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