Soyuz-7 (rocket family)

The Soyuz-7 (Союз-7) or Amur (Аму́р) is a partially-reusable, methane–fueled, orbital launch vehicle currently in the design concept stage of development by the Roscosmos State Corporation in Russia. The preliminary design process began in October 2020, with operational flights planned for no earlier than 2028. Amur is intended to substitute for the existing Soyuz-2, at a much lower per launch cost.

This is a proposed family of new Russian rockets proposed by JSC SRC Progress in the mid-2010s, to replace the legacy Soyuz for launch after the early 2020s. JSC SRC Progress had been the manufacturer and custodian of the Soyuz family design for many decades. The new design concept was a part of Project Feniks (Феникс). While all previous iterations of the Soyuz family had their roots firmly set on the R-7 ICBM legacy, the new rocket, designated Soyuz-7 in 2013, was to be a completely new design from the ground up. The proposed new design was to be based on a new propellant: LOX and liquid methane, use a new tank structure, new propulsion, and would do away with the famous Korolev Cross, and have thrust vector control in the main engine rather than using vernier engines. It was conceived in 2013 to be a scalable family with three versions covering the medium to heavy payload ranges.

The project would help to assure access to space for Russia by acting as a backup launcher in the event of problems with the Angara rocket family.

As conceived in the mid-2010s, the smallest version was to be a 270-tonne rocket, intended as a replacement of the Soyuz-2 rocket, with an expected payload to LEO of 9 t. It will use a single RD-0164 engine on the first stage, and a RD-0169 engine on the second. The first engineering design was expected to be completed by 2016, and the first flight expected as early as 2022. The use of just two stages for the base version, and the simplification of subsystems was intended to product a more reliable and less-expensive launch vehicle, with the lightest version expected to be cheaper than the Soyuz-2.

History
During an interview with the Kazakhstani magazine Space Research and Technologies during 2013, Mr. Kirilin, CEO of TSKB Progress, explained the conception of the project. When the Rus-M project was cancelled, TSKB Progress started work on a methane fueled launch vehicle under the Roscosmos Magistral research program. This work was self funded by the company, and looked to replace the Soyuz vehicle and keep the vehicle design capabilities within the company.

The venerable Soyuz rocket vehicle would be an approximately 60-year-old design by 2020 and it could not remain competitive with the new vehicles, like the Falcon 9. It was described by Progress CEO, Mr. Kirilin, as technologically and operationally hopelessly outdated. It has conical sections, where each panel is unique, it uses six engines with 24 nozzles, most rocket manufacturing tasks include a number of manual operations, it even requires five different fluids: kerosene, liquid oxygen, hydrogen peroxide, gaseous nitrogen and gaseous helium. Looking forward, the price of RG-1 fuel was going up, since it could only be distilled from a single oil field, that, by 2015, was expected to be depleted soon.

The proposed Soyuz-7 would use the same diameter for all sections of the rocket, 3.6 m, use liquid methane and liquid oxygen, have a single engine with a single nozzle on each stage, and automate most tasks. The proposed new rocket was conceived to use the existing Soyuz pads and installations after some modifications. Liquid methane is cheap, Russia has ample reserves and it has a huge installed base. It also has some important thermal and polymerizing properties that paves the way for reusable rockets. The rocket was expected to use the KBKhA RD-0164 engine in the core stages, and a methane version of the KBKhA RD-0124 in the upper stage.

During an August, 2015 interview with Ria Novosti, Mr. Kirilin stated that a preliminary design was expected in 2015 or 2016, that they intended to first develop a light version, that they anticipated an initial test flight of the first prototype in 2022 and that the propulsion would be the RD-0164 for the cores and the RD-0169 rocket engine for the upper stage.

However, this project, part of Soyuz-5, was abandoned when Soyuz-5 has evolved into a replacement for Zenit family named Irtysh, with RKK Energia as manufacturer. The methalox rocket was later renamed to Soyuz-7.

The contract for the preliminary design phase of the Amur was signed on 5 October 2020, to build "the first Russian reusable methane rocket." The design reference goals include high-reliability, operational launch cost target of US$22 million, and a reusable first stage, with an expendable second stage. Roscosmos has budgeted a "not to exceed" program cost of 70 billion rubles (US$880 million) for the development program through the first launch.

The rocket design is expected to follow the practice of SpaceX with the Falcon 9 to design the first stage for reusability. and the rocket engine to be reused 100 or more times.

Previous
In the mid-2010s, Soyuz-7 was conceived to be a scalable family, with three conceptual versions:
 * Basic version, designed to replace the Soyuz-2.1a/b rockets, would use just a first and a second stage. It was conceived to have a payload to a 200 km circular LEO orbit of 9 MT.
 * A three-core-stage version, designed as a crew carrier vehicle, that would use a central core and two equal cores on the side as boosters. This design concept was to have not an air-ignited second stage to eliminate air start risk. It was expected to have a payload to LEO of 16 t.
 * The heaviest version with maximum capability. It was expected to achieve a payload to LEO of 25 MT.

Current
In 2020, Amur is planned to be a 4.1 m-diameter two-stage-to-orbit, medium-lift vehicle of 55 m height, with a gross liftoff mass of 360 t. It is aimed to deliver a payload to low Earth orbit of 10.5 t, but could loft 12.5 t if the first stage is expended and not reused, as all traditional launch vehicles of the early space age were. Amur will launch from the Vostochny Cosmodrome in the Russian Far East.

The first stage of the rocket will use grid fins to assist with attitude control during atmospheric reentry and is planned to be powered by five RD-0169A methalox engines, which are currently being developed at the Chemical Automatics Design Bureau. The long-term target is for most of the engines to fire 100 times, but the center engine, reignited for descent through the atmosphere and again for landing operations which will include extending landing legs, will be aimed to eventually reach a life expectancy of 300 engine firings.

The ground test program for the new methalox-propellant engines is expected to be completed by late 2024.