Zarya (Russian: Заря́; lit. dawn), also known as the Functional Cargo Block or FGB (from the Russian "Функционально-грузовой блок", Funktsionalno-gruzovoy blok or ФГБ), was the first module of the International Space Station to be launched.[1] The FGB provided electrical power, storage, propulsion, and guidance to the ISS during the initial stage of assembly. With the launch and assembly in orbit of other modules with more specialized functionality, Zarya is now primarily used for storage, both inside the pressurized section and in the externally mounted fuel tanks. The Zarya is a descendant of the TKS spacecraft designed for the Russian Salyut program. The name Zarya was given to the FGB because it signified the dawn of a new era of international cooperation in space.
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The FGB design was originally intended as a module for the Russian Mir space station, but was not flown as of the end of the Mir program. A FGB cargo block was incorporated as an upper stage engine into the Polyus spacecraft, flown (unsuccessfully) on the first Energia launch.[2] With the end of the Mir program, the design was adapted to use for the International Space Station.
Zarya was paid for by the United States space agency NASA and was built from December 1994 to January 1998 in Russia at the Khrunichev State Research and Production Space Center (KhSC) in Moscow.[1] Its control system was developed by the Khartron Corp. (Kharkiv, Ukraine). The module was included as part of NASA's plan for the International Space Station (ISS) instead of Lockheed's "Bus-1" option because it was significantly cheaper (US$220 million vs. $450 million). As part of the contract Khrunichev constructed much of an identical module (referred to as "FGB-2") for contingency purposes. FGB-2 has been proposed for a variety of projects; it is now slated to be used to construct the Russian Multipurpose Laboratory Module Nauka.
Zarya weighs 19,300 kilograms (43,000 lb), is 12.55 meters (41.2 ft) long and 4.1 meters (13 ft) wide at its widest point.
The module has three docking ports, one on each end, and one on the side. The Zvezda Service Module is attached to the aft port, the Pressurized Mating Adapter PMA-1 attached to the forward port connects to the Unity Module, and the side (axial or nadir) port was used to dock with either of Russian Soyuz or Progress spacecraft until the Rassvet module was docked there permanently. Zarya has two solar arrays measuring 10.67 by 3.35 meters (35.0 by 11.0 ft) and six nickel-cadmium batteries that can provide an average of 3 kilowatts of power. These have been retracted so the P1/S1 radiators could deploy. Zarya has 16 external fuel tanks that can hold over 5.4 metric tons of propellant. Zarya also has 24 large steering jets, 12 small steering jets, and two large engines that were used for reboost and major orbital changes; with the docking of Zvezda these are now permanently disabled. Since they are no longer needed for Zarya's engines, Zarya's propellant tanks are now used to store additional fuel for Zvezda.
Zarya was launched on November 20, 1998 on a Russian Proton rocket from Baikonur Cosmodrome Site 81 in Kazakhstan to a 400 km (250 mi) high orbit with a designed lifetime of at least 15 years. After Zarya reached orbit, STS-88 launched on December 4, 1998 to attach the Unity Module.
Although only designed to fly autonomously for six to eight months, Zarya was required to do so for almost two years due to delays to the Russian Service Module, Zvezda. Zvezda was finally launched on July 12, 2000, docking with Zarya on July 26 using the Russian Kurs docking system.
Zarya initially had problems with battery charging circuits, but these were resolved. It will eventually require supplemental micro meteor shielding, as it was given an exemption to the ISS rules when it launched.
Zarya passed the 50,000-orbit mark at 15:17 UTC on August 14, 2007 during the STS-118 mission to the International Space Station.
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