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Engler, E. E.

Publications and source records attributed to Engler, E. E..

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

TERRESTRIAL EFFECTS OF NEARBY SUPERNOVAE IN THE EARLY PLEISTOCENE

Recent results have strongly confirmed that multiple supernovae happened at distances of ∼100 pc, consisting of two main events: one at 1.7–3.2 million years ago, and the other at 6.5–8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing {sup 60}Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first look at the most probable cases, combining photon and CR effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light and that chemical changes such as ozone depletion are weak. However, tropospheric ionization right down to the ground, due to the penetration of ≥TeV CRs, will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase twentyfold, which will approximately triple the overall radiation load on terrestrial organisms. Such irradiation has been linked to possible changes in climate and increased cancer and mutation rates. This may be related to a minor mass extinction around the Pliocene-Pleistocene boundary, and further research on the effects is needed.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1986

Development of Deployable Truss Concept for Space Station

A single-fold, automatically deployable and retractable, square-shaped truss concept that is a candidate for the strongback of NASA's Space Station was developed. Compact stowage within a square-shaped housing is achieved by using folded longerons and telescoping diagonal members. Deployment or retraction is accomplished, bay by bay, in a controlled manner with root strength maintained at all times. Control is accomplished by motor-driven jack-screws operated by a controller. Power, data, and fluid utility lines can be integrated onto trays that unfold with the truss. To verify performance a kinematically representative ground test article version is used.

Greenberg, H. S.↗
NASA NTRS1982

Fabricating Structural Beams

Automatic machine described in new report has demonstrated on Earth feasibility of machine fabricating beams for huge structures in space. Such structures include solar mirrors, radiometer reflectors, microwave power transmitters, solar-thermal power generators, and solar photoelectric generators, ranging in size from few hundred meters long to tens of kilometers long.

Engler, E. E.↗
NASA NTRS1981

Neutral buoyancy test results of a deployable space beam

Large erectable and deployable space structures have been studied extensively in the past few years with a view toward usage in the near future for space platforms. The paper covers in particular the operational testing of a double-cell, double-folding cubic aluminum module at the Marshall Space Flight Center Neutral Buoyancy Simulator. Joining methods, deployment kinematics, configurations and operation time lines were analyzed using the Shuttle Remote Manipulator System (RMS) and EVA crewmen. Results of the test were considered successful, with crew tasks accomplished and the structural design adequate for flight design.

Stokes, J. W.↗
NASA NTRS1980

Large space structures activity at MSFC

This paper describes a broad based set of activities which have been undertaken at the Marshall Space Flight Center (MSFC) developing technologies necessary to emplace and operate large structures in space. Progress has been made in the development of processes and equipment needed for the in space fabrication of structural members in both aluminum and graphite composite materials. Designs for member joining attachments have been completed and the evaluation of procedures for structural assembly have been simulated and evaluated utilizing the MSFC Neutral Buoyancy Facility. A concept of a flight test necessary for flight verification of the technologies for space fabrication, assembly, and operation of large space structure is described. Recently initiated is a project to develop design characteristics of a deployable structure required for the Science and Applications Space Platform (SASP). This is being accomplished through the design, fabrication, analysis, and test of a full scale ground test article which reflects the influence of system requirements of the SASP. Development of designs for erectable/deployable structures which are modular and have various applications to large space structures is in progress.

Denton, S. J.↗
NASA NTRS1978

Automated space fabrication of structural elements

A description is presented of an automated space fabrication technique for basic structural elements, taking into account as representative the design loads and requirements of the solar power satellite structure. Roll forming for continuous cap and brace members is applicable for all proposed metallic materials. Spot-welding, electron beam welding, ultrasonic welding, laser welding, cold welding, and various mechanical fastening techniques are applicable for the automated fabrication process. Termination of the formed cap and brace members can be accomplished by sawing, shearing, punching, and laser cutting. The most cost effective materials were found to be the aluminum alloys. Selected for further study were AL20224T3 and AL2219-T62. In the area of fiber composites, thermoplastic matrix materials with graphite fibers were selected for future studies.

Engler, E. E.↗
NASA NTRS1972

Composite systems utilization for space shuttle structures

Research and development of composite material systems to show applicability of these materials to shuttle structures and to demonstrate availability through a hardware development program is reported. The various configurations studied and potential areas of composite structures use are described and an outline of ongoing composite programs, complementing the indicated feasible applications, including a typical cost study, is shown. The following composite systems are investigated: Boron filaments with epoxy, polyimide, or aluminum matrix, and graphite filaments with epoxy or polyimide matrix.

Engler, E. E.↗