The Baikal fly-back booster
In cooperation with KB Salyut, the developer of the Buran orbiter, GKNPTs Khrunichev in Moscow designed a reusable fly-back booster rocket, which would serve as an alternative first stage in the Angara family of space launchers. Designated Baikal, after a Siberian lake, the reusable booster was developed in parallel with the work on more traditional "booster modules."
The Baikal stage would be equipped with a folding wing, which would be stored along the fuselage of the vehicle during the ascent of the rocket. After its separation from the second stage of the Angara rocket at an altitude of about 75 kilometers, the Baikal's wing would rotate 90 degrees into its deployed position.
The Baikal booster stage would also be equipped with an air-breathing jet engine fitted in the nose section of the rocket, which would provide a powered horizontal landing of the vehicle on a runway. Thanks to jet propulsion, the Baikal's return to Earth would look much more similar to a regular aircraft than to the US Space Shuttle or Russian Buran, which both had to rely entirely on aerodynamic gliding and had only one opportunity for landing. Baikal's jet engine would be fueled by kerosene from the same tanks which had fed the vehicle's main rocket engine during the ascent phase of the flight.
The development of the Baikal booster
Copyright © 2001 Claude Mourier
A mockup of the Baikal booster stage displayed at the air and space show in Le Bourget, France, in June 2001. Copyright © 2001 Claude Mourier
Copyright © 2001 Claude Mourier
Nose and tail sections of the Baikal booster. Copyright © 2001 Claude Mourier
Scale model of the RD-191 engine for the first stage of the Angara launcher. Copyright © 2001 by Anatoly Zak
By 2001, GKNPTs Khrunichev reportedly built four full-scale mockups of the Baikal stage, which had been tested in wind tunnels of the Central Aero- and Hydro-dynamics Institute, TsAGI, at speeds from 0.5 to 10 Mach (or speed of sound).
According to the Khrunichev's representatives at the time, the first flight of the Baikal booster could take place in 2006, if funds were provided. Unlike the rest of the Angara program, the Baikal development was conducted without direct federal support. In June 2001, during the air and space show in Le Bourget, Khrunichev said it had actively seeked investors for the project, but without success.
Although no significant practical steps toward the implementation of the Baikal concept were taken during the first decade of the 21st century, Khrunichev apparently still kept that option on the table. As late as April 2008, speaking to local representatives in Kzyl Orda, Kazakhstan, on the prospects of the Baiterek launch complex, Deputy Director General at Khrunichev enterprise, Oleg Roskin quoted reusable first and second stages of the Angara rocket as the next step in the development of the system.
Baikal family overview:
The Baikal launcher family overview (one-booster, two-stage version):
On June 4, 2018, the Fund for Prospective Research, FPI, within Roskosmos and the United Aviation Development Corporation, announced that it had selected a concept for the preliminary design of a returnable booster stage intended for a super-light reusable launcher. The proposed system was expected to deliver 600 kilograms of payload to the Sun-synchronous orbit. The FPI statement said that the design of the future rocket system was based on the technical heritage of the Baikal booster, while the accompanying rendering showed a two-stage vehicle equipped with a folding wing, practically identical to the architecture formulated almost two decades earlier.
The announcement also quoted the head of the design group at FPI, Boris Satovsky, as saying that in the course of the pre-preliminary studies, engineers compared several alternative aerodynamic architectures and conducted calculations of gas dynamics and thermal conditions for the vehicle on the return trajectory. These studies proved the availability of the necessary technical expertise for the development of a demonstrator, Satovsky said.
According to preliminary estimates, the reusable system will cut the cost of payload delivery by 1.5 or 2 times compared to traditional rockets. Every self-guided booster will be designed to fly 50 missions without replacement of its main engines burning a mix of cryogenic liquid oxygen and liquid methane. The system was expected to be based on mobile launchers and its maiden flight was scheduled for 2022, the FPI press release said.
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