"6_10_7_4_4.TXT" (26706 bytes) was created on 09-17-89 SPACE STATION FREEDOM: Goddard Space Flight Center The Goddard Space Flight Center was established in 1959 at Greenbelt, Maryland. It was NASA's first major scientific laboratory devoted entirely to the exploration of space. Named after Dr. robert Hutchings Goddard, the man recognized as the "Father of American Rocketry," the center continues its commitment to scientific research and development for space exploration. Goddard has one of the world's leading groups of scientists, engineers and administrative managers devoted to research in space, Earth sciences and applications. It employs more scientists than any other NASA center. It also is the only national laboratory that can develop, design, fabricate, test, launch and analyze space science missions using all its own resources. Today, Goddard scientists, engineers and technicians are working on advanced missions to support both terrestrial and astronomical research. The spacecraft they build and the scientific research they conduct are expanding our knowledge of the Earth, the solar system, and the universe. Goddard plays an important role in many of our nation's most challenging space missions. Goddard manages the worldwide tracking and communications network that support these missions. The network currently consists of ten ground stations, the Network Control Center, and the Tracking and Data Relay Satellite System (TDRSS). This network will also support Space Station Freedom. The Goddard Space Flight Center has supported all of this country's major space programs including the manned programs such as: Mercury, Gemini, Apollo, Skylab and Shuttle and many unmanned programs such as TIROS, NIMBUS, LANDSAT, the Orbiting Astronomical Observatory, the International Ultraviolet Explorer and many others. Goddard also manages the Delta launch vehicle program. Goddard continues to support new space missions in their areas of expertise such as the Hubble Space Telescope (HST), the Cosmic Background Explorer (COBE) and various space platforms planned for the 1990's such as the Gamma Ray Observatory (GRO), and Upper Atomspheric Research Satellite (UARS). The fundamental mission of the Goddard Space Flight Center is the expansion of knowledge of the Earth, its environment, the solar system, and the universe through the conduct of scientific research and the management, development, and use of near-Earth space systems. Goddard is a collection of specialized laboratories committed to excellence in challenging areas of research and development to ensure that the Nation and NASA maintain leadership in space science and technology. Goddard has diverse skills in science, engineering, operations, and management disciplines to provide the capability for integrating internal and external resources in effective mission management and implementation of NASA programs. Goddard's science role is to provide NASA's principal leadership and competence in space an Earth sciences; advancing scientific understanding, disseminating knowledge, and ensuring quality guidance and support to NASA's space research, technology, and flight programs. Goddard's engineering role is to excel in research, engineering, development, and application of technology for sensors, instruments, spacecraft, and complete information systems for space flight and ground system use. Goddard serves as the NASA focal point for the planning and execution of near-Earth spaceflight projects for science and applications research. Goddard manages these projects in the most productive manner possible, achieving maximum returns on the resources invested. Goddard also provides a launch range and research airport at the Wallops Flight Facility on Virginia's eastern shore for suborbital rocket, balloon, and aeronautical missions. Goddard is a team of some 3,700 civil service employees and 8,100 contractors; about 12,000 people working for the expansion of knowledge of the Earth. Goddard/Space Station Freedom Unique Activities Flight Telerobotic Servicer (FTS) Goddard is responsible for development and implementation of the FTS, including the selection of appropriate technology, conducting Shuttle demonstration flights, delivering the flight element and providing a ground based training and evaluation capability. Goddard works with other NASA centers conducting research in automation and robotics and evolutionary growth. Attached Payload Accommodations Goddard is responsible for accommodating various scientific, commercial and technology development instruments and experiments, providing utilities such as power, thermal control, data system interfaces, pointing and stability; providing attachment fixtures and other equipment necessary to properly place and operate the payloads and provide attitude determination. Unmanned Free Flying Platforms Goddard is responsible for managing the detailed design, development, test, and evaluation of the U.S. platforms that are not attached to the station but fly freely in their own orbits. The initial U.S. polar platform will support the Earth Observing System (EOS) mission. Another U.S. platform, co-orbiting with the space station in the late 1990's, will serve additional scientific users from various disciplines. Assembly, Maintenance and Servicing Goddard is responsible for developing the servicing system architecture for all flight vehicles and attached payloads to optimize station performance for user operations. Goddard works with the user community to determine requirements that impact design and evaluates capabilities such as replacement, replenishment, retrieval, storage, assembly, test and verification of intended operation. Space Station Freedom Unique Activities Flight Telerobotic Servicer Program The Flight Telerobotic Servicer (FTS) is the result of discussions between NASA and the Congress on how the Space Station Freedom program could best be utilized to enhance the technologies of robotics and machine intelligence. Mandated by Congress in the conference report accompanying NASA's FY 1986 appropriations bill, the FTS is an outgrowth of the Automation and Robotics (A&R) initiative of the project's Definition and Preliminary Design Phase ("Phase B"). The FTS is a telerobotic device capable of precise manipulations in space. It will operate with a mix of direct teleoperation and supervisory control by astronauts. It will be used to assist in assembly and servicing operations. The FTS will improve the efficiency and safety of operations. Initially intended for relatively simple tasks, the FTS capabilities will evolve over time to accommodate increasingly sophisticated operations. Invaluable not only for station operations, the FTS will have wide application in orbits beyond the reach of the present manned space transportation system. The Goddard Space Flight Center's Space Station Freedom Projects organizaton is accountable for the development and implementation of the FTS. Technical and management activities at GSFC are continuing to focus and drive the implementation of the FTS program in response to the A&R objectives of the Space Station Freedom program. Other NASA Centers support Goddard in implementing the FTS program. Early in space station planning, NASA initiated a study to determine the most effective manner of applying A&R technologies both to enhance Freedom and to provide the desired development impetus. The NASA Advanced Technology Advisory Committee (ATAC), established by NASA at the direction of Congress, evaluated the recommendations of universities, aerospace and automation related industries and government laboratories, integrating them into a comprehensive set of recommendations for further study by Phase B contractors. These recommendations may be summarized as follows: ---Automation and robotics should be a significant element of the Space Station Freedom program. ---Initially, the station should be designed to accommodate evolution and growth in automation and robotics. ---Initially, the station should utilize significant elements of automation and robotics technology. ---Criteria for the incorporation of A&R technology should be developed and promulgated. ---Verification of the performance of automated equipment should be stressed, including terrestrial and space demonstrations to validate technology for ##station use. ---Maximum use should be made of technology developed for industry and government. ---The techniques of automation should be used to enhance NASA's management capability. ---NASA should provide the measures and assessments to verify the inclusion of automation and robotics in the space station program. During the course of Phase B Study, the ATAC continued to monitor the implementation of these recommendations. As a result of the efforts to date, functions which would benefit from application of robotic technologies have been identified and robotic concepts have been evaluated. Space Station Freedom Unique Activities The FTS program will be implemented by establishing and coordinating four major elements: ---A Technology element to select, modify, and transfer evolving technology and to identify requirements for new technology. ---A Flight Demonstration element to conduct demonstration flight(s) on the NSTS prior to station assembly for verification of design and operations concepts. ---A Freedom Flight System element to deliver, operate, and evolve an FTS for ##use by the Space Station Freedom program. ---A Ground System element to provide continuing capability to evaluate and implement advanced robotic technology and to assist training operations and FTS on-orbit performance evaluation. As can be seen from the figure at the right, many other NASA, government and industry organizations are participating in the FTS program, each contributing in their areas of Center or organizational expertise. The FTS program will provide an early demonstration of the FTS capabilities onboard the Shuttle sometime in 1991. The results of that demonstration and research being conducted on the ground at the NASA Centers and contractors will be transferred into the actual flight article that will be used to assemble Space Station Freedom beginning in 1995. The role of the FTS will evolve with Space Station Freedom over time, taking on different tasks and roles consistent with the assembly, servicing, maintenance and operations activities. GODDARD SPACE FLIGHT CENTER Elements and Systems Attached Payload Accommodations Goddard is responsible for accommodating many and various scientific, commercial, and technology development instruments and experiments. The term "payload" is used to mean the total complement of specific instruments, space equipment, support hardware, software, and consumables required to accomplish a discrete activity in space. A payload, then, may be large or small, simple or complex and serve just one or many experimenters, investigators or users. Payloads can be mounted inside the pressurized volume of Space Station Freedom or outside on the structural members or truss. The outside ones are called attached payloads. Like experiments or processes in a laboratory or factory on Earth, Space Station Freedom payloads will need power, thermal control, command control, and data systems. They also need, in many cases, periodic monitoring, maintenance and perhaps repair. In some cases, the payloads may even produce a product that needs to be "harvested" or retrieved and brought back to Earth. Some payloads may want to "look" at outer space while others may want to "look" at Earth or point towards a particular star, all at the same time. This will require special pointing requirements and a special system to allow for very accurate and stable pointing. When one considers the potential for thousands of different possible experiments and operations over the useful lifetime of the space station, the challenging role Goddard has in accommodating all of the potential users becomes more apparent as does the potential for conflict over station resources. The attached payloads will initially be scientific in nature and sponsored by the NASA Office of Space Science and Applications. The disciplines include Solar System Exploration, Space Physics and Earth Science and Applications. These various disciplines endeavor to understand the origin and fundamental laws of the universe, and the solar system; to establish the scientific and technical foundation upon which to undertake both manned and unmanned explorations of the Solar System, and to specifically provide a greater understanding of the Earth, its immediate environment and the Sun. Goddard Space Station Freedom personnel will work with the sponsors and users of attached payloads to determine how their requirements can be accommodated by both design and operations. The user requirements include the following: ---Information - onboard and on the ground ---Transportation - from the Shuttle to the manned base ---Operations Planning - including integration, test and operation ---External Storage - outside the pressurized volume ---Servicing - for assembly, replacement, replenishment and storage. ---Verification - integration test & verification of payload with attached payload accommodation equipment. Goddard Space Station Freedom personnel will work with the designers and users to identify and discuss the accommodation issues in such areas as: ---Crew size - how many and how much time ---Microgravity - how little and how variable ---Available power - how much and where ---Volume - how much and where ---Experimental compatibility - between fundamentally conflicting experiments ---Payload orientation - with respect to the Earth, stars and Sun ---Attach points - on the transverse boom ---Distributed payloads - parts that are distributed to various points. GODDARD SPACE FLIGHT CENTER Elements and Systems Free-Flying Platforms Platforms are unmanned modular spacecraft designed to carry and support science, technology and commercial payloads that require exposure to space or that cannot be attached to Space Station Freedom's manned base for one reason or another. They provide facilities for a broad range of users to conduct long term independent missions and investigations. There are two such platforms associated with the Space Station Freedom's initial capabilities. One platform is in polar orbit and is the responsibility of the United States. The other is a polar orbiting platform that is the responsibility of ESA. Goddard will manage the detailed design development, test and evaluation of the U.S. polar platform now planned to be used by the Earth Observing System Program which is also managed by Goddard. The Eos program is also part of the Mission-to-Earth Program which also includes many of the 1992 International Space Year scientific activities. The first U.S. polar orbiting platform is intended for continued viewing of the Earth and is placed in a north-south orbit, thereby allowing the sensors to view the entire Earth rotating under the platform. By syncronizing the altitude (and therefore the orbital period) with the Earth's rotation and inclination of the sun, the scientists can be sure their sensors look at the desired locations on the Earth in morning and afternoon sunlight rather than darkness. This orbit is called sun-syncronous and is 705 kilometers (438 statute miles) and inclined 98.7 degrees to the equator. To achieve this, the polar platform must be launched from Vandenberg Air Force Base in California. Present planning leans toward the use of a Titan IV expendable launch vehicle. The principal goal of the Earth science and applications discipline, which will be the primary user of this polar platform, is to obtain a scientific understanding of the entire Earth system on a global scale by determining how its component parts and their interactions have evolved, how they function, and how they may be expected to continue to evolve on all may be expected to continue to evolve on all time scales. To attain these objectives, the Eos program will be carried out in conjunction with the National Oceanic and Atmospheric Administration's (NOAA) weather monitoring program. The Eos system includes a complement of instruments on the platform which will greatly enhance the scientific communities' ability to gather remotely sensed data on the Earth's land masses, its oceans, atmosphere and ice sheets. This data can be recorded on-board and played back to the ground via the TDRS network or direct broadcast to a ground station. The basic design of the U.S. platforms provides for a significant degree of commonality between both polar and co-orbiting platforms and the manned base. These design studies also look at potential instrument commonalities between NASA, ESA and Japanese platforms. Commonality implies common interfaces for all users. This should make logistics simpler, repairs more efficient and costs lower. The platforms are designed to be serviced in different ways: by the Shuttle, by rendezvous with a servicing carrier and by robots on a servicing carrier. GODDARD SPACE FLIGHT CENTER Elements and Systems Flight Telerobotic Servicer (FTS) The Need The crew will need assistance in assembling, servicing, inspecting and maintaining Space Station Freedom and all of its payloads and systems. While some extra vehicular activity (EVA) will still be required, it is more risky and expensive (in both time and dollars) than if an intelligent robot could perform some of those functions. One way to get the various jobs done is to put the astronaut's intelligence inside the station and put his or her hands and arms outside. In effect, this is what a "telerobot" accomplishes. The term "telerobot" refers to a hybrid capability for the robot to operate either under direct control of a human operator (teleoperation) or to carry out tasks by itself according to some computer rules, knowledge and sensory information but providing the ability for the human to intervene. Another way to get the job done is to provide the robot with some intelligence of its own for certain types of jobs. In effect, this is a "smart robot." The concept of the Flight Telerobotic Servicer provides a useful, reliable and safe tool to assist the crew in performing a broad range of routine tasks on both the station and the Orbiter. Design Concept The FTS project will soon be evaluating competing approaches offered by industry. In preparing for this evaluation, GSFC engineers developed their own design concept to the same requirements being studied by the competing Phase B contractors. What follows is a description of this "in-house" design concept. The actual FTS, to be built by the successful contractor, is likely to differ substantially from this description. The FTS is an unique element of Space Station Freedom, unique to spaceflight and unique to the robotics world. The FTS is a robot which is also a spacecraft, and it must be designed and built accordingly. The FTS must work in a much less structured world than an industrial robot. The FTS will be required to perform many varied tasks with varying degrees of precision throughout its expected lifetime. These tasks will increase in complexity; therefore, the system must be capable of substantial growth and evolution. The telerobot is composed of three major subassemblies: the main body, the arm positioning system and the manipulator arm assembly. The Main Body The main body contains all the major electronic components of the telerobot, as well as the grapple fixture by which the telerobot is picked up by one of the large manipulator arms, e.g., the Remote Manipulator System (RMS). The main body also contains the attachment grapple (or foot) by which the telerobot is securely fixed at the worksite. One of the features of the main body of the telerobot is that it is free to rotate about its central core and the attachment foot. This freedom to rotate allows the thermal radiators that cover three sides of the main body to be oriented for optimum heat rejection at the worksite. Main body rotation with respect to the attachment foot allows the operator of the large manipulator arm another degree of freedom to help orient the FTS foot for proper mating to the worksite attachment point. The Arm Positioning System The next major component of the telerobot is the arm positioning system that consists of two, linearly driven, tubular sections connected through an offset rotational joint. The lower section is free to rotate simultaneously with respect to both the main body and the attachment foot. The manipulator arms are free to rotate ? 180 degrees with respect to the upper section. Five degrees of freedom are obtained to position the arms relative to the telerobot main body and attachment location. There are a number of advantages to the arm positioning system: it extends the reach of the telerobot without extending the length of the manipulator arms; it allows the arms to be positioned squarely to a task so that the teleoperator interfaces with the task in a natural manner; and it allows the telerobot to reach out over objects which may come between the attachment fixture and the location of the task. The Manipulator Arm Assembly The final component of the telerobot is the manipulator arm assembly that is mounted to the end of the positioning system. It consists of the shoulder assembly that rotates ? 180 degrees about the end of the positioning system, and two, 7-degree of freedom manipulators mounted to each end of the shoulder assembly. The manipulators are 1.524 meters (5 feet) long and are configured with a shoulder, elbow, and wrist. In addition to the telerobot, the FTS includes two workstation designs: a stowable work-station in the Shuttle's aft flight deck and one that will be located inside Freedom. Design Drivers During the analysis of the requirements and task capabilities, the Goddard study team identified the following major design drivers for the FTS: ---Thermal Environment ---Independent Operation ---Manipulator Stability and Positioning ---Safety ---Mobility ---Evolution ---One-G Operation ---Human Interface The key challenges for each of these design drivers are as follows: ---Thermal Environment - The thermal environment created by space introduces unique problems in an area that is only a minor concern for terrestrial robots. In space, the only way of dissipating heat is by radiation or conduction. For several reasons, radiation was the selected method. The peak operating power is in the 1 to 2 kilowatt range including all the motors, computers, video equipment and batteries. The combined effect of all the necessary design choices produced a thermal design that is independent of Freedom that will permit indefinite operation of FTS under most conditions. ---Independent Operation - The FTS must be capable of limited operation independent of hard-wired utilities for power, data, and video from the manned base. As a result, a large battery and an RF communications system was included in the design. The FTS can never be totally independent of the space station because it always needs a firm structural attachment when working. However, the requirement for independent operation gives the FTS a tremendous amount of flexibility, allowing it to work in areas where no utility ports are located. ---Manipulator Positioning and Stability - Studies of the size of the Shuttle payload bay and Freedom's truss and required work indicate that the ideal reach envelope of the telerobot would be 5 meters (16 feet). If the telerobot is to work in these locations, it must be able to cover these types of distances. This requires a trade-off of distance vs. dexterity. A local mobility system and an arm positioning system delivers the arms to the tasks. ---Safety - Safety is of primary importance in the design of the FTS. The Phase B study approach was to set up a watchdog safety subsystem that consists of redundant radiation-hardened computers and associated sensors in the telerobot to monitor all aspects of the telerobot's operations and health. The workstation has a computer that acts as a global safety monitor for workstation operations as well as the telerobot safety subsystem. Whenever any anomalous condition is detected, the safety computers will stop all movement of the telerobot. ---Mobility - The local mobility system that is part of the in-house concept is a portable rail that can ride out to the worksite with the telerobot to provide lateral movement. The portable rail, together with the arm positioning system, allows the manipulator arms to be positioned with 6 degrees of freedom at the worksite. ---Evolution - The FTS must be able to evolve towards greater autonomous operation which will be accomplished through the incorporation of advanced hardware and software items as they become available. The FTS must be designed to easily accept these changes. GODDARD SPACE FLIGHT CENTER Space Station Freedom Organization NASA's Goddard Space Flight Center, Greenbelt, Md., is responsible for development of several of Space Station Freedom's elements and systems including the free-flying platforms, attached payload accommodations, and for planning NASA's role in servicing accommodations in support of the user payloads and satellites. Goddard is also responsible for developing the Flight Telerobotic Servicer. As the Work Package 3 Center, Goddard has established the Level III Space Station Freedom Projects organization to manage and direct its various development, scientific, engineering, and support activities. This organization reports to the Space Station Freedom Program office in Reston. A unique aspect of this organization is its responsibility to the various scientific, engineering and commercial communities that intend to utilize the station's resources. This organization represents the needs of the users by ensuring sufficient power to their experiments or payloads and a place for them on the station's truss, a physical environment that supports their experiments, robotics and crew services for their experiments, communications with their experiments, and most importantly, their experiment data. This organization currently includes approximately 100 civil servants. There are an additional 70 people working on related activities in other Goddard organizations on such areas as advanced development, robotics, and testing of prototype flight hardware.