Rocketdyne
Propulsion & Power
International Space Station
The
Rocketdyne Propulsion & Power business of The Boeing Company, is
responsible for the end-to-end electric power system (EPS) architecture for the
International Space Station. The EPS provides all user and housekeeping
electrical power and is capable of expansion as the station is assembled and grows. The EPS
consists of power generation and energy storage subsystems that feed power into the
Power Management and Distribution (PMAD) subsystem.
A
photovoltaic (PV) power generation subsystem was selected for the Space
Station. A PV system has solar arrays for power generation and chemical energy
storage (batteries) to store excess solar array energy during periods of
sunlight and provide power
during periods of shade.
Power for
the Space Station will be provided by flexible, deployable solar array wings.
This configuration minimizes the complexity of the assembly process by taking advantage of the technology
demonstrated on Space Shuttle flight STS-41B. Each 39-foot by 112-foot (11.9m by 34.2m)
wing consists of two blanket assemblies covered with solar cells. Each pair of
blankets is to be deployed
and supported by an extendable mast.
The
primary purpose of the Energy Storage Subsystem (ESS) is to provide electrical
power during the eclipse portion of each orbit. The ESS stores energy for this purpose during the
isolation portion of the orbit and is capable of providing both peaking and contingency power. The ESS
consists of six nickel-hydrogen (Ni-H2) batteries, each with a dedicated
battery charge/discharge
unit (BCDU).
The Ni/H2
battery design has been chosen for the Space Station because of its high energy
density (lightweight) and proven heritage in space applications since the early 1970's. The 160-volt, DC
Power Management and Distribution (PMAD) system is designed specifically to meet
aerospace system requirements. The system is based upon rapid semiconductor
switching DC to DC Converter
Units (DDCUs) and electromechanical devices to tailor voltage and energy levels
of the system.
The
overall distribution equipment will include cables, load converters,
regulators, switches and other electrical equipment. The overall distribution subsystem will
be composed of equipment necessary to process, control and distribute power to
other station subsystems,
elements and attached payloads.
Rocketdyne
is also responsible for providing photovoltaic array blankets that provide
power to the Russian elements of the Space Station and for integrating Russian
power sources.
In
addition to their role in the International Space Station, Rocketdyne designs
and develops the Space Shuttle Main Engine (the only large reusable liquid-fueled
rocket engine in the world), engines for Delta II and Delta III, the RS-68
engine for the Boeing Delta IV
family of expendable launch vehicles, the linear aerospike engine for NASA's
X-33 prototype reusable launch vehicle (RLV), and propulsion systems for kinetic energy weapons