Page:Advanced Automation for Space Missions.djvu/298



required (Ayres, 1952; Foster, 1963; Kallen, 1961; Luke, 1972). Component processes are all state-of-the-art. There is no need for visual processing during normal operations, and procedures are standardized so no expert systems or judgmental algorithms are required beyond the simple integration of well defined sensor data. All operations will probably be hard-automated, and materials will be moved about almost entirely in sealed vessels. If there is need for additional transport within the system a materials transit network may be erected using metal or basalt tracks, electric motors and small carrier vehicles.

If each of the 13 sector components is as complex as the HF acid leach system (certainly a gross overestimate), then the total computer control capability required is about 6 megabytes or 9.4&times;107 bits using 16-bit words. The information needed to describe the sector sufficiently for purposes of self-replication must also be estimated. Assuming that each HF leach subsystem requires 2&times;106 bits for complete description (about a 200-page printed book, or 80,000 English words), and that each valve requires about half as much (say, 100 book pages), then the total for the HF leach system is 1.8&times;108 bits. Again conservatively multiplying by 13, the total information to describe the sector components is 2.3&times;109 bits. If sector equipment is distributed across a floor space of 5000 m2, then to store a map with 1-cm placement resolution requires a memory capacity of 8&times;108 bits assuming one 16-bit word to describe the nominal status of each 1 cm2 of platform space. Note that large empty areas convey useful information and must be mapped, since they may be used for traffic routes, repair routes, temporary warehousing, etc. The total information for sector replication is thus about 3.1&times;109</SUP> bits. The information control budget is 9.4&times;10<SUP>7</SUP> bits.

5E.6 References

Allcock, Harry R.: Inorganic Polymers. Scientific American, vol. 230, March 1974, pp. 66-74.

Arnold, J. R.; Criswell, D. R.; and Waldron, R. D.: Progress Report on Experimental Program to Develop HF Acid Leach Process for Refining Lunar Soils. Paper presented at the 5th Princeton/AIAA/SSI Conference on Space Manufacturing, 18-21 May 1981, Princeton, NJ.

Ayres, Eugene: An Automatic Chemical Plant. Scientific American, vol. 187, September 1952, pp. 82-88.

Criswell, David R.: Extraterrestrial Materials Processing and Construction. NASA CR-158870, vol. 1, 1978, and vol. 2, 1980.

Dunning, Jeremy D.; and Snyder, Robert S.: Electrophoretic Separation of Lunar Soils in a Space Manufacturing Facility. Paper presented at the 5th Princeton/ AIAA/SSI Conference on Space Manufacturing, 18-21 May 1981, Princeton, NJ.

Foster, David: Modern Automation Sir Isaac Pitman and Sons, Ltd., London, 1963.

Freitas, Robert A., Jr.: A Self-Reproducing Interstellar Probe. J. British Interplanet. Sec., vol. 33, July 1980, pp. 251-264.

Ho, Darwin; and Sobon, Leon E.: Extraterrestrial Fiberglass Production Using Solar Energy. In Space Resources and Space Settlements, John Billingham, William Gilbreath, Brian O'Leary,and B. Gossett, eds. NASA SP-428, 1979, pp.225-232.

Johnson, Richard D.; and Holbrow, Charles, eds.: Space Settlements: A Design Study, NASA SP-413, 1977, 185 pp.

Kallen, Howard P., ed.: Handbook of Instrumentation and Controls. McGraw-Hill Book Co., New York, 1961.

Lee, Stuart M.: Lunar Building Materials - Some Considerations on the Use of Inorganic Polymers. In Space Resources and Space Settlements, John Billingham, William Gilbreath, Brian O'Leary, and B. Gossett, eds. NASA SP-428, 1979,pp. 233-241.

Luke, Hugh D.: Automation for Productivity. John Wiley and Sons, New York, 1972.

Oldham, William G.: The Fabrication of Microelectronic Circuits. Scientific American, vol. 237, September 1977, pp.110-128

O'Neill, Gerard K.: Engineering a Space Manufacturing Center. Astronautics and Aeronautics, vol. 14, October 1976, pp.20-28,36.

O'Neill, Gerard K.; Driggers, G.; and O'Leary, B.: New Routes to Manufacturing in Space. Astronautics and Aeronautics, vol. 18, October 1980.pp 46-51.

Phinney, W. C.; Criswell, D. R.; Drexler. E.; and Garmirian, J.: Lunar Resources and Their Utilization. In Space-Based Manufacturing from Nonterrestrial Materials,

Gerard K. O'Neill, ed., AIAA. New York, 1977, pp. 97-123. (Progress in Astronautics and Aeronautics, vol. 57.)

Vajk, J. P.; Engel, J. H.; and Shettler. J. A.: Habitat and Logistic Support Requirements for the Initiation of a Space Manufacturing Enterprise. In Space Resources and Space Settlements, John Billingham. William Gilbreath, Brian O'Leary, and B. Cossett, eds., NASA SP-428,1979, pp.61-83.

Waldron, R. D.; Erstfeld, T. E.; and Criswell, D. R.: The Role of Chemical Engineering in Space Manufacturing. Chemical Engineering, vol. 86. 12 February 1979. pp. 80-94.

Williams, Richard J.; and Jadwick. James J.: Handbook of Lunar Materials, NASA RP-1057, 1980.

Zachary, Wm. B.: A Feasibility Study on the Fabrication of Integrated Circuits and Other Electronic Components in Space Utilizing Lunar Materials. Paper presented at the 5th Pritlceton/AIAA/SSI Conference on Space Manufacturing, 18-21 May 19S1. Princeton, NJ.