Soyuz MS explained

Soyuz MS
Russian: Союз МС
Country:Russia
Operator:Roscosmos
Spacecraft Type:Human spaceflight
Design Life:200 days when docked to the International Space Station (ISS)
Manufacturer:Energia
Crew Capacity:3
Batteries:755 Ah
Orbits:Low Earth orbit
Status:Active
Built:26
Orders:3
Launched:26 (as of 11 September 2024)
Operational:1 (MS-26)
Retired:24
Failed:1 (MS-10)
First:7 July 2016 (MS-01)
Last:Active
Derivedfrom:Soyuz TMA-M
Flown With:Soyuz FG (2016–2019)
Soyuz 2.1a (2020–)
Previous:Soyuz TMA-M
Next:Orel

The Soyuz MS (; GRAU: 11F732A48) is the latest version of the Russian Soyuz spacecraft series, first launched in 2016. The "MS" stands for "modernized systems," reflecting upgrades primarily focused on the communications and navigation subsystems. An evolution of the Soyuz TMA-M spacecraft, the Soyuz MS features minimal external changes, mainly in the placement of antennas, sensors, and thrusters. It is used by Roscosmos for human spaceflight missions.

Soyuz MS-01 conducted its maiden flight on 7 July 2016, heading to the International Space Station (ISS). The mission included a two-day checkout phase to validate the spacecraft’s new design before docking with the ISS on 9 July 2016. After remaining docked to the ISS for 113 days, the crew of MS-01 returned to Earth on 30 October 2016, safely landing on the Kazakh Steppe.

The spacecraft has experienced one in-flight abort during the Soyuz MS-10 mission. Shortly after the four boosters of its Soyuz FG carrier rocket separated, one collided with its core stage. The spacecraft’s onboard computer activated the launch escape system, which performed flawlessly, quickly pulling the reentry and orbital modules away from the failing rocket. Once at a safe distance, the system jettisoned the reentry module, allowing it to descend to the ground under parachutes. The crew landed unharmed.

Design

Like all previous variants, the Soyuz MS spacecraft consists of three parts (from forward to aft in space and top to bottom when mounted on a rocket):

The orbital and descent modules contain the pressurized habitable living space. By moving as much equipment and space as possible into the orbital module, which does not have to be shielded or decelerated during re-entry, the Soyuz three-part craft is larger and lighter than two-part designs. By comparison, the Apollo spacecraft's pressurized command module provided a crew of three 6m2 of living space and had a reentry mass of ; while the Soyuz MS provides the same crew with 10m2 of living space while the reentry module weighs .

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.[1]

The vehicle is protected during launch by a nose fairing with a launch escape system, which is jettisoned after passing through the atmosphere. The spacecraft is highly automated, and its Kurs system is capable of navigating to an automatic docking at the ISS. However, a pilot can operate the spacecraft independently of ground control if necessary.

Orbital module

The forward-most section of the spacecraft is the orbital module, also referred to as the habitation module.

The module features three ports. The forward port is used for docking with the ISS, the side port is used for crew entry during ground operations and potential spacewalks, and the aft port connects to the reentry module.

Designed for multiple purposes, the orbital module provides living space for the crew while in orbit, including a toilet and additional room compared to the confined reentry module. It can hold over of cargo during launch. Since the module is jettisoned and destroyed before reentry, it is typically packed with up to of waste before being sealed off.

The modular design enables customization for specific missions without compromising the critical systems of the reentry module. In zero gravity, the module’s orientation differs from the reentry module's, with cosmonauts standing or sitting with their heads toward the docking port.

The orbital module of the Soyuz MS includes a small forward-facing window, which allows the crew, particularly the flight engineer, to assist the commander with manual docking if automated systems fail.

A hatch between the orbital and descent modules can be sealed, allowing the orbital module to serve as an airlock. Cosmonauts could theoretically exit through the side port, though this feature has never been used, as the ISS provides larger, dedicated airlocks. The side port is the crew’s entry point when boarding the spacecraft on the launch pad.

Compared to previous versions, the orbital module of the Soyuz MS has additional anti-meteoroid shielding.[2]

Descent module

The mid-section of the spacecraft is the reentry module . It is where the crew is seated 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 generates a small amount of lift due to the unequal weight distribution. The nickname was coined when nearly every automobile headlight was a circular paraboloid.

Instrumentation/propulsion module

The aft-most section of the spacecraft is the instrumentation/propulsion module, also referred to as the service module or aggregate compartment. It is subdivided into three main sections: the intermediate compartment, the instrumentation compartment, and the propulsion compartment.

The instrumentation compartment, is a pressurized container shaped like a bulging can that contains systems for temperature control, electric power supply, long-range communications, telemetry, and instruments for orientation and control. The propulsion compartment, 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 . 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, the Soyuz spacecraft detaches the orbital module before firing the main engine, which saves even more propellant and enables the descent module to return more payload. The orbital module cannot remain in orbit as an addition to a space station, as the hatch, which enables it to function as an airlock, is part of the descent module.

The parachute system is activated at an altitude of about . Two pilot parachutes deploy first, followed by a drogue chute that slows the spacecraft from NaNm/s. The main parachute then deploys, further reducing the descent rate to 7.2m/s. The heat shield is jettisoned at an altitude of about, revealing six solid-propellant soft-landing motors that fire just 1m (03feet) above the ground, slowing the descent rate to less than 2m/s. The seats inside the descent module, which are fitted with shock absorbers and liners custom molded to each crew member's body shape, cushion the final impact.[3]

Soyuz missions typically land in the evening so that recovery helicopters can more easily see the spacecraft as it descends in the 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.[4]

Soyuz MS improvements

The Soyuz MS received the following upgrades with respect to the Soyuz TMA-M:[5] [6] [7]

List of flights

External links

Notes and References

  1. Web site: Транспортный пилотируемый корабль "Союз ТМ" .
  2. Web site: Zak . Anatoly . 15 November 2024 . Soyuz-MS spacecraft . 23 November 2024 . RussianSpaceWeb.com.
  3. Web site: Way back to Earth . 6 October 2024 . www.esa.int . en.
  4. Web site: Soyuz Trio set for rare Nighttime Landing on Friday – ISS Expedition 45 .
  5. Zak . Anatoly . 5 July 2016 . Russia's Workhorse Soyuz Space Taxi Gets a Makeover . 6 July 2016 . Popular Mechanics.
  6. Web site: Zak . Anatoly . 8 July 2016 . Soyuz MS spacecraft . 6 July 2016 . RussianSpaceWeb.com.
  7. The New, Improved Soyuz Spacecraft . 8 July 2016 . Navias . Rob . NASA JSC . Space Station Live . 9 July 2016 . YouTube.
  8. Web site: Zak . Anatoly . 8 July 2016 . The Kurs-NA docking system for Soyuz MS . 9 July 2016 . RussianSpaceWeb.com.
  9. Web site: Harding . Pete . 28 July 2012 . Progress M-15M re-docks to ISS following resolution of Kurs-NA failure . 1 September 2012 . NASASpaceFlight (not associated with NASA).
  10. Web site: Zak . Anatoly . 7 July 2016 . The EKTS communications system for Soyuz MS spacecraft . 6 July 2016 . RussianSpaceWeb.com.
  11. Web site: Zak . Anatoly . 7 July 2016 . Propulsion system for the Soyuz MS spacecraft . 6 July 2016 . RussianSpaceWeb.com.
  12. Web site: Zak . Anatoly . 3 July 2016 . Soyuz rocket flies critical test mission with Progress-MS . 6 July 2016 . RussianSpaceWeb.com.
  13. Web site: 30 June 2016 . ru:Для нового корабля "Союз-МС" создали многоразовый "черный ящик" . New reusable black box for the Soyuz MS . http://ria.ru/science/20160630/1455160339.html . 9 July 2016 . Ria Novosti . Russian.
  14. Web site: Zak . Anatoly . 7 July 2016 . "Black Box" for the Soyuz MS spacecraft . 6 July 2016 . RussianSpaceWeb.com.
  15. Web site: 4 July 2016 . Launch vehicle with Soyuz MS spacecraft is on the launch pad . 6 July 2016 . Energia.
  16. Web site: First Soyuz MS flies . www.russianspaceweb.com.
  17. Web site: Soyuz MS-07 to carry fresh crew to ISS . www.russianspaceweb.com.
  18. Web site: 20 March 2020 . Грузовой корабль "Прогресс" полетит к МКС по сверхбыстрой схеме .
  19. 1484043796467929088 . roscosmos . В случае подписания между Роскосмосом и @NASA соглашения о «перекрестных» полетах на МКС Анну Кикину планируется вв… . 20 January 2022.