Service module

A service module (also known as an equipment module or instrument compartment) is a component of a

Depending upon the spacecraft architecture and system design, a typical service module usually contain the following:[1]^[2]

• batteries
  to provide electrical power to the spacecraft (batteries are also used in the crew capsule)
• Liquid hydrogen (LH₂) and liquid oxygen (LOX) for fuel cell operation and water production, with LOX also being used to provide breathing oxygen for the crew.
• Pressurized helium or nitrogen to force consumables and fuel from source tanks to their destinations.
• Guidance computer systems and related sensors
• Fuel and oxidizer for reaction control and propulsion systems.
• Thermal control systems for proper heating and cooling of above systems.

While this would be used for a "baseline" service module, a service module may also be modified for additional functions. An example would be the equipment module on

A unique inhabitable variation of the service module concept is the Functional Cargo Block developed for the Soviet TKS Transport Supply Spacecraft. In addition to full functionality of a service module, it featured a sizeable pressurized cargo bay, and a docking port – as opposed to its conventional location on the front of the re-entry capsule, which in case of the TKS instead possessed its own downscaled service module with de-orbiting thrusters – allowing the FGB to remain docked as an extension of the space station.^{[citation needed]}

Operating service modules

Zvezda (ISS module)

The Zvezda Service Module, is a module of the

At the back of the Soyuz spacecraft is the Service Module. It has a pressurized container shaped like a bulging can (instrumentation compartment, priborniy otsek) that contains systems for temperature control, electric power supply, long-range radio communications, radio telemetry, and instruments for orientation and control. A non-pressurized part of the Service Module (propulsion compartment, agregatniy otsek) contains the main engine and a liquid-fuelled propulsion system for maneuvering in orbit and initiating the descent back to Earth. Outside the Service Module are the sensors for the orientation system and the solar array, which is oriented towards the Sun by rotating the ship.

Shenzhou service module

The aft service module of the Shenzhou spacecraft contains life support and other equipment required for the functioning of Shenzhou. Two pairs of solar panels, one pair on the service module and the other pair on the orbital module, have a total area of over 40 m2 (430 ft²), indicating average electrical power over 1.5 kW.

European Service Module (Orion)

The European Service Module is the service module component of the Orion spacecraft, serving as its primary power and propulsion component until it is discarded at the end of each mission. The service module supports the crew module from launch through separation prior to reentry. It provides in-space propulsion capability for orbital transfer, attitude control, and high altitude ascent aborts. It provides the water and oxygen needed for a habitable environment, generates and stores electrical power, and maintains the temperature of the vehicle's systems and components. This module can also transport unpressurized cargo and scientific payloads.^[2]

List of past service modules

Retired

• Vostok equipment module
• Voskhod equipment module
• Gemini equipment module
• Apollo Service Module
• Apollo Lunar Module descent stage

Canceled

• CSTS service module (canceled)
• Kliper service module (canceled)
• Hermes resource module
  (canceled)

See also

• Orbital module
• Reentry capsule
• Command module (disambiguation)
• Space capsule

References