or exploration, by NASA, butimmediateofapurenaturallanguage applicationcommunicationchanneldoespossible notseematthistimeor in thenearfuture .Thefirstusesoffluentnaturallanguagein controllingrobotswillprobablybestbedoneinacontextsuchas "showandtell." Spoken language. The development of fluent spoken language recognition is expected to evolve in step with the ability of machines to understand and reason about the object domain. Thus, a NASA orientation toward funding research in this area would be misdirected. There is no obvious pressing need at this time for the Agency to intervene in the development of isolated word recognition control of robots, as this area will develop very rapidly on its own. Speech generation. Serviceable speech generation is technologically current, for the physical generation, and NASA need not take any particular steps in this area until specific implementation demands it. The more important area of machine decision of what to say is a much more difficult and undeveloped research area, and is essentially the same problem as in keyed input-visual output dialogue systems. Visual and other communication. The areas of motor and graphic interaction are ready for current implementation. NASA should consider these as tools appropriate both for its own internal use and, as with the keyed natural language, for outside users of NASA-collected data. Show and tell communication would be extremely useful in zero-g robot-assisted construction, and may have application in planetary exploration and space or lunar industrial processes current research efforts are minimal. Many of the specific capabilities of potential interest to NASA will not be developed if the space agency does not take a direct, active role. A very rudimentary form of show and tell, called "patterning," should be implemented as soon as possible for all NASA spacecraft with manipulator or other movable components under computer control. In patterning, a prototype or other model of the actual spacecraft is physically articulated in the way the actual spacecraft should behave. The model is connected to a computer through appropriate proprioceptors, and the computer writes a program which can be uploaded to the spacecraft to direct its actions. It should also be required that the model be able to execute the program in order to verify its correctness. Such a capability would greatly extend the flexibility of control of both complex devices in space and exploration craft on planets, and yet are relatively easily implementable with current techniques.
6.4 Space Manufacturing To achieve the goal of nonterrestrial utilization of materials and factory self-replication and growth, space manufacturing must progress from terrestrial simulation to low Earth orbit (LEO) experimentation with space production techniques, and ultimately to processing lunar materials and other nonterrestrial resources into feedstock for more basic product development. The central focus of this assessment is upon the technologies necessary to acquire a major space manufacturing capability starting with an automated Earth orbiting industrial experimental station established either as an independent satellite or in conjunction with a manned platform such as a manned orbiting facility or "space station."
6.4.1 Earth Orbiting Manufacturing Experiment Station There are four major components of any production system: (1) extraction and purification of raw materials, (2) forming of product components, (3) product component assembly, and (4) system control. The Earth-orbiting station will conduct experiments to determine the relative merits of alternative methods of implementing these elements in a space manufacturing facility. Product formation involves two general operations primary shaping to achieve the approximate shape and size of the component and finishing to meet all surface and dimensional requirements. The most promising primary shaping technologies for space manufacturing are casting and powder-processing techniques. When properly controlled, both methods produce parts ready for use without further processing. Casting techniques appear more versatile in terms of the range of materials (metals, ceramic, metalceramic) that can be shaped, but powder processes may outperform casting for metallic components. A detennination of the relative utility of these two processes should be one of the primary goals of the space manufacturing experiment station. The casting process is a fairly labor-intensive activity on Earth and has not been highly automated, with the exception of Strand and other continuous casters. Automated casting facilities do not generally produce a variety of parts configurations; instead, they usually make just a single shape (usually a bloom or billet) which later requires a great deal of expensive and time-consuming processing before it is usable as a machine component. Many of the finishing operations can be eliminated if the material is cast into (approximately) its final configuration using a specialized mold. The production of these molds has been automated in two instances. In investment casting, the dipping of the wax forms into ceramic slurry has been
