Zvezda Service Module Celebrates 15 Years in Orbit

Through the commotion of a very successful July which included the New Horizons mission to Pluto, the 40th anniversary of the Apollo-Soyuz Test Project, the 46^th anniversary of Apollo 11, and the Museum’s very first Kickstarter project, there is one anniversary that we may have inadvertently overlooked. In July, the Zvezda (Russian for “star”) module of the International Space Station (ISS) celebrated 15 years in orbit. It is now the longest-serving piece of hardware in orbit that has supported human spaceflight. The Russian Zvezda component was the third module launched to the ISS, but first module that was inhabitable. Today it orbits the Earth while providing life support for up to six crewmembers. Its next milestone will be this November as it celebrates 15 years of continuous occupation. The Russian Rocket and Space Corporation Energia, launched Zvezda on July 12, 2000. At the time, the press noted the launch as the first use of advertisement on a launch vehicle. The Proton rocket that launched Zvezda displayed a Pizza Hut logo on the outside. The module permanently docked with the Russian powerhouse, Zarya (“Dawn,” launched November 1998). NASA astronauts had previously docked the American-built passive module, Unity, to Zarya. With the addition of Zvezda, the space station became habitable with the long-term life support needed to host international crews. Today, Zvezda still forms the basis of the habitable portion of the ISS. Zvezda consists of two cylindrical compartments: a work compartment where the crews work and live, and a cylindrical transfer chamber which has one docking port—an unpressurized assembly compartment surrounding the transfer chamber and a spherical transfer compartment with three docking ports. Zvezda weighs about 18,051 kilograms (39,796 pounds) and is 13.1 meters (43 feet) long. Its solar panels extend its width to 29.7 meters (97 feet) wide.

The module provides station living quarters, life support systems, electrical power distribution, data processing systems, flight control systems, and propulsion systems. It also provides a communications system that includes remote command capabilities from ground flight controllers. Zvezda also serves as the main docking port for Russian Soyuz and Progress spacecraft as well as the European Automated Transfer Vehicle. Zvezda has a history that predates its orbital history by almost as long as it has been in orbit. The basic structural frame of Zvezda is known as "DOS-8.” This means that it is the eighth design in a series of Soviet and Russian long-term orbiting space stations. The air frame (internal structure) was initially built in the mid-1980s to be the core of the Mir-2 space station that was proposed to replace the Soviet-launched Mir space station in the late 1980s. This origin means that Zvezda has a similar layout to the core module (DOS-7) of the Mir space station. It was in fact, labeled as "Mir-2" for quite some time in the factory. This also links its design lineage to the original Salyut stations (1971-1987). Engineers at the Khrunichev Design Bureau completed the space frame in February 1985 and installed major internal equipment by October 1986. From then, the structure remained in storage for 14 years amid repeated program cancellations and the prolonged negotiations among the member states of the International Space Station program.

The space station that the Zvezda module was to replace was the space station Mir. Mir was the world’s first modular space station. The USSR launched its base module in 1986, Mir became the first continually-inhabited modular space station. When it approached its 15th anniversary, the space station found itself in competition with NASA and other countries for Russian human spaceflight funding. Unable to inhabit and maintain two stations at once, the Russian government de-orbited Mir into the Pacific Ocean in 2001. If you happen to look up in the night sky at a time when the ISS is visible in your area, wish it a happy birthday and many more to come.