Space 98

An all private approach to implementation of a lunar resource and ³He fusion power initiative has distinct advantages over other approaches based on a semi-quantitative evaluation of six alternative financial and management approaches, including all U.S. government, all international, all private and combinations of these three. Evaluation of several external issues, including environmental protection, developing nation benefits, and space settlement also favors the all private approach. Relative to the possibilities evaluated, an all private approach has a strongly favorable aggregate ranking as well as scoring highest in each of the three issue areas examined. These evaluations support an aggressive move toward such an initiative.

This paper attempts to examine briefly the commercial approach that this writer believes must be implemented if extraterrestrial energy and material resources are to be utilized. The practical implementation, which is consuming a tiny fraction of DASA resources, is described. The IEC fusion technology has been acquired under exclusive license from the University of Illinois, by Daimler-Benz Aerospace for development into commercially successful products. At first glance IEC has little to do with the core business of a space systems company because its early products are marketed for terrestrial applications. In reality IEC fusion may be a key aspect of cultivating a credible market for extraterrestrial resources. It may also provide enabling technology to profitably recover those material resources.

Recently, NASA requested proposals for the Mars Surveyor 2001 Orbiter, Lander, and Rover. The University of Colorado's BioServe Space Technologies Center and several industrial affiliates proposed a Mars soil toxicity instrument, BioTox, for the Lander's "soil box." The purpose of the BioTox experiment is to assess the overall toxicity of Mars soil to living organisms. Environmental toxicity is of major concern for future human missions to Mars. Prior Mars missions suggest that oxides predominate in surface soils, posing potential problems for the operation of machinery and, ultimately, problems for use in construction and habitability of a human base. An industry standard assaying method using a species of bioluminescent bacteria (Vibrio fischeri) is suggested for evaluating samples of Mars soil. Soil will be mixed into an aqueous solution, and toxicity evaluated by measuring the soil's effect on cellular respiration. It is proposed that these bacteria can be transported to Mars in a freeze-dried state, reconstituted in seconds, and the test performed in minutes. An easily performed direct photometric measurement of the light output of the organisms greatly simplifies the instrumentation. Secondary parameters also measured by this experiment are the soil pH, salinity, turbidity, scattering spectroradiometric properties of the aqueous solution, soil color, and inferences of organic versus heavy metal toxins. Although Planetary Protection guidelines encourage nonbiologically based experiments, it is believed that sterilization, a triple-walled container, and back-up fixative procedures will permit safe, effective, biological challenge experiments aboard lander missions. Sending a biological experiment to Mars provides a direct opportunity for testing biological viability in the harsh Martian world and will answer questions of relevance to human landings.

We are at the dawn of private space exploration, which will lead to the rapid growth of a space-based economy with people working, living and playing in space. This entrepreneurial sector will rely on space-based labor, services and resources, and will require an infrastructure for communications and the delivery of energy. Space resource utilization requires many prior steps before those resources and their products can be used on an economically sound basis, and each step must be profitable. Not only must there be a supply and demand for such resources, but the business, economic and technology infrastructure must be in place, created one step at a time. SpaceDev's first mission, the Near Earth Asteroid Prospector (NEAP) will be the first private mission beyond earth orbit, and the first private mission to visit and land upon another planetary body. NEAP may provide a model for how to jump start space commercialization. By making a profit with this science-based mission, the door may be opened for other entrepreneurs.

Controlling vibration of structures is essential for both space structures as well as terrestrial structures. Due to the ambient acceleration levels anticipated for the International Space Station, active vibration isolation is required to provide a quiescent acceleration environment for many science experiments. An overview is given of systems developed and flight tested in orbit for microgravity vibration isolation. Technology developed for vibration control of flexible space structures may also be applied to control of terrestrial structures such as buildings and bridges subject to wind loading or earthquake excitation. Recent developments in modern robust control for flexible space structures are shown to provide good structural vibration control while maintaining robustness to model uncertainties. Results of a mixed H₂/H_∞ control design are provided for a benchmark problem in earthquake engineering for building structural control.

The shape and pre-stress distribution in a new type of deployable antenna reflector, the Collapsible Rib-Tensioned Surface (CRTS) reflector, are investigated both analytically and experimentally. Three different surfaces, the reference surface, the equilibrium surface, and the actual surface of the reflector are introduced, and their rms errors are compared for reflectors with apertures of 1, 3, 5, and 10 m, with 6, 12, and 24 ribs. Measurements of pre-stress and shape in a one-sixth sector of a 1 m diameter reflector with 6 ribs, are compared with the predicted values.

The pultrusion process is well recognized as a cost-effective method for the production of composite structures. Exacting requirements for straightness for space structures and recreational applications (such as archery arrows) have lead to an examination of processing factors which adversely affect the successful fabrication of these components. Experiments have been conducted to examine the unwarranted causes of curvature and to develop methods for fabrication of straight components. Effect of pull alignment and thermal variations will be discussed with regards to their relative importance to the final part straightness.

Spacecraft require a variety of mechanisms to accomplish mission related functions such as deployment, articulation, and positioning of spacecraft structures and instruments. Suitable devices, using proven technologies, are available off-the-shelf. However, increasingly stringent weight, power, accuracy and other requirements for future satellites will exceed the capability of devices built with current technologies. This paper summarizes several innovative technologies that the Air Force Research Laboratory is researching to produce more efficient and accurate spacecraft mechanisms. These technologies include shape memory actuators, lightweight solar arrays, precision gimbals, magnetic bearings and robotics. Several mechanisms developed in these programs are scheduled for space flight demonstrations in 1998, 1999 and 2001.

After a brief history of use in space about two decades ago, a resurgence of interest in applications of membrane structures in space is developing. Space-based inflatable technology is of current interest to DOD and NASA, particularly since potentially large gains in lowering launch costs, through reductions in structure mass and stowed volume, are possible. In this paper we discuss some history, technical issues, and future trends for space-based inflatable structures.

A concept of cylindrical deployable space structures which enable to deploy three-dimensionally has been proposed in this study. The deployment/packaging characteristics by examining the geometrical properties have been studied. We derived design procedures with some fundamental geometrical parameters for realizing the cylindrical deployable structures, and we investigated the deployment/packaging efficiencies. Also, some applications for constructing structures in space environment were proposed.

This paper describes a method to design a structure and control system simultaneously using multiobjective optimization method based on using the Euclidean norm. In the design of the control system, the state space equations are integrated using a Runge-Kutta method for specified initial boundary condition and the constraints on maximum values of the control forces. The structural weight and weight of the actuators, are considered as the criteria functions. The design variables are the control bounds, the cross-sectional areas of the structural elements and elements of the weighting matrices. As an example to illustrate the application of an approach, a box beam idealized by rod elements is used.

This paper demonstrates the application of the recently developed damage localization theory to the damage identification of flexible aerospace manipulating systems. The system analyzed is a simulation of a NASA manipulator testbed for the research of the berthing operation of the Space Shuttle to the Space Station, which consists of two flexible links and three revolute joints. A finite element model using ten frame elements, along with the revolute joint element, has been developed to represent the manipulating system. Assume that one of the elements was damaged, the damage localization criterion has found the exact location of the damaged element.

Today, a satellite has to be designed to survive its launch environment since this is the worst-case loading condition for the satellite. This results in an over design of the satellite structure; thereby, adding extra weight to the satellite structure that could be used for additional science/commercial purposes. The USAF Research Laboratory is actively investigating an approach to minimize launch loads to satellites in the form of a whole-spacecraft launch isolator. The objective of the current effort is to reduce the launch-induced structural-borne dynamic acceleration of the satellite by insertion of an isolation system that provides the satellite a softer ride to space. This paper discusses several efforts being analyzed and managed by the USAF Research Laboratory in the area of whole-spacecraft launch isolation. These programs are targeted for small to medium class launch vehicles, but the technology is applicable to all sizes of launch vehicles. This paper presents the work performed from several of these programs, and discusses the near term flight opportunities for the Air Force Research Laboratory's whole-spacecraft isolation systems.

When constructing space machinery for operation under decreased forces of gravity or weightlessness, one is faced with a problem of terrestrial testing. This problem results from the necessity for retaining the mass of the structure, while offloading the real weight of the space unit. To simulate a decreased force of gravity (weightlessness) for terrestrial testing of various spacecraft, a family of mechanical unloading systems/devices has been developed at VNIITRANSMASH. The common method for developing such devices, as well as the experimental data obtained during testing them are of scientific and practical interest for the space machinery development engineers.

This paper deals with the data obtained in originating and developing the "Orientator" Precise-Guidance Platform (PGP) in 1996–1997 within the scope of the Russian-American "Mir-Pathfinder" program. This basic technical data are given; the characteristic features of the design, the testing techniques using a dynamic test stand of microgravitation, the methods providing mechanical and electrical interfaces of the payload located on PGP with the "Spektr" module, as well as the methods for mounting PGP on the latter in the Out-of-Spacecraft Activity of cosmonaut are discussed.

The desire to reduce launch cost and stowed volume has resulted in a renewed interest in membrane and inflatable structures in space. However, resolution depends on aperture size, and there is a practical limit to the dimensions of rigid structures deployed in space. Thus membrane reflectors promise a wide variety of applications across the electromagnetic spectrum, from radio and radar waves, to optical frequencies. Adequate on-orbit performance of these reflectors remains a technical challenge, however. In this paper, we focus on the surface accuracy of membrane reflectors, that is, their deviation from a reference profile, appropriate metrics, and corrective actions that may be employed.

The paper deals with the problems concerning the ground development work on a three-degree stabilized platform for the MARS-96 mission. The amount and sequence of testing are discussed, and the methods and essential data of testing are given.

A Vertical Stabilizer Assembly (VSA) prototype of the Space Shuttle Orbiter was modal tested with a Laser Doppler Velocimeter (LDV) and accelerometers in order to compile a data base that can be used to benchmark several damage identification techniques. The VSA was instrumented with 56 accelerometers and one force link attached to a stinger connecting a 500-lb. shaker and the structure. The LDV was used to acquire data from 84 points on one side of the VSA, 35 of which matched with accelerometer locations. Seven controlled damage scenarios were inflicted on the VSA. The test article was modal tested before and after the infliction of the damage. The damage consisted of removing bolts and rivets, disbonding of skin from the aluminum honeycomb, cutting through ribs, and skin removal. The data captured consisted of frequency response functions (FRFs) with accompanying coherence functions and time histories for two scenarios. This paper presents the results and conclusions of the comparison of the laser and accelerometer data on the basis of noise levels and magnitudes of FRFs. In addition, the advantages and disadvantages of the two techniques are discussed with respect to the setup and data acquisition times, as well as the ability to measure data on different points of the structure.

The X PRIZE is an international competition for the practical demonstration of the first reusable craft capable of taking three people to the edge of space (62 miles) and back. The X PRIZE is modeled after the great aviation prizes of the 1920's and 1930's. A particular example is the Orteig Prize of $25,000 which resulted in Charles Lindbergh's landmark flight from New York to Paris in 1927. This flight transformed aviation from the category of ‘stunts' to the beginnings of the multi-billion dollar aviation industry which has linked the world.

A design/performance matrix for horizontal take-off/horizontal landing (HTHL) hypersonic airbreathing vehicles is presented. Activities and plans for enhancing and resolving the matrix are given. A Hypersonic Systems Integration Demonstrator (HySID) vehicle concept providing a technology flight testbed from M=0 to 7 is introduced.

The Kistler Aerospace K-1 reusable launch vehicle is a complete system designed for the launch of commercial satellites to low earth orbit. The Kistler engineering team has been busy designing and building the fleet of five K-1 launch vehicles since mid- 1996. Development is on schedule to support flights tests in Fall 1998 and operational missions in 1999.

MightySat is a United States Air Force (USAF) multi-mission, small satellite program dedicated to providing rapid, frequent, on-orbit demonstrations of high-payoff space system technologies. The Air Force Research Laboratory (AFRL) is the USAF center for space technology research & development. MightySat platforms provide the on-orbit "lab bench" for responsively testing emerging technologies to ensure their readiness for operational Air Force missions. This paper focuses on the MightySat II series of vehicles being developed largely by Spectrum Astro, Inc. in Gilbert, AZ. MightySat II Flight 1 ("Sindri"), a 275 lb. satellite designed for deployment from either the Orbital/Suborbital Program (OSP) or the Space Transportation System (STS), is now in final design stages, with Critical Design Review completed November 1997. Details of the current spacecraft bus design and upcoming integration and testing (I&T) plans are discussed. The development and integration of the advanced technology payloads for Sindri, namely the (1) Fourier Transform Hyperspectral Imager (FTHSI), (2) Advanced Thruster, (3) Plume Diagnostic Experiment (PDE), (4) Quad-C40 processor (QC40), (5) Solar Array Concentrator (SAC), (6) Shaped Memory Allow Thermoplastic Tailoring Experiment (SMATTE), (7) Solar Array Flex Interconnect (SAFI), and (8) advanced composite bus structure are described. A brief summary of future MightySat II vehicles and missions (Flights 2 through 5) is also provided.

This paper presents arguments in favor of maximizing ground-based operations and maintenance (O&M) for the International Space Station and other manned orbiting facilities, utilizing high performance, flexible, evolvable ground systems to do so and developing an internationally recognized set of ground system standards to facilitate multi-node Telemetry, Tracking, and Command (TT&C).

The purpose of this study was to determine what cost advantages were likely to result from adoption of a Hub Spaceport operations strategy for RLV flight operations. The study found that launch cost reductions of 14% to 25% could result from basing RLV flight operations at a Hub Spaceport. The savings resuiting from more efficient utilization of RLVs was found to be greater than the savings resulting from eliminating the second launch facility.

Despite rigorous fire-safety policies and practices, fire incidents are possible during lunar and Martian missions. Fire behavior and hence preventive and responsive safety actions in the missions are strongly influenced by the low-gravity environments in flight and on the planetary surfaces. This paper reviews the understanding and key issues of fire safety in the missions, stressing flame spread, fire detection, suppression, and combustion performance of propellants produced from Martian resources.

The demands of fluids management in a low-gravity environment present serious challenges to the designers of such vital spacecraft elements as liquid fuel tanks, cryogen storage tanks, and systems for water recycling. A current review of technological challenges in fluids management for space-based systems is provided by Salzman concerning a selection of unresolved issues in fluids management crucial to the success of advanced space exploration. In this paper, attention is focused on isothermal capillary phenomena and the particularly nagging problems of tankage in a low-g environment: interface configurations, natural frequency) damping, and stability. The specific effects of system wettability and the moving contact line condition, are briefly reviewed. Though recent results of space experiments have added significantly to our knowledge base, deficiencies in our understanding remain. These deficiencies are outlined and an effort is recommended to update the existing "catalog" of design tools and methodologies for space-based fluids systems design and development.

We describe magnetic levitation systems for two fluids, helium and oxygen, that can be used to cancel the effects of gravity. The devices use high magnetic field gradient superconducting solenoids to achieve the lift force. The devices are designed primarily for phase transition studies. The potential for thermal stratification and convection studies in conditions that mimic long duration space flight is explored. Magnetic fluid management schemes for near-zero gravity are also described, including magnetic field requirements for variable gravity cancellation of common cryogenic fluids.

Manned and robotic missions to the Earth's moon and Mars are exposed to a continuous flux of Galactic Cosmic Rays (GCR) and occasional, but intense, fluxes of Solar Energetic Particles (SEP). These natural radiations impose hazards to manned exploration, but also present some constraints to the design of robotic missions. The hazards to interplanetary flight crews and their uncertainties have been studied recently by a National Research Council Committee. Considering the present uncertainty estimates, thick spacecraft shielding would be needed for manned missions, some of which could be accomplished with onboard equipment and expendables. For manned and robotic missions, the effects of radiation on electronics, sensors, and controls require special consideration in spacecraft design. This paper describes the GCR and SEP particle fluxes, secondary particles behind shielding, uncertainties in radiobiological effects and their impact on manned spacecraft design, as well as the major effects on spacecraft equipment. The principal calculational tools and considerations to mitigate the radiation effects are discussed, and work in progress to reduce uncertainties is included.

Utilization of extra-terrestrial resources is vital to making affordable space exploration missions a practical reality. Almost all present NASA plans and studies to explore the Moon and Mars rely heavily on the use of local resources and emphasize In-Situ Resource Utilization (ISRU) as a key enabling capability. Indigenous resources can be used in both robotic and crewed missions for enhancing the science returns, generating power and producing propellants needed for the return part of the mission. In crewed missions ISRU can also be used for construction of habitats, radiation and thermal protection shields, and generation of oxygen, water, food and other crew consumables. Achieving these goals requires an understanding of the available extra-terrestrial resources and the mining and chemical processes that will be used to generate the necessary consumables in a mass and energy efficient manner. These processes involve chemical reactions, multiphase flows, and phase change, the scaling laws for which are often not well understood even for our terrestrial environment. Focused research studies, therefore, are needed to develop models, scaling laws, and experimental data that will qualify the use of these processes for applications on the Moon and Mars. This paper presents an overview of some of the processes required to generate oxygen, water, and propellant and the key challenges faced by the designers and engineers for Mars missions. A companion paper on the issues related to lunar exploration is forthcoming.

Reduced-gravity environments are unique in that they not only represent a new set of conditions for the conduct of scientific research, but also present technical challenges that must be met in order to implement both human and robotic space exploration. In particular, transport phenomena (fluid flows and heat and mass transfer) which are often key controlling mechanisms in many physical, chemical, and biological systems are significantly different under low-gravity conditions. Many mission-operating and life-support technologies also involve transport phenomena. Predictive models for low gravity performance and operation of such technologies are inadequate or non-existent. Therefore, a knowledge base is needed for the design and development of reliable, efficient, and cost-effective space equipment and systems. Discussion will be presented in this paper on how low-gravity transport phenomena impact the operation of space systems and what gaps in knowledge need to be filled in order to develop future system designs. Some of what has been learned about low-gravity transport will also be reviewed.

Precision clocks and frequency standards are widely used in communication and navigation systems. In navigation, time and frequency references are the parameters that determine the ultimate accuracy of position location. While clocks and frequency standards are widely used in commercial, military, and NASA satellites, the emergence of new requirements in all these arenas have pointed to the need for new classes of standards with improved performance. In particular, the success of Global Positioning System (GPS) in numerous communication and navigation applications has already led to the need for small, high performance clocks to improve the present capabilities. Furthermore, many future spacecraft systems in autonomous and or cluster configurations require advanced clocks. Applications of advanced clocks will also be crucial for position location on Mars, where it is expected that a large number of probes will be deployed, and will be monitored independently. In this paper a general discussion of the clock applications will be followed by a description of advanced clocks, and projection for their anticipated future applications.

Current plans for practical missions leading to a sustained human presence on our Moon and Mars rely on utilizing their in situ resources. Initially, resource availability must be assessed followed by the development of economically acceptable and technically feasible extractive processes. In regard to metals processing and fabrication, the lower gravity level on the Moon (0.125 g) and Mars (0.369 g) will dramatically change the presently accepted hierarchy of materials in terms of specific properties, a factor which must be understood and exploited. Furthermore, significant changes are expected in the behavior of liquid metals during processing. In metal casting, for example, mold filling and associated solidification processes have to be reevaluated. Finally, microstructural development and therefore material properties, presently being documented through on-going research in microgravity science and applications, need to be understood and scaled to the reduced gravity environments. These and other issues are addressed in this paper.

Two classes of material processing scenarios will feature prominently in future interplanetary exploration: in situ production using locally available materials in lunar or planetary landings and high performance structural materials which carve out a set of properties for uniquely hostile space environments. To be competitive, high performance materials must typically offer orders of magnitude improvements in thermal conductivity or insulation, deliver high strength-to-weight ratios, or provide superior durability (low corrosion and/or ablative character, e.g., in heat shields). The space-related environmental parameters of high radiation flux, low weight, and superior reliability limits many typical aerospace materials to a short list comprising high performance alloys, nanocomposites and thin-layer metal laminates (Al-Cu, Al-Ag) with typical dimensions less than the Frank-Reed-type (e.g., packing flaws or ‘weak' points crystallographically) dislocation source. Extremely light weight carbon-carbon composites and carbon aerogels will be presented as novel examples which define broadened material parameters, particularly owing to their extreme thermal insulation (R-32-64) and low densities (<0.01 g/cm³) approaching that of air itself. Even with these low-weight payload additions, rocket thrust limits and transport costs will always place a premium on assembling as much structural and life support resources upon interplanetary, lunar, or asteroid arrival. As an example, for in situ lunar glass manufacture, solar furnaces reaching 1700° C for pure silica glass manufacture in situ are compared with sol-gel technology and acid-leached ultrapure (< 0.1% FeO) silica aerogel precursors.

One of the most important elements of a human planetary base is power production. Lunar data make it clear that several types of solar-to-electric converters can be manufactured on the Moon. Materials research and processing demonstrations are suggested that can be carried out on Earth, the Space Transportation System (STS), the International Space Station (ISS), and on the Moon to advance the in situ production of solar-to-electric power systems on the Moon. Many of the technologies will be applicable to Mars, the silicate moons, and asteroids.

Processing of Lunar/Mars raw materials into usable structural and thermal components for use on a Lunar/Mars base will be essential for human habitation. One such component will be glass fiber which can be used in a number of applications. Glass fiber has been produced from two lunar soil simulants. These two materials simulate lunar mare and lunar highlands soil compositions. Short fibers containing recrystallized areas were produced from the as-received simulants. Doping the highland simulant with 8 weight percent boria yielded a material which could be spun continuously. The effects of lunar gravity on glass fiber formation were studied utilizing NASA's KC135 aircraft. Gravity was found to play a role in crystallization and final fiber diameter.

Soil mechanics and geological investigations on Mars or the Moon are described herein, using a novel mobility system, designated as the "Elastic Loop Mobility System (ELMS)". ELMS was developed as a spin-off of the U.S. Lunar Roving Vehicle (LRV) which operated on the Moon during the Apollo 15, 16, and 17 Missions. Extensive testing of the ELMS, both on soft soil and on rigid obstacles, has shown that the ELMS outperforms by far both the LRV and the two unmanned, self-propelled Soviet rovers, Lunokhod 1 and 2, which landed on the Moon in the western part of Mare Imbrium, aboard the spacecraft Luna 17 and 21. In this paper, examples of soil mechanics and geological investigations that can be conducted either by an unmanned, self-propelled ELMS rover, or by an ELMS attached to a Martian Lander are discussed, along with the associated instrumentation. Through such investigations, ascertaining the existence of some primitive forms of past or present life on Martian or Lunar geological formations may become possible, in addition to obtaining numerous data on the mechanical and physico-chemical properties of Martian or Lunar soils along long traverses.

Manipulator Flight Demonstration (MFD) was launched in August 1997 on the Space Shuttle Discovery. The MFD is to demonstrate function and performance of the Robot Arm similar to the Small Fine Arm (SFA) of Japanese Experiment Module (JEM) of the International Space Station (ISS) prior to its launch. This paper reports the MFD mission objectives and the design features, and summarizes the results of its flight experiment results. In general behavior and performance of the system has followed closely predictions made by simulations.

It is proposed as a case study that the Russian space station MIR could be privatized for tourism and maybe other commercial uses. With the imminent arrival of the International Space Station, the original purpose for MIR will have been fulfilled, and this paper explains some of the parameters involved with extending the life of MIR for the suggested commercial uses and considers the elements of an associated business plan.

The lunar south pole region may contain frozen volatiles such as water and carbon dioxide in surface depressions which are permanently dark. The low Sun angles of the region create these permanently dark areas and also provide nearby regions of long term sunlight and moderate temperatures which benefit robotic exploration. In this paper a concept for a robotic explorer named Icebreaker is presented. It is designed to take advantage of the south pole environment and to find and analyze frozen volatiles. Icebreaker is an innovative new spacecraft concept which combines the functionality of traditional landing craft and mobile robots into one integrated vehicle. This type of vehicle will allow larger science packages to be delivered to the planets. Icebreaker will acquire samples with a drill and determine the presence and composition of volatiles inside cold traps using a Regolith Evolved Gas Analyzer (REGA).

The growing interest in asteroids and asteroid science and the decreasing cost of space missions have seriously motivated the issue of utilizing asteroids for their inherent mineral worth. One aspect of mining operations on asteroids explored here concerns the dynamics of debris and samples that may be ejected from the surface during mining or exploratory operations. The fate of such particles lofted from the surface are of great importance, for they may interfere with orbital operations about the body and, in the worst case, populate an asteroid with a transient "atmosphere" that might render orbital operations unsafe for a significant period of time. Conversely, the low escape speeds on asteroids might enhance remote sensing operations. An orbiting craft could sample different parts of the asteroid by shooting a high-speed projectile into a test location, and then collecting or remotely analyzing the material in the resultant ejecta field. This technique has been suggested for use in a number of upcoming asteroid and comet probes. We begin with a brief overview of the relevant dynamics of objects lofted at low speed from the surface of an asteroid, and then analyze the effects of impacts into an asteroid surface.

After the first permanent lunar base has been established, an effective means of surface transportation will be needed to expand human activities to other areas of the Moon. This paper discusses the development of a railroad as a practical means of transportation on the Moon. The rail network can be constructed from indigenous materials by tele-operated robots at the lunar base. As the railroad grows outward from the lunar base, it will provide transportation for its own growth and for other construction projects such as the lunar electric power grid and telecommunications network. The lunar railroad will provide ready access to remote areas of the Moon, such as permanently shadowed craters in the south pole region that may contain valuable deposits of water ice and hydrocarbons. Eventually, the lunar rail system will be expanded to all geographic areas of interest, thus facilitating the global exploration and development of the Moon.

This concept proposes to use thermal processes alone to extract water from the lunar South Pole and launch payloads to low lunar orbit. Thermal steam rockets would use water propellant for space transportation. The estimated mass of a space water tanker powered by a nuclear heated steam rocket suggests it can be designed for launch in the Space Shuttle bay. The performance depends on the feasibility of a nuclear reactor rocket engine producing steam at 1100 degrees Kelvin, with a power density of 150 Megawatts per ton of rocket, and operating for thousands of 20 minute cycles. An example uses reject heat from a small nuclear electric power supply to melt 17,800 tons per year of lunar ice. A nuclear heated steam rocket would use the propellant water to launch and deliver 3,800 tons of water per year to a 100 km low lunar orbit.

Findings from space technology have been combined with advancements in terrestrial science to refine concepts of Earth structure and composition. Dating of samples from the near side of the Moon indicate the last impacts there to have been eons ago. However, collisions of comets and meteors with other planets and the Earth continue. The Earth's outer shell, the lithosphere, and its underlying region, the mantle, may contain sizeable inclusions of incompletely differentiated materials. Analysis of spacecraft trajectories and orbits shows that the Earth has the highest mean density of all the planets, affirming the massiveness of its central core. This and the variations of lunar motion suggest that stress changes in the mantle may cause heating, strain and magma flow in the structurally weak layer below the crust. These effects are associated with tectonic activity, including vulcanism, earthquakes, and other deformations of the habitable surface of the Earth. In this concept, ocean tides are also influenced by the Earth's internal stress changes. Strain in the mantle induces bending of the relatively thin, highly fractured crustal plates which form the ocean floor. Flexure of these plates then causes tidal flow of the overlying water. The Earth model arising from this approach may be helpful in analysis of surface deformations and subsurface geophysics.

Lincoln Laboratory has a long history of developing electro-optical space surveillance technology for resident space object search, detection, orbit determination, and catalog maintenance. Recent advances in large format, highly sensitive CCDs make possible the application of these technologies to the detection and cataloging of asteroids, including Near Earth Objects (NEOs). When equipped with the new Lincoln Laboratory focal plane, camera and signal processing technology, the modest sized (1-meter class) Air Force Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) telescopes have considerable capability to conduct sensitive, large coverage searches for earth crossing and main belt asteroids. Field measurements have indicated that CCD-equipped GEODSS telescopes are capable of achieving a limiting magnitude of 22, over a 2-square degree field-of-view, with less than 100 seconds of integration. This is comparable to the sensitivity of considerably larger telescopes equipped with commercial cameras. In addition to the high sensitivity, the Lincoln CCD is configured for frame transfer operations which are well suited to high coverage rate asteroid search operations because each frame can be readout while the next frame is integrating. Technology development for asteroid search operations has been conducted at the Lincoln Laboratory Experimental Test Site in Socorro, NM over the past two years. Initial results, reported during the Space 96 meeting, indicated that the search system, now known as LINEAR (LIncoln Near Earth Asteroid Research), had considerable promise. Using the new large format 2560X1960 pixel, frame transfer CCD camera, forty-nine new asteroids were discovered over a period of several months, including one NEO. In addition, observations on seventy-nine knwn objects were collected and provided to the Minor Planet Center (MPC). Since those initial attempts, the search operations have been considerably improved and automated. Data acquisition has been streamlined, detection algorithms have been updated and the signal processing of the resulting data has been closely integrated with the data acquisition process. Field tests started again in January of 1997, with the objective of quantifying the capability of the search system to find new asteroids and provide quality metric measurements to the Minor Planet Center. Since the large 2560 x 1960 pixel CCD camera was unavailable during this time, an older 1024 x 1024 pixel CCD camera was used. The smaller format camera has slightly less sensitivity than the larger camera and fills only about 1/5^th of the field-of-view of the GEODSS telescope (which is filled by the larger chip). Observations were conducted over the dark of the moon periods during the months of March, April and May. Each search area was covered three times over a period of three to seven days to generate discovery observations of each new object that could be limited from day to day. The Minor Planet Center requires that newly discovered objects be observed over at least two nights before granting the object a designation. In spite of the fact that a small format camera was employed during the search operations, the productivity was quite large during each of the observing runs. The search program was capable of repeatedly covering an area extending 15 deg. by 10 deg. over a period of a few days, to a limiting visual magnitude of approximately 21^st. These series of observations validate that the Air Force GEODSS upgrade technology is quite effective when applied to the problem of discovering asteroids. Future development of this capability is planned to incorporate the large format, more sensitive camera and to automate the operations so that they may be run remotely or in a fully unattended operations mode. These enhancements will increase the already high search productivity of the LINEAR program by providing considerably higher sky coverage rates and allowing operations on more nights.

The Ballistic Missile Technology Office of the Air Force Research Laboratory, Kirtland AFB, NM, in cooperation with the Theater Targets Product Office of the US Army Space and Missile Defense Command, Huntsville, Alabama, launched a sub-orbital missile flight from White Sands Missile Range on 29 January 1997. Designated Missile Technology Demonstration-2 (MTD-2), it was the second flight of its kind with the principle objective of demonstrating Global Positioning System (GPS) and Differential GPS (DGPS) technology in an application to range safety and tracking. The MTD-1, successfully flown on 16 August 1996, was the first. MTD-2 was composed of a SR-19 booster and the Maneuvering Tactical Target Vehicle (MTTV) which is based on the Pershing II maneuvering reentry vehicle. In addition to the GPS/Inertial Navigation System (INS) and DGPS/Inertial Measurement Unit (IMU) systems, both MTD-1 and MTD-2 flew an experiment package consisting of an earth penetrator instrumented with accelerometer packages. The MTD-2 went unstable when the first bending mode of the flight vehicle was excited at approximately six seconds into the flight. The instability resulted from the control system going into a limit cycle while trying to control the unstable mode. This resulted in the thrust vector control actuator hydraulic fluid being prematurely expended 26 seconds into the flight. The trajectory was nominal up until that time, afterwards the vehicle began to tumble and the vehicle was destroyed by Range Safety at 62 seconds. In this paper the MTD-2 vehicle configuration, the GPS/INS experiments and DGPS/IMU guidance systems, and the penetrator/accelerometer experiments are described. The contributing factors leading to flight termination of the MTD-2 vehicle are discussed with emphasis placed on lessons learned and applied. GPS data were transmitted from the MTD-2 vehicle throughout the entire flight resulting in a very accurate record of the trajectory up until the time of flight termination. This paper contains a summary of the GPS experiment results and their potential future application to range safety and tracking, which may ultimately reduce US dependence on costly range instrumentation while improving flight safety systems.

Lunar missions were simulated to evaluate the trajectory of sending a satellite into a polar, lunar orbit using a commercial off-the-shelf (COTS) software package. Satellite Tool Kit (STK) was used for modeling and visualization purposes. The results of this simulation were that a launch, parking orbit, and transfer orbit were successfully calculated and modeled. However, the STK version used was designed only for Earth orbiting missions. Therefore, a final lunar, polar orbit could not be modeled. The calculations necessary to design and model a lunar mission are attainable. STK in the absence of an interplanetary module, however productive in Earth orbital analysis and visualization, is not the best tool for lunar mission design and analysis.

The following discussion outlines a few of the various applications possible utilizing Augmented Reality (AR) and Virtual Reality (VR) technology in the aerospace industry. Not only will applications be identified within payload processing, but also some additional applications unique to AR technology. Any technologies in their infancy have technical challenges, and these are no exception. A brief discussion of these challenges will be beneficial in accurately describing their current development status. This discussion is motivated by actual research initiatives that have begun at the Kennedy Space Center within the Payload Customer Outreach Office. It is intended to be an introduction to these emerging technologies, but an attempt will be made to be rigorous without having rigor mortise. Although the process is still in it's infancy, the technologies show great promise.

A permanent lunar base will require an operating agricultural facility that provides food and a recycling capability. That agricultural facility, regardless of its structural properties, will need to be supplied with plant material to maintain its operations. Additional plant material will be needed for base air cleaning and out gas control. Methods by which these plant materials are supplied are addressed. Additionally, the specific requirements for and inherent problems in each method are discussed.

The awareness of special comets and asteroids called Near Earth Objects (NEO's) has been growing. What is the possibility of intercepting, capturing and placing such objects into low earth orbit, and subsequently using them as sources of energy, materials, and water for orbiting platforms? To this end we evaluated the ability of a neural network to accurately learn the dynamics of these objects, and from this data, adjust firing sequences and intensities to efficiently capture NEO's. We simulated the dynamics of NEO's using energy models, and caused neural networks to learn these dynamics. This would lead to a control strategy that possibly applies firing bursts to drop an NEO from sun orbit into low earth orbit. Conceptually, the neural network will control apparatus that would be set up on an NEO passing by, and the firing sequence initiated on the next pass, perhaps one to several years later. The neural network would learn the NEO's dynamics, and fine tune itself by sensing the response to each firing burst. The main objective was to determine how best to train the neural network by developing training-sample-size criteria. Our procedure was to develop an equation for the minimum training-sample-size, then train the neural network on this set, and finally, test the neural network's ability to predict future NEO trajectories. For the assumed conditions of our test problem, the results were that less than 700 observations of NEO trajectory were necessary to train the neural network. This network then predicted the next 2000 trajectory observations with only gradual loss in accuracy. By comparison, using the same training criteria on linear state variable models gave equal or better results in our tests on industrial mineral processing circuits. Thus we concluded that, in general, the non-linear nature of neural networks was not as important as our stringent training criteria.

SpaceDev is a publicly traded (trading symbol: SPDV) corporation engaged in the commercialization of routine space exploration utilizing existing technologies. SpaceDev intends to design, construct and test an unmanned spacecraft (the Near Earth Asteroid Prospector or NEAP), fly NEAP and its commercial payload of science instruments to a targeted near earth asteroid residing beyond earth's orbit, and successfully land one or more scientific instruments on the asteroid, and communicate the scientific data to earth. Once it achieves its goal of asteroid rendezvous and valuable data collection, SpaceDev believes it will be positioned to become the premier provider of high quality and low cost space-related consulting, design, planning and support services and products.

This paper reviews current state-of-the-art drilling technology practiced today in the mining, petroleum, water, and other drilling industries. The typical performance and operational issues are discussed. In addition, parameters controlling the drilling efficiency are outlined. There are several combinations of drilling available today. These equipment and methodologies are based on extensive practical experience with drilling projects and the daily challenges in all areas of drilling. Drilling in an extraterrestrial environment, such as the Moon or Mars, requires the evaluation of the applicability of current drilling techniques and their practicality for this environment. Equipment shipment cost, mass and volume, available energy and machine power, cleaning medium, and performance under vacuum and intense temperatures are factors to be considered. This paper evaluates the principal drilling techniques and how they might be adapted to be suitable for utilization in space exploration.

The European Space Agency (ESA) has studied the performance of future space-based optical interferometers. Included was an analysis of a candidate design of a lunar surface instrument with a 5-km separation between the indivdual telescopes. The report predicted that observations on the Moon would be impeded by an incessant rain of micrometorites which would disrupt interferograms approximately every 7 seconds via seismic disturbances. Examination of 8 years of data from the Apollo seismic stations shows that a disruptive seismic event from a meteorite striking the Moon should occur no more than once a year at any given site.

Three types of lunar soil simulant were experimentally produced from volcanic rocks mined in Japan in order to provide useful environments for various function tests. First, a basic simulant was made from lava basalt, and later, advanced simulants were produced by blending crushed ilmenite and/or olivine with the basic simulant. Fundamental properties of the simulants including chemical composition, density, particle size distribution, and shear strength were measured and compared with those of actual lunar soil and other lunar soil simulants. In addition to these tests, thermal and electrostatic properties of the basic simulant were evaluated. On the basis of the test results, it was concluded that the major chemical composition and physical properties of lunar soil could be simulated to some extent by blending several terrestrial minerals.

We have developed a simulant for the oxidized soil of Mars to support scientific research, engineering studies and education. JSC Mars-1 is the <1 mm size fraction of altered volcanic ash from a Hawaiian cinder cone. The simulant closely matches the reflectance spectrum and approximates the mineralogy, chemical composition, grain size, density, porosity and magnetic properties of Martian soil. JSC Mars-1 is currently available to qualified investigators and educators.

The cost of having human operators on the moon is seen to be prohibitive to the commercialization of lunar resources. Teleoperation is commonly used in the remote control of terrestrial mining equipment. Teleoperating mining equipment on the Moon from the Earth is attractive but involves a transmission loop time delay of 4 to 10 seconds. A human operator can handle time delays of about 1 second in simple teleoperation applications. By increasing the autonomy of the remote vehicle it may be possible to extend the acceptable telecontrol time delay to the required 10 seconds without drastically reducing the performance of the remote equipment. A project team has been put together at the University of Saskatchewan to investigate Long Delay Teleoperation for Applications in Mining. The project is studying the use of approximate reasoning using Fuzzy, Neural, and Genetic algorithms to extend the acceptable time delay for automated mining equipment to 10 seconds. This project is being funded by NSERC, the Canadian Space Agency, and a mining equipment manufacturer, Prairie Machine and Parts (Equipment Division).

In order to provide a simple and cost effective power supply for lunar base construction and operation, an orbital satellite approach for the power generation source is proposed. The power system would be solar (photovoltaic) or perhaps, initially, nuclear. The power would be transmitted from the satellite by microwave beaming to a simple lunar receiving system: wire mesh. Deployment of such a concept will enhance the prospects of robust and timely lunar base development.

Recent experiments by the investigators have shown that practically sized helical anchors can provide significant resistance to uplift forces in the lunar simulant JSC-1. Properly scaled to account for differences in the gravity fields between the benchtop environment on Earth and the lunar surface, these experiments provide valuable insight into the likely behavior of anchors in uplift on the Moon. Preliminary results of these uplift experiments are presented and discussed. Further, installation torque was monitored during the installation of these augered-anchors, and these torque data appear to correlate with the soil strength, providing a consistent indication of soil strength with depth. Properly calibrated, these anchors might serve a dual purpose on a surface rover, providing stability during difficult maneuvers and simultaneously providing valuable information on the nature of the subsurface soils. These issues are discussed.

Dust adhesion is a function of the thickness of gas adsorbed to dust particle surfaces. Surface cleanliness is a dimensionless parameter related to the inverse of adsorbed gas thickness. A model is presented to determine surface cleanliness and its effect on dust adhesion. The model is used to predict dust adhesion to aluminum, titanium, glass, rock, and nylon on the Moon, Mars, Mercury, Venus, and Earth. Adhesion determinations compare well with previous laboratory measurements. Methods of dust mitigation based on reducing surface cleanliness are discussed.

Means for sub-surface investigations are of great interest for the exploration of planetary bodies such as the Moon, Mars and comets, in the future scenarios intending to send probes to their surfaces. To this aim, in-depth penetration may be performed either by drilling or by self-propelled devices. To reach a depth of several meters in loose to hard compact soil, self-propulsion has a great advantage of simplicity over drilling, as it does not require the complex autonomous assembly of several drill sections. The mobile penetrometer presented here is an original device of this category. As payload, this exploration device may carry various sensors, for instance, thermal, seismic, optical, or a camera lens. It may be implemented with in-situ analysis devices, or be used to take and retrieve samples at various depths. The current prototype has a diameter of 1.9 cm, length 32.5 cm, a mass 0.4 kg, and an average power consumption of 2 W (max. 5 W). Further size and mass reduction to diameter 1.3 cm, length 25 cm and 0.25 kg are feasible. An approximately equivalent mass is estimated for the penetrometer support and release system, which supports the penetrometer at the start of penetration. The principle of this mobile penetrometer has been invented and patented by the Russian Mobile Vehicle Engineering Institute (VNIITRANSMASH) in St. Petersburg, which has already built a large size functional prototype. They developed its miniaturisation and spatialisation for the requirements of cometary, Moon and Mars environment in the frame of an European Space Agency (ESA) study led by Tecnospazio, in which DLR is responsible for testing.

Robotic missions to Mars are listed and some results of each past mission are noted. What is known of the Mars environment is discussed. Mars surface features are outlined. The likely engineering properties of soils on the Martian surface are postulated based on expected soil forming mechanisms and the thermal environment found on Mars. Key questions to be answered are the effects of water, water ice, and carbon dioxide on soil behavior. Areas for future investigation and research are suggested.

A suitable simulant of solar wind helium implanted into lunar ilmenite (FeTiO₃) is required by the current study of the diffusivity and activation energy of helium in high titanium lunar regoliths. Terrestrial analogs of lunar ilmenite have been analyzed using electron microprobe analysis and were selected according to hematite and geikielite content. Sample surfaces were prepared by argon sputter cleaning using Plasma Source Ion Implantation (PSII), and helium was immediately implanted at 4–5 KeV using PSII. Isochronal annealing of the samples revealed helium evolution with temperature similar to the helium release of the Apollo 11 regoliths.

NASA's Human Exploration and Development of Space (HEDS) Enterprise is defining architectures and requirements for human exploration that radically reduce the costs of such missions through the use of advanced technologies, commercial partnerships and innovative systems strategies. In addition, the HEDS Enterprise is collaborating with the Space Science Enterprise to acquire needed early knowledge about Mars and to demonstrate critical technologies via robotic missions. This paper provides an overview of the technological challenges facing NASA as it prepares for human exploration. Emphasis is placed on identifying the key technologies including those which will provide the most return in terms of reducing total mission cost and/or reducing potential risk to the mission crew. Top-level requirements are provided for those critical enabling technology options currently under consideration.

In the 1960's, the Surveyor program was undertaken to collect data and test technologies which would pave the way for humans to set foot on the moon. As NASA contemplates a human mission to Mars, the Mars Surveyor program will similarly lead the way for human explorers. Beginning with missions set to fly in 2001, NASA's lead center for human exploration, JSC, and its lead center for robotic exploration, JPL, will join forces to begin acquiring the data and demonstrating the technologies required to send humans to the red planet in the second decade of the new millennium. The 2001 Surveyor Orbiter will test the technique of aerobraking to capture into Martian orbit, and will carry an instrument to measure the radiation environment in Martian orbit. The 2001 Lander will likewise carry a radiation monitor which will document the radiation environment at the surface. The combination of the two instruments will provide scientists and engineers with data about the radiation shielding capabilities of Mars atmosphere. The lander will also carry an instrument to measure characteristics of the Martian soil and dust such as particle size and shape, toxicity, reactivity, and elements harmful to humans. It will also demonstrate two technologies critical to future human missions: precision landing and in-situ resource utilization (ISRU). Precision landing will be accomplished by altering the Surveyor entry vehicle to provide lift and control. By flying a controlled entry rather than the ballistic entry of all previous Mars missions, the size of the landing footprint will be greatly reduced. ISRU is a technology critical to reducing the cost of human exploration, and the ISRU demonstration will test the components of a propellant production system which come in contact with the Martian environment in addition to producing small quantities of oxygen from the Martian atmosphere. Future robotic missions will continue to respond to the need for data sets and technology demonstrations needed to reduce the cost and risk of eventual human missions to Mars. Planning teams are currently considering high bandwidth communications, biconic entry vehicles, and a full end-to-end demonstration of an ISRU propellant production system with an accompanying propulsion demonstration for the 2003 Mars Surveyor mission. The 2005 mission will be dedicated to returning selected Martian samples to Earth where they can be studied in great detail.

During 1992 – 1994 work was done by personnel representing several NASA field centers to formulate a mission scenario that addresses human exploration of Mars. This scenario describes an approach for the first human missions to Mars, utilizing systems and operations that are technically feasible, have reasonable risks, and have relatively low costs. It was understood that this scenario could be improved through refinement of the analyses initially performed and by introducing new technology as that technology matured. Various analyses and trade studies have been underway at many NASA field centers since work on the initial version of the mission scenario was completed This paper briefly recaps the piloted Mars mission as originally developed to set the stage for a description of some of the work recently completed. Two topics will be highlighted; first, an aerocapture analysis illustrates the refinement of some of the initial analyses for the mission scenario; and second, an alternative technology, low thrust propulsion to perform part of the Earth departure maneuver, that appears to equal, if not improve, the overall performance of the mission architecture.

Anorthite rocks found in Hokkaido, Japan have chemical compositions similar to those of lunar anorthite rocks brought back from Highland regions of the Moon. Because of the compositional similarity, Hokkaido anorthite was used in this laboratory study in which simulated lunar cement was made through a high temperature sintering process, rapid quenching, and proper grinding. The needed mortar was prepared by mixing one part of the obtained lunar cement (or Portland cement for reference cubes) and two parts of river sand that met the JIS requirements. The Dry-Mix/Steam-Injection (DMSI) method that was developed solely for the future lunar construction and the conventional wet-mix procedure that was intended to make reference cubes were applied to make series of 40 mm mortar cubes. All test cubes including the wet-mix ones after 28-day curing in a moist room were subjected to compression tests at 1(DMSI), 3(wet-mix), 7, 28, and 180 days(only OPC-DMSI) of moist curing. Measured compressive strengths for wet-mix cubes made with simulated lunar cement were relatively low, only 5.8 N/mm², and those of DMSI cubes were remarkably high, 24.3 N/mm², after 180 days of air curing. Samples of tested cubes at 0, 20, 60, 270, and 330 days of vacuum exposure of 10^–4 torr were tested to determine pore-size distributions and incremental pore as well as cumulative pore-volumes at selected vacuum exposure ages. It concluded that the DMSI cubes showed no imminent pore-size changes but the wet-mix cubes had surprising variations. This paper presents quantitative data on effect of vacuum on simulated lunar cement mortar. This preliminary study program produced useful information that signifies the applicability of concrete to future lunar construction. Nonetheless, a one-year time frame is too short for a vacuum related durability study. We hope to carry out a more comprehensive test program with a minimum of 3-year time frame for the follow-up study.

In recent years there has been interest in conducting research on the use of concrete as a building material for extraterrestrial applications. The potential availability of concrete-making materials at remote locations like the moon also make concrete a practical choice from an economic point of view. This paper contains a review of some basic chemical admixture technology used to enhance performance of concrete made on earth today. Chemical admixture technology that is used to extend or accelerate setting characteristics, entrain air, reduce water content, increase cohesiveness and compressive strength, improve durability or provide secondary reinforcement of concrete will be presented. It is the potential adaptation of chemical admixture technologies to extraterrestrial concrete construction that may enhance the ease with which concrete could be used in these remote locations. The paper will provide examples of hypothetical concrete construction applications where chemical admixture technology may provide a benefit to extraterrestrial concrete construction. This paper assumes that portland cement and water will be the binder of the aggregate materials used in making concrete.

The development of permanent lunar bases is constrained by the performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. Cement would eventually have to be manufactured in situ through high-temperature processing of the lunar regolith. A possible alternative is to replace the binding mix of concrete (cement and water) with sulfur, the most abundant volatile on the lunar surface. Sulfur can be extracted from lunar soils by heating, demanding only moderate temperatures; it is also a by-product of oxygen extraction reactions. The economic viability and properties of sulfur-based concrete make it a suitable material for the first lunar construction activities, with a wide range of applications. The possible use of sulfur concrete imposes new constraints to the first base site selection.

The constituents of inorganic materials available on the Moon and Mars are similar to those on Earth. Calcium oxide concentrations, the primary factor for the production of portland cement, of these materials are substantially less than that of companion terrestrial materials. However, cementitious materials with desirable hydraulic characteristics can be produced with raw materials having a calcium oxide content of approximately 10% by weight. How lunar and Martian soils could be used to manufacture cement under extraterrestrial conditions is the subject of this paper.

A steady-state model for first order of magnitude estimates of lunar base masses is presented. The main focus of the model is upon the derivation of initial and annual resupply mass estimates for a lunar base at certain development stages. These estimates are a function of several thousand input parameters and boundary conditions such as crew size, lunar base location, and environmental conditions, but also specific system masses, specific power requirements, and specific thermal loads. This integrated lunar base model indicates which systems and subsystems have the greatest mass impact on the overall base. Also, brief overviews of possible activties at a lunar base and of lunar development strategies are given.

We have characterized the Aristarchus Plateau (24°N 52°W) as a potential landing site for an in-situ resource utilization (ISRU) demonstration. Recent advance planning for a human return to the Moon indicates that large cost savings can result from using locally produced oxygen, and recent JSC laboratory results indicate that iron-rich pyroclastic dark mantling deposits may be the richest oxygen resource on the Moon. The geologic diversity and large volume of Fe-rich pyroclastic material present at the Aristarchus site make it an ideal target for extracting O₂, H₂ and halogens. This paper describes (1) the current understanding of the geology of Aristarchus plateau, (2) the resource potential of the Aristarchus plateau, and (3) presents two candidate landing sites on the plateau for future lunar activities.

It is effective to cover a lunar base module with 2 to 3 meters thickness of regolith for shielding from hazards. In this paper, a simple means of providing a shield wall in an early phase of lunar base construction is proposed. A deployable folding jacket, consisting of metal or fiber reinforced sheet, is to be pre-installed on the habitation module. The jacket is to be developed after positioning the module on Moon from Earth. After the module is delivered to the lunar surface, the jacket is deployed. The deployed jacket is larger than the module by 2 to 3 meters. After the jacket is deployed, the space between the module and the jacket is filled with regolith by dozer and conveyor to provide required shielding.

The utilization of extraterrestrial resources will become a key element in space exploration and colonization of the Moon and Mars in the 21st century. Indeed, the development and operation of in-situ manufacturing plants are required to enable the establishment of permanent lunar and Martian bases and colonies. Oxygen manufacture for life support and propulsion will be the most important process for the first of these plants. This will be followed by the development of add-on facilities for the manufacture of additional products and materials using the byproducts of lunar oxygen production, e.g., iron, silicon and slag, followed by the development of permanent lunar bases and colonies for commercial development on the Moon and from the Moon for the benefit of space science, exploration and utilization and, most importantly, Earth and humankind. Commercial development on the Moon is discussed, e.g., (1) the potential value of the manufacture of oxygen and silane to support lunar-based transportation systems for exploration and colonization of the near and far sides of the Moon, (2) the manufacture of iron, ferrosilicon, and ceramic products to support the construction of advanced lunar bases and colonies, and (3) the manufacture of high purity silicon wafers to support solar electric power generation.

While interest in space certainly continues, public financial support for our Federal civil space program continues to erode. In response to this public judgment, its leaders should see two most fundamental space activities commence soon: (a) space should begin to be opened up to the general public by our private sector, and (b) the government should commence further human exploration and initial settlement of the Moon and Mars. A novel "Economic-Political Compact" is suggested by which the inherent interests of the latter would prompt the former, and some of the taxes generated by general public space travel and tourism businesses would pay for the latter. This "Compact" would modernize the basic incentive structure of our civil space program's human space flight activities; set NASA out upon its most basic long-term mission; revitalize its general public constituency; and further our Country's space-related economic growth.

This paper reviews some of the literature which has been developed during the last century on the topic of space resource utilization. The sources cited in this summary include books, articles, technical publications, conference and workshop proceedings, and NASA-sponsored studies on the topics ranging from mining, processing and chemical separation of lunar and asteroidal resources to construction, human habitation and space-based industry using the in-situ resources of space.

In response to U.S. President Bill Clinton's request to the public to propose innovative ideas to usher in the new millennium, a concept architecture employing civil space activities is proposed in this paper. Any new project aspiring to celebrate the new millennium should have significant symbolic and metaphorical content for all of humanity. It must appeal to all segments of society. The project should be economically viable without jeopardizing other programs, and executable in two years with minimum investment in research and technology. Finally, it should bring the peoples of the world together in celebrating the true the spirit of humanity, and the United States should play a leadership role in creating it. A Lunar Humanity Repository would exemplify all of those project qualifications. The idea behind the Lunar Humanity Repository is to encode the collective knowledge of the cultures of the world into an extensive electronic database that would then be placed safely and securely on the moon. This system could then be remotely accessed by people on Earth, and periodically updated like an evolutionary, celestial time capsule. The confluence of several technologies that has occurred in the past decade including the emergence of the World Wide Web and interactive multimedia technologies are crucial to supporting this project. To conclude, a project start date should be established for January 1998, which would give us two years to build and launch the facility to the moon atop an existing heavy-lift launcher. For less than a billion in 1998 dollars, we can have a unique, evolutionary, interactive multimedia facility for those who wish to access, interpret and cherish the evolution of our species, the history of our civilizations, our rich and diverse cultural heritage, and life on Earth for generations to come.

Several commercial launch facilities are in development in the United States. U.S. federal government space policy appears to have had little influence on this development. Is the federal government performing the correct role within the space launch enterprise; should its role be larger, smaller, or different? A larger role would be to implement a government technology policy aimed at strengthening selected U.S. firms' ability to compete in world markets. A smaller role would be to leave the enterprise uninfluenced and unregulated. The federal government has had limited success in encouraging commercial firms to use federally owned launch facilities, in part because they have not been constructed as infrastructure, and are therefore relatively inflexible and inefficient. What specific actions should the federal government take to make the total launch enterprise more efficient?

Space enthusiasts have branded the Moon Treaty, 1979, as the archenemy of space development. However, that treaty calls for a new regime of agreements to take effect if and when lunar exploration and exploitation is deemed to be ready. The regime intended may have been another set of UN treaties, but that is not necessary. Instead, nations may enact pattern legislation that puts entities with municipal development agendas into place, ones that defer to civil engineering standards for space rather than social engineering politics for the UN. Such authorities may be the new regime required by the Moon Treaty of 1979. There is nothing in the document itself that delimits the concept of regime to UN auspices. This paper will describe the relevant entities (like the Lunar Economic Development Authority, LEDA), compare treaty burden compliance aspects, and explain how the Moon Agreement of 1979 may actually assist in a legal and space policy manner, in the creation of a new regime, without disrupting the space development agenda. LEDA will accede to the 1979 Moon Treaty and organize development of the lunar venue under its favorable terms: nations could participate without ratifying the Moon Treaty itself.

In a companion paper the observation is made that the public's financial support of our Federal civil space program has been eroding throughout this decade, and that this erosion is expected to continue for the foreseeable future. The reason for this waning support is that the things that our civil space leaders choose to do are simply not found to be important enough by our general public compared to other Federal activities in such areas as crime prevention, education improvement, health service delivery, pollution control. There is something missing in the civil space program of the world's greatest democracy — it is not open to personal participation therein by our general public. One way, perhaps the most direct and comprehensive way, is to see our private sector provide space travel and tourism trips to the general public. Today's space travel and tourism prospects are outlined and recommendations made to business and government leaders.

The United States has the technological capability to establish a robust space transportation, habitation and logistical support infrastructure in the first decade of the new century. This infrastructure will benefit all three sectors of the U.S. space program—commercial, civil and national defense—by providing shared capabilities that will improve the safety, reliability and affordability of all three sectors' primary space operations. This paper proposes specific technical approaches for establishing such an integrated infrastructure. The proposed infrastructure includes: reusable launch vehicles (RLV) for "airline-like" access to low Earth orbit (LEO); large spaceports in LEO capable of providing safe habitation for 100–150 people; and an integrated network of logistical support capabilities utilizing these RLVs and spaceports. The need for integrated planning to define and develop this common infrastructure is discussed.

With the passing of the cold war, highly potent military assets belonging to the super powers are being dismantled and destroyed. This concept architecture paper addresses an alternative potential use for surplus super power nuclear arsenals for humanitarian purposes. An idea to exploit this valuable asset for preserving humanity against an extraterrestrial threat such as a rogue asteroid is explored.

As the policies and posturing among traditional rivals shift in the aftermath of the cold war era, unusual uses of military assets become possible. In this concept architecture paper, the use of nuclear submarines for conducting a Mars mission simulation is portrayed. Merits and economic advantages are described.

This project depicts an evolving vision of an Earth orbital facility that would gradually build up our capability to repair and service satellites in distress. Starting with orbital debris mitigation operations and missions like placing spacecraft in their intended orbits, station relocation and plane change operations or safely decommissioning aging and useless stations in orbit, the proposed orbital infrastructure will grow to be able to handle tasks like the specific replacement of malfunctioning or degraded subsystems aboard sub-optimally operating satellites in order to enhance their performance and life expectancy as well as evolve their capability, using a modular strategy. Preliminary studies are presented as to the nature of the projected Earth orbital environment by the turn of the century and expected mission opportunities for this architecture are explored. Alternative concepts for satellite repair facility configurations are depicted and related issues regarding the maintenance and evolution of such an infrastructure are discussed. Potential projects stemming from this open-ended architecture are also portrayed.

The closely interconnected domains of space exploration and resources exploitation have been of interest to the European Space Agency (ESA) over the last few years. This paper summarises our recent work and our current planning and thinking on these subjects, ranging from the planned exploration missions to the identification of potential future European contributions in an international scenario, and of European interests in the long term.

The PERMANENT World Wide Web curatorial site at http://www.permanent.com focuses specifically on space industrialization using asteroidal and lunar materials. A recent addition to the site is a conference mail system which will bridge the gap between in-person conferences, and make the latter more productive. The conference mail system is a WWW messageboard gatewayed to an e-mail mailing list, thus providing users their choice of medium, and a user-friendly on-line archive. This paper briefly covers the purpose, content and structure of the PERMANENT WWW site, and expands upon the conference mail system which is useful for jointly further developing the web site and our common interests. The site offers many potential benefits to those in R&D, managers, investors and producers of public relations materials.

This paper outlines a proposal for the development of a space business infrastructure at the lunar venue. It includes a description of principals and activities for a rising tide of space business infrastructure development at the lunar venue in particular and the solar system in general.

One of the uses that has been proposed for fully reusable launch vehicles is "space tourism", the making of short visits to low Earth orbit by fare-paying passengers. This seems to offer the potential to generate a large commercial market, of the order of tens of launches per day, which could amortize the development cost of a new generation of reusable launch vehicles. Recently there has been a considerable increase in research concerning this possibility, with an international symposium being held in Bremen, Germany in March 1997, a session being held on the subject for the first time at the 1997 IAF Congress, the Space Transportation Association in Washington DC publishing a report on it in collaboration with NASA, and the AIAA holding a workshop on the subject in January 1998, among other activities. Once businesses start to offer travel services to low Earth orbit, it is expected that orbiting "hotels" will be developed to enable guests to enjoy a variety of entertainments in Earth orbit. One feature of such hotels will be sports centers providing guests the opportunity to enjoy moving about freely in weightlessness, or "zero gravity". This paper considers one possible facility in such a sports center, namely a rotating, artificial-gravity swimming pool.

The potential market for liquid oxygen produced at the lunar surface for use by passenger launch vehicles and accommodation facilities in low Earth orbit (LEO) is estimated. It is concluded that oxygen may be the first major commercial lunar export, and so low Earth orbit tourism is potentially very important for lunar development.

Many in the space community who advocate the human exploration and colonization of the solar system regard these activities as the destiny of the human race. This essay will examine the origins and highlight the evolution of this belief. The notions of destiny and inevitability, as proclaimed by the exploration advocates, are juxtaposed with the concepts of self-determination and freedom resulting from human rationality as proposed by the philosopher Immanuel Kant. It is demonstrated that the assertions of the exploration advocates exhibit a fundamentalism based on an assumption — that is, an article of faith that is not shared by the political and social communities that must support the exploration advocates if successful human space exploration policies, as they are now defined, are to be established. As an alternative to the concept of destiny, it is proposed that the nature of our explorations may have to change to accommodate the human exploration of the solar system.

The way in which political actors interact to coordinate international cooperative political outcomes in space exploration and development of space is systematically assessed by applying policy models of international cooperation. This assessment is accomplished through an analysis of cooperative case studies from 1957 to 1997. The results of this study indicate that international cooperation is sensitive to the type of political actors involved and the values those actors place on power, interests, policy preferences and knowledge decision-making dynamics. Application of the policy models and policy recommendations to enhance cooperative decision-making processes in space exploration and development of space are presented and discussed.

An Internet-based Space Solar Power Workshop (SSPW) is offered in association with the Space 98 & Robotics 98 conference. This is a conceptual collaboration on how to design, build, finance, market, support, operate and maintain a fleet of SPS's and their assembly line, including a small support crew of colonists on the moon, according to many designers. The workshop creates proposals to deliver 300,000 Mwe to the world electric power market by 2020. Financial and engineering experience-rated evaluations of each proposal are organic to the workshop.

It is generally accepted that continued large-scale exploration and development of the Moon would depend more on the private sector than on governments. There are two reasons for this. The first is that governments do not have excess funds. Instead, cutting budgets and downsizing are the primary concerns. The second and more important reason is that there is little public support for Space in general. While most people, including even a few elected officials, understand the importance of national efforts in Space, national spans of attention tend to be short. Therefore, since Space requires a long time frame, it cannot retain the attention of citizen or government, and it has a difficult time attracting investor financing. A new paradigm is needed for the further development of Space, in general, and the Moon, in particular. In particular, it is necessary to deconstruct such a long-term project into independently financeable units that have dual use potential. This essay proposes such a framework in general terms. This approach has not been suggested elsewhere.

The International Space Station (ISS) is the largest cooperative scientific program in history. The program depends on the collective scientific expertise from fifteen nations: The United States-NASA, Japan-NASDA, Russia, Canada-CSA, and eleven European countries-ESA. Once the ISS is operating in orbit, the crew will conduct experiments from the fields of biotechnology and gravitational biology to combustion and fluid physics. These experiments could lead to advancements that will improve many aspects of our lives ranging from materials formulation to manufacturing processes to pollution control to new medical treatments.

The magnetoplasmadynamic (MPD) thruster is a high specific impulse (I_sp) and thrust electric propulsion concept which is used on some satellites for station keeping and orbit transfer. In this paper, I investigate a super MPD thruster that has substantially greater I_sp than conventional thrusters, and so may be a part of a viable propulsion system for deep space exploration These super MPD thrusters are driven by much larger electrical currents than usual. Using the MACH2 computer code, I perform a series of numerical experiments to investigate the acceleration of argon from the sound speed at the inflow point to an average exhaust velocity of up to 600 times the sound speed with four different nozzle designs. I conclude that a straight nozzle performs poorly, but nozzles of 30° and 45° generate an I_sp of up to 2 x 10⁴s. A 60° nozzle also produces large I_sp, but at such a severe angle, the flow begins to separate from the nozzle wall, and this nozzle may be too large for some applications.

This paper explains recent findings on man-made debris in space, including several examples of damage known to be caused by debris, such as the damage to the Hubble Space Telescope and the loss of the Tethered Satellite System. The paper summarizes the main causes of debris and what can be done about them. It outlines what various space agencies have done to minimize the problem, as well as what is planned for the future to protect our Outer Space interests from harm. The National Aeronautic and Space Administration (NASA)'s Long Duration Exposure Facility (LDEF) sustained over 32,000 impacts during the six years it was in space, showing that there was much more debris up there than previously thought. Detailed cataloguing revealed that over half of the damage was from man-made objects. The United Nations (UN) and The International Telecommunications Satellite Organization (INTELSAT), as well as many countries, maintain registries of objects launched into space, and have guidelines for their disposal. NASA's statistical analysis showed that the part of the shuttle most vulnerable to damage from debris was not the windows, as thought, but the two freon-filled radiator loops. If they were disabled, the shuttle would be forced to land within a day. NASA's Space Surveillance Network (SSN) can only reliably track objects at least 10 cm. across, but most damage is from debris much smaller than that. Most space debris appears to be the remains of explosions caused by stored propellants and pressurants or because of open electrical circuits and batteries. It has been shown that shutting down all power systems, discharging all batteries, and insulating all pyrotechnics can prevent explosions from occurring. All components of the spacecraft should be tethered to it or contained in some way. Another solution is to send spacecraft into orbits further away from Earth.

This paper is a summary of the advantages and disadvantages of the Strategic Defense Initiative (SDI), or "STAR WARS". It explains the methods proposed by the SDI, the advantages, which include accuracy, response time, and cost, and the problems with this type of defense. This paper includes recommendations on a course of action for the United States. This paper was written by a Chemistry student at Eldorado High School for the high school session sponsored by the American Society of Civil Engineers in Albuquerque, New Mexico.

Mars, the fourth planet from the sun, has already been explored quite extensively. There have been seven missions to Mars since 1964. There are many incentives for humans to continue to explore Mars. The purpose of this paper is to provide a rationale for Mars exploration. Benefits of Mars exploration include development of new technologies, mining resources on Mars, improved understanding of the history and processes of earth, possible human colonization, international cooperation, and above all, the challenge of exploration. The main factors inhibiting exploration of Mars include the great monetary cost, danger to the explorers, and distraction from Earth's problems. However, comparing the cost of Mars exploration with other expenditures such as the costs of maintaining a modern military may make Mars exploration appear more realistic. Upon analysis, the benefits of Mars exploration appear to greatly outweigh the costs.

Osteoporosis is a disease characterized by loss of bone tissue mass, which affects a large portion of the American public. Astronauts in space for a long duration also experience an accelerated form of this disease. Space station research focuses on finding methods of preventing bone demineralization on space flights as well as finding treatments for those affected by osteoporosis.

This paper discusses the benefits of the Pioneer, Voyager, and Galileo reconnaissance missions to Jupiter. It includes basic information on Jupiter, background information on each of the missions, spacecraft information, and what each mission has discovered. It supports the exploration of Jupiter and explains why Jupiter should be explored. This paper is written by a student for the 6^th International Conference and Exposition on Engineering, Construction, and Operations in Space.

An environment without gravity or with unusual concentrations of oxygen has detrimental effects on blood. Blood plasma volume, red blood cell mass, and total blood volume decrease in outer space. Hypotheses have been formed to explain these decreases. The reasons for the decreases are not entirely understood and should be further studied as space exploration continues. Possible solutions have also been proposed and should be tested and used in the future.

The United States government and NASA should continue to support the Russian space station Mir. In spite of the many problems, the United States pays 100 million dollars a year to use the Mir space station. Sending money and astronauts to Mir is necessary to further the joint space work with other countries. Members of the Mir crew conduct critical experiments and make key observations of the Earth. In 1998 many countries will begin work on an international space station whose primary goal is to create and produce a long term, completely functional space station. Astronauts from the United States who have been to Mir gain experience that will be useful for the organization of the international space station. It is imperative that the United States be involved with other countries in the future exploration of space.