Massive Sunnyvale-Built Solar Arrays Launched to International Space Station
The first of
four pairs of massive solar arrays for the International Space
Station, built at Lockheed Martin Space Systems in Sunnyvale, were
launched aboard the space shuttle Endeavour to the International Space
Station on November 30, 2000. During the 12-day mission, astronauts
will connect the package of giant solar arrays and associated
electronics, batteries, radiators, and support structure to the
Station. Subsequent pairs of arrays will be delivered on shuttle
flights currently scheduled for 2002, 2003, and 2006.
“We’re enormously pleased to see the first pair of flight wings
headed for the International Space Station, while work continues here
on the remaining flight articles, ” said Ron Paulson, Vice President,
Remote Sensing and Space Science, at Space Systems in Sunnyvale. “A
very thorough series of tests and analysis has demonstrated to us that
this complex technology will harness the Sun’s energy for the Space
Station and provide the power required for many years to come on this
vitally important international mission.”
The functional testing of the solar array flight hardware has
involved several extension and retraction cycles of the 107-foot
deployment mast and solar array blankets. Additionally, all individual
solar panel circuits have been flash-tested with simulated sunlight to
verify output power. Further, a close inspection has ensured that
individual solar cells can withstand the harsh environment of space
while converting sunlight into electricity. Arrays have also been
exposed to harsh vacuum and thermal environments that simulate
conditions 200 miles above the Earth’s surface, and tested further in
an acoustic chamber to simulate the violent shaking vibrations that
accompany launch aboard the Space Shuttle. The technology has already
been flight proven in a demonstration prototype solar array
replacement flown by NASA and Space Systems on the Russian MIR space
station.
The Space Systems ISS solar arrays are the largest deployable
space structure ever built and will be by far, the most powerful
electricity-producing arrays ever put into orbit. When the Station is
completed a total of eight flexible, deployable solar array wings will
generate the reliable, continuous power for the on-orbit operation of
the ISS systems. The eight array wings were designed and built under a
$450 million contract from the Boeing-Rocketdyne Division in Canoga
Park, Calif., for delivery to the Boeing Company and NASA.
Each of the eight wings consists of a mast assembly and two solar
array blankets. Each blanket has 84 panels, of which 82 are populated
with solar cells. Each panel contains 200 solar cells. The eight
photovoltaic arrays thus accommodate a total of 262,400 solar cells.
When fully deployed in space, the active area of the eight wings, each
107 by 38-feet, will encompass an area of 32,528-sq. ft., and will
provide power to the ISS for 15 years.
In addition to the arrays, Space Systems in Sunnyvale has also
designed and built other elements for the Space Station that will be
launched on future shuttle missions. Rotary mechanical joints for the
ISS will move the solar arrays and thermal radiators into positions
relative to the Sun that will optimize their individual functions.
These mechanical joints are the largest mechanisms ever designed to
operate in a space environment.
The two Solar Alpha Rotary Joints (SARJ) are each 10.5 ft diameter
and 40 inches long. Their purpose is to maintain the solar arrays in
an optimal orientation to the Sun while the entire Space Station
orbits the Earth once every 90 minutes. Drive motors in each SARJ will
move the arrays through 360 degrees of motion at four degrees per
minute.
The Thermal Radiator Rotary Joints (TRRJ) are each five and a half
feet long and three feet in diameter. Their purpose is to maintain the
Space Station thermal radiators in an edge-on orientation to the sun
that maximizes the dissipation of heat from the radiators.
Space Systems has also produced the Trace Contaminant Control
System, an advanced air processing and filtering system that will
ensure that over 200 various trace chemical contaminants, generated
from material off-gassing and metabolic functions in the Space Station
atmosphere, remain within allowable concentration levels. It will
become an integral part of the Space Station’s Cabin Air
Revitalization Subsystem.
Lockheed Martin Space Systems in Sunnyvale, CA, is a leading
supplier of satellites and space systems to military, civil government
and commercial communications organizations around the world. These
spacecraft and systems have enhanced military and commercial
communications; provided new and timely remote-sensing information;
and furnished new data for thousands of scientists studying our planet
and the universe.
For more information, high and low resolution photos of the solar
array, see our website at http://lmms.external.lmco.com
