last update: December 19, 2020

All rights reserved

insider content



Watch animation: 10 seconds / 960 KB / Streaming QuickTime


Click here for still image Copyright © 2007 Anatoly Zak

ABOVE: The Soyuz spacecraft (right) links up with the KVRB space tug in the low Earth orbit. Launched by the Angara-5 rocket, the KVRB would be powerful enough to enable the Soyuz to enter orbit around the Moon rather than simply loop behind it, as it would be the case, when using the Block D upper stage. The Soyuz itself is retrofitted with the Fregat upper stage for increased propulsion capability. Copyright © 2007 Anatoly Zak


GKNPTs Khrunichev's experience in development of 12KRB stage could play a crucial role in the KVTK project. Credit: ILS