Engineering topics

Sadeh, Willy Z.

Publications and source records attributed to Sadeh, Willy Z..

14 records

NASA NTRS1995

Inflatable structures for a lunar base

The first step in the human expansion into space consists of the construction of a human-tended base on the Moon. Establishment of a lunar base depends upon the development of a structure capable of accomodating human life and activities in a shirt sleeve environment. Design and construction of a structure on the Moon require addressing a host of issues and loads that are not encountered on Earth. A lunar structure is essentially a pressure vessel since the internal pressure is the dominating load. The external pressure is effectively an absolute vacuum and the dead loads from both the material mass and a protective regolith layer are quite small due to low lunar gravity. An inflatable structure made of a thin membrane integrated with an inflated supporting frame is highly efficient in resisting the internal pressure loading and the dead loads. Preliminary design computations for a generic lunar inflatable structure are presented.

Sadeh, Willy Z.↗

NASA NTRS1993

A strategy for a lunar base

A strategy for the establishment of a human-tended base on the moon that involves an evolutionary development spanning from an exploratory encampment to a self-sufficient lunar base is proposed. Four strategic architectural stages in the evolutionary human exploration and settlement of the moon, based on specified engineering requirements and feasible enabling technologies, are proposed. The four stages are: (1) exploratory; (2) pioneering; (3) outpost; and (4) base. Overall goals and specific objectives, functional requirements, structural characteristics, construction conditions, life support systems requirements, and supporting systems needed for lunar exploration and utilization in each stage are identified and discussed.

Sadeh, Willy Z.↗

NASA NTRS1993

Inflatable structures - A concept for lunar and Martian structures

The paper discusses a modular inflatable structure concept for structures on Mars and the moon (where a human tended base will be constructed as a preliminary to a manned mission to Mars). Attention is also given to the environmental characteristics on the moon, Mars, and the earth, structural requirements for a generic structure for either moon or Mars, the moon/Mars design conditions, and the advantages of inflatable structures. Preliminary design calculations for a generic inflated module of size 6.1 x 6.1 x 3 m are presented.

Sadeh, Willy Z.↗

NASA NTRS1993

Characterization of Minnesota lunar simulant for plant growth

Processing of lunar regolith into a plant growth medium is crucial in the development of a regenerative life support system for a lunar base. Plants, which are the core of such a system, produce food and oxygen for humans and, at the same time, consume carbon dioxide. Because of the scarcity of lunar regolith, simulants must be used to infer its properties and to develop procedures for weathering and chemical analyses. The Minnesota Lunar Simulant (MLS) has been identified to date as the best available simulant for lunar regolith. Results of the dissolution studies reveal that appropriately fertilized MLS can be a suitable medium for plant growth. The techniques used in conducting these studies can be extended to investigate the suitability of actual lunar regolith as a plant growth medium. Dissolution experiments were conducted using the MLS to determine its nutritional and toxicity characteristics for plant growth and to develop weathering and chemical analysis techniques. Two weathering regimes, one with water and one with dilute organic acids simulating the root rhizosphere microenvironment, were investigated. Elemental concentrations were measured using inductively-coupled-plasma (ICP) emission spectrometry and ion chromatography (IC). The geochemical speciation model, MINTEQA2, was used to determine the major solution species and the minerals controlling them. Acidification was found to be a useful method for increasing cation concentrations to meaningful levels. Initial results indicate that MLS weathers to give neutral to slightly basic solutions which contain acceptable amounts of the essential elements required for plant nutrition (i.e., potassium, calcium, magnesium, sulfur, zinc, sodium, silicon, manganese, copper, chlorine, boron, molybdenum, and cobalt). Elements that need to be supplemented include carbon, nitrogen, and perhaps phosphorus and iron. Trace metals in solution were present at nontoxic levels.

Oglesby, James P.↗

NASA NTRS1992

An international approach to Mission to Planet Earth

The new international political constellation resulting from the disintegration of the Soviet Union opens up unique opportunities for cooperation in the space arena. Precedents since 1955 indicate a pervasive interest in mutual cooperation to use military reconnaissance and surveillance satellites for space observations to enforce treaty verification and compliance. One of the avenues that offer immediate prospects for fruitful cooperation is the incorporation of the military reconnaissance and surveillance satellite capabilities of both U.S. and Russia into the Mission to Planet Earth. Formation of a United Nations Satellite (UNSAT) fleet drawn from the American and Russian space assets is proposed. The role of UNSAT is to provide world wide monitoring of both military and enviromental activities under the umbrella of the Mission to Planet Earth.

Lawrence, Robert M.↗

NASA NTRS1992

Composite materials microstructure for radiation shielding

Shielding against radiation is a concern for applications on earth, in space, and on extraterrestrial surfaces. On earth EMI is an important factor, while in space and on extraterrestrial surfaces particle (high charge-Z and high energy-E) radiation is a critical issue. Conventional metallic materials currently used for EMI shielding incur large weight penalties. To overcome this weight penalty, ultra-lightweight composite materials utilizing fillers ranging from carbon microballoons to silver coated ceramic microballoons are proposed. The crucial shielding requirement is conductivity of the constituent materials, while the hollow microballoon geometry is utilized to yield low weight. Methods of processing and composition effects are examined and these results are compared to the effectiveness of varying the conductive microballoon material. The resulting ultralightweight materials, developed for EMI shielding, can be tailored through the application of the understanding of the relative effects of variables such as those tested. Initial experimental results reveal that these tailored ultralightweight composite materials are superior to traditional aluminum shielding at only a small fraction of the weight.

Radford, Donald W.↗

NASA NTRS1992

Geometric modeling of inflatable structures for lunar base

A modular inflatable structure consisting of thin, composite membranes is presented for use in a lunar base. Results from a linear elastic analysis of the structure indicate that it is feasible in the lunar environment. Further analysis requires solving nonlinear equations and accurately specifying the geometries of the structural members. A computerized geometric modeling technique, using bicubic Bezier surfaces to generate the geometries of the inflatable structure, was conducted. Simulated results are used to create three-dimensional wire frames and solid renderings of the individual components of the inflatable structure. The component geometries are connected into modules, which are then assembled based upon the desired architecture of the structure.

Nowak, Paul S.↗

NASA NTRS1992

Inflatable structures for a lunar base habitat

Design and construction of a structure on the moon requires addressing a host of issues not encountered on earth. A modular quilted inflatable structure consisting of thin membranes of composite material integrated with supporting columns and arches is proposed. An initial linear analysis of the proposed structure is briefly reviewed. The actual response of an inflatable membrane is nonlinear and, hence, a nonlinear numerical analysis for the stresses and displacements was undertaken. Initial results clearly indicate that an inflatable structure is a feasible concept and is ideally suited for a lunar structure.

Nowak, Paul S.↗

NASA NTRS1992

An analysis of an inflatable module for planetary surfaces

Design and construction of a structure on planetary surfaces requires addressing a host of issues not encountered on earth. A modular quilted inflatable structure consisting of thin membranes of composite material integrated with supporting columns and arches is proposed. An initial linear analysis of the structure is briefly reviewed. The actual response of an inflatable membrane is nonlinear and, hence, a nonlinear numerical analysis of the stresses and displacements was undertaken. Results based on the loadings on a lunar structure clearly indicate that an inflatable structure is a feasible concept and is ideally suited for a planetary surface structure.

Nowak, Paul S.↗

NASA NTRS1992

Composite materials for structures on planetary surfaces

The physical and mechanical properties of advanced composite materials as related to their use in structures on planetary surfaces are reviewed. Polymer matrix composites are recommended as the best materials in the first exploration stages. Achievement of mechanical properties, physical properties, improved processability, and ease of assembly required on planetary surfaces depends on the tailorability of composites.

Radford, Donald W.↗

NASA NTRS1992

Space Civil Engineering option - A progress report

Space Civil Engineering is an emerging engineering discipline that focuses on extending and expanding Civil Engineering to the development, operation, and maintenance of infrastructures on celestial bodies. Space Civil Engineering is presently being developed as a new discipline within the Department of Civil Engineering at Colorado State University and with support of the NASA Space Grant College Program. Academic programs geared toward creating Space Civil Engineering Options at both undergraduate and graduate levels are being formulated. Basic ideas and concepts and the current status of the curriculum in the Space Civil Engineering Option primarily at the undergraduate level are presented.

Criswell, Marvin E.↗

NASA NTRS1991

Material issues for lunar/Martian structures

Development of structures in the lunar/Martian environment depends upon the use of the most appropriate materials. Advanced composite materials are apparently the best candidates for use in structures on planetary surfaces and in space in view of their unique properties, tailorability and light weight. The physical and mechanical properties of advanced composite materials as related to their use in lunar/Martian structures are reviewed. Polymer matrix composites are recommended as the best materials in the first exploration stages of a lunar/Martian base. Increased use of ceramic and metal matrix composites is expected in the more advanced exploration stages. The pressing need for the development of tailored radiation shielding composite materials is discussed.

Radford, Donald W.↗

NASA NTRS1991

Space civil engineering - A new discipline

Space Civil Engineering is an emerging engineering discipline that focuses on extending and expanding the Civil Engineering know-how and practice to the development and maintenance of infrastructure on celestial bodies. Space Civil Engineering is presently being developed as a new discipline within the Department of Civil Engineering at Colorado State University under a recently established NASA Space Grant College Program. Academic programs geared toward creating Space Civil Engineering Options at both undergraduate and graduate levels are being formulated. Basic ideas and concepts of the curriculum in the Space Civil Engineering Option at both undergraduate and graduate levels are presented. The role of Space Civil Engineering in the Space Program is discussed.

Sadeh, Willy Z.↗

NASA NTRS1990

FACE computer simulation

A computer simulation of the FACE (Flexible Arm Controls Experiment) was conducted to assess its design for use in the Space Shuttle. The FACE is supposed to be a 14-ft long articulate structure with 4 degrees of freedom, consisting of shoulder pitch and yaw, elbow pitch, and wrist pitch. Kinematics of the FACE was simulated to obtain data on arm operation, function, workspace and interaction. Payload capture ability was modeled. The simulation indicates the capability for detailed kinematic simulation and payload capture ability analysis, and the feasibility of real-time simulation was determined. In addition, the potential for interactive real-time training through integration of the simulation with various interface controllers was revealed. At this stage, the flexibility of the arm was not yet considered.

Sadeh, Willy Z.↗