SPACE STUDIES INSTITUTE
VOLUME XXI ISSUE 2
ABOUT THIS ISSUE…
As you can see, we have changed the format of the newsletter! SSI Update will be published on a quarterly basis, but will be expanded in content. We will bring you more in depth technical articles, as well as more complete reports on SSI-sponsored research. The newsletter will be printed on coated, but recycled paper and remain in this easy-to-read three column format. These changes are in response to our poll conducted last year on what you would like to see, and how you would like to see it. We welcome your comments and suggestions.
Research Project Announced: George Friedman announces SSI research initiative (details, page 2). This research project follows the systematic approach to space exploration, development and manufacturing which Dr. O’Neill began in the mid 1970s. Since we have many new members who may not have read the following three articles, we are reprinting them here. Please note each has been edited to delete duplicate figures and pictures. Copies of the original pieces may be ordered through SSI.
High Frontier-Technical Progress, A Resolution, Commitments by Gerard K. O’Neill, March 1978, is reprinted beginning on page 1. In this article O’Neill announced the formation of SSI, urged that research be carried out on a full-time basis, and predicted, “Unless we remain forever planet-bound, the new millennium will surely see the emigration of humanity, not only to the far reaches of our solar system, but beyond.”
The Low (Profile) Road to Space Manufacturing by Gerard K. O’Neill, March 1978, is reprinted beginning on page 3. O’Neill describes a scenario in which, under the launch constraints of the late 1970s and early 1980s, “we might be able to reach the point at which space manufacturing will begin to regenerate and grow exponentially.” He also outlines the plans to construct Mass-Driver II.
New Routes to Manufacturing in Space by O’Neill, Driggers and O’Leary, October 1980, begins on page 11. This article details bootstrapping” scenarios to achieve the capability of producing fuel, components for deep-space research vessels, radio telescopes, and large high-power satellites, and large orbital facilities in space from lunar materials. It also describes SSI’s commitment to conduct research, disseminate accurate information, and chart coherent, consistent research paths, which we continue to strive towards today.
Brief Conference Report: A brief report on the SSI Conference on Space Manufacturing appears on page 15, along with information for ordering the proceedings at a pre-publication price and the audio tape of Dr. John Lewis’s inspiring banquet address.
The Planetary Defense Workshop: Dr. George Friedman reports on his participation in the recent Planetary Defense Workshop and the importance of near-Earth objects to SSI’s challenge of opening the High Frontier on page 10.
Recommended Reading: Three books (and information on ordering) are listed in this quarter’s recommended reading list on page 15. They are: STS-71, MIR-1/Shuttle Mission Profile, MIR-1 Space Station, The Greatest Adventure, and Rain of Iron and Ice. These are, of course, in addition to The High Frontier and Technology Edge.
SSI Research Noted: A reprint of the article which appeared in the May 15, 1995 edition of Aviation Week and Space Technology, “‘Air Spike’ Could Ease Hypersonic Flight Problems,” is found on pages 8 and 9. This article reports on the positive lab results achieved by SSI researcher, Dr. Leik Myrabo. This work was also reported in the May 22 issue of Business Week. As an SSI member, you share in his success!
HIGH FRONTIER –
Technical Progress, A Resolution, Commitments
by Gerard K. O’Neill, March 1978, Princeton University
Some nine years have now passed since began exploring the possibility that our generation might open a new ecological range for humanity; a range of unlimited volume, three-dimensional rather than Earth’s two, and blessed with unlimited clean solar energy and a reservoir of materials vastly greater than our beleaguered Earth could ever provide. In the first several years, I became convinced of the inevitability of a large-scale movement of humanity into space, not for mystical reasons but rather for the same ones that have always pushed us toward new ecological ranges: because whenever a new range opens there is a burst of growth in wealth and opportunity, and the species that makes the transition is for a time at least – free of the restrictions imposed by Darwinian competition.
The article that follows, on “The Low (Profile) Road to Space Manufacturing,” represents the line of thinking I have been pursuing for nearly two years. It is engineering – and economics – oriented, and makes no concession to popular interest – for example, to interest in large Earthlike space colonies. Yet I have gradually come to realize that we in engineering and science, who feel so much more comfortable with this nuts-and-bolts reasoning, are missing entirely a lesson that everyday experience teaches: The public grasps instinctively the significance of a new ecological range, because such a move has so many parallels in Earth’s history. Like the 19th century’s westward movement, its greatest significance is new opportunity for people. Again and again I have done interviews, spending hours to lead writers or hosts through the logic of manufacturing from nonterrestrial sources – only to see editors or producers, with sure instincts for public interest, zero in on the excitement of a new frontier movement for ordinary people.
That lesson was reinforced a few months ago by the extraordinary set of events that led to the introduction by Congressman Olin Teague of the House Concurrent Resolution 451:
“That the Congress hereby finds and declares the following national policy: … that every feasible means now shall be mobilized to explore and assess the resources of the “high frontier” of outer space, to better understand and to make practical beneficial uses of these resources…
“To determine the feasibility, potential consequences, advantages of developing as a national goal for the year 2000 the first manned structures in space for the conversion of solar energy and other extraterrestrial resources to the peaceable and practical use of human beings everywhere.”
That initiative came from a citizen’s group in cooperation with members of the House of Representatives. They sought language that would include not only manufacturing in nearby space, but also the longer term goal of human movement into the new “High Frontier.”
The timing of the Resolution may be premature; it may fail; or even if it passes, its effect may be diluted and diverted by the forces of reaction with which every new movement must contend; but as one of my good friends in the government put it, “You can’t put the genie back in the bottle.”
To many of us who have struggled through the past several months of Washington politics, however, it does seem that we are in the midst of an attempt to “put the genie back into the bottle.” Fortunately, that attempt has come too late. If it had come three years earlier, and been supported by independent, nongovernmental organizations like the AIAA, the “High Frontier” concept could have been discredited before it had time to develop its conferences, its NASA studies, and the rest of the solid, professional literature that has now given it a hold on reality. In the behind-the-scenes attempts by highly placed officials to block or deflect the Teague resolution, the AIAA publications were vital as evidence that the new concepts were more than Sunday-supplement entertainment.
Now that its first year is past and it has a chance to find its feet, the new Administration (Carter) will have an opportunity to do solid homework on the “High Frontier” concept. Good work can be done under Federal sponsorship in the next few years – if the Administration can overcome the no-growth philosophy it entered with. That philosophy was based on the old-fashioned idea that wealth can only flow from resources within the Earth’s biosphere that space beyond spy-satellite altitude will be an arena only for scientific observation.
If these educational attempts fail, what then? In the past months, a number of people, especially students, have asked me fearfully if I would give up and turn to easier, less controversial topics if the Executive Branch made a determined effort to stamp out research into the “High Frontier.” I say, no, and so do friends to whom this work owes so much. Those of us intimately involved in the research feel sure that we are on the right track, that we are carrying on an activity that will benefit humanity immensely, either soon or a little later. To walk away from that, whatever the environment, would be an act of cowardice. As long as we can keep the work going, in any way that we can, we will. If funding from the Executive Branch ceases (it was suspended for two months in the autumn of ’77), we will keep the work going from other sources, either from Washington, from state capitals, or from private funds.
To that end a small, independent institute has been set up, the Space Studies Institute. A few friends and I operate it without drawing salaries, and it depends for its life on tax-deductible private donations. Already it has served a vital role, permitting us to keep research going while no money was flowing from Washington. It will be the only source of funds for materials to build the second mass-driver model, described briefly in the following article. Friends within the aerospace profession who feel that our work should go on can insure that it will by supporting the Institute.
How should the “High Frontier” concept be linked to the overall body of aerospace research?
First, the time for “summer studies” clearly has passed. The 1977 study, based on the general logic of the “Low (Profile)” article, went about as far as any group can reasonably expect to go within the limits of a short-term, intensive review. The group leaders of that study agreed unanimously that the work should be continued full-time. Essential elements like mass-drivers and chemical processing plants must be tested in model form; minimum investment scenarios like that of the following article must be raised from an individual, intuitive level to the objectivity of computer programs flexible enough to accept and measure sensitivities to various guesses on R&D costs and time-scales.
If its “Low (Profile)” version, the “High Frontier” concept should be a salable, common sense item of national research. The most severe physical problems now facing this country and the world are the limits on available energy and materials. The Shuttle opens up routine access to virtually limitless materials and energy. Never mind, for the moment, the question of what will be the first large-scale use of nonterrestrial materials. Building satellite power stations may be the first use, but the satellite-power concept could die before being realized, whether because of some flaw in the concept itself, or because some alternative energy technology may be developed that appears more economical. Bypassing satellite power stations could slow but need not stop a well-thought-out space-based manufacturing program, if the basic thrust of the program is to open up the nonterrestrial reserves for use in space.
A space-based manufacturing program based on the Shuttle as the carrier of equipment to low orbit makes sense because the Sun shines full time in space, the lunar gravitational potential is only one-twenty-second that of the Earth, and there are material resources vastly greater than we could use even in hundreds of years reachable in the inner part of the solar system without our having to fight strong gravitational fields. In the long run, those unalterable facts are going to determine the arena of our activity – whatever the particular products first made in large tonnages in space, and whenever large-scale practical returns come, in the 1990s or only in the next century.
We tend to forget that there is more than a hundred-year mark soon to be passed. There is also a millennium. Unless we remain forever planet-bound, the new millennium will surely see the emigration of humanity not only to the far reaches of our solar system but beyond. Now that we realize the possibility of Earthlike habitation in space, all star systems become potential sites for colonies, whether or not those systems have planets.
Governmental myopia may delay for a while the movement into the “High Frontier,” but we should not be discouraged. Governments have the habit of being myopic. Perhaps also we should not feel too badly if some other nation than our own seizes the initiative. Several have the technological ability given a decade or so of intensive effort. As scientists and engineers we can take comfort in the fact that the numbers in our favor are constants of nature; time is on their side, and on ours.
SSI RESEARCH PROJECT ANNOUNCED:
“Seeds of Technology for Seeds in Space” or more formally … Exploratory overview and evaluation of key enabling technologies which will robustly fulfill the High Frontier mission.
In this study, consideration will be given to the colonization of space habitats, cheap access to space, utilization of space resources, establishments of solar power satellites and the general establishment of a more hospitable environment by the propositioning of stores of material and energy in space.
Study Team: Principal Investigator: George Bekey, assisted by George Friedman and 2-3 graduate students at the USC Robotics Research Laboratory. (Neither Bekey or Friedman will receive compensation).
Study Background: The following considerations differ from O’Neill’s original assumptions and will now be addressed:
(1) conventional launch systems have fallen far short of their goals to deliver mass to orbit at low cost
(2) advances in miniaturized electronics and mechanical systems as well as telerobotics have far exceeded the projections of even a decade ago, permitting the opportunity to make much more effective use of whatever mass we do get into orbit
(3) the perceived population of NEOs has increased enormously in the past decade, making available far more material resources with less required energy than the lunar surface.
Study Scope: The telerobotics size range will cover present-day meter sizes down to the eventual nanometer sizes with special attention given to the more immediately available sizes of centimeters to millimeters. The range of functionality will include teleoperation, cooperative activity (robot/man; robot/robot), delegated artificial intelligence, and replication.
Deliverables and Schedule: November 1, 1995: Final report and presentation materials.
THE LOW (PROFILE) ROAD TO SPACE MANUFACTURING
by Gerard K. O’Neill, Professor of Physics. Princeton University.
Early in 1977, an exciting new possibility for speeding space industrialization came up. Several of us at MIT checked out working-model hardware for it in the spring of that year. An independent NASA-supported study that summer wrung out the concept much more thoroughly, with similar results. In this article, I will outline the concept in its original brief form, and note significant changes made as a result of the detailed review.
In the autumn of 1976 the articles from the 1976 NASA-Ames Summer Study on Space Manufacturing from Non-Terrestrial Materials were completed. They gave us for the first time necessary formulae for optimizing the design of magnetic “mass-drivers.” In addition, they gave us detailed numbers on space-manufacturing plants: mass, throughput of materials, power requirements, and workforce needs.
The new data suggested to me that, within the lift constraints of the Shuttle era, we might be able to reach the “takeoff point” at which space manufacturing will begin to regenerate and grow exponentially in its culture medium of full-time solar energy and lunar derived materials. Although caution is always advisable, it may not be an overstatement to describe the new work as a substantial advance.
It has several components:
– A method by which the Shuttle could be upgraded to geosynchronous capability.
– Planning of a minimal facility on the lunar surface, from which materials could be transferred – at low cost – into free space.
– Evaluation of a processing and fabrication facility in space.
– Calculation of the inputs required in order for an initial facility to grow to the takeoff point.
Combining these building-blocks, I find that the total requirement for lift from the Earth may be equivalent only to a few dozen Shuttle flights per year for several years.
For both technical and political reasons, we must squeeze the most performance, payback, and productive lifetime out of the Shuttle operational era. Our first problem is that the missions with a high potential economically – satellite power system deployment and the utilization of nonterrestrial materials – go to geosynchronous or lunar orbits; but the Shuttle is a low-orbit machine. Is there a way to bypass this problem and give the Shuttle geosynchronous orbit capability?
The conventional answer has been no, other than by accepting a penalty in payload transferred, through the necessity of carrying propellant as payload during the Earth-to-low orbit lift. That penalty would reduce the Shuttle’s modest payload (29 metric tons per flight) by a factor of 2 to 4 – to a point too low for the seeding of a space-manufacturing program even of minimal type.
The problem in fundamental terms: the Shuttle can accumulate payloads in low-Earth orbit; to raise them to geosynchronous orbit would take energy, reaction mass, and an engine able to use them.
Solar energy is available, and has long been considered the prime candidate to power ion or plasma engines for deep-space missions. But to raise accumulated Shuttle payloads, several hundred tons at a time, from low to high orbit would take an engine of substantial thrust. In order to escape the loss in payload incurred by transporting propellant to orbit, a geosynchronous system would also need another source of reaction mass.
As designed the Shuttle Orbiter carries no fuel for its main engines. It must bring its external tank (35 metric tons empty weight) almost to orbital energy. But either by the sacrifice of a few percent in payload to additional OMS (orbital maneuvering system) propellant or by storing hydrogen slush rather than liquid hydrogen, the external tankage could be brought into orbit to serve as reaction mass. To prevent the reaction mass from becoming a hazard to orbiting spacecraft, it should be ground into a fine powder, and after acceleration by and release from the carrier bucket, dispersed by being charged electrostatically. From 60 Shuttle flights per year, the reaction mass powder entering the atmosphere would amount to less than 1% of natural micrometeorites.2
The electromagnetic mass-driver (noted October 1976 A/A, page 23) seems to be the best, and perhaps the only, reaction engine with adequate specific impulse, thrust, and efficiency to use so unlike a substance as powdered Shuttle external tankage as reaction mass. Essentially a linear electric motor, the mass-driver uses small buckets, constrained laterally by magnetic forces, to accelerate liquid or solid payloads to high velocity before releasing them and returning for reuse.
Once the processing of lunar materials in space begins, almost surely liquid oxygen will become the optimum material for reaction mass. Oxygen constitutes 40% of lunar surface soil, is likely to be a waste product from its processing, should be easy to handle as a liquid, and after acceleration, would disperse by boiling to molecular form.
The third of the three articles contains formulas and numbers on which designs for a mass-driver reaction engine can be based.3,4,5
Later articles summarize without derivation formulas for optimizing system mass, based on the most recent theoretical work.6,7 We have
now established as a baseline a system in which each bucket has just two coils, the drive circuits are of two phases in quadrature, and the current in each drive coil oscillates through one complete sine wave as each bucket coil passes.
The 1977 NASA-Ames Study concluded that total system mass changes little with cross-sectional dimensions. For constant throughput, system mass changes by only 50% as payload varies by a factor of over 1000. To keep the driver length within practical limits, it must use high acceleration (several hundred Earth-gravities).
The mass-driver employs superconductors only in the buckets; the stationary drive windings are of ordinary aluminum. For commercially available superconductors, field strength limits are not reached even at accelerations of more than 1000 g. (Mainly for historical reasons, the earlier calculations on mass-drivers were based on rectangular geometries similar to those of an MIT Magneplane transportation concept.9 Calculations indicate tight-coupled axial structures, advocated by H. Kolm of MIT, to be lighter by more than a factor of 2 for the same performance.5)
At a nominal 60 flights per year, the Shuttle can bring to low orbit approximately 1700 tons of payload and 2100 tons of reaction mass (i.e., external tanks). For spiral orbits, missions to lunar distance require an engine with specific impulse in the general range of 1000 sec, if the engine is to be returned and a substantial payload carried. A mass-driver of that sort would have these characteristics based on the latest 1977 Study results:
|Exhaust velocity, m/sec||10,000|
|Specific impulse Isp||1,020|
|Bucket acceleration, m/sec2||10,000|
|Engine electrical components mass,
including power, tons
|Total engine mass, tons||170|
|Round trip time to lunar orbit, days||200|
|Reaction mass use rate,
|Payload from low-Earth orbit to
lunar orbit, tons/yr
The 1977 Study identified as a major necessary development for reaching this performance, reducing the weight of a silicon controlled rectifier to only a few times the weight of the silicon wafer alone. Present silicon rectifiers, designed for entirely different service with high duty cycles, weigh far more.8
Until the 1977 Study, the mechanical stability of the long, thin mass-driver structure as buckets accelerated and decelerated remained unclear. After a great deal of work the Study concluded that the machine would just remain stable. Therefore, the system mass includes a yardarm and guywire structure with slow acting servomechanisms to maintain straightness. (The Stanford Two-Mile Electron Accelerator, located almost on top of the San Andreas earthquake fault line, is given occasional adjustments based on a laser-beam sight line. Its aperture is about 1 cm.)
The nominal design just outlined would give more than twice the specific impulse of the Space Shuttle Main Engine, which is the state of the art for large chemical rockets.
To the best of my knowledge, no physical upper limit on mass-driver output velocity exists (other than c); but the optimum Isp for missions in the Earth-Moon system is 800-1000.
So we should be able to lift about 1300 tons/yr of Shuttle payloads from low-Earth to lunar orbit, without having to devote additional Shuttle flights to carrying propellant. What minimal facility would then be necessary on the Moon to convey lunar materials into space?
My original estimates centered on 1050 tons. A more detailed evaluation carried out during the 1977 study concluded with a figure of just under 1000 tons. 8 The axial mass-driver for the lunar surface contributes less than a quarter of the total excluding its foundations. That machine would be sized for an eventual throughput of 600,000 tons/yr. but the photovoltaic array first sent to the Moon could handle only a twentieth as much throughput. The machine parameters are:
|Design maximum velocity, m/sec||2400|
|Total length (accel. + decel.), m||4320|
|Efficiency, d.c. to kinetic power||%96|
|Photovoltaic power supply (at lunar surface),
|Waste-heat radiators, tons/Mw||20|
The mass budget figures in tons for initial lunar-surface operations would be as follows:
|Axial mass-driver electrical components||232|
|Photovoltaic power supply (for 30,000 tons/yr)||93|
|Downrange course-correction stations||50|
|Habitat (temporary for 50, long-tour for 10)||300|
(50 people, 1 year, at 10 kg/d)
|Silicon and glass-fiber plant
for materials encapsulation
In addition resupply for a 10-person crew using 10 kg per person per day would total 37 tons per year.
To soft-land that equipment, an equal quantity of propellant must be brought to lunar orbit. For operations both on the lunar surface and in space, we must ante up about 2800 tons of Shuttle payloads – about 100 Shuttle flights – to commence transporting materials from the lunar surface to a precise point in space. The 2800 tons breaks down as follows:
|Total lunar surface equipment and supplies||1085|
|Propellants (LOX-Hi) to soft-land||1085|
|Mass receiver (diam of 110 m) at L-2||100|
|Habitat in space (30 people, at 10 T)||300|
|Lunar lander (LOX-H2 engines,
|Shuttle and interorbital crew module||11|
|Interorbital tub (LOX-H2 engine,
|Supplies for personnel in space
(for 1 yr at 10 kg per person)
The 1977 Summer Study obtained a similar total from a slightly different mix. Lunar landers and personnel transfer tugs had more mass, but converting spent Shuttle external tanks to 21-person habitats for use on the Moon and in space saved substantial mass. Those habitats could be spun on cables to create normal gravity, and would be divided into private apartments, one for each person in the original workforce.
At the first plateau a number of milestones would be reached: proof of the concept of lunar materials transport, provision of large quantities of reaction mass for all later operations, and opening of a large reserve of mass for shielding manned operations at geosynchronous or higher orbit.
In reaching this plateau it will not have been necessary to learn how to chemically process or fabricate from lunar materials, nor to learn how to set up agriculture in space.
Once at the plateau, with the availability of lunar soil as reaction mass, the throughput of equipment from the Earth to geosynchronous and higher orbits will no longer depend on powdered Shuttle tankage. (That might be a good time to deploy a Shuttle-derived lift vehicle, so that subsequent launch operations can be of lower cost.)
The next step requires chemical processing, making oxygen in lunar materials (40% by weight) available as propellant for lunar landers, as vaporizable liquid reaction mass (able to be used more freely in mass-drivers than can solids), and as the most important component of a breathable atmosphere for workers in space.
During the setup of the pilot-plant operation in space, the key numbers (as estimated in the 1976 NASA-Ames study) would be:10
Assumed process plant efficiency, %60
Input average composition, %
|Throughput/ power, tons/year
|Process and fabrication plant
throughput (includes radiators
but not power supply),
tons/year-ton of plant
|Photovoltaic power in space,
|Labor utilization (Si plus
|Resupply needs (after oxygen
extraction becomes practical),
kg/person per day
|LEO to high orbit mass penalty
|Factor of 4|
Totals for process and fabrication:
|Output fabricated Si and metals,
|Plant mass, tons||150|
|Power-supply mass (at 5.3
|Habitat requirement (at 10 tons
per person), tons
The 1977 Study updated these numbers, but the major conceptual breakthrough on chemical processing during 1977 was laying out a new basic process flow chart depending on a carbo-chlorination reaction rather than on carbo-thermic reduction of aluminum-bearing minerals. The change reduced the peak temperature in the system by a thousand degrees to bring it in line with normal industrial practice here on Earth.
Once chemical processing is tested and working, the next step is fabricating a limited range of products from chemically separated lunar materials, such as photovoltaic arrays (lunar material, 20% silicon by weight) and thermal radiators to upgrade both the lunar launcher and the processing/fabrication plants in space. Products might later include structural components. We estimate an output of about 9000 tons per year of fabricated components-of these, about 20% would be photovoltaic arrays and 80% would he habitat components.
Together with 1800 tons/year from the Earth (21 flights/year of a Shuttle-derived freight rocket) and 750 people per year (13 Shuttle flights), this system would grow at a rate of 150,000 tons of additional throughput per year. When that growth reaches 630,000 tons throughput per year, or 190,000 tons/year of fabricated output products, the system output would equal in mass two 10,000-Mw satellite power stations per year.11
Minimum transport investment up to that point comes to just under 300 flights from Earth to low orbit, or about 42 flights per year averaged over seven years; of these, over half would be Shuttle flights (STS) and the remainder Shuttle-derived lift vehicles (SDLVs).
F-2 summarizes recommended transport investment. It includes additional safety factors – mainly 96 additional SDLV flights to provide the 3000-person workforce in space with 8400 more tons of supplies. These may be in the form of 1 ton of organics per person to stock later space farming, of 2 kg per person per day of emergency resupplies adequate for two years, and 4300 tons of Earth-built components for habitats or for products exportable to geosynchronous orbit.
If (as assumed) space agriculture has not yet been developed, 25 SDLV flights per year will be required to transport food to the 3000-person work force, at 2 kg per person per day. At $20 million per flight, that will add about a dollar per point to the cost of fabricated products. (The rate of developing agriculture in space will likely be affected less by direct lift-cost economics than by the need to maintain workforce morale by providing enjoyable fresh foods.)
The range of output products and the rate of diversification of products will depend on the economics of construction in space vs. lift from Earth. To sustain rapid exponential growth, an increasing share of the total must be built in space. For example, if 5% of the output products’ mass must still be obtained from Earth when 600,000 tons per year is being processed, about 100 flights per year of a Shuttle-derived freight rocket will be required to transport that 5% to low orbit. Strong economic incentives will exist at that time both to diversify industry in space and to upgrade Earth-to-low-orbit transport, either by a reusable Shuttle first stage or by a wholly new (possibly single-stage) vehicle. The justification for such developments will be far easier then, after several years of intensive Shuttle use and the continuing pressure of space productivity, than in the early 1980s.
The 1977 Study traced the time-line for another decade, to a point where the entire market for new generator capacity worldwide apparently might be provided by space-built satellite power. That Study found the market 25 years from now would be $200-400 billion per year. It found exponential growth essential for beating interest costs, and ran into the biggest uncertainty over what fraction of the products assembled in space must be hauled from Earth. As both studies in the past two years have concluded, effort must go into designing fabricated products optimized for construction from lunar materials. The exercise resembles substitution studies carried out in wartime or when cartels threaten supplies. Lacking the lunar-materials option, we would still be making studies of that kind in these next years, as materials shortages and cartels increasingly rule our industries.
For the limited span of time covered by F-2, the most uncertain numbers appear human related: habitat mass, productivity, duration of tours of duty, and fraction of the workforce engaged in export labor. The latter two have been ignored in this simplified treatment. The time-line appears rather insensitive to those numbers until the first plateau; after that the actual growth rate depends on them more.
The takeoff point in space manufacturing will reflect our cultural values. It might be defined in one way as the point at which the rate of value-generation exceeds the rate of investment, the latter including development, construction, transport, and interest charges.
R&D cost estimation is a notoriously uncertain business. Given the transport economies just outlined, R&D costs may dominate the total investment required to reach the takeoff point. R&D costs have ranged from as little as $6 million per ton in 1960 dollars for a throwaway rocket whose engines had already been developed, the Saturn V, to over $200 million per ton for the Apollo Command Module.
To estimate R&D costs for space manufacturing, it seems best to use a modem example: Shuttle R&D totals $6.3 billion.12 Of that total, I take two-thirds as devoted to the Orbiter, a complex but reusable 68-ton vehicle. Orbiter R&D costs approximately $62 million per ton. The relatively simple external tank and one SRB total 76 tons, and cost $28 million per ton for R&D.
The components of the space-manufacturing program just described have been analyzed for cost on that basis, as summarized in F-3. Mass-driver structures were estimated on the basis of individual non-equivalent sections every 51 in bucket velocity. The crew-transport module for 60 people was taken as a Shuttle payload of 11 tons dry mass, and the workforce habitat module was assigned a mass of 12 tons. To compare this primitive approach with the more detailed estimates made during the 1977 study, all mass-driver R&D in F-3 costs $2.4 billion. Several months later different persons obtained a figure of $3.3 billion, which includes construction of several mass-driver tugs and an extensive program of unmanned observations by lunar polar orbiter and exploration by roving lander. No sensible person would conclude from that a figure of $2.7 billion ± 20%. Other estimates, equally defensible, were higher and lower by factors of two.
F-3 shows a range of cost estimates for some items for which there are data from previous studies of orbital transfer vehicles, space stations, a lunar base, and a Shuttle derived lift vehicle. All estimates are necessarily rough and do not consider overall integration, government infrastructure, and commonality with other applications, but they do serve to show that the investments fall in a reasonable range.
Both studies reveal clearly that reaching the economic takeoff point does not require large monolithic habitats (“space colonies”). Furthermore, colonies could not be developed like aerospace hardware, for R&D cost reasons. When the time comes to build such structures, they will have to be designed and constructed like ships or like buildings rather than like jet aircraft. Space-farms, like monolithic habitats, do not appear to be essential in reaching the takeoff point.
The 1976 Ames Study concluded that over the range of 1 to 30 kg/sec in throughput, chemical extraction and fabrication plant mass and power should be proportional to throughput. For minimizing R&D costs, therefore, it seems best to design such plants for moderate size (1 kg/sec or 30,000 ton/yr) and then to parallel identical units.
It is reassuring to find that most of the necessary early R&D steps have potential benefit to all large-scale high-orbital activity, whether or not using lunar materials.
To indicate the uncertainty of R&D cost estimation, in a recent NASA Johnson Space Center study, a large, fully reusable Class IV launch vehicle was assigned an R&D cost of $6 million per ton – a factor of ten below the figure used in this article, and one seventh of the average for the Shuttle. 11
Until far more detailed work is done, it seems premature to argue which, if any, of these estimates is near the truth. I use the higher figures mainly to be on the safe side.
The required R&D investment falls naturally into three blocks:
1. All items necessary to reach the first plateau, at which point the base would begin putting 30,000 tons per year of lunar materials into space. That first block would cost $34,000 million or $700 million per year spread over five years – a sum and rate well within governmental R&D funding patterns, being far less than the annual Department of Energy budget for nuclear-power R&D, and well under peak funding for Shuttle development.
2. SDLV development plus intermediate level ($400 million per year) research on processing and fabrication. This would cost $700 million per year for two years – also within government precedents.
3. A remaining $14 billion for processing and fabrication development falls intermediate in scale between Shuttle and Apollo R&D. The processing-design group at the 1977 study rather strongly believed that estimate far too high. If that figure is high, it is likely to be compensated for by errors in the other direction made on other items.
In brief, the gradual, step-by-step approach to space manufacturing comes within the general range of NASA funding, at least until processing and fabrication plants must be developed. If a decision on R&D funding of the third block were delayed until then, at that point prospective investors would know that the major questions of lunar-materials transfer, of low-cost interorbital transport, and of the long-term health of workers in space had been answered. If the requirement then existed for large tonnages of manufactured products in geosynchronous orbit, funding for additional R&D would be easier to justify than it would likely have been earlier.
A total of $14 billion in R&D funding spread over several years comes within the ability of the private sector. In 1990, for example, the electric utilities will have to be investing in new generator capacity at a rate of more than $20 billion per year. Even in 1977 the life-insurance companies, major financiers for the utilities, disposed of some $45 billion in investment cash flow.
In a stepwise approach, the items requiring relatively large R&D expenditures can be deferred to a late stage in the program, when the most unusual and therefore high-technical risk items have been proven, and when profits from manufacturing are in sight.
On the Advisory Panel of our Task Group on Large Space Structures formed by the Universities Space Research Association, we have several senior executives of major utilities and life-insurance companies. The Advisory Panel has discussed R&D funding of a space-manufacturing program at some length. They feel private sources of capital unlikely to appear on a significant scale, that is, on the scale of tens of billions, until technical risks have fallen to the level of hydroelectric power. They agree that demonstrations of lunar-materials transport, of satellite power transmission, and of the processing of lunar materials to pure elements in space would constitute adequate reduction of risks. After that, our financial friends assure us, there should be no difficulty in obtaining ample private funding for a rapid buildup if the economic estimates show clearly that space-manufactured satellite power will undersell that from coal and the atom.
Given the breakthrough in transport economy described here, the pacing item in the development of space manufacturing appears to be the start of processing R&D.
Many development scenarios are possible, and I provide one (F-4) as illustration. It delays the peak of the third block of R&D funding until the two-year period for emplacing the lunar-materials transport system, and is consistent with F-2. A still more cautious scenario would insert an additional decision delay until starting the transport of lunar materials, and would make the third block of R&D funding a more highly peaked three-year effort.
F-2 and F-4, combined with a hardware cost assessment of $110/kg, a 10% interest rate in constant dollars (17% discounting), and an assigned value of $60/kg for fabricated export products made in space, allow calculation of the takeoff point as six years after the start of the lift. I assume that the equipment to be located in space will cost on Earth eighteen times as much per kilogram as the value per kilogram in geosynchronous orbit of the products fabricated in space. The first is based on the cost of military aircraft, while the second is based on satellite power stations of 83,000 tons mass,11 figures as worth $500/kw at the busbar on Earth. For the timeline of F-6, the total program up to takeoff would cost $24 billion, exclusive of interest. After “takeoff,” debt retirement and earnings would accelerate rapidly.
The 1977 Study considered many points not brought up in my simplified argument: workforce selection and training costs, salary costs, crew-exchange times and resulting transport loads, and an overall higher estimate of R&D costs. It reached quite similar conclusions on times and buildup rates, but gave a total investment up to the takeoff point of more like $50-60 billion – about the cost of an Apollo project in today’s dollars.
Both efforts constitute simply first cuts toward a generally promising approach. Better answers, or still more efficient scenarios, will have to await longer-term or continuous studies using the well-known but expensive techniques of critical-path analysis and cost/benefit theory embodied in large, thorough, flexible computer programs.
The mass-driver clearly plays a key role in the development of space manufacturing. Without that, or something equivalent to it, the upgrading of the Shuttle, lunar-materials transfer, and low-cost interorbital transport will all be impossible. Recognizing that fact, the propulsion division of NASA’s Office of Advanced Science and Technology has recently begun support of mass-driver research at a modest level. As a first step, a group of student volunteers, together with Prof. Kolm and myself, built a 2-m-long mass-driver of larger caliber than the Shuttle upper-stage engine.13 The model was built almost entirely of scrap or surplus materials. The group completed the mass-driver in three months, and demonstrated it at the May 9-12 Princeton/AIAA Conference on Space Manufacturing, at the final briefing of the 1977 Ames Study, and at the California Aerospace Day celebration a few hours before the first Shuttle free flight.
Unfortunately, the uncertainties of changing administrations in Washington have delayed funding for a second, much higher-performance model. Funds assured at the time of writing would not even buy materials for that model, the superconducting bucket of which would reach a speed of 700 mph in 5 m to impart an acceleration of 1000g’s in a vacuum. Partly to end these delays, a group of us has formed the Space Studies Institute, a non-profit corporation able to receive tax deductible subscriptions.14 Subscriptions from persons of all ages and backgrounds have already begun flowing in, and we will depend on them to construct the second model of the mass-driver. The officers of the Space Studies Institute serve without salary, so funds donated can be applied with close to 100% efficiency.
From a practical viewpoint, the most significant conclusion of the recent work is that the Shuttle, far from being a limited device poorly suited to the tasks now emerging as of greatest economic value, may prove an excellent launch vehicle even for an ambitious, large-scale program of space manufacturing.
1. The 1976 NASA-Ames/OAST Summer Study on Space Manufacturing of Non-Terrestrial Materials, published in Dec 1977 by AIAA as Progress in Astronautics and Aeronautics: Space-Based Manufacturing from Non-Terrestrial Materials, referred to below as SMNTM, Progress Series Vol. 57, series editor, Martin Summerfield, volume editor, G.K. O’Neill, volume assistant editor, B. O’Leary.
2. Allen, C.W., Astrophysical Quantities, Third Edition, p. 157, Athlone Press, London, 1973.
3. O’Neill, G.K., “The Colonization of Space,” Physics Today, Vol. 27, No. 9, Sep 1974, pp. 32-40.
4. Chilton, F., Hibbs, 8., Kolm, H., O’Neill, G.K., and Phillips, J., “Electromagnetic MassDrivers,” in SMNTM.
5. Chilton, F., Hibbs, B., Kolm, H., O’Neill, G.K., and Phillips, J., “Mass-Driver Applications,” in SMNTM.
6. O’Neill, G.K., “Mass-Driver as Shuttle Upper Stage,” in Proceedings, 1977 Princeton/ AIAA Conference on Space Manufacturing, AIAA, 1977.
7. Kolm, H., and O’Neill, G.K., “Mass-Drivers for Lunar Materials Transport and as Reaction Engines,” in Proceedings, 1977 IAF Conference on Astronautics, Prague.
8. Space Manufacturing/Space Settlements, the 1977 NASA-Ames Study to be published as single NASA Special Publication containing 16 articles and an introduction, in progress.
9. Kolm, H., et al, “The Magneplane System,” Economic Evaluation of Space Solar Power Concepts,” Vol. 1, summary, JSC-11568, Aug 31, 1976, NASA Johnson Space Center, Houston, Tex.
12. Thompson, R., “The Space Shuttle System Progress Report,” AIAA Preprint No. 77-338.
13 . Kolm. H., “Axial Mass-Driver Reference Design,” in Proceedings, 1977 Princeton/AIAA Conference on Space Manufacturing, AIAA, 1977.
14. Space Studies Institute, Princeton, NJ 08540.
‘AIR SPIKE’ COULD EASE HYPERSONIC FLIGHT PROBLEMS
STANLEY W. KANDEBO/NEW YORK.
AVIATION WEEK & SPACE TECHNOLOGY/ May 15, 1995
Researchers at Rensselaer Polytechnic Institute believe they have demonstrated an “air spike” concept that could reduce the drag and heat transfer problems associated with hypersonic flight.
The concept was formulated by Leik Myrabo, an associate professor of mechanical engineering at Rensselaer and Yuri Raizer of the Moscow-based Russian Academy of Science’s Institute for Problems in Mechanics. It was apparently demonstrated late last month in tests at Rensselaer’s Mach 25 shock tunnel.
According to Myrabo, the concept would offer designers the capability to actively control the external aerodynamics and thermodynamics of an advanced trans-atmospheric vehicle by substituting directed energy for mass – typically in the form of a sharp nosed structure. With this capability, traditional hypersonic design rules would change, and ultralight, blunt-bodied, lens-shaped or saucer-shaped single-stage-to-orbit vehicles could emerge.
Traditional sharp-nosed hypersonic vehicles generate a conical bow shock wave that causes massive heating at the tip of the craft’s nose. The air spike concept uses concentrated energy projected forward off a moving vehicle to drive air radially from the path of the craft and to transform the traditional conical bow shock into a weaker, parabolic-shaped oblique shock one tilted strongly aft with respect to a hypersonic vehicle.
Using the air spike, a pocket of low density, low-pressure, hot air in the shape of a paraboloid of revolution is formed in front of the vehicle, reducing the drag and heat transfer effects normally encountered by a hypersonic craft. Estimates indicate that an air spike equipped vehicle traveling at Mach 25 (orbital velocity) with respect to the exterior of the oblique shock wave would actually be subjected to Mach 3 conditions within the pocket formed behind the wave.
Another benefit of the directed energy air spike is that it can be used to help compress air for vehicle propulsion, particularly if the vehicle has a lens or saucer shape. According to Myrabo, the oblique shock generated by the air spike can be controlled to continuously pass the rim of the craft at a distance equivalent to one tenth of the radius of the vehicle. As the craft moves forward, air inside the pocket gets compressed between the oblique shock and the rim of the vehicle. Although localized heating at the vehicle rim is severe, “there are ways to mitigate it by manipulating the geometry [of the structure], and we plan to examine them,” he said.
According to Myrabo, an air spike formed by directed energy also has several advantages over a structural spike, the most important being the type of shock that is produced.
“The air spike effect is best modeled as a cylindrical blast wave that expands into a parabola given the forward flight of a vehicle. Because it is a blast wave, a very low density air pocket forms behind it, and that in turn reduces heat transfer effects,” he said.
In contrast, a structural spike generates a concial shock wave, and the air behind it is significantly denser than that found behind a blast wave. As a result, the drag and heat transfer effects associated with the air spike “are not replicated,” Myrabo said.
In the recent laboratory tests a 6-in.-dia., blunt-bodied aluminum model similar in shape to an Apollo command module heat shield was tested in the 2 ft.-dia. test section of Rensselaer’s Mach 25-class, 60 ft.-long shock tunnel. The energy to create the oblique shock waves associated with the air spike was provided by an electric arc plasma torch placed on a sting extending about 5.5 in. in front of the test model.
Calculations made prior to the experiments indicated that a conical shockwave impinging on the heat shield model would be generated by the plasma torch and its sting under Mach 10 free stream velocity conditions – if the torch were not operating. With the tool operating at 34 kw., however, an oblique shock was formed under the same Mach 10 conditions. The calculations and oblique shock were confirmed in Schlieren images (see photo).
According to Myrabo, approximately 35 calibration and test runs were made in the shock tunnel. About 10 were dedicated to demonstrating the air spike concept – “and they did,” he said. Since the tests were conducted on a shoestring budget assembled by Myrabo, the models were not instrumented, and specific temperatures and pressures behind the oblique wave were not measured. “We were attempting only to determine the validity of the concept,” Myrabo said.
The next step in his proposed test program is to conduct similar tests at speeds up to Mach 25 . Follow-on tests with instrumented models would be next, depending on funding, Myrabo said.
Myrabo’s air spike concept follows a wide range of work conducted in the late 1950s and in the 1960s. However, much of that work used chemical rocket exhausts, water and other “mass-intensive” on-board systems to manipulate shockwaves in front of a hypersonic vehicle. Myrabo and Russian researchers originally proposed air spikes generated by lasers; they now propose using microwaves.
Myrabo has been working on the “air spike” concept since 1993, and the conceptual work with Raizer was supported by the Space Studies Institute (SSI) near Princeton, N.J., to examine vehicles capable of driving earth-to-orbit transportation costs down by a factor of 100 to 1,000 in the next century.
One important assumption mode by the SSI study, however, was that an adequate space power infrastructure would exist. That includes orbiting satellites capable of transforming solar energy into microwaves that can be transmitted to Earth.
Using his Air Spike, Myrabo’s SSI study proposes that a single-passenger, 10-meter-dia., double-hulled, single-stage-to-orbit craft fabricated from silicon carbide materials is possible in the next century. Helium, pressurized to two atm., would circulate in the 1-cm. interspace between the 0.125-mm.-thick double hulls to cool the lens or saucer-shaped vehicle.
Myrabo also has been associated with the former Strategic Defense Initiative Office. Work performed for the SDIO, USAF and NASA centered on pulse detonation wave engines powered by groundbased lasers. In tests at the Naval Research Laboratory about three years ago, the Pharos 3 laser was able to create enough overpressure above a flat plate to generate a pulse equivalent to about 180 Newtons per megawatt – about as efficient “as an early jet engine,” Myrabo said.
Similar subsequent tests in the U.S. reached pulse levels as high as 250 Newtons per megawatt, while the Russians claim to have reached levels as high as 500 Newtons per megawatt.
Propulsion for Myrabo’s lens or saucer shaped air spike vehicle at speeds up to Mach 1 is provided by a pulse detonation wave engine similar to that studied in the SDIO’s laser propulsion program. However, the power used to accelerate and “explode” or expand the highly compressed air at the rim of Myrabo’s craft would be provided by an off-board microwave system, not lasers. Pressures of 25 to 35 atm. should be achievable, he said.
For speeds above Mach 1, the vehicle would rely on a magnetohydrodynamic fan engine. The lens-shaped craft would have an interior rectifying antenna to absorb pulsed, focused, microwave power on the outside of the vehicle to ionize air forced to the rim of the craft by the air spike. The rectennas also would pulse electric power through the ionized air and, in conjunction with two superconducting magnets ringing the craft, accelerate the air aft past the vehicle. According to Myrabo, this drive system also tends to eliminate sonic booms by eliminating pressure discontinuities, so the vehicle is silent but very bright in hypersonic operation.
Citing calculations made by Brice Cassenti, a senior principal engineer at the United Technologies Research Center, Myrabo estimates that the gas between the vehicle’s twin hulls, protected by the air spike, would rise in temperature only 25K during a flight to orbital velocity. Ultimately vehicles of this type could reach speeds as high as Mach 50.
Myrabo concedes the vehicle described in the SSI study is highly futuristic, but contends that the apparent confirmation of the air spike phenomenon could place it as little as a generation away.
A step toward demonstrating the capabilities of a full sized vehicle could be the construction and launch of a smaller satellite sized vehicle using an air breathing pulsejet engine and a pulsed microwave chemical rocket. The microwave source would be a ground-based generator.
Preliminary estimates indicate this type of machine would weigh about 30 kg. (66 lb.) and have a payload capacity of 15 kg. (33 lb.). Average microwave power would have to be about 30 megawatts, while peak power would be about 3 gigawatts (3,000 megawatts). Myrabo believes this smaller satellite vehicle could be constructed as soon as five years after launch of a dedicated project, despite the heavy peak power demands.
NASA and Air Force officials are interested in the air spike concept. They recognize there may be no immediate payoff.
“NASA is interested in a variety of advanced space transportation candidates for development after RLV [recoverable launch vehicle], and this is one of them. However, some of the component technologies from the air spike vehicle may have more immediate significance,” John Mankins, manager of advanced concept studies at NASA headquarters, said.
[[2016 note: John Mankins is an SSI Senior Advisor and his book The Case for Space Solar Power is available now at Amazon.com]]
One area where the air spike could have more near-term effect is thermal protection systems, because the concept minimizes thermal effects on hypersonic bodies.
Others at NASA also view the “air spike” concept as one that is “interesting.” “It’s new, it’s different and shows imagination, but it’s restricted in application, because there are limits to the amount of microwave power that can be transmitted through air. That (limit) tends to relegate this to fairly small payloads, on the order of 250 to 500 kg. (550 to 1,100 lb.),” Dennis Bushnell, NASA-Langley’s senior scientist said. Another drawback is that the vehicle would require a “technology stretch” in all areas, he added.
Still, Bushnell believes the concept is worthy of further study, particularly since an air spike has the potential to reduce drag and lessen sonic boom generation in a high speed commercial transport (HSCT).
A potential stumbling block to this application may be the weight and size of the microwave generator needed to create the oblique shock wave. “No one has done the numbers yet [performed an energy balance], so we don’t know what the answer would be [regarding system efficiency and drag reduction],” Bushnell said. Also unknown is the effect of concentrated microwaves on the Earth’s ozone layer, an important consideration in any HSCT application.
THE PLANETARY DEFENSE WORKSHOP
A Planetary Defense Workshop was held at the Lawrence Livermore National Laboratory from May 22-26, in Livermore, California. Almost all the participants of the previous Detection Workshop and Intercept Workshop were present, as well as representatives from NASA, the Department of Energy, the US Air Force, Navy, several universities, Russia, Italy and China. SSI was represented by George Friedman, SSI Executive VP and Research Director, and John Lewis, SSI Senior Advisor and Program Chair of our May 1995 Conference on Space Manufacturing in Princeton.
John Lewis presented a paper on “Physical and Chemical Properties of Near-Earth-Objects.” George Friedman presented two papers: “Responding to the Potential Threat of a Near-Earth-Object Impact – an AIAA position paper,” and “The Application of Risk Management to the NEO Threat.” Overall, over 50 papers were presented, accompanied by extremely spirited discussion. A Workshop Proceedings is planned to be published within a few months.
The “NEO” community has made remarkable progress the last half decade. Stimulated by a 1990 AIAA position paper, the US Congress directed NASA to conduct two workshops: one for NEO detection and another for NEO intercept. These were very good efforts, but it was apparent that a stronger systems perspective was needed. Sparked by the Shoemaker-Levy 9 impact on Jupiter last summer, Congress asked NASA to take a much closer look at NEO issues, and the so-called “Shoemaker committee” was formed (this committee was still hard at work during the workshop.) The integration of the two separate workshops into one Planetary Defense Workshop was a major step forward by surfacing many issues common to both detection and intercept and by inviting the enthusiastic participation of the Air Force Space Command. On the technical side, a major advance in understanding the severity of the threat involved the recognition that objects as small as 100 meters in diameter, if striking an ocean, could cause millions of casualties to Earth’s coastal cities through tsunami formation. Previously, the community’s assessment was that only NEOs of 1 km or larger could cause substantial casualties.
A few of you have expressed a concern that SSI’s limited resources might be diluted if we took an undue interest in the NEO problem. I envision that SSI’s contribution to this area will be limited to the personal involvement of a few key contributors. Jim Burke and Gregg Maryniak attended the earlier workshops; John Lewis and I attended the integrated Planetary Defense Workshop. These involvements are necessary for us to maintain our professional standing in the field. John Lewis strengthens his reputation as an international expert in the resources of near-Earth space. I was able to continue my relationship with John Rather, the chairman of the first Intercept Workshop, and – very significantly deeply involved at NASA Headquarters in the reevaluation of the Space Power Satellite, a project strongly supported by SSI since our inception.
I am firmly convinced that reasonable support such as outlined above is directly beneficial to SSI’s goals (in addition to saving humanity from possible extinction). If we can help achieve the approval of an international program to accelerate the detection of NEOs, the benefits to SSI’s mission will be enormous. According to the latest estimates presented at the workshop, near-Earth space is populated by 1500 asteroids and 1000 comets over 1 km in diameter. We presently have detected only a few percent of these objects, and if we extrapolate the present rate of discovery by the small band of dedicated astronomers working on NEOs, it will take literally centuries to attain the “90% catalog.” Furthermore, as we recognize the tsunami threat more, objects as small as 100 min diameter will be included in the search. It is estimated that there are over 100,000 asteroids of this size, each weighing a billion tons or more! These NEOs represent a far greater material resource than the lunar surface and have only an infinitesimal gravity well. The goal of the accelerated detection program would be to attain the “95% catalog” of all NEOs within decades, rather than centuries. If any of these NEOs proves threatening to Earth, steps will be taken to mitigate the threat. In the far more likely case, SSI and the world will have the challenge of a High Frontier that is far more proximate than any of us could have dreamt only a decade ago.
We have just concluded a successful conference. This year there were many new faces in addition to many familiar ones. There was a wealth of new and substantial papers, which included six papers from SSI-sponsored researchers. A special presentation was made by Vladimir Syromiatnikov, chief designer and engineer of the docking system to be used on the upcoming MIR/Shuttle mission. Vladimir first spoke of the possibilities of the docking system at the SSI Conference in May, 1991, during an SSI-sponsored trip from the then Soviet Union.
The most dramatic and exciting demonstration of the conference was the wireless power beaming demonstration by William C. Brown. Dr. Brown powered both a bank of lights and a tethered helicopter using wireless power transmission. At one point in the demonstration, he stepped into the power beam which effectively blocked most of the power to the helicopter causing it to nearly stop.
On Saturday, May 6, SSI hosted a banquet at the Institute for Advanced Study. Over 90 people were in attendance to hear John Lewis’s banquet address. John received a standing ovation for his inspiring speech which will be part of the published proceedings. (This address is also available on audio cassette.)
The proceedings for the recent Conference on Space Manufacturing will be published in hard cover format by AIAA. The volume may be purchased at a special prepublication price until August 1. The price for SSI or AIAA members is $40, after August 1 it will be $69.95. This price includes shipping via Book Rate. You can expect the volume in early fall.
Dr. Lewis’s banquet address is available on audio cassette through SSI for $10.
NEW ROUTES TO MANUFACTURING IN SPACE
By Gerard K. O’Neill Princeton University, Gerald Driggers L-5 Society, Brian O’Leary Consultant, Space Studies Institute
Because of energy costs it makes sense to use lunar materials for the construction of products needed in space. Less than a twentieth of the energy to bring a ton to orbit from the Earth will bring it there from the Moon. That is a permanent fact of nature, and over the past several years a number of studies, of successively higher sophistication, have sought the best ways to exploit it.1,2 One study, “The Low Profile Road to Space Manufacturing” published in A/A in 1978,3 assumed a need to bring from Earth all the transportation, processing, and fabrication equipment necessary to transport lunar materials, separate them into their constituent elements, and fabricate them into finished products. The study presumed a “mass driver,” a form of linear synchronous electric motor capable of accelerating materials to high speeds to launch them from the Moon and, operating as a reaction engine, to move heavy equipment between orbits in space.
In the three years since the “Low Profile” article was first drafted, mass-driver research has been intensified. Private financing supported construction of a first model, crude but effective. Later funding was assumed by the NASA Division of Propulsion and Power, acting through NASA’s Lewis Research Center. Having doubled in each of three years, mass-driver funding reached $450,000 this year.
The research is carried out in a joint program of Princeton University, which has responsibility for developing the accelerator ($175,000) and MIT, which has responsibility for the superconducting bucket and cryogenic system ($75,000). A model designed for an acceleration of 500 gravities is near completion and has successfully passed its quarter-power tests. The two portions of the program are directed by G.K. O’Neill and H.H. Kolm. Mass-drivers have many potential applications, including launch from the Earth of nuclear wastes, but NASA’s main interest is in the development of mass-drivers as high-efficiency reaction engines of substantial thrust.
The “Low Profile” article described a scenario in which approximately 1000 tons of mass-driver, power-supply, mining, and life support equipment would be landed on the Moon. At first this equipment would be able to launch 30,000 tons per year of lunar materials into space. An additional 2000 tons of processing, fabrication, and life-support equipment would be emplaced in high orbit, sized to receive the initial throughput of lunar material. For several years this high-orbit equipment would produce 9000 tons per year of fabricated products of three kinds: solar-cell arrays to supply power for the lunar mass-driver and the factory in space, crew quarters for workers brought to high orbit for several-month tours of duty, and thermal radiators. After three to five years growth would be rapid.
By adding 1800 tons per year of complex labor-intensive components brought up from Earth, the industrial plant capacity would increase at the rate of 150,000 tons of throughput per year to 630,000 tons per year. That would be sufficient for the manufacture of nearly all components for two 10,000-Mw satellite power stations (SPS) per year, for a value-produced of at least $20 billion per year. In the “Low Profile” article it was estimated that the total investment to the point of “economic takeoff” would be $24 billion.
That approach was then examined in much greater detail by the second of two NASA-Ames Research Center studies on space manufacturing.2 About 50 persons, mainly scientists and engineers, took part in it. They confirmed that the “Low Profile” approach would substantially reduce the investment needed to reach a given level of industrial throughput, and found that the total investment cost to reach 630,000 tons per year of throughput (i.e., roughly $20 billion per year of product in the form of SPS) would be about $30 billion if mass-drivers were used as reaction engines, and about twice that if chemical rockets were used instead.
These studies had included, in a limited way, the concept of bootstrapping” – the use of industry in space to yield, as finished products, some components identical to those of the industry itself. That partial self-replication clearly was a key to cost-cutting and to rapid exponential growth of industry in space, within the limits of Shuttle-era transportation to orbit.
Additional areas important for cost reduction remained unexplored. The first was “scaling”: how small could each building block of the complete facility be made, while still preserving a constant ratio between tons per year of throughput and tons of mass of the building-block itself? It was also important to know what fraction of the industrial plant in space (measured in tonnage of capital equipment) could in fact be produced there. Some indication of the probable range of answers can be obtained from subsequent NASA supported studies from which the bootstrapping concept was specifically excluded. The first, by GD/Convair under the direction of Edward Bock,4 concluded that approximately 90% of the mass of an SPS could be built from lunar material. The second, an MIT study directed by Rene Miller and David Smith,5 arrived at a higher figure: 96%.
It became clear that a coherent, consistent exploration of further research areas such as automation could not be carried out with government funding alone, because the late 1970s were a time of severe trial for NASA, marred by attacks on the agency, reorganizations, shifts of direction, jurisdictional uncertainties, and rapid turnover of personnel. To overcome these limitations, the Space Studies Institute (SSI) was formed in 1977. A nonprofit corporation operating as a source of research funding, its founding members serve without salary, and its income from individual tax-deductible donations goes mainly into research in the hard sciences, aimed at the early use of the resources beyond Earth’s biosphere for human benefit. The remainder of SSI’s income goes into supplying accurate information on the same topic to the public, but SSI does not lobby. Its fiscal management is conservative, and it begins research projects only when funding for them over an extended period is assured. SSI has well over 2000 subscribers and is growing rapidly. Much of its support comes as five-year pledges from SSI Senior Associates.
SSI has supported three research projects, all successful. The first was on mass-drivers constuction of the first model and initial design of the second, now being built under NASA funding. The second was on orbital mechanics, carried out as a Ph.D. theseis project in the Physics Dept. at Princeton University. The third was the research being described for the first time in this article.
During 1978 and 1979, SSI sponsored a series of workshops, aiming to define more precisely the minimum size of an industrial facility able to process lunar materials into pure elements to serve as feedstock for industry in space. Workshop participants were: J. Arnold, E. Bock, J. Burke, D. Criswell, G. Driggers, C. Gould, C. Majors, B. O’Leary, G.K. O’Neill, C. Rosen, W. Thompson, and R. Waldron. The workshop group, building on the large data-base assembled by early 1978 and on new sources of information, found it possible to shift down, by about one order of magnitude, the minimum investment required to begin rapid exponential growth of industry in space. The workshop group did not find any theoretical limit that would constrain still further improvements.
T-1 lists the group’s assumptions. As in the 1977 “Low Profile” study, it was found that R&D costs dominate any candidate program. Cost estimation figures used in this work, as in the earlier, reflect Shuttle experience and are in the range $30-65 million per ton of unique equipment developed. To minimize R&D costs and development risks, the workshop group made the following basic assumptions:
– For Earth-to-orbit transportation, only the Shuttle (unmodified) would be used.
– For interorbital transfer of both freight and crews, and for lunar landers, presenttechnology LOX-hydrogen rockets would be used.
-The degree of automation would he no greater than now commonly practiced in automobile assembly plants in several countries.
T-1 Assumptions Common to All Scenarios
Earth-to-orbit transportation assumes Space Shuttle operational in 1985 (29 metric tons to low Earth orbit [LEO]). Orbit-to-orhit transports and lunar lander employ liquid hydrogm (LH)/liquid oxygen (lox) rockets yielding vacuum specific impulse of 470 sec at 6:1 mixture ratio; velocity increments impulsive; oxygen derived from lunar materials (40% oxygen by weight). LLO means low lunar orbit. Life-support systems would be initially open-loop Shuttle type, hut later partially closed as in space-station studies, with water and oxygen recycled; makeup oxygen would be taken from lunar materials. Electric power systems assume specific masses (kg/kw) derived from SEPS and SPS design studies: 25-kw size, 12 kg/kw; 100-kw, 10 kg/kw; 1000-kw, 8 kg/kw; < 5 x 105 kw,6 kg/kw. Chemical processing of lunar material: plant-mass-to-throughput rations constant with size; study for NASA-JSC indicates 0.01 ton/hour of throughput per ton of plant mass. Ref 3 assumptions apply to R&D costs.
|Mass ratios for lox-hydrogen rockets|
|Trip||Round-trip systems||One-way systems|
|LEO to LLO||3.26||2.73|
|Propellant in LEO/payload in LLO||2.13||1.62|
|LLO to Moon (cargo)||1.85||0.76*|
|LLO to Moon (man-rated)||1.95||—|
*Mass of decent propellant/mass of payload on the Moon.
The last assumption requires explanation. For some years the concepts of “artificial intelligence” and “self-replicating machines” (von Neumann machines) have been prominent, and a good deal of research on the theme of artificial intelligence has been carried out over the past twenty years. It was the judgement of the workshop group that it would be uneconomical and unnecessary to push artificial intelligence to the limit of total machine autonomy. Round-trip communications to the Moon take only 2.7 sec. A great many jobs can thus be controlled from Earth through radio/video links supplemented hy local microprocessor control of motions on the 3-sec time scale. (W. Bradley, then of IDA, coined the word “telefactor” for such systems – see the May 1967 A /A, page 32 – and they are commonplace in remote-piloted vehicles.) The workshop group also judged it uneconomical to push for total self-repair of machines, because nature (ably assisted by Murphy’s Law) usually comes up with failure modes that no reasonable amount of engineering can predict. The indispensable person in space will be the repairman, and it is going beyond present technology to think of replacing him in every eventuality – by another machine.
As for total self-replication, the workshop group felt that there was economic benefit to be obtained by constructing in space the large, simple, repetitive components or industry, but that it did not make sense to try to build in space labor-intensive, lightweight items such as computers and the precision components of machine tools. From a number of representative pieces of production machinery, the group concluded that 95% was a reasonable figure for the initial replication-fraction. The percentage would increase as industry in space enlarged and became more sophisticated.
The workshop group considered industry emplaced both in space and on the Moon, whichever site appeared most cost-effective, and assumed the early use of lunar oxygen in propellants. It noted that a number of R&D items (spacesuits, small quarters for crews, lifesupport equipment for duty tours of several months, moderate-size interorbital transfer vehicles) will be required in any manned space program of the 1980s, so need not be charged against this one.
The practical experience of Charles Rosen, founder of the Robotics and Automation Div. of Stanford Research Institute and president of the Machine Intelligence Corp., was essential for obtaining realistic numbers on automation. The word “robot” in this article, following his definition, means a relatively inexpensive ($50,000) machine built up from a commercial hand-arm system (Unimate), a video camera if necessary, and a minicomputer. Increasing factory output (measured in tons of product per man-year) by roughly a factor of ten through the use of such robots has proved commercially cost-effective. About 5000 industrial robots (very few of them equipped with vision systems) are in use today. Japan has about 40%, the US, slightly fewer, and Europe, about 20%. The working group concluded that such robots could be used effectively in space for fabrication, such as forming or welding, materials handling, inspection, assembly and simple repairs, such as unbolting the flanges of a chemical-reaction vessel, replacing the vessel with a spare, then inserting bolts and tightening and checking for leaks. All these operations could be supervised by humans on Earth through video and other sensors, and the minicomputer programs would be changed as necessary to meet production requirements.
State of the art industrial robots, just now being introduced into industry on a commercial basis, can pick off a moving belt the body and head of a compressor-unit, place the head correctly, and then insert bolts and tighten them to specifications. Instead of “artificial intelligence,” this system operates on the more modest level of “semi-autonomy,” in which the machine carries out a repetitive task itself, but “hollers for help” if it breaks or encounters a situation for which it has not been programmed. The working group assumed only that level of automation in the scenario it favored.
By 1979 considerable interest in robotics was also developing within NASA. So far it has been rather general and theoretical, and has focused on total self-replication of full automated systems. A NASA-sponsored study group recommended that the agency “adopt a policy of vigorous and imaginative research” in computer science, machine intelligence and robotics in support of broad NASA objectives.” Later, in a September 1979 speech to the Commonwealth Club in San Francisco, NASA Administrator, Robert A. Frosch, said: “It appears possible to start with the investment necessary to put 100 tons of machinery on the Moon, and after 20 years of machine reproduction, to have an energy plant and manufacturing capability equivalent to the ability to manufacture 20 billion pounds (10 million tons) of aluminum per year… I believe that the technology is presently available [to build such self-replicating machines] and that the necessary development could be done in a decade or so.”
Based on several years of theoretical study, much of it under the direction of David Criswell of the Lunar and Planetary Institute,7 self-contained, automated processing plants appear able to produce from lunar soil 99% pure elements (Fe, Al, Si, Ti) and a large quantity of oxygen. Further processing, also automated, would be needed for end-uses requiring higher purity, such as semiconductorgrade silicon. Alloying elements would be brought from Earth.
The working group considered in detail five scenarios for the buildup of industry in space. Of these, it found three particularly attractive:
Case 1. A manufacturing facility, manned by a crew of three, entirely on the lunar surface. Its products would be “exported” by chemical rocket. At some point mass-drivers and their power supplies might replace the rockets.
Case 2. A fully-automated manufacturing facility, remotely supervised from the Earth, with provision for occasional visits by repair crews. Transportation of products would be by rocket.
Case 3. A manned facility on the Moon, for operating a mass-driver launcher to transport lunar materials to a collection point in space and for replicating mass-drivers. All other processing and fabrication would be done in a manned orbital facility in permanent sunlight. This case differs from earlier studies in its use of automation and telefactors, its initiation at a smaller size, and its high degree of self-replication.
T-2 Scenarios for Early Stage of Lunar-Materials Processing
Case I. Manned lunar manufacturing solar-cell arraysand mass-drivers on the Moon. Could deliver raw materials into space. Case II. Unmanned lunar manufacturing. Products less versatile, growth rate limited except for repetitive production ofa simple set of metal pieces over a long time. Case III. Manned mass driver with space manufacturing. Could produce wide range of products in space plus mass-drivers on Moon. Could bootstrap in two years to production rate of 1,000,000 ton/yr.
|Characteristic||Case I||Case II||Case III|
|Lunar-landed payload, tons||41a||15b||107c|
|Initial rate of production. ton/yr||240||80||1800|
|Replication (doubling) time of large components, days||45||90||90|
|Shuttle flights initial||15||15||36|
|For crew supportd||2||–||2|
|R&D and deployment investment, $109||5||3||6|
aIncluding a crew of three. bAs 1-ton modules. cPlus 89 tons deployed in high Earth orbit. dPer year.
F-1 and T-2 give more information on each of the three scenarios. R&D costs were calculated based on Shuttle experience.3
Of the three scenarios, Case 1 proves particularly effective for the rapid buildup of mass-drivers on the Moon, but is not very flexible in terms of products delivered to high orbit. Its transport costs, even with lunar oxygen, run much higher than those of a lunar massdriver. Case 2 is the most extreme in terms of required technology development, and its R&D costs are probably much more uncertain that those of Cases 1 and 3.
Case 3 appears to offer the best mix of conservative technological requirements, reasonably high initial throughput, and provision of a wide range of products in high orbit, particularly those that are large and fragile or that require for any reason production or location in zero-g. Therefore a detailed study was made of the mass-driver design which, in or that require for any reason production or location in zero-g. Therefore a detailed study was made of the mass-driver design which, in Case 3, would be replicated and emplaced as parallel units on the Moon. The mass-driver lunar launcher would be easily constructable (point design, not optimized), based on current densities obtained some years ago in superconductors (used here for the bucket coils) and on ordinary aluminum used for driver coils and for vacuum capacitors. Siliconcontrolled rectifier (SCR) switches used for the design would have present-day current densities, current rise-rates, and power dissipation in silicon wafers. We assume an SCR mass 40 times that of the wafer alone. The launcher would have the following parameters:
|Throughput (operating lunar-days
|Max. velocity, m/sec||2400|
|Total length, m||538|
|Photovoltaic power supply,
|Repetition rate, Hz||0.52|
|Max. voltage, v||7100|
|Winding mass, tons||8.3|
|Feeder mass, tons||6.9|
|SCR mass, tons||10.8|
|Kinetic power mass, tons||4.7|
|Total mass (electrical components only), tons||53|
|Total mass (including
50% for structure), tons
For Cases 1 and 3, where only a level of automation known to be attainable was assumed, the greatest remaining uncertainty appeared to be in the area of the “machine shop,” the facility that would take pure elements in the form of sheet-rolls, bars or ingots and convert them to finished products. Figures of 0.001-0.01 ton per hour of output per ton (tons/hr-ton) of machine-shop mass were collected from earlier studies, and a figure near the lower end, 0.002 tons/hr-ton was adopted. Case 3 appeared capable of achieving 100,000 tons per year of output after two years of bootstrapping. Obviously a strong incentive would exist by then for increasing the range of products built in space and for ungrading the Earth-to-orbit and interorbital transport systems.
All three cases appeared capable of achieving high levels of productivity for investments considerable less than $10 billion. They would be in the range of the Alaskan pipeline ($7 billion), and much lower than the Churchill Falls, Quebec electric power system, both of which were private ventures.
The scale in these three approaches permits the profitable use of nonterrestrial materials whether or not solar power satellites turn out to be practical. The economically optimum scenario would be to bootstrap to the level of production (tons/year) adequate for the current market, and then devote the production to revenue-producing sales until the size or range of the market expanded further. Marketable products would include:
– Oxygen as fuel for interorbital vehicles and as reaction mass for ion thrusters and mass-drivers.
– Components for large deep-space research vessels, radio telescopes, and large high-power satellites.
– Raw lunar soil as reaction mass for deep-space missions and as shielding against radiation.
– Large orbital facilities for human occupation (scientific, recreational, and medical). If SPS turns out to be viable (we note in passing that Convair’s study indicated that the use of lunar materials could save 30% of SPS cost even without bootstrapping) marketable products for space-based industry could expand to include 10 to 40 10-Gw power satellites per year, with a value of $100 to $400 billion per year.
If the investment for space-based industry does not range beyond that for previous privately financed ventures, the barrier to the development of the energy and material resources in space will be, not money, but payback time. Only when the interval between low-risk investment and payback drops to about five years can substantial private capital be attracted to any venture. The Space Studies Institute has the long-term goal of penetrating that barrier by establishing, through hardware demonstration, the feasibility of every essential technical building-block in a complete production system. Many of those building-blocks, fortunately, already exist or are under development for other reasons. SSI’s resources are therefore concentrated on those few areas that are both essential and unfunded. In the near future it will support exploration of scenarios of the kind pioneered by the effort described here plus development of chemical-processing equipment of benchtop scale for separating simulated lunar soils into pure elements.
1. O’Neill, Gerard K., “Space Colonies and Energy Supply to Earth,” Dec 5, 1975, Science, pp. 943-947
2. O’Neill, Gerard K., and O’Leary, Brian, eds., Space-Based Manufacturing from Nonterrestrial Materials, AIAA, New York, 1977; Billingham, John, Gilbreath, William, and O’Leary, eds., Space Resources and Space Settlements, NASA SP 428, NASA Washington, DC, 1979; Grey, Jerry, ed., Space Manufacturing Facilities, I, II, AIAA, New York, 1977.
3. O’Neill, Gerard K., “The Low (Profile) Road to Space Manufacturing,” March 1978 Astronautics& Aeronautics(A/A), Vol. 16, No. 3, pp. 18-32.
4. Bock, Edward, “Lunar Resources Utilization for Space Construction, NAS-9-15560 DRL-T-1451, NASA Johnson Space Center, GD/Convair Contractor Report, 1979.
5. Miller, Rene H., and Smith, David, Extraterrestrial Processing and Manufacturing of Large Space Systems, CR-161293, NASA Marshall Space Flight Center, Huntsville, AL, 1979.
6. Machine intelligence and Robotics: Report 730-51, Sep 1979.
7. Criswell, David, Extraterrestrial Materials Processing and Construction, NASA Johnson Space Center, Houston, Tex., 1978.
MISSION PROFILE FOR STS-71 MIR-1 AND SPACE SHUTTLE RENDEZVOUS
|LAUNCH SITE||KSC Pad 39A|
|Alternite Site||EDW, NOR|
|ABORT LANDING SITES||Return to KSC
|ABORT ONCE AROUND||KSC, NOR|
|DURATION||10 flight days + 1 potential extension dayRobert Gibson, Commander
Charles Precourt, Pilot
Ellen Baker, Mission Specialist
Greg Harbough, Mission Specialist
Bonnie Dunbar , Mission Specialist
Nikolai Budarin , Mission Specialist,
MIR 19 Flight Engineer
Anatoly Solovyev, Mission Specialist,
Norm Thagard, Mission Specialist,
Vladimir Dezhurov, MIR 18 Commander
|CARGO BAY PAYLOADS||Orbiter Docking System
Spacelab Long Module
|IN-CABIN PAYLOADS||IMAX (IMAX in-cabin camera)|
|HIGHLIGHTS||First Shuttle/MIR docking mission
First exchange of MIR crews using Shuttle
Return of US astronaut (Thagard) from MIR
|LEAD FLIGHT DIRECTOR||Bob Castle|
|FLIGHT INTEGRATION||Kathy Leary|
|LEAD FLIGHT ACTIVITIES||John Curry|
SYNOPSIS OF FLIGHT
STS 71 is the third in a series of cooperative missions between NASA and the Russian Space Agency. The first mission STS 60, flew a Russian cosmonaut in January, 1994. The second mission, STS 63, performed a rendezvous and approach to 35 feet from the Russian Space Station.
The primary objectives of STS-71 are to rendezvous and dock with the MIR-1 Space Station, conduct joint science on long-duration crew persons, perform a crew exchange of the MIR-1 cosmonauts, and demonstrate the Russian docking mechanism for potential use by the Shuttle when docking with the International Space Station. The STS 71 launch will be preceded 90 days earlier by the launch of a Russian Soyuz spacecraft with American astronaut Dr. Norm Thagard and two Russian cosmonauts. Thagard will conduct various life and material science experiments onboard MIR-1. Two Russian cosmonauts will be part of the STS 71 crew and will replace two Russian cosmonauts on MIR-1. Returning with the STS 71 crew will be two Russian cosmonauts and Dr. Thagard, resulting in a mission with 7 crew members launching and 8 crew members landing.
MIR-2 RENDEZVOUS AND DOCKING OPERATIONS
Following a launch insertion to 170 nautical miles, a series of burns will be performed to raise Atlantis’ altitude to 210 nautical miles. The Shuttle will arrive on the + V-bar at a distance of 400 feet from MIR-1 on orbit 29. The Shuttle will station keep to time docking over a Russian ground station. The over flight of a Russian ground station is required to protect Moscow’s ability to send MIR-1 free drift command in case of a docking system failure. Shuttle approaches inside 250 feet will be designed to remain inside a predefined corridor that is necessary to maintain acceptable plume loads on MIR-1. Docking over a Russian ground station is planned for orbit 30.
Energia RSC has recently presented new LIRA attitude requirements requiring the Shuttle to approach the space station with the nose out-of-plane for a defined set of beta angles. After assessment, the Flight Techniques Panel has decided to incorporate an Rbar approach for those missions that require an approach with the nose out-of-plane. Approaches that can be made in-plane will be planned for an in-plane R-bar approach. The approaches have been named SNOOPY (Shuttle Nose Out Of Plane Yawl) and SNP (Shuttle Nose In Plane) R-bar.
At mechanical capture, both spacecraft will assume free drift mode. Both vehicles remain in free drift until hard mate, approximately 15-20 minutes later. After hard mate, the Shuttle maneuvers the stack to the appropriate attitude designed to provide sun on the solar arrays, and the interface tunnel is checked for contamination and pressure leaks. If the tunnel is found to be sealed, transfer hatches are opened after ventilation.
SHUTILE/MIR JOINT OPERATIONS
Five days of mated operations are planned. The Shuttle will control the mated stack during the first 2.5 days and MIR-1 will control during the second 2.5 days. To align Shuttle Inertia Measurements (IMUs) and to protect thermal concerns, the timeline and Shuttle propellant budget included two mated maneuvers a day.
Transfer hatch opening is accomplished over the Russian ground station and American Tracking and Data Relay Satellite (TDRS) zones of communication. A greeting by the crews will be televised to the two control centers. The initial hatch opening will be followed by a welcome ceremony. After the ceremony, the MIR-1 crew will receive a safety briefing on emergency escape procedures and will transfer their Soyuz seat inserts. The briefing is required before any crew members are allowed on board MIR and should be completed prior to the sleep period on docking day.
Activities scheduled with each duty day during docked operations include joint science operations, a one hour meal, MIR 18/19 crew handover, MIR 18 countermeasures, MIR and Shuttle maintenance, and public affairs activities.
Five hours of joint science operations with each of the MIR 18 crew members will occur each docked day. The actual joint science activities performed during the mission will be negotiated through the Science Working Group. Science activities will include body mass measuring, metabolic operations, blood sampling, countermeasure protocols, and equipment transfers. Three hours each day will be scheduled for MIR 18 to 19 operations handover.
Undocking on orbit 106 will be planned so that physical undocking will occur at the beginning of coverage over Russian ground stations. Since docking was chosen so that the crew sleep cycle is to a descending landing opportunity, the undock will also occur at the end of the crew day. Prior to undock, the MIR solar arrays will be configured to the undock position. MIR will maintain attitude control of the stack up to the point of undock. The undock command is sent by the Shuttle crew from the aft flight deck. Prior to this command, MIR will command the stack to free drift mode. Approximately 4-6 minutes later, the latches will be open and the two spacecraft will begin to separate from each other. Once the latches are open, the Shuttle will configure its Digital Auto Pilot (DAP) to Local Vertical Local Horizontal (LVLH) attitude control and begin a LOW Z backaway maneuver along the same corridor used for the approach. After the docking system petals are clear, MIR will assume active attitude control to ensure safe separation of the spacecraft during backaway. The Shuttle crew will inform the MIR crew when the separation has reached 250 feet, after which MIR will assume an attitude ensuring charging of the MIR solar arrays.
Once outside the 250 foot corridor the orbiter will transition toward the V-bar until 400 feet where the Shuttle will begin a twice orbital flyaround of the MIR. When Atlantis reaches the R-bar for the second time, a retrograde separation maneuver will be executed, ending the joint phase of the mission.
MIR I SPACE STATION: A Technical Overview
A 230-page document translated from Russian into English details lessons learned, remote sensing, reentry technology, docking systems, mission control and MIR I experiment requirements. $79 plus shipping
RAIN OF IRON AND ICE
The Very Real Threat of Comet and Asteroid Bombardment By John S. Lewis, this book discusses the very real danger of a comet or asteroid hitting the Earth. This author examines recent evidence of sudden, dramatic extinction of species in the geologic and paleontologic record and assesses the risks to planet Earth. $25 plus shipping
THE GREATEST ADVENTURE
60 space adventures written by those who lived them (includes the first Moon landing and Apollo 13), 160 color, large-format photographs and Russian stories and pictures never before published. Special Order Dept.,GA, Publishers Group West, 4065 Hollis, Emeryville, CA $39.95
THE THREAT OF LARGE EARTH-ORBIT CROSSING ASTEROIDS
Hearing before the Subcommittee on Space of the Committee on Science, Space, and Technology, US House of Representatives, March 24, 1993. $25 plus shipping
ABOUT THE INSTITUTE
The Space Studies Institute is a nonprofit, international, research and educational organization. Founded in 1977, it is dedicated to opening the high frontier of space.
SSI’s goals include using the material wealth and solar energy of space to improve the human condition both for those who live on Earth and those who live in space, and to build Earth-like habitats in space to expand the ecological range of humanity throughout the solar system and ultimately, perhaps, throughout the galaxy.
To this end, SSI has conducted and is conducting pioneering research into advanced space propulsion, the extraction and processing of nonterrestrial materials for engineering purposes, and the identification and location of lunar and asteroidal resources.
Following are four opportunities for participation in SSI activities:
SSI’s Corporate Membership program offers access to SSI’s broad base of technical advisors, access to a resume pool, and access to exhibit space at the biennial SSI Conference on Space Manufacturing. Research partnerships are encouraged.
Senior Associate Program
The Senior Associates Program is currently SSI’s largest source of funds for High Frontier research and education. The program also provides a way for anyone interested in the High Frontier to play a key role in making space colonization and space manufacturing achievable within our lifetimes. Following is a description of the program.
The Senior Associate program was created in 1979 to generate the steady funds that SSI needs to conduct research projects, most of which require money for several years. Today we have about 1,000 active Senior Associates; 537 Senior Associates are on their second, third, or fourth pledge. The program provides about 60% of SSI’s annual budget and is essential to both our research and educational activities.
Senior Associates receive special benefits as our thanks for their support. These benefits include invitations to special events, free mailings of publications by SSI, NASA, and other space organizations; and confidential newsletters, describing SSI developments before they are made public.
However, most people become Senior Associates because they want to see space colonization become a reality; they give muchneeded funds and join the group of people working to create the High Frontier in our lifetimes. As Senior Associates, they also meet others who share their enthusiasm for space exploration and development. Each Senior Associate makes a five-year pledge to SSI, choosing one of the ranks below:
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Payments can be made annually, semiannually, quarterly, or monthly.
Each Senior Associate receives a number with his or her rank, indicating when he or she joined the program. For example, the next person to join could become Fellow 368, or Distinguished Colleague 126. Each Senior Associate receives a certificate, signed by SSI’s president, as a permanent record that he or she was one of the first people who gave critical support to the High Frontier. The names of the Senior Associates will also be permanently maintained by SSI to provide historians with the names of early High Frontier supporters.
SSI Membership is open to individuals worldwide. All members receive the lnstitute’s newsletter, which is published bimonthly and keeps all SSI members abreast of SSI research, an SSI membership card and decal. Membership fee: Regular $25.00; Senior Citizen or Student $15.00; non-US addresses, please add $10.00.
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SSI Board of Directors
Dr. Roger O’Neill, Chairman
Prof. Freeman Dyson, President
Dr. Joseph P. Allen
Mr. James Burke
Dr. George Friedman
Mr. Morris Hornik
Mr. Gregg Maryniak
Mr. William O’Boyle
Dr. Fred Rose
Dr. Lee Valentine
Board of Governing Members
Mr. James Burke
Prof. Freeman Dyson
Mr. W. Brandt Goldsworthy
Ms. Bettie Greber, Executive Director
Mr. James Laramie
Mr. Gregg Maryniak
Mr. William O’Boyle
Ms. Tasha O’Neill
Dr. David Odom
Dr. Fred Rose
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Board of Senior Advisors
Col. J. Paul Barringer
Barringer Crater Company
Mr. Richard Boudreault
Dr. William C. Brown
Mr. Christopher J. Faranetta
NPO Energia, Ltd.
Mr. George Gallup, Jr.
Mr. Richard E. Gertsch
Colorado School of Mines
Mr. Alex Gimarc
Dr. Peter Glaser
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Ms. Kathy Keeton
Mr. Jeffrey Manber
NPO Energia, Ltd.
Dr. Rashmi Mayur
Mr. Burt Rutan
Scaled Composites, Inc.
Mr. Steven Vetter
ABOUT THE NEXT ISSUE…
Conference Report and Summary: The next issue will include a short summary of each session, a complete listing of papers and authors, and pictures of key presentations.
DCX Update: A short follow-up article on the DCX featured in the November/December 1993 issue will be included.
Lunar Prospector: The Lunar Prospector, originally designed with SSI support, was chosen by NASA to be launched to the Moon in June, 1997.
Solar Power Satellites: A paper “Thin-Film Disc-Shaped Large Space Structures (Sunsat or Solar Sail: A Proposed Construction/Assembly Method)” by Eric Flint will be featured.
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