Progress MS-18 (79P) | Soyuz 2.1a

Lift Off Time
October 28, 2021 – 00:00:32 UTC | 03:00:32 MSK
Mission Name
Progress MS-18 (79P)a resupply mission to the International Space Station (ISS)
Launch Provider
(What rocket company launched it?)
(Who paid for this?)
Soyuz 2.1a
Launch Location
Launch Complex 31/6, Baikonur Cosmodrome, Kazakhstan
Payload mass
~2,550 kg (5,600 lb) of cargo
Where did the spacecraft go?
It rendezvoused with the ISS, ~400 km low Earth orbit (LEO) at a 51.65° inclination
Did they attempt to recover the first stage?
No, Soyuz is not capable of recovery
Where did the first stage land?
The boosters crashed into the steppes of Kazakhstan
Did they attempt to recover the fairings?
No, Soyuz is not capable of recovery
Were these fairings new?
This was the:
– 6th uncrewed mission to the ISS of 2021
– 18th launch of a Progress MS spacecraft
– 56th mission of Soyuz 2.1a rocket
– 79th cargo delivery to the ISS 
– 170th flight of a Progress spacecraft
– 105th orbital launch attempt of 2021
(98th successful)
Where to re-watch
Launch Livestream
Docking Livestream

How did it go?

Progress MS-18 (79P) is a cargo resupply mission that rendezvoused with the International Space Station (ISS) on October 30, 2021. ROSCOSMOS launched it using an uncrewed Progress MS spacecraft atop a Soyuz 2.1a launch vehicle. The rocket lifted off from Launch Complex 31/6, at the Baikonur Cosmodrome, in Kazakhstan. This mission marked the 18th flight of the Progress MS capsule and the 79th cargo delivery to the space station.

The Progress MS spacecraft, the Progress MS-18 mission (79P)
The Progress MS spacecraft ready for the 79P resupply mission to the ISS (Credit: ROSCOSMOS)

Progress MS-18 (79P)


Progress MS-18 carried propellant and pressurized gases with a total mass of 603 kg, as well as food, 420 liters of water for the Rodnik system, biological experiments, and other cargo and equipment with a total mass of 1,490 kg. Overall, this mission brought approximately 2,550 kg of cargo to support the Expedition 66 on the ISS.

Progress MS-18 Mission Profile

Progress MS separated from the third stage of the Soyuz 2.1a at ~9 min after launch. The capsule arrived at the ISS two days later, on Saturday, October 30, at 01:31:19 UTC (04:31:19 MSK). The Progress MS capsule autonomously docked to the aft port of the Zvezda Service Module. The resupply spacecraft will spend about seven months at the station before undocking and deorbiting.

On this mission, it was expected that ROSCOSMOS would test some elements of the fast rendezvous technique that in the future will allow to reach the ISS in just one orbit or about two hours. It is reported that first tests were performed on the Progress MS-17 mission that launched on June 30, 2021. There, the spacecraft entered the coelliptic orbit required for this one-orbit scheme and stayed there for about 50 min. However, it has not been reported yet whether or not this test took place on this mission. If everything goes as planned, it will be possible to introduce the one-orbit rendezvous scheme for the Progress MS-20 mission.

Approximate Timeline

From Lift-Off
– 00:00:15Engine start sequence
+ 00:01:58First stage separation
+ 00:03:03Fairing jettison
+ 00:04:47Second stage separation
+ 00:04:57Tail section separation
+ 00:08:45Third stage main engine cutoff
+ 00:08:49Progress MS separation

What is Soyuz 2.1a?

ROSCOSMOS’s Soyuz is a multi-use medium-lift launch vehicle that was introduced in far 1966 and since then has been the workhorse of the Soviet/Russian space program. It is capable to launch civilian and military satellites, as well as cargo and crewed missions to the ISS. Over the decades, several variants of the Soyuz rocket have been developed. Soyuz 2.1a is one of its latest iterations that belongs to the Soyuz-2 rocket family.

Soyuz 2.1a rocket at the Baikonur Cosmodrome, Progress MS-16 mission
Soyuz 2.1a is starting its Progress MS-16 mission. (Credit: ROSCOSMOS)

The rocket consists of three stages, all of them are expendable. When launching to the ISS, Soyuz-2 can be flown with either a Progress capsule or a Soyuz spacecraft. On the Progress MS-18 mission, the Progress MS module was used to deliver cargo to the ISS.

Soyuz 2.1a is about 46.3 meters (152 ft) in height and 2.95 meters (9 feet) in diameter. The vehicle’s total lift-off mass is approximately 312,000 kg (688,000 lb). The rocket’s payload lift capacity to low-Earth orbit (LEO) is between 6,600 and 7,400 kg depending on the launch site.

Soyuz 2.1a with the Khokhloma decorative painting getting ready for the Progress MS-18 mission.
Soyuz 2.1a with the Khokhloma decorative painting getting ready for the Progress MS-18 mission. (Credit: ROSCOSMOS)

This mission was dedicated to the 800th anniversary of Nizhny Novgorod (Russia’s fifth largest city by population) in 2021 and the cooperation agreement between the government of this city and ROSCOSMOS. This is why the Soyuz 2.1 rocket was decorated with patterns of the Khokhloma painting that originated in Nizhny Novgorod and was first mentioned in 1659.


First StageSecond StageThird Stage
Engine 4 RD-107ARD-108ARD-0110
Total Thrust 840 kN (188,720 lbf),
sea level
1,020 kN (229,290 lbf),
792 kN (178,140 lbf),
sea level
922 kN (207,240 lbf),
298 kN (67,000 lbf),
Specific Impulse (ISP)263 s, sea level
320 s, vacuum
258 s, sea level
321 s, vacuum
326 s, vacuum

Side Boosters

The first stage of the Soyuz 2.1a rocket is composed of 4 side boosters that are powered by RD-107A engines. Each one of the boosters has a conical shape and a dry weight of 3,784 kg. It is approximately 19.6 meters in length, with a diameter of 2.7 meters. Each side booster has two vernier thrusters that are used for flight control.

The RD-107A engine runs on rocket-grade kerosene (RP-1) and liquid oxygen (LOx). The propellants are stored in the pressurized aluminum alloy tanks, the kerosine tank is located in the cylindrical part of the booster, and the LOx one is in the conical section. Each one of those engines has 4 combustion chambers and together they are capable of producing a thrust of 840 kN at sea level and 1,020 kN in a vacuum.

"Korolev cross", Progress MS-16 mission, Soyuz 2.1a
“Korolev cross” seen during Stage I separation on the Progress MS-16 mission. (Credit: ROSCOSMOS’s livestream)

Perhaps, the most spectacular moment of the Soyuz-2 rocket’s launch is the separation of the first stage. It happens approximately 2 minutes after the launch. The boosters perform a pattern, known as the “Korolev cross” (named after Sergei Korolev, a very important figure of the USSR space program and history).

Second and Third Stages

The center core stage is powered by a single RD-108A engine, and the upper stage is fitted with a single RD-0110 engine. Both of these engines run on rocket-grade kerosene and LOx and have 4 combustion chambers. The second stage is 27.10 meters long, with a diameter of 2.95 meters, and a dry mass of 6,545 kg. It has 4 vernier thrusters for three-axis flight control.

The third stage of a Soyuz-2 rocket has a height of 6.7 meters, a diameter of 2.7 meters, and a dry mass of 2,355 kg. One interesting thing about the engine on this stage is that it starts its ignition sequence prior to stage separation. This process is called “hot fire staging”.

Progress MS Spacecraft

The Progress module is a space “truck” for delivering cargo to the ISS. Its design is largely derived from the Soyuz spacecraft that serves for the transportation of astronauts to the ISS. The Progress capsule is 7.9 meters in length and 2.7 meters in diameter. It consists of three parts: a pressurized cargo module, a propellant compartment, and a rear service module (like the Soyuz spacecraft).

Unlike Cargo Dragon 2, it is not designed to bring cargo back to Earth. This is because the three modules on Progress are not capable to split before re-entry. Therefore, after unloading the cargo, the crew progressively fills it only with trash. At the end of its mission, the spaceship separates from the ISS, performs a deorbit burn, and entirely burns up upon re-entry in Earth’s atmosphere.

Progress MS-11 (72P) approaching the ISS Pirs node during Expedition 59
Progress MS-11 (72P) approaching the ISS. (Credit: NASA)

The MS series is the latest modernized variation of the Progress spacecraft that began flying in December 2015. Among the introduced upgrades are improved orbital debris shielding, a new flight-control and navigation systems, as well as a new external compartment that can be used for satellite deployment. 

Kurs-NA Automatic Docking System

Like the Soyuz spacecraft, Progress MS is equipped with a Kurs-NA automatic docking system that was first tested on the Progress M-15M mission in July 2012. Compared to its ancestor, Kurs-A, the new system has only one AO-753A rendezvous antenna. Kurs-A had five (two 2AO-VKA and three AKR-VKA) of them. This antenna broadcasts radar pulses that are needed to determine the altitude and relative position of the spacecraft to the ISS. Moreover, Kurs-NA uses less power than Kurs-A.

Roscosmos cosmonaut Sergey Ryzhikov and the TORU system
Expedition 64 Commander Sergey Ryzhikov practices using the tele-robotically operated rendezvous unit (TORU). (Credit: NASA)

In addition, the Progress MS spacecraft can be docked to the ISS manually by the docking system called the Tele-Robotically Operated Rendevous unit (TORU). This manual system serves as a backup to Kurs-NA in emergency situations and is located inside the Zvezda service module. On the Progress MS-16 mission, the control of the capsule had to be switched over to the TORU due to a signal strength issue of the Kurs system.

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