Zarya

From Wikipedia, the free encyclopedia

Zarya module as seen from STS-88 (NASA)

Zarya (Russian: Заря́; lit. sunrise), also known as the Functional Cargo Block or the FGB (the Russian acronym for "функционально-грузовой блок"), was the first module launched of the International Space Station. The FGB provided electrical power, storage, propulsion, and guidance to the ISS during the initial stage of assembly. As other modules with more specialized functionality are constructed, the Zarya's role will primarily be storage, both inside the pressurized section and in the externally mounted fuel tanks.

It is officially owned and paid for by the United States, but it was built from December 1994 to January 1998 in Russia in the Khrunichev State Research and Production Space Center (KhSC) in Moscow. It was included as part of the plan instead of Lockheed's 'Bus-1' option because it would be significantly cheaper ($220 million vs. $450 million). As part of the contract, Khrunichev constructed most of an identical module (referred to as "FGB-2") for contingency purposes. This has been proposed for a variety of projects, including a potential replacement for Progress spacecraft, the Docking and Stowage module, the Universal Docking module, a commercial space module, or an independent space station.

Launch of Zarya module

The Zarya is a descendant of the TKS spacecraft designed for the Russian Salyut program. It weighs 19,300 kg (42,600 pounds). It is 12.55 m (41.2 feet) long and 4.1 m (13.5 feet) wide at its widest point. It was launched on a Russian Proton rocket from Baikonur Cosmodrome, Kazakhstan, on November 20, 1998 to a 400 km (250 statute mile) high orbit, with a designed lifetime of at least 15 years.

After Zarya reached orbit, the Space Shuttle Endeavour 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 fly autonomously for almost two years due to delays to the Russian Service Module, Zvezda. Finally, on July 12, 2000, Zvezda was launched and docked on July 26 using the Russian Kurs system.

Zarya has three docking ports, one on each end, and one on the side. Zvezda is attached to one of the ends, the Unity Module to the other, with the side (the axial or nadir port) used to dock with either a Russian Soyuz or a Progress spacecraft. It has two solar arrays, measuring 10.67 m by 3.35 m, and six nickel-cadmium batteries that can provide on average 3 kilowatts of power. Zarya has 16 external fuel tanks that can hold over 6 metric tons of propellant, with 24 large steering jets, 12 small steering jets, and two large engines for reboost and major orbital changes.

The name "Zarya", meaning "Sunrise" in Russian, was given to the FGB because it signified the dawn of a new era of international cooperation in space.

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.