"6_10_2.TXT" (13431 bytes) was created on 12-07-87 WORK PACKAGE 1 Marshall Space Flight Center is responsible for Space Station Program Work Package 1, including responsibility for the laboratory module, habitation module, logistics elements and fabrication of the primary structure for the resource nodes. Marshall also is responsible for development of the environmental control and life support system, internal components of the audio/visual and thermal control systems, as well as for operational capability development for users in the laboratory module. The Johnson Space Center, through special provisions within the Work Package 1 contact, will exercise technical direction for the manned space subsystems. LABORATORY MODULE The U.S. laboratory module will be cylindrical, measuring approximately 44 feet long and 14 feet in diameter and will provide a shirt-sleeve environment for performing laboratory functions. The laboratory module will be capable of supporting multi-discipline payloads including materials research and development activities, materials processing demonstrations, life sciences research and other space science investigations requiring a pressurized area. User-provided equipment that can be housed in the laboratory module include furnaces for growing semiconductor crystals, electrokinetic devices for separating pharmaceuticals, support equipment needed to carry out a wide spectrum of low-gravity experiments and applications, and a centrifuge for variable gravity experiments in life sciences. HABITATION MODULE Facilities for eating, sleeping, personal hygiene, waste management, recreation, health maintenance and other functions requiring pressurized space will be provided in the habitation module. The module will be the same size as the laboratory module and will accommodate up to 8 astronauts. Using the health maintenance facility, astronauts will be able to monitor their health through vital signs, X-rays and blood samples. There also will be exercise equipment for daily physical conditioning. LOGISTICS ELEMENTS These include elements required for transporting cargo to or from the Space Station for the resupply of items required for the crew, station, and payloads; and for on-orbit storage of these cargos. A key element will be the pressurized logistics carrier, which will carry items used inside the Space Station modules. The other elements include unpressurized logistics carriers used for transporting spares used external to the Space Station modules, fluids and propellants. ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM (ECLSS) The ECLSS will provide a shirt-sleeve environment for the astronauts in all pressurized modules on the Space Station. A key feature is the regenerative design employed in the air revitalization and water reclamation systems. RESOURCE NODE STRUCTURE The resource nodes are required to interconnect the primary pressurized elements of the manned portion of the Space Station and also will house certain key control functions. The equipment provided by Work Package 1 consists of the resource node structures, berthing mechanisms, racks, ECLSS, internal thermal control, and internal audio and video communication systems. WORK PACKAGE 2 NASA's Johnson Space Center is responsible for the design, development, verification, assembly and delivery of the Work Package 2 Space Station flight elements and systems, which include the integrated truss assembly, propulsion assembly, mobile servicing system transporter, resource node design and outfitting, external thermal control, data management, operations management, communication and tracking, extravehicular systems and guidance, navigation and control systems, and the airlocks. JSC also is responsible for the attachment systems to the STS for its periodic visits. Additionally, JSC is responsible for flight crews, crew training and crew emergency return definition, and for operational capability development associated with operations planning. JSC will provide technical direction to the contractor for the design and development of all manned space subsystems. INTEGRATED TRUSS ASSEMBLY The integrated truss assembly is the Space Station structural framework to which the modules, solar power arrays, external experiments, Earth- and astronomical-viewing instruments, and mobile transporter will be attached. PROPULSION ASSEMBLY The propulsion assembly will be used to adjust or maintain the orbit of the Space Station to keep it at the required altitude. Work package 2 has responsibility for the overall propulsion system. Technical direction for the thruster assembly elements of the propulsion system will be provided by MSFC. MOBILE TRANSPORTER SYSTEM The mobile servicing system will be a multi-purpose mechanism equipped with robotic arms to help assemble and maintain the Space Station. The contractor will build the mobile base; Canada will provide the mobile servicing system which includes robotic arms and special purpose dextrous manipulators. RESOURCE NODES The resource nodes house most of the command and control systems for the Space Station as well as being the connecting passageways for the habitation and laboratory modules. Work Package 2 will outfit the node structures provided by Work Package 1 to accomplish the objectives of each node. EVA SYSTEMS Extravehicular activity (EVA) systems includes equipment such as the extravehicular mobility unit (EMU) or spacesuit, provisions for communication, physiological monitoring, and data transmission, EVA crew rescue and equipment retrieval provision, and EVA procedures. Airlocks for crewmember extravehicular activity also will be designed as part of Work Package 2. EXTERNAL THERMAL CONTROL The external thermal system provides cooling and heat rejection to control temperatures of electronics and other Space Station hardware located outside the modules and nodes. ATTACHMENT SYSTEMS In addition to devices permitting Space Station docking by the Space Shuttle and logistics resupply modules, this includes systems for attaching experiment packages and other external hardware to the truss structure. GUIDANCE, NAVIGATION AND CONTROL SYSTEM (GN&C) The guidance, navigation and control system is composed of a core system and traffic management functions. The core system function provides attitude and orbital state maintenance, supports the pointing of the power system and thermal radiators, accomplishes periodic reboost maneuvers, and provides Space Station attitude information to other systems and users. The traffic management function provides for controlling all traffic in the area around the Space Station, including docking and berthing operations and trajectories determination of vehicles and objects which may intersect the orbit of the Space Station. COMMUNICATIONS AND TRACKING SYSTEM (C&T) The communications and tracking system is composed of six subsystems: space-to-space communications with crew members during extravehicular activity, aboard the Space Shuttle, and with the Orbital Maneuvering Vehicle; space-to-ground communications through the Tracking and Data Relay Satellite System to ground data networks; internal and external voice communication through the audio subsystem; internal and external video requirements through the video subsystem; management of C&T resources and data distribution through the control and monitor subsystem; and navigation data through the tracking subsystem. DATA MANAGEMENT SYSTEM (DMS) The data management system provides the hardware and software resources that interconnect onboard systems, payloads, and operations to perform data and information management. Functional services provided by DMS include data processing, data acquistion and distribution, data storage, and the user interface to permit control and monitoring of systems and experiments. Crew safety is an essential consideration in the development of the Space Station. A major system failure aboard the Space Station, injuries or illness may require the return of crew members to Earth during a period when the Space Shuttle is unavailable. NASA's Johnson Space Center has responsibility for conducting definition-phase studies of a Crew Emergency Return Vehicle which could be used to supplement the Shuttle in such circumstances. WORK PACKAGE 3 NASA'S Goddard Space Flight Center is responsible for development of several of the Station's elements including the free-flying platforms and attached payload accommodations, and for planning NASA's role in satellite servicing. Goddard also has responsibility for developing the Flight Telerobotic Servicer which is being procured through a separate competition. FREE-FLYING PLATFORMS Goddard will manage the detailed design, development, test and evaluation of the automated free-flying polar platform. This unmanned platform will feature modular construction to permit on- orbit ease of serviceability and flexibility for accommodating a variety of scientific observations. ATTACHED PAYLOAD ACCOMMODATIONS The Space Station attached payloads are the instruments and experiments designed to gather scientific data while attached directly to the truss framework of the Space Station. Goddard is responsible for providing utilities such as power, thermal control, data handling, pointing stability and other equipment needed to operate the payloads and for insuring that the instruments are pointed at the intended targets. Two attachment points are provided, one of the attach points is fixed and the other has an articulated pointing system. FLIGHT TELEROBOTIC SERVICER Goddard is responsible for building the Flight Telerobotic Servicer. This system will be capable of in-space assembly of Station elements and payload servicing. As the system is evolved, it will perform telerobotic servicing and repair of spacecraft visiting the Space Station. In the future, a telerobotic servicer-equipped Orbital Maneuvering Vehicle could retrieve, as well as service, spacecraft beyond the Space Station's orbit. WORK PACKAGE 4 Lewis Research Center is responsible for the end-to-end electric power system architecture for the Space Station and for providing the solar arrays, batteries, and common power distribution components to the platforms. The power system includes power generation and storage, and the management and distribution of power to the final user interface. The electric power system is required to have the capability to deliver 75 kW of electric power with a growth potential to 300 kW. POWER GENERATION Initially, Space Station power will be provided by eight flexible, deployable solar array wings. This configuration minimizes the complexity of the assembly process by taking advantage of the technology demonstrated on Space Shuttle flights. Each 32- by 96-foot wing consists of two blanket assemblies covered with solar cells. These are stowed in blanket boxes which are attached to a deployment canister. Each pair of blankets is to be deployed and supported on a coilable, continuous longeron mast. A tension mechanism will supply tension to the blanket as it reaches complete extension. The entire wing will be tied structurally to the transverse boom by means of the beta gimbal assembly. To provide the power needed during the period of Space Station assembly, two solar wings and other elements of the power system are scheduled to be carried up on each of the first two Space Station assembly flights. These four wings will provide 37.5 kw of power. The remaining four panels will be delivered on orbit after the permanently-manned configuration is reached. Lewis also is responsible for developing and testing proof of concept hardware for the solar dynamic power module to prepare for the growth phase of the Station. In addition, sufficient preliminary design efforts will be performed to insure that the Space Station can accommodate the solar dynamic modules. POWER STORAGE Ni-H2 batteries will store the energy produced by the solar arrays. A battery pack is made up of 23 Ni-H2 cells, wiring harness and mechanical/thermal support components. On discharge, this operates near 28 v which allows the flexibility to connect several packs in series to obtain a high voltage system for the Space Station and platforms or use of single packs as a candidate for other low voltage applications. Ni-H2 batteries offer minimum weight and high reliability with minimum redundancy required for the polar platform. During the eclipse periods, power is supplied by the energy storage systems. POWER MANAGEMENT AND DISTRIBUTION (PMAD) The 20 kHz PMAD system is designed specifically to meet aerospace requirements. It is based upon rapid semiconductor switching, low stored reactive energy, and cycle-by-cycle control of energy flow, allowing tailoring of voltage levels. It is user friendly and can easily accommodate all types of user loads. The PMAD system will deliver controlled power to many scattered loads. The high frequency ac power system was selected to provide higher efficiency, lower cost and improved safety. - end -