Space Station Freedom Program Research Articles

Statistical Energy Modeling Techniques for Space Station Truss Segments

Statistical energy analysis (SEA) was performed on models of International Space Station (ISS) truss segments. These segments are large truss structures built up from I-beam members. The purpose of this analytical program is to determine the random vibration environment for equipment mounted on these segments. The equipment is mounted to secondary structural built-up plates in most instances. In general, the secondary structure is more rigid than typical aerospace structures because of the large spans between the primary truss members. This presents a challenge to the SEA methodology because of the low modal density of both the primary and the secondary structure, and novel approaches to the problem were identified. The need to test verify these modeling approaches was apparent. On the previous Space Station Freedom program, a developmental vibroacoustic test of a space station-like truss segment was conducted. The development test specimen was modeled in a similar manner to the ISS segments and predicted responses were compared with test data. This paper discusses the modeling methods determined to be effective for these structures

4.1.4 System Engineering in an Integrated Product Team Organization

AbstractThis paper presents a discussion of the functions of a system engineering organization in an integrated product team (IPT) setting. IPTs are being adapted widely as a more efficient means for accomplishing large product developments. Recent examples include the US Air Force F‐22 fighter program. Additionally, when management difficulties plagued NASA's Space Station Freedom program, NASA responded by implementing an IPT management structure for the program.A brief review of classical system engineering functions as described by government and academic texts and a resultant synopsis are followed by a brief review of the IPT organizational schema. Subsequent discussion presents a paradigm for system engineering within an IPT setting, and describes the similarity in function of the analysis and integration teams (AITs) within an IPT versus classical systems engineering functions. A conclusion is supported that by controlling the scope of the system engineering task, the function of AITs is comparable to that of classical system engineering organizations. Finally, system engineering within NASA's International Space Station Alpha (ISSA) program is presented as example of a system engineering application within an IPT setting.

Space station freedom ground systems program—A survey

The Space Station Freedom will be a permanently manned, low-Earth orbit research facility, elements of which are being provided by the United States, Canada, countries of the European Space Agency and Japan. The facility will be assembled in space and operated well into the twenty-first century. The ground infrastructure must be able to support both assembly and long-term operations. The infrastructure will consist of ground facilities, support systems and the associated planning and management procedures. The key facilities identified to support Space Station Freedom Program (SSFP) integrated operations and their SSFP roles will be described in detail in this paper. Requirements for the integrated ground infrastructure are developed and controlled within the SSFP requirements documentation and baselining processes. A Ground Systems Program directive summarizes key operations functions, roles and responsibilities of the various program participants. During 1992, the SSFP is conducting a major program review of the ground infrastructure including the definition of all facility and support system functional capabilities, interfaces and dataflow requirements. Operations functionality and interface verification tests are being identified and operations readiness dates are being established.

Hydrogen-based rechargeable battery systems: Military, aerospace, and terrestrial applications—I. Nickel-hydrogen batteries

Abstract Eagle-Picher Industries currently has three hydrogen-based battery systems under development and in production, for a variety of military, aerospace, and terrestrial applications. These are the nickel-hydrogen (NiH 2 ), nickel-metal hydride (NiMH), and silver-metal hydride (AgMH) battery systems. Nickel-hydrogen batteries are the system of choice for both geostationery (GEO) and low-earth-orbit (LEO) communications and surveillance satellites. Eagle-Picher NiH 2 batteries have been in use in the aerospace industry for over 15 years and have accumulated more than 95,000,000 cell-hours in orbital spacecraft operation without a single failure. Cells have completed more than 88,000 accelerated LEO charge/discharge cycles and more than 30 eclipse seasons in GEO testing. Advanced NiH 2 batteries are currently being built for the Space Station Freedom program. This advanced aerospace technology is also being adapted to terrestrial applications such as remote location power systems, electric vehicles, utility load leveling, and the telecommunications industry. Two additional papers are planned. Part II of the series will cover aerospace and commercial nickel-metal hydride batteries and part III will concern the newly developed silver-metal hydride battery system.

Space Station Freedom: An overview

The paper describes the progress which the Space Station Freedom Program has achieved during the fiscal year 1991 and the plans for the future.

Technology planning for long range utilization of Space Station Freedom

Over the course of the operational life of Space Station Freedom (SSF), technologies used for spacecraft design and use will advance. In some cases, such as data management, components or systems initially incorporated in the design may become obsolete in a relatively short period of time. In order to assure that SSF can benefit from new technologies, beneficial technologies must be identified, development of beneficial technologies must be tracked and advocated where appropriate, the design must accommodate technology upgrades, and a process for transferring technologies into the flight program must be implemented. The NASA Office of Space Flight, in coordination with the SSF program, has developed a consolidated listing of high priority technology requirements in support of overall Agency technology development planning. Included in this list are technologies which support increased utilization of SSF, enhance crew safety or productivity, or reduce operations costs. Efforts to ensure development of these technologies have begun, and a mechanism for technology transfer has been developed.

System Integration Applications of Information Systems in the Space Station Freedom Program

ABSTRACTThe development of large scale systems necessarily involves a large number of engineering organizations, each working individually to design separate components which will ultimately be integrated. If these organizations are to work concurrently, routine and methodological communication between the engineering organizations is required. One necessary product of this communication is the timely specification and design of the components' mating interfaces.The Space Station Freedom (S.S. Freedom) program is a multinational venture, with participating agencies including the National Aeronautics and Space Administration (United States), the National Space Development Agency of Japan, the Canadian Space Agency, the European Space Agency, and the Italian Space Agency. To integrate a project of this scale, with such a large number of participants, a very large quantity of interface development is required to allow the design of the S.S. Freedom's components to proceed concurrently around the world. This paper briefly describes the scope of the system integration task in the S.S. Freedom program and discusses the utilization of an electronic information system specifically developed to facilitate the efficient organization and timely completion of interface design activities.

Verification of Space Station Freedom elements and systems

Space Station Freedom is composed of many distributed systems and elements being designed, built and tested at various work centers and international locations. The station will be assembed on orbit over a period of time greater than 4 years with the station conducting research and experimentation throughout the assembly process. Because of this extended time period of assembly and limited available resources, it is impractical to perform an integrated ground test of the complete orbital assembly. Accordingly, the Space Station Freedom Program verification program offers a unique challenge not experienced in other programs. The Space Station Freedom verification program includes development, qualification, acceptance and prelaunch phases to ensure that the station will meet the design and operational requirements prior to launch. This verification program places emphasis on verifying on the ground the physical and functional compatibility of interfaces for the different elements and launch packages prior to their being mated on orbit.

Isssues in Developing Control Zones for International Space Operations

Cooperative missions in earth orbit can be facilitated by developing a strategy to regulate the manner in which vehicles interact in orbit. One means of implementing such a strategy is to utilize a control zones technique that assigns different types of orbital operations to specific regions of space surrounding a vehicle. Considered here are issues associated with developing a control zones technique to regulate the interactions of spacecraft in proximity to a manned vehicle. Technical and planning issues, flight hardware and software issues, mission management parameter, and other constraints are discussed. Also covered are manned and unmanned vehicle operations, and manual versus automated flight control. A review of the strategies utilized by the Apollo Soyuz Test Project and the Space Station Freedom Program is also presented.

An innovative approach for distributed and integrated resources planning for the Space Station Freedom

The widely distributed nature of the Space Station Freedom program, plus continuous multi-year operations will force program planners to develop innovative planning concepts. The traditional centralized planning operation will not be adequate. It will be replaced by multiple small planning centers working within guidelines issued by a central planning authority. Plans will not be optimized; rather, operating efficiency and user flexibility will be blended to satisfy program goals. The key to this new approach is the application of new planning methodologies and system development technologies to accommodate distributed resources that must be integrated. Resources will be distributed to the multiple planning entities in such a way that, when the several plans are built and then integrated, they will fit together with minimal modification. The plan itself will be an envelope schedule containing resource limits and constraint boundaries within which users will be free to make choices of the specific activities they will execute, up to the time of execution. Some level of margin within program guidelines will be built in to allow for variation and unforeseen change. This paper presents the authors' recommended planning approach and cites two NASA systems being developed that will utilize these resource distribution/integration planning concepts, methodologies and development technologies.

Collection, compaction and storage of solid waste for space missions

Efficient trash collection and volume reduction becomes very important during extended, manned space flight missions because of the high rate of crew member generated trash and the limited volume available to store this trash. Trash management in manned space flight vehicles requires that the following considerations be addressed: definition of the trash model including quantities/rates of generation and the physico-chemical characteristics of the trash; methods of collection and temporary stowage prior to treatment or processing; the method of treatment/processing to affect biochemical stabilization and volume reduction; and storage of treated/ processed trash prior to final disposition. This paper discusses trash management design approaches with focus on trash collection, compaction and storage. This paper also discusses the trash compactor design currently being developed for the Space Station Freedom program.

Networked Simulation for Team Training of Space Station Astronauts, Ground Controllers, and Scientists: A Training and Development Environment

The purpose of this paper is to describe plans for the Space Station Training Facility (SSTF) which has been designed to meet the envisioned training needs for Space Station Freedom. To meet these needs, the SSTF will integrate networked simulators with real-world systems in five training modes: Stand-Alone, Combined, Joint-Combined, Integrated, and Joint-Integrated. This paper describes the five training modes within the context of three training scenarios. In addition, this paper describes an authoring system which will support the rapid integration of new real-world system changes in the Space Station Freedom Program.

Collection, compaction and storage of solid waste for space missions.

Efficient trash collection and volume reduction becomes very important during extended, manned space flight missions because of the high rate of crew member generated trash and the limited volume available to store this trash. Trash management in manned space flight vehicles requires that the following considerations be addressed: definition of the trash model including quantities/rates of generation and the physico-chemical characteristics of the trash; methods of collection and temporary stowage prior to treatment or processing; the methods of treatment/processing to affect biochemical stabilization and volume reduction; and storage of treated/processed trash prior to final disposition. This paper discusses trash management design approaches with focus on trash collection, compaction and storage. This paper also discusses the trash compactor design currently being developed for the Space Station Freedom program.

Future international cooperation on space stations

In the course of the next thirty years, extensive international cooperation in space may become the norm rather than the exception. The benefits from the mutual application and exchange of assets and knowledge may enable the development of projects that no nation could afford alone. Cooperation on technical projects may also yield political benefits such as alliance building, although potentially at a cost of making the program hostage to the vagaries of international politics. Successful past cooperative projects include the Apollo-Soyuz Test Project, Spacelab and Soviet Salyut and Mir space stations. The ongoing Space Station Freedom program is offering the first sustained long term opportunity for international cooperation in space. In addition to enabling potential advances in science and technology development, the station may serve as the stepping stone for future international efforts in areas such as planetary exploration. Any significant future increase in international cooperation would likely need to include both the United States and the Soviet Union. Such cooperation could offer many unique possibilities, including interactions between the Freedom and Mir. Indeed the success of future manned exploration missions may well depend on how well space-faring nations learn to cooperate with each other. International involvement in technical programs always creates an additional element of complexity regarding the technical requirements and resource management of a project. However, the experience of international cooperation to date tells us that there can be significant gains, both tangible and symbolic, from international participation.

Hand Controller Commonality Evaluation Process

Remotely controlled devices will be used extensively to support Space Station Freedom on-orbit assembly, maintenance, and payloads. These include crane-type or remote manipulator systems (RMS), dexterous robots, and remotely-piloted free flyers. A hand controller evaluation process has been established at NASA's Johnson Space Center to determine the appropriate hand controller configurations required to support these devices. Three test facilities include dynamic computer simulations, kinematic computer simulations, and physical simulations. The dynamic simulator supported a rate-controlled RMS and a free flyer. The kinematic simulator supported a rate-controlled RMS and a rate or position-controlled dexterous manipulator. The physical simulator supported a rate, position, or force-reflecting dexterous manipulator. Standard interfaces were developed to evaluate six different hand controllers in all three facilities. The hand controllers included six degree-of-freedom (DOF) position and rate mini-master and joystick controllers, and three-DOF rate controllers. There were six tasks and four non-astronaut subjects per task. All six controllers were tested for each task. Six astronauts then completed all tasks using all controllers for each task. Data collected included task performance data, subjective comments, and anthropometric data. The results of these evaluations were then used to make hand controller configuration recommendations to the Space Station Freedom Program.

Overview of the space station communications networks

Within the Space Station Freedom Program (SSSP), the communications and dataprocessing capabilities that will be used to handle the operational and scientific information needs will be provided by a space station information and communications system. This system will be composed of a variety of elements, networks, and subnetworks. The networks and how they are interconnected are described. The discussion covers communications system elements and services, elements of the onboard systems, wide-area transport network elements, and command and control elements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Space station freedom crew training

The nature of the Space Station Freedom Program presents an array of new and enhanced challenges which need to be addressed en route to developing an effective and affordable infrastructure for crew training. Such an infrastructure is essential for the safety and success of the program. The three major challenges that affect crew training are the long lifetime of the program (thirty years), the interdependence of successive increments, and the participation of the three International Partners (Canada, European Space Agency, and Japan) and a myriad of experimenters. This paper addresses these major challenges as they drive the development of a crew training capability and the actual conduct of crew training.

Space Station Freedom resistojet system study

The resistojet propulsion assembly is designed as a simple, long-life system that offers operational flexibility to the Space Station Freedom program. It can dispose of a wide variety of typical Space Station Freedom waste fluids by using them as propellants for orbital maintenance. A nominal operation mode offers relatively high specific impulse with long life, whereas a low-temperature mode can propulsively dispose of mixtures that contain oxygen or hydrocarbons without reducing thruster life or generating particulates in the plume. A low-duty cycle and a plume that is confined to a small aft region minimizes the impacts on the users. Simple interfaces with other space station systems facilitate integration.