Engineering:Soyuz MS

Short description: Latest revision of the Soyuz spacecraft

Soyuz MS (Союз МС)

Soyuz MS-20 approaching the ISS
Manufacturer	Energia
Country of origin	Russia
Operator	Roscosmos
Specifications
Spacecraft type	Crewed spaceflight
Design life	210 days when docked to International Space Station (ISS)
Launch mass	7,080 kg (15,610 lb)
Crew capacity	3
Volume	10.5 m3 (370 cu ft)
Batteries	755 Ah
Regime	Low Earth orbit
Dimensions
Solar array span	7.48 m (24.5 ft) 10.7 m (35 ft) with solar panels deployed
Width	2.72 m (8 ft 11 in)
Production
Status	Active
Built	24
Launched	24 (as of 15 Sep 2023)
Operational	2
Retired	22 (not including MS-10)
Failed	1 (Soyuz MS-10)
Maiden launch	Soyuz MS-01 (7 July 2016)
Last launch	Active
Related spacecraft
Derived from	Soyuz TMA-M
← Soyuz TMA-M Orel →

The Soyuz MS (Russian: Союз МС; GRAU: 11F732A48) is a revision of the Russian spacecraft series Soyuz first launched in 2016. It is an evolution of the Soyuz TMA-M spacecraft, with modernization mostly concentrated on the communications and navigation subsystems. It is used by Roscosmos for human spaceflight. The Soyuz MS has minimal external changes with respect to the Soyuz TMA-M, mostly limited to antennas and sensors, as well as the thruster placement.

The first launch was Soyuz MS-01 on 7 July 2016, aboard a Soyuz-FG launch vehicle towards the International Space Station (ISS). The trip included a two-day checkout phase for the design before docking with the ISS on 9 July 2016.

Design

Exploded plan of the Soyuz MS spacecraft and its Soyuz FG rocket

A Soyuz spacecraft consists of three parts (from front to back):

• A spheroid orbital module,
• A small aerodynamic reentry module,
• A cylindrical service module with solar panels attached.

The first two portions are habitable living space. By moving as much as possible into the orbital module, which does not have to be shielded or decelerated during re-entry, the Soyuz three-part craft is both larger and lighter than the two-part Apollo spacecraft's command module. The Apollo command module had six cubic meters of living space and a mass of 5000 kg; the three-part Soyuz provided the same crew with nine cubic meters of living space, an airlock, and a service module for the mass of the Apollo capsule alone. This does not take into consideration the orbital module that could be used in place of the LM in Apollo.

Soyuz can carry up to three cosmonauts and provide life support for them for about 30 person-days. The life support system provides a nitrogen/oxygen atmosphere at sea level partial pressures. The atmosphere is regenerated through KO₂ cylinders, which absorb most of the CO₂ and water produced by the crew and regenerates the oxygen, and LiOH cylinders which absorb leftover CO₂. Estimated deliverable payload weight is up to 200 kg and up to 65 kg can be returned.

The vehicle is protected during launch by a nose fairing, which is jettisoned after passing through the atmosphere. It has an automatic docking system. The spacecraft can be operated automatically, or by a pilot independently of ground control.

Orbital Module (BO)

Soyuz spacecraft's Orbital Module

The forepart of the spacecraft is the orbital module ((in Russian): бытовой отсек (БО), Bitovoy otsek (BO)) also known as the Habitation section. It houses all the equipment that is not needed for reentry, such as experiments, cameras or cargo. Commonly, it is used as both eating area and lavatory. At its far end, it also contains the docking port. This module also contains a toilet, docking avionics and communications gear. On the latest Soyuz versions, a small window was introduced, providing the crew with a forward view.

A hatch between it and the descent module can be closed so as to isolate it to act as an airlock if needed with cosmonauts exiting through its side port (at the bottom of this picture, near the descent module). On the launch pad, cosmonauts enter the spacecraft through this port.

This separation also lets the orbital module be customized to the mission with less risk to the life-critical descent module. The convention of orientation in zero gravity differs from that of the descent module, as cosmonauts stand or sit with their heads to the docking port.

Reentry Module (SA)

Soyuz spacecraft's Descent Module

The reentry module ((in Russian): спускаемый аппарат (СА), Spuskaemiy apparat (SA)) is used for launch and the journey back to Earth. It is covered by a heat-resistant covering to protect it during re-entry. It is slowed initially by the atmosphere, then by a braking parachute, followed by the main parachute which slows the craft for landing. At one meter above the ground, solid-fuel braking engines mounted behind the heat shield are fired to give a soft landing. One of the design requirements for the reentry module was for it to have the highest possible volumetric efficiency (internal volume divided by hull area). The best shape for this is a sphere, but such a shape can provide no lift, which results in a purely ballistic reentry. Ballistic reentries are hard on the occupants due to high deceleration and can't be steered beyond their initial deorbit burn. That is why it was decided to go with the "headlight" shape that the Soyuz uses — a hemispherical forward area joined by a barely angled conical section (seven degrees) to a classic spherical section heat shield. This shape allows a small amount of lift to be generated due to the unequal weight distribution. The nickname was coined at a time when nearly every automobile headlight was a circular paraboloid.

Service Module (PAO)

Soyuz spacecraft's Instrumentation/Propulsion Module

At the back of the vehicle is the service module ((in Russian): приборно-агрегатный отсек (ПАО), Priborno-Agregatniy Otsek (PAO)). It has an instrumentation compartment ((in Russian): приборный отсек (ПО), Priborniy Otsek (PO)), a pressurized container shaped like a bulging can that contains systems for temperature control, electric power supply, long-range radio communications, radio telemetry, and instruments for orientation and control. The propulsion compartment ((in Russian): агрегатный отсек (АО), Agregatniy Otsek (AO)), a non-pressurized part of the service module, contains the main engine and a spare: liquid-fuel propulsion systems for maneuvering in orbit and initiating the descent back to Earth. The spacecraft also has a system of low-thrust engines for orientation, attached to the intermediate compartment ((in Russian): переходной отсек (ПхО), Perekhodnoi Otsek (PkhO)). Outside the service module are the sensors for the orientation system and the solar array, which is oriented towards the sun by rotating the spacecraft.

Re-entry procedure

Because its modular construction differs from that of previous designs, the Soyuz has an unusual sequence of events prior to re-entry. The spacecraft is turned engine-forward and the main engine is fired for de-orbiting fully 180° ahead of its planned landing site. This requires the least propellant for re-entry, the spacecraft traveling on an elliptical Hohmann orbit to a point where it will be low enough in the atmosphere to re-enter.

Early Soyuz spacecraft would then have the service and orbital modules detach simultaneously. As they are connected by tubing and electrical cables to the descent module, this would aid in their separation and avoid having the descent module alter its orientation. Later Soyuz spacecraft detach the orbital module before firing the main engine, which saves even more propellant, enabling the descent module to return more payload. In no case can the orbital module remain in orbit as an addition to a space station, for the hatch enabling it to function as an airlock is part of the descent module.

Re-entry firing is typically done on the "dawn" side of the Earth, so that the spacecraft can be seen by recovery helicopters as it descends in the evening twilight, illuminated by the sun when it is above the shadow of the Earth. Since the beginning of Soyuz missions to the ISS, only five have performed nighttime landings.

Soyuz MS improvements

The Soyuz MS received the following upgrades with respect to the Soyuz TMA-M:

• The fixed solar panels of the SEP (Russian: CЭП, Система Электропитания) power supply system have had their photovoltaic cell efficiency improved to 14% (from 12%) and collective area increased by 1.1 m² (12 sq ft).
• A fifth battery with 155 amp-hour capacity known as 906V was added to support the increased energy consumption from the improved electronics.
• Additional micro-meteoroid protective layer was added to the BO orbital module.
• The new computer (TsVM-101), weighs one-eighth that of its predecessor (8.3 kg versus 70 kg) while also being much smaller than the previous Argon-16 computer.
• While (As of July 2016) it is not known whether the propulsion system is still called KTDU-80, it has been significantly modified. While previously the system had 16 high thrust DPO-B and six low thrust DPO-M in one propellant supply circuit, and six other low thrust DPO-M on a different circuit, now all 28 thrusters are high thrust DPO-B, arranged in 14 pairs. Each propellant supply circuit handles 14 DPO-B, with each element of each thruster pair being fed by a different circuit. This provides full fault tolerance for thruster or propellant circuit failure. The new arrangement adds fault tolerance for docking and undocking with one failed thruster or de-orbit with two failed thrusters. Also, the number of DPO-B in the aft section has been doubled to eight, improving the de-orbit fault tolerance.
• The propellant consumption signal, EFIR was redesigned to avoid false positives on propellant consumption.
• The avionics unit, BA DPO (Russian: БА ДПО, Блоки Автоматики подсистема Двигателей Причаливания и Ориентации), had to be modified for changes in the RCS.
• Instead of relying on ground stations for orbital determination and correction, the now-included Satellite Navigation System ASN-K (Russian: АСН-К, Аппаратура Спутниковой Навигации) relies on GLONASS and GPS signals for navigation. It uses four fixed antennas to achieve a positioning accuracy of 5 m (16 ft), and aims to reduce that number to as little as 3 cm (1.2 in) and to achieve an attitude accuracy of 0.5°.
• The old radio command system, the BRTS (Russian: БРТС Бортовая Радио-техническая Система) that relied on the Kvant-V was replaced with an integrated communications and telemetry system, EKTS (Russian: ЕКТС, Единая Kомандно-Телеметрическая Система). It can use not only the Very high frequency (VHF) and Ultra high frequency (UHF) ground stations but, thanks to the addition of an S-band antenna, the Luch Constellation as well, to have theoretical 85% of real time connection to ground control. But since the S-band antenna is fixed and Soyuz spacecraft cruises in a slow longitudinal rotation, in practice this capability might be limited due to lack of antenna pointing capability. It may also be able to use the American TDRS and the European EDRS in the future.
• The old information and telemetry system, MBITS (Russian: МБИТС, МалогаБаритная Информационно-Телеметрическая Система), has been fully integrated into the EKTS.
• The old VHF radio communication system (Russian: Система Телефонно-Телеграфной Связи) Rassvet-M (Russian: Рассвет-М) was replaced with the Rassvet-3BM (Russian: Рассвет-3БМ) system that has been integrated into the EKTS.
• The old 38G6 antennas are replaced with four omnidirectional antennas (two on the solar panels tips and two in the PAO) plus one S-band phased array, also in the PAO.
• The descent module communication and telemetry system also received upgrades that will eventually lead to having a voice channel in addition to the present telemetry.
• The EKTS system also includes a COSPAS-SARSAT transponder to transmit its coordinates to ground control in real time during parachute fall and landing.
• All the changes introduced with the EKTS enable the Soyuz to use the same ground segment terminals as the Russian Segment of the ISS.
• The new Kurs-NA (Russian: Курс-НА) automatic docking system is now made indigenously in Russia. Developed by Sergei Medvedev of AO NII TP, it is claimed to be 25 kg (55 lb) lighter, 30% less voluminous and use 25% less power. An AO-753A phased array antenna replaced the 2AO-VKA antenna and three AKR-VKA antennas, while the two 2ASF-M-VKA antenna were moved to fixed positions further back.
• The docking system received a backup electric driving mechanism.
• Instead of the analog TV system Klest-M (Russian: Клест-М), the spacecraft uses a digital TV system based on MPEG-2, which makes it possible to maintain communications between the spacecraft and the station via a space-to-space RF link and reduces interferences.
• A new Digital Backup Loop Control Unit, BURK (Russian: БУРК, Блок Управления Резервным Контуром), developed by RSC Energia, replaced the old avionics, the Motion and Orientation Control Unit, BUPO (Russian: БУПО, Блок Управления Причаливанием и Ориентацией) and the signal conversion unit BPS (Russian: БПС, Блок Преобразования Сигналов).
• The upgrade also replaces the old Rate Sensor Unit BDUS-3M (Russian: БДУС-3М, Блок Датчиков Угловых Скоростей) with the new BDUS-3A (Russian: БДУС-3А).
• The old halogen headlights, SMI-4 (Russian: СМИ-4), have been replaced with the LED powered headlight SFOK (Russian: СФОК).
• A new black box SZI-M (Russian: СЗИ-М, Система Запоминания Информации) that records voice and data during the mission was added under the pilot's seat in the descent module. The dual unit module was developed at AO RKS corporation in Moscow with the use of indigenous electronics. It has a capacity of 4 Gb and a recording speed of 256 Kb/s. It is designed to tolerate falls of 150 m/s (490 ft/s) and is rated for 100,000 overwrite cycles and 10 reuses. It can also tolerate 700 °C (1,292 °F) for 30 minutes.

List of flights

Soyuz MS-02 in September 2016

Soyuz MS-05 docked to Rassvet during Expedition 53

Soyuz MS-15 ascending to orbit

Soyuz MS flights will continue until at least Soyuz MS-23, with regular crew rotation Soyuz flights being reduced from four a year to two a year with the introduction of Commercial Crew (CCP) flights contracted by NASA. Starting from 2021, Roscosmos is marketing the spacecraft for dedicated commercial missions ranging from ~10 days to six months. Currently, Roscosmos has three such flights booked, Soyuz MS-20 in 2021 and Soyuz MS-23 in 2022, plus a currently unnumbered flight scheduled for 2023.

Mission	Crew	Notes	Duration
Completed
Soyuz MS-01	Anatoli Ivanishin Takuya Onishi Kathleen Rubins	Delivered Expedition 48/49 crew to ISS. Originally scheduled to ferry the ISS-47/48 crew to ISS although switched with Soyuz TMA-20M due to delays.	115 days
Soyuz MS-02	Sergey Ryzhikov Andrei Borisenko Shane Kimbrough	Delivered Expedition 49/50 crew to ISS. Soyuz MS-02 marked the final Soyuz to carry two Russian crew members until Soyuz MS-16 due to Roscosmos deciding to reduce the Russian crew on the ISS.	173 days
Soyuz MS-03	Oleg Novitsky Thomas Pesquet Peggy Whitson	Delivered Expedition 50/51 crew to ISS. Whitson landed on Soyuz MS-04 following 288 days in space, breaking the record for the longest single spaceflight for a woman.	196 days
Soyuz MS-04	Fyodor Yurchikhin Jack D. Fischer	Delivered Expedition 51/52 crew to ISS. Crew was reduced to two following a Russian decision to reduce the number of crew members on the Russian Orbital Segment.	136 days
Soyuz MS-05	Sergey Ryazansky Randolph Bresnik Paolo Nespoli	Delivered Expedition 52/53 crew to ISS. Nespoli became the first European astronaut to fly two ISS long-duration flights and took the record for the second longest amount of time in space for a European.	139 days
Soyuz MS-06	Alexander Misurkin Mark T. Vande Hei Joseph M. Acaba	Delivered Expedition 53/54 crew to ISS. Misurkin and Vande Hei were originally assigned to Soyuz MS-04, although they were pushed back due a change in the ISS flight program, Acaba was added by NASA later.	168 days
Soyuz MS-07	Anton Shkaplerov Scott D. Tingle Norishige Kanai	Delivered Expedition 54/55 crew to ISS. The launch was advanced forward in order to avoid it happening during the Christmas holidays, meaning the older two-day rendezvous scheme was needed.	168 days
Soyuz MS-08	Oleg Artemyev Andrew J. Feustel Richard R. Arnold	Delivered Expedition 55/56 crew to ISS.	198 days
Soyuz MS-09	Sergey Prokopyev Alexander Gerst Serena Auñón-Chancellor	Delivered Expedition 56/57 crew to ISS. In August 2018, a hole was detected in the spacecraft's orbital module. Two cosmonauts did a spacewalk later in the year to inspect it.	196 days
Soyuz MS-10	Aleksey Ovchinin Nick Hague	Intended to deliver Expedition 57/58 crew to ISS, flight aborted. Both crew members were reassigned to Soyuz MS-12 and flew six months later on 14 March 2019.	19m, 41s
Soyuz MS-11	Oleg Kononenko David Saint-Jacques Anne McClain	Delivered Expedition 58/59 crew to ISS, launch was advanced following Soyuz MS-10 in order to avoid de-crewing the ISS.	204 days
Soyuz MS-12	Aleksey Ovchinin Nick Hague Christina Koch	Delivered Expedition 59/60 crew to ISS. Koch landed on Soyuz MS-13 and spent 328 days in space. Her seat was occupied by Hazza Al Mansouri for landing.	203 days
Soyuz MS-13	Aleksandr Skvortsov Luca Parmitano Andrew R. Morgan	Delivered Expedition 60/61 crew to ISS. Morgan landed on Soyuz MS-15 following 272 days in space. Christina Koch returned in his seat. Her flight broke Peggy Whitson's record for the longest female spaceflight.	201 days
Soyuz MS-14	N/A	Uncrewed test flight to validate Soyuz for use on Soyuz-2.1a booster. First docking attempted was aborted due to an issue on Poisk. Three days later, the spacecraft successfully docked to Zvezda.	15 days
Soyuz MS-15	Oleg Skripochka Jessica Meir Hazza Al Mansouri	Delivered Expedition 61/62/EP-19 crew to ISS. Al Mansouri became the first person from the UAE to fly in space. He landed on Soyuz MS-12 after eight days in space as part of Visiting Expedition 19.	205 days
Soyuz MS-16	Anatoli Ivanishin Ivan Vagner Christopher Cassidy	Delivered Expedition 62/63 crew to ISS. Nikolai Tikhonov and Andrei Babkin were originally assigned to the flight, although they were pushed back and replaced by Ivanishin and Vagner due to a medical issues.	195 days
Soyuz MS-17	Sergey Ryzhikov Sergey Kud-Sverchkov Kathleen Rubins	Delivered Expedition 63/64 crew to ISS. Marked the crewed first use of the "ultra-fast" three hour rendezvous with the ISS previously tested with Progress spacecraft.	185 days
Soyuz MS-18	Oleg Novitsky Pyotr Dubrov Mark T. Vande Hei	Delivered Expedition 64/65 crew to the ISS. Dubrov and Vande Hei were transferred to Expedition 66 for a year mission and returned to Earth on Soyuz MS-19 with Anton Shkaplerov after 355 days in space.	191 days
Soyuz MS-19	Anton Shkaplerov Klim Shipenko Yulia Peresild	Delivered one Russian cosmonaut for Expedition 65/66 and two spaceflight participants for a movie project called The Challenge. The two spaceflight participants returned to Earth on Soyuz MS-18 with Oleg Novitsky after eleven days in space.	176 days
Soyuz MS-20	Alexander Misurkin Yusaku Maezawa Yozo Hirano	Delivered one Russian cosmonaut and two Space Adventures tourists to the ISS. The crew spent 12 days in space.	12 days
Soyuz MS-21	Oleg Artemyev Denis Matveev Sergey Korsakov	Delivered three Russian cosmonauts for Expedition 66/67 crew to ISS.	194 days
Soyuz MS-22	Sergey Prokopyev Dmitry Petelin Francisco Rubio	Delivered Expedition 67/68 crew to ISS. All three crew members were transferred to Expedition 69 for a year mission due to a coolant leak and returned to Earth on Soyuz MS-23 after 371 days in space. MS-22 returned to Earth uncrewed.	187 days
Soyuz MS-23	-	Uncrewed flight to replace the damaged Soyuz MS-22, which had a coolant leak and returned to Earth uncrewed.	215 days
In-Progress
Soyuz MS-24	Oleg Kononenko Nikolai Chub Loral O'Hara	All three crew members were originally planned to fly on Soyuz MS-23, but they were pushed back due to a coolant leak on Soyuz MS-22, which returned to Earth uncrewed, that required MS-23 to be launched uncrewed as its replacement. Delivered Expedition 69/70 crew to ISS. Kononenko and Chub will be transferred to Expedition 71 for a year mission and return to Earth on Soyuz MS-25 with Tracy Caldwell Dyson after 374 days in space.	~ 180 days (planned)
Planned
Soyuz MS-25	Oleg Novitsky Marina Vasilevskaya Tracy Caldwell Dyson	Planned to rotate future ISS crew. Will deliver Expedition 70/71 crew to ISS. Novitsky and Vasilevskaya will return to Earth on Soyuz MS-24 with Loral O'Hara after twelve days in space.	~ 180 days (planned)
Soyuz MS-26	Aleksey Ovchinin Ivan Vagner Donald Pettit	Planned to rotate future ISS crew. Will deliver Expedition 71/72 crew to ISS.	~ 180 days (planned)
Soyuz MS-27	Sergey Ryzhikov Sergey Mikajew Kirill Peskov	Planned to rotate future ISS crew. Will deliver Expedition 72/73 crew to ISS.	~ 180 days (planned)
Soyuz MS-28	Sergey Kud-Sverchkov Aleksey Zabrickij TBA	Planned to rotate future ISS crew. Will deliver Expedition 73/74 crew to ISS.	~ 180 days (planned)
Soyuz MS-29	Oleg Artemyev TBA TBA	Planned to rotate future ISS crew. Will deliver Expedition 74/75 crew to ISS.	~ 180 days (planned)

External links

• www.russianspaceweb.com – The Soyuz MS spacecraft