| | NASA - Zvezda Service Module |
 | | The Service Module was the first fully Russian contribution to the International Space Station and serves as the early cornerstone for the first human habitation of the station. |
 | | The module provides the early station living quarters, life support system, electrical power distribution, data processing system, flight control system and propulsion system. |
 | | Although many of these systems are being supplemented or replaced by U.S. station components, the Service Module will always remain the structural and functional center of the Russian segment of the International Space Station. |
| www.nasa.gov /mission_pages/station/structure/elements/sm.html (156 words) |