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At least 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Performance measures from the explorer platform berthing experiment

The Explorer Platform is a Modular Mission Spacecraft: it has several subunits that are designed to be replaced on orbit. The Goddard Space Flight Center Robotics Lab undertook an experiment to evaluate various robotic approaches to replacing one of the units; a large (approximately 1 meter by 1 meter by 0.5 meter) power box. The hardware consists of a Robotics Research Corporation K-1607 (RRC) manipulator mounted on a large gantry robot, a Kraft handcontroller for teleoperation of RRC, a Lightweight Servicing Tool (LST) mounted on the RRC, and an Explorer Platform mockup (EP) with a removable box (MMS) that has fixtures that mate with the LST. Sensors include a wrist wrench sensor on the RRC and Capaciflectors mounted on the LST and the MMS. There are also several cameras, but no machine vision is used. The control system for the RRC is entirely written by Goddard; it consists of Ada code on three Multibus I 386/387 CPU boards doing the real-time robot control, and C on a 386 PC processing Capaciflector data. The gantry is not moved during this experiment. The task is the exchange of the MMS; it is removed and replaced. This involves four basic steps: mating the LST to the MMS, demating the MMS from the EP, mating the MMS to the EP, and demating the LST form the MMS. Each of the mating steps must be preceeded by an alignment to bring the mechanical fixtures within their capture range. Two basic approaches to alignment are explored: teleoperation with the operator viewing thru cameras, and Capaciflector based autonomy. To evaluate the two alignment approaches, several runs were run with each approach and the final pose was recorded. Comparing this to the ideal alignment pose gives accuracy and repeatability data. In addition the wrenches exerted during the mating tasks were recorded; this gives information on how the alignment step affects the mating step. There are also two approaches to mating; teleoperation, and impedance based autonomy. The wrench data taken during mating using these two approaches is used to evaluate them. Section 2 describes the alignment results, section 3 describes the mating results, and finally Section 4 gives some conclusions.

Leake, Stephen↗
NASA NTRS1994

An ethnographic object-oriented analysis of explorer presence in a volcanic terrain environment: Claims and evidence

An ethnographic field study was conducted to investigate the nature of presence in field geology, and to develop specifications for domain-based planetary exploration systems utilizing virtual presence. Two planetary geologists were accompanied on a multi-day geologic field trip that they had arranged for their own scientific purposes, which centered on an investigation of the extraordinary xenolith/nodule deposits in the Kaupulehu lava flow of Hualalai Volcano, on the island of Hawaii. The geologists were observed during the course of their field investigations and interviewed regarding their activities and ideas. Analysis of the interview resulted in the identification of key domain entities and their attributes, relations among the entities, and explorer interactions with the environment. The results support and extend the author's previously reported continuity theory of presence, indicating that presence in field geology is characterized by persistent engagement with objects associated by metonymic relations. The results also provide design specifications for virtual planetary exploration systems, including an integrating structure for disparate data integration. Finally, the results suggest that unobtrusive participant observation coupled with field interviews is an effective research methodology for engineering ethnography.

Mcgreevy, Michael W.↗
NASA NTRS1993

Benefits gained and lessons learned from NASA's Small Explorer (SMEX) Program

NASA's Small Explorer Program (SMEX) is a sustained program of scientific satellites limited in mass to 200-300 kg (depending on orbital inclination) for a 500-km circular orbit. The SMEX program was undertaken to obtain the benefits of scientific yield, short development time, and high flight rate, with the goal to launch a mission every year. NASA also uses the program to train engineers and managers in designing and developing spacecraft. The phases of a SMEX mission life cycle are described including the competitive selection of missions through announcement of opportunity and evaluation of proposals, the definition of mission and system requirements, design and development of the spacecraft, testing, launch, and operations. Program content of some SMEX missions is then reviewed. The first SMEX mission was the Solar, Anomalous, and Magnetospheric Particle Explorer, which confirmed that anomalous cosmic rays are only partially ionized atoms. The Fast Auroral Snapshot Explorer was intended to measure the electric, magnetic, and time-variable fields and to record particle flow in the auroral acceleration region. A future mission is the Submillimeter Wave Astronomy Satellite to examine low-level molecular transitions.

Gilman, David↗
NASA NTRS1993

Baseline antenna design for space exploration initiative

A key element of the future NASA Space Exploration Initiative (SEI) mission is the lunar and Mars telecommunication system. This system will provide voice, image, and data transmission to monitor unmanned missions to conduct experiments, and to provide radiometric data for navigation. In the later half of 1991, a study was conducted on antennas for the Mars Exploration Communication. Six antenna configurations were examined: three reflector and three phased array. The conclusion was that due to wide-angle scan requirement, and multiple simultaneous tracking beams, phased arrays are more suitable. For most part, this report studies phased array antenna designs for two different applications for Space Exploration Initiative. It also studies one design for a tri-reflector type antenna. These antennas will be based on a Mars orbiting satellite.

Chen, Y. L.↗
NASA NTRS1993

NASA's Small Explorer spacecraft - Flight proven, high performance, reliable, and still small

NASA's Small Explorer (SMEX) project has developed a series of highly capable small satellites that are being used to support astrophysics and space physics investigations. These satellites, while both small and economical, give up nothing in performance and versatility to the larger satellites developed over the past 15 years within the Explorer program. Innovative engineering and new technology advances have increased the potential scientific return of the SMEX spacecraft to a level comparable to larger carriers. The design has struck a balance between mission risk and cost that has allowed for the development of an extremely capable spacecraft. The first SMEX mission, Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX), has been in orbit since July 1992 and is continuing to perform well. It has proven the merits of this design approach. This paper describes the fundamental strategies and technologies used in developing the design. It outlines the key elements of the system architecture and describes the capabilities and merits of the major subsystems. Major design trade-offs are highlighted. Emphasis is placed on the innovative attitude control system which was developed for the SAMPEX mission. The paper also describes the unique SMEX approach to mission operations.

Watzin, James G.↗
NASA NTRS1994

Supervised space robots are needed in space exploration

High level systems engineering models were developed to simulate and analyze the types, numbers, and roles of intelligent systems, including supervised autonomous robots, which will be required to support human space exploration. Conventional and intelligent systems were compared for two missions: (1) a 20-year option 5A space exploration; and (2) the First Lunar Outpost (FLO). These studies indicate that use of supervised intelligent systems on planet surfaces will 'enable' human space exploration. The author points out that space robotics can be considered a form of the emerging technology of field robotics and solutions to many space applications will apply to problems relative to operating in Earth-based hazardous environments.

Erickson, Jon D.↗
NASA NTRS1992

Medicine on Mars: Remote medical care and the space exploration initiative

Mars exploration missions as described in the Synthesis Group report will involve extended exposures of crew members to remote, hazardous environments for up to 100 days. Maintenance of crew health and performance will be critical to ensure mission success. Because of the great distances between the Earth and Mars, round trip telecommunication will take from seven to forty minutes and immediate return to Earth will not be feasible: an autonomous medical care system that integrates preventive, occupational, and environmental aspects of health care and provides diagnostic and treatment capabilities will be necessary. Providing medical care for Mars explorers will pose some unique technical and engineering challenges. Medical care equipment will need to be designed to be modular and portable to ensure that it is interchangeable between vehicle and planetary surface elements. Miniaturization will be necessary to reduce mass and volume. Computerized systems that automatically acquire and manage medical information and provide medical references (literature), decision support, and automated medical record keeping will be a crucial part of a Martian medical care system. Medical care will also rely on remote consultation with Earth-based specialists. This presentation will provide an overview of the health and medical concerns associated with Mars exploration missions and will describe some specific concepts for Mars medical care systems.

Simmons, S. C.↗
NASA NTRS1994

Terrain modelling and motion planning for an autonomous exploration rover

To assess the feasibility of planetary exploration missions using rovers, the French national agency CNES, with a consortium of European laboratories and industrial concerns, has initiated the Eureka project, 'Illustration of an Autonomous Robot for the Exploration of Space' (IARES). IARES is a demonstrator composed of a rover and a ground station, linked by telemetry and telecommand. It is aimed at verifying, on earth, robotic concepts developed by the RISP group of French laboratories (LAAS, INRIA, CERT, LETI) to perform scientific missions such as autonomous terrain sample collecting over large areas. To cope with the actual needs of planet exploration, IARES suitability is assessed through constraints on limited bandwidth, time delay and on-board resources. This autonomy relies heavily on robust onboard trajectory generation capabilities. This paper presents the main functions of the IARES navigation sub-system and shows how they are combined to allow movement in Mars-like environments. Section 2 gives an overall description of the IARES system. Section 3 details the functions of the Navigation sub-system, and finally, section 4 illustrates with a simple example the use of these functions.

Richard, F.↗
NASA NTRS1990

[Space Exploration Initiative]

Future Mars exploration missions and operations are discussed using computer animation along with proposed vehicles and equipment, for example, a Mars surface land rover. There is a Presidential Address by President George Bush where he discusses future goals for space exploration. This video also outlines the Outreach Program, which offers the public the chance to suggest new ideas for space research and exploration.

Source record↗
NASA NTRS1994

Future NASA plans for exobiology and solar system exploration

The prominence of exobiology as a part of the NASA program in solar system exploration reached its peak during the Viking missions of the mid-1970's. Even before those missions were finished, the Exobiology Program had been transferred out of the Division responsible for solar system exploration, and many of the direct ties to future missions became more difficult to make, providing a bureaucratic impediment to the conduct of exobiology research in space. Early in 1993, the Exobiology Program was brought back in to the Solar System Exploration Division, as an integral part of NASA's program to study this and other solar systems. As such, the Program stands to gain from an overall broad investment in missions that will study Mars, small bodies such as asteroids and comets, and outer planetary bodies such as Saturn, Titan, and even Pluto. Additional opportunities may be forthcoming on the Moon and elsewhere in Earth-orbit. Ground-based studies will continue to be an important foundation for work in space, while additional effects will be continue to use ground-based astronomical instruments to study other planetary systems, and to search for life on planets around other stars. This paper provides a current planning and budgetary prospectus on the future of Exobiology in NASA.

Rummel, John D.↗
NASA NTRS1995

Exobiological exploration of Mars

Of all the other planets in the solar system, Mars remains the most promising for further elucidating concepts about chemical evolution and the origin of life. Strategies were developed to pursue three exobiological objectives for Mars exploration: determining the abundance and distribution of the biogenic elements and organic compounds, detecting evidence of an ancient biota on Mars, and determining whether indigenous organisms exist anywhere on the planet. The three strategies are quite similar and, in fact, share the same sequence of phases. In the first phase, each requires global reconnaissance and remote sensing by orbiters to select sites of interest for detailed in situ analyses. In the second phase, lander missions are conducted to characterize the chemical and physical properties of the selected sites. The third phase involves conducting 'critical' experiments at sites whose properties make them particularly attractive for exobiology. These critical experiments would include, for example, identification of organics, detection of fossils, and detection of extant life. The fourth phase is the detailed analysis of samples returned from these sites in Earth-based laboratories to confirm and extend previous discoveries. Finally, in the fifth phase, human exploration is needed to establish the geological settings for the earlier findings or to discover and explore sites that are not accessible to robotic spacecraft.

Klein, H. P.↗
NASA NTRS1995

The transition region and coronal explorer (TRACE)

The transition region and coronal explorer (TRACE) NASA small explorer mission and instrument are presented. The TRACE scientific investigation explores the relationships between fine-scale magnetic fields and the associated solar plasma structures. The instrument collects images of solar plasmas at temperatures from 10(exp 4) to 10(exp 7) K with one arcsec spatial resolution. The design specifications of the trace instrument are presented.

Title, Alan↗
NASA NTRS1996

Exploring Mars for Evidence of Past or Present Life: Roles of Robotic and Human Missions

During the coming decade, robotic field science will play a fundamental role in exploring Mars for evidence of past life and/or prebiotic chemistry. To create a context for such exploration, we especially need to understand the mineralogy and chemistry of the Martian surface. We have learned that the preservation of biological signatures in rocks on Earth is favored by rapid mineralization processes that are restricted to a comparatively small number of geological settings. Thus, a detailed knowledge of surface mineralogy will provide valuable clues about past Martian environments as a necessary context for future exobiological exploration.

Farmer, Jack D.↗
NASA NTRS1997

The Polar Exploration of Mars

Apart from the Earth, Mars is the only planet in our Solar System to possess significant and traversable polar caps that could potentially play host to a long term program of human polar exploration. Such explorations may provide valuable information on the structure of the martian poles, both geologically and from the point of view of gaining an increased insight into volatile cycling in the martian atmosphere, past and present. Here some initial considerations are made on the nature and methods for the human exploration of the martian poles and the scientific objectives that might be prioritized for such missions. The first proposed strategies and routes for overland Mars polar expeditions, using the nature of terrestrial polar expedition attempts as a template, are also suggested.

Cockell, C. S.↗
NASA NTRS1997

Shielding Strategies for Human Space Exploration

A group of twenty-nine scientists and engineers convened a 'Workshop on Shielding Strategies for Human Space Exploration' at the Lyndon B. Johnson Space Center in Houston, Texas. The provision of shielding for a Mars mission or a Lunar base from the hazards of space radiations is a critical technology since astronaut radiation safety depends on it and shielding safety factors to control risk uncertainty appear to be great. The purpose of the workshop was to define requirements for the development and evaluation of high performance shield materials and designs and to develop ideas regarding approaches to radiation shielding. The workshop was organized to review the recent experience on shielding strategies gained in studies of the 'Space Exploration Initiative (SEI),' to review the current knowledge base for making shield assessment, to examine a basis for new shielding strategies, and to recommend a strategy for developing the required technologies for a return to the moon or for Mars exploration. The uniqueness of the current workshop arises from the expected long duration of the missions without the protective cover of the geomagnetic field in which the usually small and even neglected effects of the galactic cosmic rays (GCR) can no longer be ignored. It is the peculiarity of these radiations for which the inter-action physics and biological action are yet to be fully understood.

Wilson J. W.↗
NASA NTRS1998

Mars Human Exploration Reference Mission

This presentation proposes the next steps for human exploration of Mars. The presentation reviews the reasons for human exploration of Mars. Two different trajectories are proposed: (1) for a long stay mission, and (2) for a short term mission, which could also include a swing by Venus. A reference mission scenario is investigated, which includes forward deployment of two cargo missions, followed by a human piloted mission. The power needs of such a mission include nuclear thermal propulsion, and the possible use of Mars in situ resources. The exploration will require electric propulsion, stationary power source, and a mobile power source. The trajectories required for electric propulsion of earth are shown, and the engineering of a Mars Transportation Habitat are reviewed.

Drake, Bret↗
NASA NTRS1998

Preparing for Human Exploration

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.

Drake, Bret G.↗
NASA NTRS1998

Exploration of the Moon with Remote Sensing, Ground-Penetrating Radar, and the Regolith-Evolved Gas Analyzer (REGA)

There are two important reasons to explore the Moon. First, we would like to know more about the Moon itself: its history, its geology, its chemistry, and its diversity. Second, we would like to apply this knowledge to a useful purpose. namely finding and using lunar resources. As a result of the recent Clementine and Lunar Prospector missions, we now have global data on the regional surface mineralogy of the Moon, and we have good reason to believe that water exists in the lunar polar regions. However, there is still very little information about the subsurface. If we wish to go to the lunar polar regions to extract water, or if we wish to go anywhere else on the Moon and extract (or learn) anything at all, we need information in three dimensions an understanding of what lies below the surface, both shallow and deep. The terrestrial mining industry provides an example of the logical steps that lead to an understanding of where resources are located and their economic significance. Surface maps are examined to determine likely locations for detailed study. Geochemical soil sample surveys, using broad or narrow grid patterns, are then used to gather additional data. Next, a detailed surface map is developed for a selected area, along with an interpretation of the subsurface structure that would give rise to the observed features. After that, further sampling and geophysical exploration are used to validate and refine the original interpretation, as well as to make further exploration/ mining decisions. Integrating remotely sensed, geophysical, and sample datasets gives the maximum likelihood of a correct interpretation of the subsurface geology and surface morphology. Apollo-era geophysical and automated sampling experiments sought to look beyond the upper few microns of the lunar surface. These experiments, including ground-penetrating radar and spectrometry, proved the usefulness of these methods for determining the best sites for lunar bases and lunar mining operations.

Cooper, B. L.↗