Proceedings of the Thirteenth SSI/Princeton Conference on Space Manufacturing
May 8-11, 1997
Published by Space Studies Institute
Linked titles go to full papers
(text-searchable PDFs)
[More to come]
More Princeton Conferences on Space Manufacturing
KEYNOTES AND CONFERENCE SUMMARY
SPECIAL PRESENTATIONS
Balancing Molecular Nanotechnology-Based Space Transportation and Space Manufacturing Using Location Theory: A Preliminary Look. Tom McKendree, Molecular Manufacturing Shortcut Group.
Abstract: An introduction to extending location theory to operations in space, and an investigation of estimated capabilities for space transportation and space manufacturing, given molecular nanotechnology. Presents four models for siting an orbiting manufacturing facility with respect to two inputs and one market location, each progressively adding cost elements. Addresses space transportation using molecular nanotechnology, with a focus on solar sails and rotating tethers. Addresses space manufacturing with a focus on the particular strengths of space manufacturing and molecular manufacturing. Identifies two system concepts for using molecular manufacturing in space. Identifies open issues, and urges further work in the area.
Alphatown: The First Human Town in Space. Rick N. Tumlinson, Space Frontier Foundation, FINDS. [PDF]
NSS Abstract: It is proposed the the International Space Station be transformed into a frontier town called “Alpha” according to the following principles: (1) After completion of the assembly phase, all US government transportation needs to and from Alpha will be competitively bid for by US private firms. (2) The government will put in place legislation to actively encourage and regulate the development and recycling of all space assets. (3) All expansion of habitable physical structure of the US portion of Alpha will be commercially leased from US private firms. (4) All additional energy requirements aboard Alpha after assembly is completed will be supplied by commercial vendors.
Sub-Kilogram Intelligent Tele-Robots (SKIT) for Asteroid Exploration and Exploitation. Alberto Behar and George Bekey; University of Southern California; George Friedman; Space Studies Institute. [PDF 5.5 MB]
Abstract: Given current miniaturization trends in robotics, AI, and communications there is now an opportunity to plant “seeds” in space. These “seeds” would bring a reduction in the enormous cost associated with sending human explorers to distant space objects when newly designed small tele-robots could perform the precursor missions. In light of this, our project was to investigate new generations of smaller, networked tele-robots, named “SKIT’s”, for exploring the abundant and rich untapped resources of asteroids. We are performing hardware/software simulation studies to determine the relative merits of using sub-kilogram robots for this type of work. A typical scenario for this research would be to release a number of vehicles with some communication capability, and with a specialization of functions on a simulated landscape. Humans would control the overall deployment policy but the tele-robots would have some autonomy to deal with obstacles. This paper is an attempt to elucidate the challenges of robotics for asteroids and detail some proposed solutions. It presents a tradeoff study performed to develop the SKIT concept and a subsequent simulation and demonstration of the concept. A unique challenge of this research was to produce substantial results in 1 years’ time given the constraint of designing and building devices that are sub-kilogram. Although the requirement of <1 kg for each robot puts forth a challenge to previous modes of thinking, it actually allows new modes where we can benefit from high coverage, high full-system-level reliability, and low cost.
The SSI Research Overview. George Friedman, Space Studies Institute. [PDF]
NSS Abstract: The SSI board of directors approved in November 1995 the following four new research thrusts: SKIT (sub-kilogram intelligent telerobots), MNTS (molecular nanotechnology for space), ADNEO (acceleration of the detection of near-Earth objects) and QSRS (Quest for self-replicating systems).
I: ASTEROIDS AND NONTERRESTRIAL MATERIALS
The Deimos Water Company. David Kuck, Oracle, AZ. [PDF 2.5 MB]
Abstract: Deimos, the outer moon of Mars, is presently the only probable early known accessible source of water to LEO (Low Earth Orbit) or HEEO (Highly Eccentric Earth Orbit). It is the most accessible small body that is “geophysically” anomalous for outgassing in the inner solar system, and thus is a probable source for water ice. Water is needed in LEO and Martian exploration for propellant, life support, and as a chemical and physical process media. None of the above will be accomplished unless it is for a profit.
Noble Metals and Semiconductors from Metal-Bearing Asteroids. Jeffrey Kargel, Flagstaff, AZ.
Abstract: Precious metals and semiconducting elements in iron meteorites (the metallic cores of asteroids) are natural resources potentially worth tens of billions of dollars annually. Up to 187 ppm of precious metals (the platinum-group metals, gold, and rhenium) may be extracted and imported to Earth because of their high economic and industrial value. >1000 ppm of semiconductors may be extracted as byproducts of PGM mining (or vice versa) and used by a future space solar power industry. Meteorites help in the formulation of mining strategy and provide a basis for resource exploration. Most asteroid cores are compositionally inhomogeneous, and many contain rich, accessible ores, but resource exploration by spacecraft is needed to identify and map them.
Towards Asteroids and Resources: Use of Muscle Wires. Kumar Ramohalli and Chad Hicks, University of Arizona.
Abstract: The concept of In-Situ Resource Utilization (ISRU) for significantly reduced costs in space exploration is examined in the light of a new technology, namely, muscle wires. These shape memory alloys have the ability to convert electrical (or thermal) energy into mechanical energy through predictable deformations/strain. This, in turn, can be translated into a number of different motions and actuations for the exploration of asteroids. The technology is particularly applicable to asteroids where the gravity forces are likely to be very small, compared to the usual forces associated with sample collection, examination and retrieval. In this paper, several applications of muscle wires are explored including translation of the linear motion into rotary motion, actuation of a robot arm for a sample retrieval, application of mechanical force to deploy structures such as a photovoltaic array, and a simple tilting of thrusters for vector control. Hardware demonstration is included. It is indicated that muscle wire technology has an important role in the future of asteroidal explorations.
Implications of Molecular Nanotechnology for Space Resources. Stephen L. Gillett, University of Nevada.
Abstract: The widespread perception that the extraction of resources is a fundamentally expensive process is incorrect; the expense results from a clumsy technology that largely relies on the heat-driven partitioning of elements into coexisting phases. The extractive feats of biological systems, which carry out isothermal separation of diverse molecular species by means of molecular mechanisms, furnish a striking contrast. Technological means to carry out similar separations are currently primitive largely due to the absence of atomistic control in their fabrication; however, a strong demand for efficient, selective extraction at low concentrations exists in pollution control and is driving further development. Such applications are obviously a near-term motivation for molecular nanotechnology (MNT), the design and construction of macroscopic objects at molecular scale. As such separation technologies mature and costs fall, they will blur the distinction between a “pollutant” and a “resource”, which will make space-based resources unlikely to be attractive for terrestrial use. Although MNT is likely to be vital in space development, it probably will render the structural metals that dominate current practice unimportant, and hence native asteroidal metals may prove irrelevant. Carbon and silicates are instead likely to prove most valuable.
Possible Use of Surface Tension to Shape Space Structures. Kenneth Stapleford, Dover, DE. [PDF 1.7 MB]
Abstract: An argument is presented predicting the possibility of thick walled surface tension bubbles in zero gravity space. Liquid vapor pressure is suggested as the main factor limiting bubble size in space vacuum. The several orders of magnitude change in liquid vapor pressure near the freezing point make the expansion of large metallic bubbles possible at low temperatures while small bubble size at high temperature allows the heat separation of high and low vapor pressure materials in space vacuum. This makes possible the conversion of any space rock with metallic content into a thick walled metallic bubble by heating to a high temperature and inserting a gas producing pellet as it cools. The beneficial effects of these spheres in orbit near Venus is discussed. An ice cube in mercury experiment in space is recommended along with a computation to predict the size bubble the experiment will produce.
Decision Points. David Kuck, Oracle, AZ. [PDF 3.0 MB]
Abstract: Exploitation of extraterrestrial mineral resources will follow practices in terrestrial mineral exploitation. In the various steps in exploration many decision points must be met and passed to undertake the next step toward development of the possible resource into a mine. For a resource to become a mine it must be able to show a profit. The decision points that follow must be met and passed successfully before going on to the next step along the road to discovery and development of a mineral deposit into a mine.
II: TRANSPORTATION AND STRUCTURES
Slingatron Dynamics and Launch to LEO. Derek A. Tidman, Mclean, VA. [PDF 1.8 MB]
Abstract: A circular mass accelerator concept called a slingatron is described in which a large projectile could be accelerated to high velocity using a relatively low power input (compared to a hypervelocity gun). Two examples are given in which a slingatron could be used to launch an object into Earth orbit. The first would use a slingatron of ring radius 640 meters and a low elevation launch at 8 km/sec. The second case is intended as a small scale test machine of ring radius 40 meters that would launch a projectile vertically at 2 km/sec. The projectile could be an encased light gas gun (like a long rod penetrator) that would, upon reaching its peak altitude of about 160 km, fire a small mass at 7.5 km/sec to the East into LEO before dropping back to Earth for re-use via guided parachute.
Laser Propelled Flight Experiments at the High Energy Laser Systems Test Facility (HELSTF). Leik Myrabo, Rennselaer Polytechnic Institute.
Abstract: This presentation summarized the progress made to date on the Lightcraft Technology Demonstrator (LTD) flight test program, since the first 12-14 July, 1996 experiments at the High Energy Laser Systems Test Facility (HELSTF), White Sands Missile Range, NM. The current 15-cm diameter, 60-gm vehicles are designed to fly on the 10 kilowatt power level available from the PLVTS pulsed carbon dioxide laser (1 Kj pulses at 10 Hz, 30 usec duration). The axisymmetric vehicles are propelled by airbreathing pulsed detonation engines (PDE) with an infinite fuel specific impulse. Several engine geometries were tested in the process of evolving the current flight configuration. Impulse coupling coefficients (N-s of impulse per MJ of laser energy) have been measure with several ballistic pendulums as well as a piezoelectric load cell, and fall in the range of 100 to 200 N/MW. A pressure transducer instrumented model has captured the time-resolved pressures over the engine’s thrust surface. Horizontal and vertical wire-guided flights have been demonstrated, with up to 1.6-2.0 Gs acceleration measured by a photo-optic array. The first brief free-flight of a Lightcraft occurred during the April 21-24 tests. Spin-stabilized free-flights with active tracking/beam control are planned for June. The presentation included videotape footage of Lightcraft flights, photographs of numerous test engines and experimental hardware and a summary of engine performance.
The Soyuz Spacecraft Today and Tomorrow. Christopher Faranetta and Vladimir Syromiatnikov, Energia, Ltd. [PDF 1.8 MB]
Abstract: The Soyuz spacecraft has been in use since the late 1960s. To effectively meet the needs of various past programs, the Soyuz has undergone four main evolutions. Today, the projected near-future increases in manned space flight activity may serve as a catalyst to design a completely new and larger spacecraft based on the proven flight heritage of Soyuz technology. An advanced Soyuz spacecraft derived from the present day model has potential as a component to reusable launch vehicle (RLV) and other programs. To leverage global aerospace manufacturing skills, and gain access to international markets, the advanced Soyuz could be manufactured internationally using private funding.
Stabilization of the External Tank for Use as a Large Space Platform. W. D. Kelly, Triton Systems, DBA. [PDF 5.0 MB]
Abstract: Use of magnetic passive dampers is recommended to stabilize the Space Shuttle External Tank in free flight for on-orbit applications. Longitudinal alignment along the radius vector allows for gravity gradient passive stabilization, but, without a damping mechanism, there is no inherent means of eliminating disturbance accelerations and buildup of pendular motions lead to spin or tumbling. Review of previous magnetic, passive dampers is provided drawing from the Long Duration Exposure Facility (LDEF) flight and Space Station program studies for early assembly flights. Basic physical models of the damper-spacecraft combination are discussed: damper capabilities and limitations. Peliminary damper design analysis is demonstrated.
Design of a Micro-Gravity Spherical Space Habitat. Kenneth Stapleford, Dover, DE. [PDF 2.3 MB]
Abstract: The paper examines the problem of converting a large spherical metallic shell in space, rotating once each 24 hours, into a desirable human habitat. A design equation for sizing window and cooling surface, as a function of solar distance, is developed. Shell coating, agricultural land creation and irrigation drainage problems are considered along with the advantages of a larger sphere size in coping with the catastrophe of shell damage or cooling system failure while also providing the possibility of cooling air flow and water flow without pumps. The Location and angle of the axis of rotation are discussed as are the pleasure and problems of micro-gravity living Rate of Rotation.
III: INTERNATIONAL, LEGAL AND ECONOMIC CONSIDERATIONS
The Space Settlement Campaign: A Tool for Social Acceptance and Support for the Space Settlement Concept. Steven M. Wolfe, Space Frontier Foundation.
Abstract: This paper will demonstrate that the human settlement of space will be appreciably advanced if the principal tenets of the space settlement agenda can become part of our societal belief system. It also lays out a rationale and blueprint for the Space Settlement Campaign, a focused initiative to gain public acceptance and support for human settlement of space in the fastest time frame possible. Influencing public opinion is essential to the effective implementation of policy initiatives-whether its agreement on traffic laws or the adherence to environmental protection laws. Unless society as a whole believes that a new policy or law is important, the change will likely be greeted with indifference or worse, with negativism. Space settlement activists have been effective inside the Washington beltway at influencing public policy that is indirectly related to space settlement, such as the ‘cheap access to space” campaign of the Space Frontier Foundation. Unfortunately, their policy successes that directly relate to settlement have been diminished or negated because public opinion was not consistent with the new policies. To succeed, activists must turn their attention to the public with an educational campaign that brings the space settlement vision to the fore of social consciousness. Proponents of space settlement vision can benefit from the experiences of other social movements such as the civil rights and environmental. The Space Settlement Campaign will emulate the actions of other movements in an effort to bring greater attention to the space settlement cause. At the heart of the campaign is the Declaration for Space Settlement, a statement that embodies the beliefs and commitments of a generation determined to secure a more exciting and prosperous future for humanity. Supporting activities of the Campaign include an interactive Web site; public events, rallies and marches; publications; legislative and policy initiatives; and educational programs.
Observations on the Infrastructure and Space Commercialization Problem. W. D. Kelly, Triton Systems, DBA.
Abstract: Society debates reconciling government controls and commercial incentives, especially for frontier development, an issue space interests confront seeking cheap access to low earth orbit by government or commercial program. Mars human expedition plans, commemorating the 1969 lunar landing, foundered on costs increased by absence of significant government or commercial orbital infrastructure. Nearing year 2000, contrasts remain between technically feasible space settlement aims and modest commercial launcher capabilities, but evolutionary “adaptations” significantly change the picture. Commercially developed rockets are growing large enough to lift resupply vehicles to the International Space Station; perhaps even ferry personnel. New engines plus still not fully exploited rendezvous technology supports this trend. A contracted service development model, initiated with Atlas-II and Delta-II rockets, applies as well to orbital rendezvous and delivery craft essential for space industrialization or outfitting interplanetary expeditions. Blended commercial-government programs are examined.
International Cooperative Decision-Making for Space Exploration into the 21St Century. Eligar Sadeh, Willy F. Sadeh, and James P. Lester, Colorado State University.
Abstract: International cooperative decision-making is important for space exploration and development into the 21st century. A model of international cooperation is conceptualized and applied to formulate decision-making functions. These functions explain how political actors bargain and negotiate to reach cooperative political outcomes. On the basis of the model and functions, recommendations, which have the potential to enhance international cooperation for space exploration and development missions and enterprises, are advanced.
The Potential Role of a Space Development Bank in Accelerating the Commercial Development of Space. Thomas L. Matula, College of West Virginia.
Abstract: A major barrier to space commercialization is the lack of financing for large space commerce ventures. The financial challenges faced by space commercialization are similar to the financial challenges faced by developing countries. Both developing countries and space commercialization are constrained by the lack of long-term low-cost financing. The creation of numerous development banks following World War II provided a solution to the long-term financing problems faced by developing countries. This paper proposes the creation of a United States Space Development Bank as a solution to the similar problems of financing large space commerce ventures. Created by federal legislation and located in the U.S. Department of Commerce, a space development bank would provide a source of “patient” long-term financing for space commerce. In additional, a space development bank would provide a source of reliable space commerce information to both policy makers and space entrepreneurs. The space development bank would also function as a powerful advocate for space commerce, providing American industry with a strong partner for the developing competition for domination of the emerging transglobal economy.
Economical Retrieval of Space Debris. Paul Roseman, New York, NY.
Abstract: Arguably, the least expensive to recover and most instantly useful in-situ materials available in space are those available as debris in low earth orbit (LEO). These include high grade aluminum, steel, and other space-worthy materials. This paper presents a model and price point for economically retrieving this debris while still in LEO. The author posits that retrieved debris could be recycled and/or reused for other purposes. The author outlines a plan to launch and operate two satellites in LEO: one stationary and one a rover. The stationary satellite would beam solar power to the rover, which would then use this power to energize ion drives. They, in turn, would drive the rover to rendezvous with and capture debris. It would then return it to the stationary satellite. The cost of the rover as well as the costs of financing, launching and operating it are presented and weighed against the current price per-pound of launching any type of payload. The plan does not include the cost of the stationary satellite, or the cost of converting the recovered debris into usable materials. Nevertheless, the calculations show that the owner of the rover could profitably retrieve 3000 pounds of debris per month while selling it for $200 per pound. All calculations are based on current-market costs, and as such, serve as a starting point for the discussion of the economics of recycling space debris.
Towards a Code of Conduct for the Exercise of Intellectual Property Rights (IPR) in Space Activities — Moderation of the Monopoly? Bradford Lee Smith, Alcatel Alsthom Recherche.
Abstract: Intellectual Property Rights (IPR) are regarded as an insurance for high-risk industrial investments in technology. However existing patent law affords no firm basis for territorial extension to extraterrestrial activities on orbit and beyond. In order to attract substantial private investments for commercial space activities, legal certainty is a prerequisite, in particular in order to accurately assess potential infringement liability. The existing legal framework is a patchwork of unilateral territorial extensions (cf. US Space Bill), doctrine based on maritime law, a smattering of US case law, and the one shot InterGovernmental Agreement (IGA) for the international space station Alpha. This explosive mixture is likely to raise more legal problems than it solves. It must not be forgotten that IPR is a competitive weapon, whose principal goal is to secure and enforce a temporary monopoly for the owner. As such, in its known forms, IPR is fundamentally antithetical to the “common benefit” tenants of the Outer Space Treaty (OST). This contradiction will be illustrated with a few real-life examples (HAC, TRW). These examples reinforce the conclusion that national patent laws and the provisions of the OST may readily lead to conflict. But how may such conflicts be resolved? Legal certainty may be best obtained by establishing a universal legal framework by treaty among nations having an interest in space activities. Further, the drafting of such a treaty should include provisions for the sharing of progress in space technologies for the benefit of all mankind, in conformity with the spirit of the OST. The author proposes that the traditional IPR monopoly be diluted by a “code of conduct” consisting of treaty provisions for the use of IPR in space applications. Inspiration may be found in other fields with a similar broad interest for mankind, for example human genomes, medicinal plants, telecommunications standardisation, etc. Compulsory cross licensing could be proposed among signatory nations under fair and reasonable terms and conditions, perhaps with a predefined royalty scheme based on a percentage of profits (rather than a percentage of revenues). Such a clearly defined sharing policy is necessary to allow would-be spacefaring nations now in the starting blocks to catch up to those whose space supremacy has been acquired by decades of defense-related, taxpayer funding during the cold-war space race. Continuing to apply traditional IPR monopoly thinking to space activities will only perpetuate competition and conflict in place of cooperation and sharing of benefits of space activities for the common benefit of mankind.
SETI Telescope Relationship to Lunar Infrastructure and Implications on Keeping Far Side Radio Frequency Free. Robert L DeBiase, Staten Island, NY.
Abstract: Because of increasing radio frequency interference, the SETI community is looking for sites to build a radio telescope free of RFI — the lunar far side is a logical choice. The effort will be driven by the need to get something working relatively soon, build something that can be expanded upon later and the high cost of space transportation. This paper considers telescope implementation models and how various ones can facilitate cost sharing with groups outside the SETI community by development and use of common infrastructure elements. It considers how the need to get something useful working with one mission limits the infrastructure elements that can be initially created and as well as the extensibility of the models. Finally, the paper considers how much the various implementation strategies keep the lunar far side free of RFI for SETI.
Environmental Regulation of Solar System Resources. Lawrence Roberts, City University of New York School of Law.
Abstract: Success in the exploitation of the space environment will depend over the long term on the use of the non-renewable resources of the solar system. How those resources are developed will depend in turn upon the legal regime which emerges to manage them. Ideally, such a legal structure should promote the efficient use of the tangible and intangible benefits made possible by celestial material and equitably apportion environmental interests (both terrestrial and extra-terrestrial) and development concerns. Unfortunately, the existing environmental standards for space resources embodied in the Outer Space Treaty and related international agreements are ill suited to managing the environmental dilemma of the high frontier. Drafted in an era of occasional, state sponsored exploration, these outdated, ambiguous and difficult to enforce instruments can not hope to cope with the institutional demands of private resource development. This paper proposes that an international legal structure which institutes a cogent, private property system, promotes an integrated liability standard for private as well as public entities, makes use of existing civil judicial mechanisms and establishes a tailored method for the creation of limited “traditional” environmental regulation can greatly mitigate or eliminate the flaws engendered by the existing legal regime.
Earth to Space: I Can’t Hear You; Selling Off Our Future to the Highest Bidder. James E. Dunstan, Haley Bader and Potts, PLC.
Abstract: Recently, two related U.S. policy shifts have placed in grave danger the future ability of private companies to explore and develop space, because they may not be able to communicate with the satellites, robots, and even humans, deployed on the High Frontier. This paper will examine those two policy changes – the reallocation of spectrum from government to private use, and the auctioning off of spectrum to the highest bidder – and make some recommendations as to how the space community can work together to preserve spectrum for future space uses.
IV: WIRELESS POWER TRANSMISSION
The Early History of Wireless Power Transmission. William C. Brown, MPT Systems.
Abstract: The history of WPT, or Wireless Power transmission, from the work of Hertz in the late nineteenth century to 1975 is addressed, using nine demonstrations as the historical markers. In 1888 Hertz demonstrated pulsed power transmission at 500 MHz. The first microwave demonstration occurred in 1963 with overall efficiency (ratio of DC power out to DC power in) of 13%. In a series of three more demonstrations this efficiency was raised to 54% in 1975. In 1975 power was beamed by microwaves over a distance of one mile with a DC output of over 30 kilowatts of power at the receiving end. Of especial importance was the internationally televised demonstration of a microwave powered helicopter in 1964.
The World Petroleum Life-Cycle: Encircling the Production Peak. Richard C. Duncan, Institute of Energy and Man.
Abstract: This paper presents a new method for predicting petroleum production. The method is used to predict production from 1996 to 2040 for the top 41 oil-bearing nations, seven geographical regions, OPEC versus non-OPEC groups, and the World total. Findings: The FSU and Saudi Arabia will lead the nations. The Middle East commands the regions. OPEC overtakes non-OPEC in 2006 and dominates thenceforth. World production peaks at 28.5 billion barrels in 2005, and then falls to 10.9 billion barrels in 2040 — a decline of 62% in 35 years. Details of the new method are given in the Appendix.
The Potential Role of Space Solar Power in Beginning Large-Scale Commercial Manufacturing in Space. John Mankins, NASA Headquarters.
Abstract: Diverse studies have been made of potential approaches to begin large-scale space industrialization. The late 1970s saw a crescendo in these efforts with the major Department of Energy and NASA studies of solar power satellites (SPS). Unfortunately, although those studies established the technical feasibility of SPS, the immense initial costs associated with the 1979 SPS Reference System Concept led to a termination of all official activity in the US. During 1995-1996, NASA conducted a far-reaching reexamination of the technologies, systems concepts and terrestrial markets that might be involved in future space solar power (SSP) systems. The principal objective of this “fresh look” study was to determine whether a solar power satellite (SPS) and associated systems could be defined that could deliver energy into terrestrial electrical power grids at prices equal to or below ground alternatives in a variety of markets, do so without major environmental drawbacks, and which could be developed at a fraction of the initial investment projected for the SPS Reference System of the late 1970s. Several innovative concepts were defined and a variety of new technology applications considered, including solid state microwave transmitters, extremely large tension-stabilized structures (both tethers and inflatable structures), and autonomously, self-assembling systems using advanced in-space computing systems. A key ground rule to achieve initial cost goals was to avoid wherever possible the design, development, test and evaluation costs associated with SSP-unique infrastructure, such as fully reusable, heavy lift launch vehicles. As a result, the use of extraterrestrial materials was ground-ruled out of initial system concepts. However, once terrestrially-manufactured SPS become economically viable, the opportunity exists to replace key system elements with lower cost extraterrestrial materials. This “SPS materials displacement strategy” may well be the first major economic impetuous toward large-scale space manufacturing. This paper presents a strategic summary of the results of the “Fresh Look” Study, including architectures, systems concepts and technologies. It also provides a preliminary assessment of the technical and economic opportunities for displacing terrestrially-manufacturing SPS system elements with space-manufactured systems.
SPS Based Emergency Power Supply for Disaster Prevention and Alleviation. Eric M. Flint, German Aerospace Research Establishment.
Abstract: In this paper, a new possible usage of solar power satellites, emergency power supply, is discussed. Seven application areas ranging from power supply for active vibration control devices during earthquakes to independent power supply during power blackouts are introduced. All applications rely on low density power (to avoid potential long term exposure health issues) beamed to distributed rectennas. Technical issues arising from beaming antenna and rectenna design are reviewed and it is shown that no problems are foreseen except for the uncertainty about long term microwave exposure limits and potential electrical interference effects. This is followed by two case studies where the first shows that a full scale traditional SPS using phased beaming could provide emergency power to up to 5 different locations using the standard 35° lat., 75 Km2 beamed energy footprint, at a beam center power density of 50 W/m2. If a wider coverage area was needed the used beaming aperture could be reduced by about 50% resulting in a 300 Km2 footprint also with a maximum power density of 50 W/m2. The second case study briefly shows that a technology demonstrator sized SPS could provide useful emergency power supply services. Possible ways to use this capability to secure extra revenue or financing are discussed. While a solar power satellite probably can not be justified solely on its potential to save human lives, this, combined with the more traditional application of baseline power generation, could help serve to make the concept of a Solar Power Satellite even more economically and politically attractive.
Energy and Information From Orbit: Technologies for the Greenhouse Century. Seth D.Potter and Martin I. Hoffert, New York University.
Abstract: Solar power satellites (SPS) have been proposed as a means of supplying carbon-free energy during the 21st century. The relatively high areal power densities that SPS’s would provide give them an advantage over other renewable energy sources. However, the laws of physics mandate huge SPS’s if they are placed in geostationary orbit, leading to large first costs. New technologies such as advanced launch vehicles and thin-film materials may bring down these costs. Constellations of satellites in low Earth orbit which supply both power and communications may minimize the financial and technical risk of space power. SPS’s can thus contribute to environmentally safe economic development during the years to come.
V: BIOMEDICAL CONSIDERATIONS
Design of Extended Range EVA PLSS Systems: Lessons from Terrestrial Exploration Missions. William C. Stone, National Institute of Standards and Technology.
Abstract: As plans progress for construction and maintenance of the international space station and, more importantly, private missions to LEO and beyond become viable, serious thought will need to be given to re-engineering EVA (space suit) systems to achieve greater range and reliability at dramatically reduced cost. This paper discusses alternative architectures for fully closed cycle portable life support systems (PLSS) that have been built and tested over the last decade for use in hazardous subaquatic environments. Fault tolerant design, both for the mechanical and computational hardware elements, was employed in the development of four generations of prototype devices. The culmination of these designs was successfully used to explore a 600 meter long underwater tunnel which began at a depth of 1353 meters vertically beneath the surface of the earth in southern Mexico. Lessons relating to survival and range enhancement on orbital and lunar EVA missions are presented.
The Study of the Effects of Long Duration Space Flight on the Central Nervous System Using Modem Imaging Techniques. Andrew B. Newberg and Abass Alvi, University of Pennsylvania Medical Center.
Abstract: A number of changes have been shown to occur in the central nervous system (CNS) during exposure to the space flight environment. If human beings are to plan interplanetary missions or establish permanent space habitats, it must be determined if there will be any detrimental changes to the CNS from long duration exposure to the space environment. Research to date has focused primarily on the short term changes in the CNS as the result of space flight. The space environment has many factors such as weightlessness, electromagnetic fields, and radiation, that may affect the function and structure of the CNS. The CNS changes already shown to occur during long duration space flight include neurovestibular disturbances, alterations in sensory perception, changes in proprioception, cephalic fluid shifts, psychological and cognitive alterations. Recent progress in the ability to study brain morphology and function in vivo in the human brain could provide the opportunity to investigate many of the changes that occur in the CNS as a result of space flight. These methods include positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) and have been widely used in the study of neurological and psychological disorders. These imaging techniques will be reviewed with respect to their current applications in order to suggest future directions of research in the study of the effects of space flight on the CNS.
Inflatable Structures for Moon/Mars Surface. Willy Z. Sadeh, Jenine E. Abarbanel, and Marvin E. Criswell, Center for Engineering Infrastructure and Sciences in Space, Colorado State University.
Abstract: A structure on the Lunar and/or Martian surface acts as a pressure vessel since the internal pressure is the dominant load in the absence of a substantial external atmosphere. A generic inflatable module is proposed as an efficient and functional structure for use on the Moon/Mars surface. Each module consists of thin membranes supported by a pressurized framing system. Module characteristics, including membrane thicknesses and mass, are presented.
Cybersurgery: A New Vision for General Surgery. Richard Satava, Advanced Research Projects Administration and Yale University School of Medicine.
Abstract: Star Wars! Cyberspace! To the public these words inspire visions of space ships, computer generated worlds and alien life forms, but to the scientific and medical communities these words epitomize the reality that extraordinary technologic success can be accomplished through selfless sacrifice and uncompromising scientific rigor applied to a bold and creative vision that dares to challenge the impossible. Efforts of this magnitude reshape the foundations of science and mandate a realignment of thought processes. When current vocabulary contains no words to adequately encompass these germinating ideas, it is necessary to resort to neologisms. Cybersurgery cannot be defined, rather it is a synthesis, with the description of the individual technologies contributing to the meaning on a scientific, intuitive and emotional level. The reader must distill the essence of cybersurgery by imprinting their personal experience and interpretation upon these printed words.
VI: ROBOTICS
Mars Rovers: Past, Present and Future. Donna Shirley and Jacob R. Matijevec, Jet Propulsion Laboratory.
Abstract: Since the 1960′s there have been efforts world-wide to develop robotic mobile vehicles for traversing planetary surfaces. Two Lunakhods were successfully operated on the Moon in the early 1970′s, but since then there have been no planetary rovers. Developments in mobility, navigation, power, computation, and thermal control have now allowed a small, 11.5 kg rover named Sojourner Truth to be heading for Mars. Sojourner will explore an area within site of the Pathfinder lander’s camera, making measurements of the surface properties, and imaging rocks and obtaining their elemental composition. Future U.S., and perhaps Russian rovers are planned to go to Mars in 2001, 2003, 2007 and 2011 to rove 10 kilometers or so and collect samples for return to earth by missions launched in 2005, 2009 and 2013.
Teleoperation Strategies for Exploring and Utilizing the Resources of Space. S. Potter and M. Hoffert, New York University; C. Wegner and D.B. Karron, Computer-Aided Surgery, Inc.
Abstract: The exploration and exploitation of space will require an optimal combination of human beings and machines. The latter may be either on-site, or a long distance from the space-based activity. Sending sensory input to, and receiving direction from, human beings at a remote location is known as telepresence and teleoperation. Its uses will include mining and processing lunar materials, assembling large space structures, and assisting in remote emergency surgery. Extraterrestrial teleoperation is constrained by the velocity of light, whose round-trip travel time between the Earth and the Moon is 2.6 seconds. The cutting edge in teleoperated terrestrial surgery is described. Visual feedback in teleoperation is limited by latency, computational and bandwidth requirements, image generation lag, operator fatigue, etc. Sound feedback can overcome some of these limitations. Teleoperational methods being developed for terrestrial surgery can be extended to various space-based activities. To handle these different tasks, various teleoperation strategies are described. Serving in place of gravitational cues, perhaps virtual audio can help us navigate on the high frontier.
End-Effector Vibration Suppression of a Flexible Manifulating System by Using Piezoelectric Actuators. Ji Y. Shen, William McGinley, and Lonnie Sharpe, Jr., North Carolina A&T University.
Abstract: Attenuating start-up and stopping vibrations when maneuvering large payloads attached to flexible manipulator systems is a great concern for many space missions. To address this concern, it was proposed that the use of smart materials, and their applications in smart structures, may provide an effective method of control for aerospace structures. In this paper, a modified finite element model has been developed to simulate the performance of piezoelectric ceramic actuators, and was applied to a flexible two-arm manipulator system. Connected to a control voltage, the piezoelectric actuators produce control moments based on the optimal control theory. The computer simulation modeled the end-effector vibration suppression of the NASA manipulator testbed for berthing operations of the Space Shuttle to the Space Station. The results of the simulation show that the bonded piezoelectric actuators can effectively suppress follow-up vibrations of the end-effector, stimulated by some external disturbance.
