L5 News, September 1976
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On the Cover: A NASA artist’s conception of This Page: Interior of the “Bernal Sphere.” In CONTENTS the exterior of the “Bernal Sphere” space this year’s NASA Study on Space 3. J. Peter Vajk: 1976 Summer Study colony, a space-habitat for some 10,000 Manufacturing, habitats of this kind, efficient 5. C.H. Holbrow: 1975 Study Report people. The inhabitants, members of the in their use of materials and structurally strong, workforce of a space manufacturing complex, are thought of as possible next steps beyond 6. K. Eric Drexler: Another View would return after work to homes on the inner earlier, transitional structures of a more 7. Ann Elizabeth Robinson: Space surface of a large sphere, nearly a mile in utilitarian design. lndustrialization Contracts Awarded by NASA circumference, rotating to provide them with The “equator” of the rotating habitat is gravity comparable to that of the Earth. Their nearly a mile in circumference, and near it 7. Carolyn Henson: Sklarew to Head SAI Team habitat would be fully shielded against cosmic wanders a small river whose shores are made rays and solar flares by a non-rotating spherical of lunar sand. Natural sunshine is brought 8. O’Neill to Teach at MIT shell, accumulated from the slag of industrial inside through external mirrors. Rotation of 8. 1000 Women Apply for Astronaut Status processes carried out on lunar surface material. the sphere at about 1.9 RPM would produce 8. Single-Stage-to-Orbit Study Outside the shielded area agricultural crops, gravity of Earth-normal intensity at the 9. Ann Elizabeth Robinson: Satellite Solar far less sensitive to radiation than are humans, equator, gradually diminishing to zero at the Systems, ERDA, and Space Colonization would be grown in the intense sunlight of “poles,” where human-powered flight and 9. The lnternational Space Hall of Fame space. Docking areas and zero-gravity industries other low-gravity sports would become easy. 10. Ian Richards, James Kempf: are shown at each end of the space-community, For the short distances within the space-habitat, Space Farming: The Debate Goes On as are flat surfaces to radiate away the waste automobiles would be unnecessary, and 11. Conferences: heat of the habitat into the cold of outer space. transport would be on foot or bicycle. A climb Third Princeton/AIAA Conference on In the 1976 NASA Study on Space from the equator past the small villages on the Space Manufacturing Facilities Manufacturing, just completed, habitats of this hillsides, to the rotation axis where gravity Seventh Intersociety Conference on type, very efficient in their use of materials for would be zero, would take about 20 minutes. Environmental Systems shielding, are thought of as possible next steps A corridor at the axis would permit floating in 12. Jon Coopersmith: lnstitute on Man and beyond more utilitarian structures. These zero-gravity out to the agricultural areas, the Science Conference Report would be shielded versions of the agricultural observatories, the docking ports, and the 13. Keith Henson: Lecture Tour areas shown here. industries. 14. Tom Heppenheimer: Home, Home on In the economics of space-manufacturing, Lagrange Copyright 1976 L-5 Society the provision of attractive living areas of this 17. Spend a Day on Mars 1620 N. Park Ave., Tucson, AZ 85719 kind appears to be worthwhile relatively early (602) 622-2633 18. lnside L-5 All Rights Reserved: Printed in the U.S.A. in the program, because families so located 19. Letters News Media may quote up to 100 words from could remain for several years at a time, rather L-5 News without permission. For quotes in 19. Keith Henson: Boosters of Big Boosters, excess of 100 words, prior permission from than coming for short tours of duty at high Take Note L-5 Society is necessary. cost for transportation. 2 LATEST DEVELOPMENTS IN SPACE INDUSTRIALIZATION, SATELLITE SOLAR POWER, AND SPACE HABITATS NUMBER 13 A NEWSLETTER FROM THE L-5 SOCIETY SEPTEMBER 1976 NASA Ames 1976 SUMMER STUDY 10 cm/sec longitudinally, 1 cm/sec Catcher, 60,000 km away, must be quite J. Peter Vajk laterally, and 0.1 cm/sec vertically. small, the dispersion is still minute only On July 30, NASA Ames Research Each “sled” would be subjected to a 150 kilometers downrange from launch. Center in Mountain View, California, thrust somewhat smaller than the thrusts If the payloads are initially aimed hosted a press briefing to present a required for magnetic levitation train slightly below horizontal, then final summary of the results of this year’s systems planned for terrestrial use, but guidance can be provided by letting the summer study on space manufacturing, since these sleds are much lighter than payloads fly through a l-meter sponsored by NASA, Stanford University, railcars, much higher accelerations would diameter “tunnel” about 100 meters in and the American Society for Engineering result. Chilton said his team would have length placed on a suitable plateau or Education. Gerry O’Neill presented a designed the system to provide 1000 G mountain 150 km away from release. brief overview of the project, and then acceleration with total confidence that it Fine-tuning to 1mm/sec in all three axes introduced, in turn, the other four would work, but O’Neill told him nobody could be provided by zapping the payload speakers. would believe it, so they stuck to only with an electron beam and then using Frank Chilton discussed the new 100 G! (It should be remarked that the electrostatic plates to adjust the velocity. design for the Mass Driver which would Sprint ABM missile accelerates at well Chilton did not expect, however, that it launch packages of lunar soil from the over 50 G). The sleds contain would be necessary to go to such Moon for use as raw materials in space superconducting electromagnet coils, extremes, as initial release velocities manufacturing. Basic design parameters with the entire liquid helium system should be within that level of precision included a capacity of 600,000 metric completely sealed tight; the sleds are anyhow. tons per year in 20 kilogram packages never exposed to sunlight. Total Total mass for the launch system accelerated up to escape velocity, tracklength is about 4 kilometers. (including the Rube Goldberg downrange 2.4 km/sec, with tolerances in velocity Since the dispersion between “tunnel”) is down 40% from previous components at release of less than consecutive payloads on arrival at the estimates. Based on present solar energy technologies or small nuclear reactors, the mass needed would be 4067 metric tons; with extrapolated values for solar MASS-DRIVER (0.6-6.0 MILLION TONS/YEAR THROUGHPUT) energy sources, the mass would drop to 3067 tons. About 100 workers would be ELECTRIC POWER needed initially to assemble and align the system, but only about 20 would be needed to maintain and operate it. Brian O’Leary then discussed the extensive computer calculations which were done to pin down the launch precision required for the Mass Driver. Precision needed depends on the location PASSIVE GUIDEWAY (BUCKET RETURN) on the Moon of the launch point. The dispersion in payloads is least sensitive to velocity errors at release if the launcher LOAD COOL is placed at about lunar longitude 33.1°. BALANCE (Looking up at the Moon in the sky, that RECHECK PAYLOAD + CASTING SURFACE means the launch point would be about RETURN AND MINE half-way from the middle of the Moon’s TO LINE CHECKING face to the right limb of the Moon.) Extensive calculations were also done to define the Catcher’s orbit. Because the 3 600,000 metric tons per year will be NOMINAL PRELIMINARY MASS-DRIVER SECTION about 500 megawatts, corresponding to (HALF - SIZE) about one square kilometer of solar collector area. Gerry Driggers concluded the presentation with a discussion of fabrication, logistics, timetables, and costs. A careful analysis of what parts of power satellites could be easily fabricated in space at an early stage of space industrialization showed that about 91% of the mass of a silicon photovoltaic cell power satellite could be built in space, with only 9% shipped up from Earth. For a turbogenerator-based power satellite, however, only 68% of the mass could be readily fabricated in space, so that the photovoltaic system appears to have a very strong advantage, at least initially, even if the total mass required for it is significantly higher. The chemical extraction plant could be housed in a more or less cylindrically shaped “factory” about 50 meters in Moon’s revolution around the Earth each that the L-5 Society might have to diameter by about 140 meters in length, month does not keep perfectly in step rename itself the “Two-to-One Resonance while the fabrication machinery would with the Moon’s rotation on its own axis, Orbit Society.” require about a 100 meter extension of the launch site does not stay in a fixed William Phinney then discussed the that same cylinder. position relative to the Lagrange libration problems of chemical processing in space Three different scenarios were points. To minimize the work the to extract metals, oxygen, silicon, and developed for a Space Manufacturing Catcher has to do to follow the stream of calcium from the lunar soil, with some Facility/Solar Power Satellite program. payloads coming up from the Moon, it preliminary description of lunar soil The most conservative was based on turns out that the Catcher should make a composition variations among the six “minimum concurrency,” that is, once-a-month orbit around L-2 with a Apollo landing sites. For example, soils development of each part of the system radius of about 10,000 km, with the from the lunar highlands were relatively is undertaken only after other parts on Catcher’s orbit standing on edge relative more rich in aluminum than were soils which it depends have been fully to the Earth-Moon orbital plane.