With the disintegration of the USSR in 1991, developers of the Soyuz rocket, along with the rest of the nation's space industry, wanted to consolidate its subcontractor network inside the Russian Federation. To accomplish the goal, TsSKB Progress in the city of Samara, developed a new version of its workhorse Soyuz launcher, under research and development plan dubbed Rus. According to the upgrade plan, the Soyuz-2 rocket would sport a brand-new RD-0124 (14D23) closed-cycle engine on its third stage.
The 30-ton-thrust RD-0124 engine developed for the Soyuz-2 launcher would have roughly same dimensions (height: 2,327 millimeters, diameter: 1,470 millimeters) and the basic design as the veteran RD-0110 engine on the third stage of the previous Soyuz rockets. The main difference would be the introduction of the so-called closed-cycle system, where oxidizer gas used to drive the engine's pumps, would be then directed into the combustion chamber, where it would burn with the rest of the propellant, rather then being dumped overboard. Such upgrade would increase the performance of the engine and, as the result, the payload of the launcher by some 950 kilograms. A version of RD-0124 was also intended for the Angara rocket.
A special ignition propellant is used to activate the combustion of the engine and pyrotechnic devices used to control the engine's work. Each of four combustion chambers can gimbal along a single axis to steer the vehicle. (145)
Initial tests firings of the RD-0124 engine reportedly started in 1996 and were completed in February 2004 at KBKhA design bureau in Voronezh. At the time, representatives of the company were quoted as saying that the mass production of the engine could start as early as 2005.
Another test firing (in Voronezh) was conducted on December 27, 2005, clearing the way to full-scale tests of the entire third stage (Block I) of the Soyuz-2-1b rocket at NIIKhimmash facility in Sergiev Posad.
On May 3, 2011, KBKhA announced that "certification" tests of RD-0124 were successfully concluded in Voronezh, declaring the engine operational. By that time, RD-0124 had already flew four missions on the Soyuz-2-1b rocket. The engine accumulated a total burn time of 55,000 seconds in 225 tests, some of which were exceeding the real-life operational conditions of the engine. Another firing, characterized as control and technical testing, took place on Sept. 10, 2011. The head of Roskosmos, Vladimir Popovkin, personally oversaw the test in Voronezh.
RD-0124A for Angara
In April 2012, the RD-0124A engine, intended for the second stage (URM-2) of the Angara family of rockets, underwent climatic tests in a special cold chamber at the KBKhA design bureau in Voronezh in order to certify it for operational conditions at Russian launch sites. Following the climatic tests, the same engine was scheduled to perform three firing tests.
On Dec. 25, 2012, the RD-0124A engine fired for 753 seconds at KBKhA's climatic test chamber in Voronezh to confirm its performance after nine months of climatic tests. Two more tests were still scheduled during 2013, followed by inter-agency certification tests in 2014. The test firing program was to certify the propulsion system for both Soyuz-2.1b and the Angara rocket.
The last tune-up firing of RD-0124A engine was conducted in Voronezh on June 10, 2013, concluding autonomous test program. From the end of June, KBKhA promised to start inter-agency tests of the engine, which would pave the way to the serial production of the engine. Three inter-agency tests of the RD-0124A engine took place from July 16 until Aug. 27, 2013, clearing the way to its use on the Angara rocket beginning in 2014, KBKhA announced on Sept. 3, 2013.
Also in 2013, KBKhA proposed a number of upgrades to the RD-0124A engine, including the introduction of the thrust control nozzles instead of the current gimbal mechanism of the main combustion chamber. The company also proposed to equip the engine with a cutoff system based on a full consumption of any of the propellant components. These upgrades promised to cut the production cost and the mass of the engine, increase the rocket's payload and overall reliability of the propulsion system.
In 2013, KBKhA design bureau conducted the initial development work on a one-chamber replacement for the RD-0124A engine designated RD-0125A. According to the company, the new engine would have a lower mass and a higher thrust and it would be easier to manufacture than its predecessor.
RD-0124M for Sunkar/Soyuz-5
In 2017, NPO Energomash announced a new version of the RD-0124 engine, which was designated RD-0124M and intended for the Sunkar/Soyuz-5 rocket.
Comparison of RD-0110 and RD-0124 engine performance (120):
The four-chamber RD-0110 engine, which was used for several decades on the third stage of the Soyuz family of launchers became the focus of upgrades needed to build the Soyuz-2 launcher. Copyright © 2001 Anatoly Zak