摘要:

Routine travel to and from Mars demands an efficient, rapid, low cost means of two-way transportation. To answer this need, we have invented an architecture consisting of two spinning tether systems in highly elliptical orbits about each planet. At Earth, a payload is picked up near periapsis and tossed a half-rotation later, still near periapsis, at a velocity sufficient to send the payload on a high-speed trajectory to Mars. At Mars, it is caught near periapsis and is released a short time later on a suborbital reentry trajectory. The system works in both directions and is reusable. Energy and momentum lost by the throwing tethers can be restored either by catching incoming payloads or by propellantless tether propulsion methods. Tethers with tip velocities of 2.5 km per second can send payloads to Mars in as little as 90 days if aeroslowing is used at Mars. Tether-to-tether transfers without aeroslowing may be accomplished in about 130 to 160 days. Tether systems using commercially available tether materials at reasonable safety factors can be as little as 15 times the mass of the payload being handled. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357896

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The Mars Atmosphere Resource Recovery System (MARRS) is a process that extracts oxygen and other minor components from the Martian surface atmosphere. The thin atmospheric gases are compressed, the carbon dioxide(CO2)is liquefied, and the lighter components are recovered and purified. Energy as heat re-expands theCO2to produce the electrical and mechanical power need to compress and capture the atmosphere. MARRS takes unique advantage of the low ambient temperature on the Martian surface to separate oxygen and water from the bulkCO2in an efficient, lightweight package. The availability of liquidCO2in unlimited amounts enables efficient, open-cycle processes for reserve and emergency power, transportation and industrial uses. Together with a nuclear heat source, MARRS can satisfy many of the requirements for consumables and propellants for a human or large robotic presence on Mars. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357897

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A solar-powered airplane is proposed to explore the atmospheric environment of Venus. Venus has several advantages for a solar airplane. At the top of the cloud level, the solar intensity is comparable to or greater than terrestrial solar intensities. The Earthlike atmospheric pressure means that the power required for flight is lower for Venus than that of Mars, and the slow rotation of Venus allows an airplane to be designed for continuous sunlight, with no energy storage needed for night-time flight. These factors mean that Venus is perhaps the easiest planet in the solar system for flight of a long-duration solar airplane. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357898

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A method is described by which silicon photovoltaic (PV) devices can be directly deposited onto the lunar regolith using primarily lunar materials. In sequence, a robotic “crawler” moving at slow speed sequentially melts the top layer of regolith and deposits a conducting layer, a doped silicon, a top conducting grid, and an antireflective coating by vacuum evaporation techniques. Concentrated solar energy is utilized as the energy source. Development of this capability would significantly lower the cost of electrical energy on the Moon and would enable a range of other activities, including lower cost propellant production, human outposts with complete food-growth capabilities, and advanced materials production. Low cost energy could affect the economics of propellants in space by allowing the extraction of solar wind hydrogen from the lunar regolith. This would allow the economical export of propellants and other materials to space, first to an Earth-Moon Lagrangian Point and potentially to low Earth orbit. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357899

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A major objective for NASA exploration of Mars is to determine whether life has existed on Mars in the past, and whether such life on Mars may persist to the present day. On Earth, life exists in all niches in which water exists in liquid form for at least a portion of the year. On Mars, any liquid water would have to be a highly concentrated brine solution. It is likely, therefore, that any present-day Martian microorganisms would be similar to terrestrial halophiles. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357900

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

This study intends to clarify how people acquire visual information and recognize their orientation in a zero gravity environment. An experiment was conducted using virtual reality. In Study 1, each subject was given tasks in which a subject moves through virtual reality from the central room into one of six rooms such as operation room and habitation room. Textures composed by alphabetical letters were stuck on the six surrounding surfaces of the central cubic room. Visual information of the cubic room and the degree-of-freedom of motion were varied, and the subjects’ performance was measured. To some extent, the experiment produced a subjective sense of weightlessness. Moreover, we identified different strategies of spatial cognition and behavior under conditions of virtual weightlessness. In Study 2, subjects’ orientational skills were tested with pointing and orienting tasks. Subjects followed virtual routes that were constructed of three or four rectangular modules that were connected by the cubical modules. Each subject moved from one end to the other end, and pointed to the start point and reproduced the experienced route using a scale model. The shapes of the routes were changed systematically. Analyses of the results indicate that the ability of special cognition changes with such variables as the number of corners of routes, the geometric number of fields and the number of fields with consideration to the body posture. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357901

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. We present the results of LED-treatment of cells grown in culture and the effects of LEDs on patients’ chronic and acute wounds. LED-technology is also biologically optimal for photodynamic therapy of cancer and we discuss our successes using LEDs in conjunction with light-activated chemotherapeutic drugs. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357902

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A cost effective approach for the deployment of manned habitats on planetary surfaces is the use of robotic precursor missions for such tasks as the deployment and servicing of power systems and ISRU generators, construction of beaconed roadways, and the site preparation and deployment of manned habitat modules. Limitations in the lifetime, dexterous manipulation capabilities, control system architectures, mobility, and the overall degree of autonomy of the current generation of planetary rovers such as Sojourner will have to be addressed before such a long term effort can be undertaken. Ongoing work in the Surface Systems Thrust Area under NASA’s Cross Enterprise Technology Development Program (CETDP) in the area of robotic outposts is enabling many of the technology developments necessary for such an ambitious undertaking. This effort includes a strong cross section of University and NASA Center partners. The program includes the development of control architectures, ISRU systems, and new mobility designs for a sustained long term presence on planetary surfaces. This paper reviews some recent results from the JPL tasks under the Program and provides a roadmap for integration into robotic precursor missions in the 2010-2015 timeframe. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357903

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Methods are needed to improve the capabilities of autonomous robots to perform tasks that are difficult for contemporary robots, and to identify those tasks that robots cannot perform. Additionally, in the realm of remote handling, methods are needed to assess which tasks and/or subtasks are candidates for automation. We are developing a new approach to understanding the capability of autonomous robotic systems. This approach uses formalized methods for determining theachievabilityof tasks for robots, that is, the likelihood that an autonomous robot or telerobot can successfully complete a particular task. Any autonomous system may be represented in achievability space by the volume describing that system’s capabilities within the 3-axis space delineated by perception, cognition, and action. This volume may be thought of as a probability density with achievability decreasing as the distance from the centroid of the volume increases. Similarly, any task may be represented within achievability space. However, as tasks have more finite requirements for perception, cognition, and action, each may be represented as a point (or, more accurately, as a small sphere) within achievability space. Analysis of achievability can serve to identify,a priori, the survivability of robotic systems and the likelihood of mission success; it can be used to plan a mission or portions of a mission; it can be used to modify a mission plan to accommodate unpredicted occurrences; it can also serve to identify needs for modifications to robotic systems or tasks to improve achievability. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357904

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The experiments described in this paper are part of a larger joint MIT/NASA research effort that focuses on the development of a methodology for designing and evaluating integrated interfaces for highly dexterous and multifunctional telerobots. Specifically, a telerobotic workstation is being designed for an Extravehicular Activity (EVA) anthropomorphic space station telerobot. Previous researchers have designed telerobotic workstations based upon performance of discrete subsets of tasks (for example, peg-in-hole, tracking, etc.) without regard for transitions that operators go through between tasks performed sequentially in the context of larger integrated tasks. The exploratory research experiments presented here took an integrated approach and assessed how subjects operating a full-immersion telerobot perform during the transitions between sub-tasks of two common EVA tasks. Preliminary results show that up to 30&percent; of total task time is spent gaining and maintaining Situation Awareness (SA) of their task space and environment during transitions. Although task performance improves over the two trial days, the percentage of time spent on SA remains the same. This method identifies areas where workstation displays and feedback mechanisms are most needed to increase operator performance and decrease operator workload—areas that previous research methods have not been able to address. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1357905

出版商:AIP    

年代:1901

数据来源: AIP