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Results for “Engineering constraints”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Corey, Kenneth A.↗
NASA NTRSDate not supplied

Unbounded Learning Environments as an Approach to Preserving Design Flexibility Demonstrated With Nasa Stem Enhancement in Earth Science (SEES) Students

The Artemis Lunar program is providing opportunity for young scientists and engineers to contribute towards leading edge design concepts regarding early on-surface work areas that are aligned with major national initiatives. Therefore, it is imperative in any discovery process that those young scientists and engineers be provided the bandwidth or operating in a ‘greenfield’ technology environment that encourages new ideas, and perhaps the discovery of ideas that would not be realized within typical structured engineering constraints. To facilitate this concept, the use of unbounded teaching methods was utilized to provide a low-constraint environment from which students can design and discover the requirements that are bounded by the natural environment of the lunar surface, and then build up design requirements un-hindered by budgetary and/or logistics realizations of the moment funding capabilities. Specifically, this design exercise provided the students to operate with unlimited budgets, and unlimited up-mass lifts to the lunar surface to develop a preliminary feasible process for establishing a working lunar research based upon the near-area permanently shadowed regions within the lunar surface. In concept, working near PSRs will be advantageous as they receive near eternal shielding from solar radiation and may potentially host numerous volatile substances such as water ice, methane, hydrogen sulfide and helium-3 that will be the target of scientific investigation and in-situ resource utilization ISRU. The advantage of an upstream working area is that the quality of return materials could potentially be exponential when including an upstream analysis prior to earth-return missions. Furthermore, it’s well known within the scientific and engineering community that working with the base materials in front of human eyes elucidates new features and observations that may not survive when stored and shipped to Earth. Finally, it is theorized that these methods and techniques developing on the lunar surface would be applicable to other planets or cometary surfaces.

Education↗
NASA NTRS1963

Fusion Propulson System Requirements for an Interstellar Probe

An examination of the engine constraints for a fusion-propelled vehicle indicates that minimum flight times for a probe to a 5 light-year star will be approximately 50 years. The principal restraint on the vehicle is the radiator weight and size necessary to dissipate the heat which enters the chamber walls from the fusion plasma. However, it is interesting, at least theoretically, that the confining magnetic field strength is of reasonable magnitude, 2 to 3 x 10(exp5) gauss, and the confinement time is approximately 0.1 sec.

FUSION↗
NASA NTRS1972

Analysis of the Radio Astronomy Explorer lunar orbit mission.

The second Radio Astronomy Explorer spacecraft (RAE-B) is planned to be inserted into lunar orbit in 1973. The transfer trajectory design, lunar orbit selection and launch opportunities are developed in relation to the spacecraft mass properties, propulsion capability and the scientific, environmental and engineering constraints. Alternative midcourse guidance and lunar orbit trim strategies are analyzed and compared. A means of achieving a launch window without varying launch azimuth and park orbit coast time is described. The resulting mission design is characterized by near-minimum energy lunar transfer trajectories and low eccentricity, retrograde critical inclination lunar orbits. Acceptable launch periods are shown to exist for six consecutive months and for two to four consecutive days per month.

Groves, R. T.↗
NASA NTRS1975

CCD imaging instruments for planetary spacecraft applications

The development of new spacecraft camera systems to be used in conjunction with CCD sensors is reported. A brief overview of the science objectives and engineering constraints which influence the design of cameras for deep space is followed by a review of two current development programs, one leading to a line scan imager and the other to an area array frame camera. For each of these, a general description of the imager is given. It is evident that currently available CCDs fall short of requirements in some respects.

Reilly, T. H.↗
NASA NTRS1974

Space Shuttle food galley design concept

A food galley has been designed for the crew compartment of the NASA Space Shuttle Orbiter. The rationale for the definition of this design was based upon assignment of priorities to each functional element of the total food system. Principle priority categories were assigned in the following order: food quality, nutrition, food packaging, menu acceptance, meal preparation efficiency, total system weight, total system volume, and total power requirements. Hence, the galley was designed using an 'inside-out' approach which first considered the food and related biological functions and subsequently proceeded 'outward' from the food to encompass supporting hardware. The resulting galley is an optimal design incorporating appropriate priorities for trade-offs between biological and engineering constraints. This design approach is offered as a model for the design of life support systems.

Heidelbaugh, N. D.↗
NASA NTRS1988

The use of the Tethered Satellite System to perform low density aerothermodynamics studies

The Tethered Satellite System (TSS) is a cooperative space system development activity being carried out by USA and Italy. Within TSS, the Shuttle Tethered Aerothermodynamic Research Facility (STARFAC) concept has the potential to provide access to vast portions of the upper atmosphere for the purpose of atmospheric and aerothermodynamic research. The implementation of this capability will push Tether System (TS) state of the art to its limits; the primary problems being tether/satellite drag, heating, tension control, deployment/retrieval control. In this paper parametric studies are accomplished to assess some of these problems and to delineate the tradeoffs available to missions design to meet the engineering constraints. The utilization of aerodynamic rather than spherical shapes - (TSS) - as well as elementary satellite thrusting and lift are included in the present study.

Carlomagno, Giovanni M.↗
NASA NTRS1991

Vaporization Would Cool Primary Battery

Temperature of discharging high-power-density primary battery maintained below specified level by evaporation of suitable liquid from jacket surrounding battery, according to proposal. Pressure-relief valve regulates pressure and boiling temperature of liquid. Less material needed in cooling by vaporization than in cooling by melting. Technique used to cool batteries in situations in which engineering constraints on volume, mass, and location prevent attachment of cooling fins, heat pipes, or like.

Bhandari, Pradeep↗
NASA NTRS1992

Dark-cycle monitoring of biological subjects on Space Station Freedom

The operational environment for biological research on Space Station Freedom will incorporate video technology for monitoring plant and animal subjects. The video coverage must include dark-cycle monitoring because early experiments will use rodents that are nocturnal and therefore most active during the dark part of the daily cycle. Scientific requirements for monitoring during the dark cycle are exacting. Infrared (IR) or near-IR sensors are required. The trade-offs between these two types of sensors are based on engineering constraints, sensitivity spectra, and the quality of imagery possible from each type. This paper presents results of a study conducted by the Biological Flight Research Projects Office in conjunction with the Spacecraft Data Systems Branch at ARC to investigate the use of charged-coupled-device and IR cameras to meet the scientific requirements. Also examined is the effect of low levels of near-IR illumination on the circadian rhythm in rats.

Chuang, Sherry↗
NASA NTRS1992

Electrostatic propulsion using C60 molecules

An evaluation is made of the potential benefits of C60 molecules as a basis for ion propulsion. Because C60 is storable, its use may result in a larger usable propellant fraction than previous methods of cluster ion propulsion. C60 may also relax such engineering constraints as grid spacing, which restrict the performance of noble gas ion propulsion. The behavior of C60 in a plasma discharge environment, as well as various electron impact cross sections of the molecule, will greatly afftect the feasibility of the concept.

Leifer, Stephanie D.↗
NASA NTRS1992

Dark cycle monitoring of biological specimens on Space Station Freedom

The operational environment for biological research on Space Station Freedom will incorporate video technology for monitoring plant and animal subjects. The video coverage must include dark-cycle monitoring because early experiments will use rodents that are nocturnal and therefore most active during the dark part of the daily cycle. Scientific requirements for monitoring during the dark cycle are exacting. Infrared (IR) or near-IR sensors are required. The trade-offs between these two types of sensors are based on engineering constraints, sensitivity spectra, and the quality of imagery possible from each type. This paper presents results of a study conducted by the Biological Flight Research Projects Office in conjunction with the Spacecraft Data Systems Branch at ARC to investigate the use of charged-coupled-device and IR cameras to meet the scientific requirements. Also examined is the effect of low levels of near-IR illumination on the circadian rhythm in rats.

Mian, Arshad↗
NASA NTRS1992

The initial exploration of Mars - Rationale for a return mission to Chryse Planitia and the Viking 1 Lander

A discussion of the concepts behind planning a landing site on Mars is presented. On the basis of the engineering constraints and the scientific objectives which are likely to be imposed on the first few missions to the surface, reasons for supporting a return to Chryse Planitia and the Viking 1 landing site are given. Samples from the Hesperian ridged plains would be useful in establishing an absolute age for the present crater chronology, and samples of soils from the vicinity of the Viking 1 lander would be useful in determining the significance of the results from the Viking biological experiments. Soil samples would provide consistency between unmanned and manned missions, may contain fossil microorganisms, and could be useful in determining the mechanism responsible for outflow channel formation.

Craddock, Robert A.↗
NASA NTRS1993

Mars Analog Site Study (MASS)

Many proposed missions to Mars involve landing vehicles, including the Mars 94/96 (Russia), Mars Environmental Survey (MESUR, US), and the Marsnet (ESA) missions. Most landers involve in situ measurements of rock and soil compositions, study of local geology by imaging, and establishment of seismic and meteorological networks. The selection of landing sites on Mars is a complex process that must meet engineering constraints and scientific objectives, using available and anticipated data. The goal of the MASS project is to conduct an 'end-to-end' test of the site selection process using Earth analogs.

Greeley, R.↗
NASA NTRS1994

Rationale for a Mars Pathfinder mission to Chryse Planitia and the Viking 1 lander

Presently the landing site for Mars Pathfinder will be constrained to latitudes between 0 deg and 30 deg N to facilitate communication with earth and to allow the lander and rover solar arrays to generate the maximum possible power. The reference elevation of the site must also be below 0 km so that the descent parachute, a Viking derivative, has sufficient time to open and slow the lander to the correct terminal velocity. Although Mars has as much land surface area as the continental crust of the earth, such engineering constraints immediately limit the number of possible landing sites to only three broad areas: Amazonis, Chryse, and Isidis Planitia. Of these, both Chryse and Isidis Planitia stand out as the sites offering the most information to address several broad scientific topics.

Craddock, Robert A.↗