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Zarya, which means 'Dawn' when
translated to English, is a US component of the station although it
was built and launched by Russia. The module was built by the
Khrunichev State Research and Production Space Center (KhSC) in
Moscow, under a subcontract to The Boeing Company for NASA.
Zarya will provide orientation
control, communications and electrical power and was attached to Unity
for several months before the launch of the third component, "Zvezda",
a Russian-provided crew living quarters and early station core also
known as the Service Module. The Service Module enhances or replace
many functions of Zarya. Later in the station's assembly sequence, the
Zarya module will be used primarily for its storage capacity and
external fuel tanks.
Zarya's solar arrays and six
nickel-cadmium batteries can provide an average of 3 kilowatts of
electrical power. Each of the two solar arrays is 10.7 metres long and
3.4 metres wide. Using the Russian 'Kurs' rendezvous system, Zarya
performed an automated and remotely piloted rendezvous and docking
with Zvezda, the Service Module in orbit. Its docking ports can
accommodate Soyuz piloted spacecraft and unpiloted Progress re-supply
spacecraft. The module has been modified to allow it to be refueled by
a Progress vehicle docked to its down-facing port if necessary.
Zarya's 16 fuel tanks combined
can hold more than 6 tonnes of propellant. The attitude control system
for the module includes 24 large steering jets and 12 small steering
jets. Two large engines are available for reboosting the space station
and making major orbital changes. Construction of the Zarya module
began at KhSC in 1994 December. It was shipped to the Baikonur
Cosmodrome to begin launch preparations 1998 January.
After reaching the initial
elliptical orbit and separating from the Proton's third stage, a set
of pre-programmed commands automatically activated the module's
systems and deployed the solar arrays and communications antennas
(although the latter gave problems and had to be assisted to full
deployment by space walking astronauts). On ensuing days after several
operational tests, the module was commanded to fire its engines and
circularise its orbit at an altitude of about 390 kilometres.
The module was named Zarya in
tribute to the new beginning in space that was ushered in by its
launch as the first component of the International Space Station. The
module is symbolic of the dawn of a new era of joint space flight
between all of the station's international partners. In orbit, Zarya
sees 16 new sunrises every 24 hours, one on each revolution of Earth.
Its launch was the dawn of a new
era of human space flight, the beginning of an international venture
of unprecedented scale. |
