Soyuz-2

Soyuz-2.1a

Soyuz‑2.1a introduced the digital flight control system, replacing the analog unit used on previous Soyuz rockets.^[2] The system enabled in-flight trajectory adjustments and supported larger payload fairings, permitting the launch of heavier commercial satellites.^[14]

The vehicle uses upgraded RD-107A and RD-108A engines, featuring over 1,000 single-component injectors replacing earlier dual-component designs, improving combustion efficiency and increasing specific impulse by approximately 5-second (0.049 km/s).^[15][2]

The third stage retained the RD-0110 engine but adopted enlarged propellant tanks and a revised structure shared with Soyuz-2.1b. Combined with the lighter avionics, these changes increased payload capacity by about 300 kilograms (660 lb).^[3][16]

The first Soyuz‑2.1a launch took place on 8 November 2004 from Plesetsk Cosmodrome Site 43 with a boilerplate payload simulating a Zenit-8 reconnaissance satellite.^[2]

Soyuz-2.1b

Soyuz 2.1b retains the upgrades of the 2.1a and introduces a new third stage powered by the RD-0124 engine. Using oxygen-rich staged combustion, the engine increases specific impulse from 326 to 359 seconds (3.20 to 3.52 km/s). Although maximum thrust was slightly reduced from 298 to 294 kilonewtons (67,000 to 66,000 lb_f), extended burn time with the same propellant load improved overall performance.

The enhanced third stage significantly increased payload capability. From the Baikonur Cosmodrome, payload capacity to low Earth orbit rose from approximately 7,430 kilograms (16,380 lb) for the 2.1a to 8,670 kilograms (19,110 lb) for the 2.1b.^[17][18]

The first Soyuz‑2.1b launch occurred on 26 July 2008 from Plesetsk Cosmodrome Site 43 with a classified military payload.^[19]

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  Closeup of booster and core stage engines of a Soyuz‑2.1a during launch
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  Soyuz‑2.1a prepared for Soyuz MS-26
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  Soyuz‑2.1b prepared for GLONASS-K2 satellite launch
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  From left to right: Soyuz‑2.1v, Soyuz‑2.1b, Soyuz‑2.1a (crewed variant), and the proposed Soyuz‑5

Suborbital test flight

On 8 November 2004, at 18:30 UTC, the first Soyuz‑2 rocket, in the Soyuz‑2.1a configuration, was launched from the Plesetsk Cosmodrome in Russia. The rocket followed a suborbital trajectory, with the third stage and Boilerplate landing in the Pacific Ocean.

Maiden launch

The first attempt at launching a Soyuz‑2 to orbit with the MetOp-A satellite occurred on 17 July 2006. It was scrubbed two hours before the launch by an automatic sequence after the onboard computer failed to check the launch azimuth. Fuelling of the rocket was underway at the time, and all launch complex equipment and onboard preliminary checks had proceeded without incident. The rocket was left fuelled on the launch pad for the next attempt on 18 July 2006. Launch was eventually conducted on 19 October 2006.

First crewed mission

The first crewed launch of Soyuz‑2 took place on 9 April 2020, carrying Soyuz MS-16 to the ISS.

Naphthyl fuel

Following successful ground testing, a naphthyl (Russian: нафтил) fueled Soyuz‑2.1b launch took place on 22 October 2022 at Vostochny. Naphthyl is an environmentally safe hydrocarbon fuel with fewer aromatic compounds than kerosene, which also slightly improves engine performance. There are only minor differences in thermal properties, viscosity, and surface tension, so this did not require significant engine changes.^[27]

Planned launches