ISS Russian Segment

Service Module Zvezda

Service module Zvezda

Service module Zvezda

Service Module Zvezda is the main (core) module of the ISS Russian Segment.


  • controlling the ISS Russian Segment (that is, controlling all the other ISS RS);
  • providing attitude control for the entire space station from ISS RS side;
  • providing life support for the space station crew;
  • interactions during integrated control of the entire ISS, provided by the central computer of the US segment located in the LAB module.

Key specifications

Parameter Value

Mass in orbit after separation from the LV, kg

20 295

Body length, mm

13 110

Maximum diameter, mm

4 350

Volume of pressurized compartments, m3


Crew habitable volume, m3


Life support for the crew of

up to 6

Solar array wing span, mm

29 730

The area of photovoltaic elements, m2


Maximum solar array output power, kW


Major onboard systems of the Service Module that are responsible for its control through all the mission phases: the onboard equipment control system, guidance, navigation and control system and the onboard digital computer system were developed on the basis of experience gained in the Mir space station construction, taking into account new functions that are driven by the ISS RS operation as a part of the space station and its interfaces with the US segment.

Structurally, SM Zvezda consists of four compartments: three pressurized compartments - Transfer Compartment, Work Compartment and Transfer Chamber, as well as unpressurized Propulsion Compartment, which houses a Combined Propulsion Unit.

The Transfer Compartment is intended to provide crew transfer between SM and other ISS modules. It also serves as an airlock during spacewalks. The outer surface is covered with MLI panels and micrometeoroid shields. Transfer Compartment has four windows.

The Work Compartment is intended for accommodating the major part of the SM onboard systems and equipment supporting crew life and work. The total length of the Work Compartment is 7.7 m, the pressurized volume with the equipment is 75.0 m3, the crew habitable volume is 35.1 m3. Interior panels separate the living area from instrumentation area, as well as from the Work Compartment body. The Work Compartment has eight windows. The living areas in the Work Compartment are equipped with crew life support equipment. Located in the smaller diameter area of the Work Compartment is the central station for space station control including control units and caution and warning panels. Located in the larger diameter area of the Working Compartment are two personal crew cabins, sanitary compartment with a washstand and sanitation unit, a galley with refrigerator/freezer, working table with restraints, medical equipment, equipment for physical exercise, a small airlock to dispose of waste containers and launch small satellites.

On the outside, the body of the Work Compartment is covered with multilayer insulation (MLI). Installed on the cylindrical parts are radiators, which also serve as micrometeoroid shields. The areas that are left unprotected by the radiators are covered with honeycomb carbon plastic shields.

The transfer chamber is intended for crew transfer between SM and Soyuz/Progress spacecraft docked to the rear docking port. For external observations, the transfer chamber has two windows, and there is a TV camera attached to it on the outside.

The transfer chamber has one passive docking port located along the SM longitudinal axis. The port is intended for docking of cargo and transportation spacecraft, including Russian spacecraft Soyuz TM, Soyuz TMA, Soyuz TMA-M, Soyuz MS, Progress M, Progress M-M and Progress MS, as well as European automatic spacecraft ATV. For external observations, the transfer chamber has two windows, and there is a TV camera attached to it on the outside.

The propulsion compartment contains combined propulsion system hardware.

Service Module Zvezda was launched on July 12, 2000, at 8 h 56 min 6 s Moscow Daylight Saving Time. Zvezda module docked with the Zarya + Unity modules which had docked earlier on the fourteenth day of its free flight on July 26, at 4 h 45 min Moscow Daylight Saving Time.

July 26 through November 2, 2000, the Service Module stayed within ISS in the so called "unmanned" mode. On August 6, cargo spacecraft Progress M1-3 was launched, which delivered to SM the hardware (about 615 kg) for outfitting its onboard systems to support the space station operation with the crew onboard. On September 8, 2000, launched along with US astronauts onboard a Space Shuttle (Atlantis STS-106 2.2) were Y.I. Malenchenko and B.V. Morukov. They unloaded Progress M1-3, installed service equipment, carried out adjustment, repair and maintenance on the SM onboard systems in order to prepare them for the arrival of the first expedition ISS-1.

On November 2, 2000, the International Space Station began to be operated in continuous manned mode.

Service module Zvezda as a part of ISS

Service module Zvezda as a part of ISS

ISS Crew

Hoshide  AkihikoHoshide

leg Novitskiy Novitskiy

Petr Dubrov Dubrov

Mark Vande Hei Vande Hei

Robert Shane

Megan McArthur McArthur