Engineering topics

Goslee, J. W.

Publications and source records attributed to Goslee, J. W..

11 records

NASA NTRS1989

Concept for a lunar He-3 transporter using an in-orbit modified shuttle external tank

A concept is presented for the transport of gaseous He-3 in temperature equilibrium with the liquid hydrogen and liquid oxygen in a modified lunar shuttle external tank. The concept first describes the internal modifications to accommodate He-3, and then, the external modifications to incorporate a propulsion system and an aerobrake. Estimates of the system masses and an assessment of propulsion requirements show the round trip capability. The concept also includes a description of the lunar orbit servicing and transfer operations.

Butterfield, A. J.↗

NASA NTRS1985

Electrostatic forming and testing of polymer films on a 16-foot diameter test fixture

The large space systems technology program investigated different forms of large, lightweight, deployable structures which could be carried on the Space Shuttle. Different forms and concepts of antennas as a type of large space system were investigated. The electrostatically controlled membrane reflector made of metallized material concept was chosen. The concept is a good candidate for creating an antenna with high surface quality and has the ability to be packaged and deployed from the Shuttle with a significant reduction in weight compared to other antenna types.

Goslee, J. W.↗

NASA NTRS1984

Measurement of electrostatically formed antennas using photogrammetry and theodolites

An antenna concept is presently being evaluated which has extremely low mass and high surface precision for potential depolyment from the Space Shuttle. This antenna concept derives its reflector surface quality from the application of electrostatic forces to tension and form a thin membrane into the desired concave reflector surface. The Shuttle-deployed antenna would have a diameter of 100 meters and an RMS surface smoothness of 10 to 1 mm for operation at 1 to 10 GHz. NASA Langley Research Center (LaRC) has built, and is currently testing, a subscale (1/20 scale) membrane reflector model of such an antenna. Several surface measurement systems were evaluated as part of the experimental surface measuring efforts. The surface measurement systems are addressed as well as some of the preliminary measurement results.

Goslee, J. W.↗

NASA NTRS1984

Adaptive microwave reflector

As an interim step in going to the 100-meter reflector that was evaluated, a 5-meter reflector is proposed to test the electrostatic concept under space conditions. Some of the issues which require the space environment for evaluation are the following questions: Can deployment of a box ring structure with a thin film reflector attached be manually deployed? In the absence of humidity, can a 0.3-mil aluminized Kapton film reflector be formed by the electrostatic process suitable for antenna applications? Can the photogrammetric process be used to evaluate the reflector surface with pictures taken from the payload handling station? Can the space charging effect be evaluated with the 5-meter reflector attached to the Shuttle? Does the outgassing of moisture from 0.3-mil Kapton film affect its reflector capability? A box ring truss support structure and an automatic sequence deployment system are discussed.

Goslee, J. W.↗

NASA NTRS1984

Microwave reflector characterization using simple instruments in EVA

An antenna with rigid panels which can be measured under ground conditions, carried to space in a packaged condition, deployed into a form similar to the Earth-measured one, measured under space conditions, restowed, and brought back to Earth so that the original measurements can be verified is the type being proposed for this experiment. The antenna chosen will be measured under ground conditions, carried aloft, deployed into its antenna shape, lifted by the remote manipulator system to a position where it can be sighted by two astronauts at the two theodolites, and held there until the surface characterization can be completed. An alternate method would be to use photogrammetry and take pictures of the surface from the payload handling station. After the surface characterization is completed, the antenna will be folded and restowed into the Shuttle bay for return to Earth. The surface characterization will be repeated on Earth after its return for verification both of the original measurement taken on Earth and the measurement taken in space.

Goslee, J. W.↗

NASA NTRS1982

Electrostatic membrane antenna concept testing

The electrostatic concept is evaluated to determine its feasibility for future antenna applications. The concept tested illustrates how the individual power supplies are connected to concentric electrodes located in back of the plastic membrane which is the reflective surface.

Goslee, J. W.↗

NASA NTRS1981

Biaxial and electrostatic tensioning effects on thin membrane materials

Thin membrane materials were subjected to biaxial and electrostatic tensioning loads to study techniques for maintaining surface smoothness of a thin membrane antenna. The basic mechanical and electrical setup for the tests is described and preliminary measurements of surface smoothness and surface deviation are presented.

Hinson, W. F.↗

NASA NTRS1981

Electrostatic membrane antenna concept studies

The development of an electrostatic membrane antenna for large space structure applications is discussed. Problems encountered in fabricating 4.88 m (16 foot) diameter thin film membranes are addressed. The development of a test fixture for evaluating the membranes and the comparison of surface measurement systems are also discussed.

Goslee, J. W.↗

NASA NTRS1981

Test progress on the electrostatic membrane reflector

NASA is currently developing a low mass antenna which derives its reflector surface quality from the application of electrostatic forces to form a thin membrane into the desired concave reflector surface. The shuttle-deployed antenna would have a diameter of 100 m and an RMS surface smoothness of 10 to 1 mm for operation at 1 to 10 GHz. Surface quality measurements have been made on a highly deformable elastic membrane, pressurized by electrostatic forces. Included are the effects of the perimeter boundary, splicing of the membrane, the long-scale smoothness of commercial membranes, and the spatial controllability of the membrane using voltage adjustments to alter the electrostatic forces. The electrostatic membrane was found to operate well in an open-loop sense, showing a high degree of position stability and negligible power consumption in dry air. Visco-electric creep was not evident, but the polymer membrane did expand and contract considerably due to its hygroscopic expansion coefficient. A residual roughness of about 0.75 mm existed with the polymer used in these tests; this error is attributed to seams and membrane anisotropy where the material is stiffer in one direction.

Goslee, J. W.↗

NASA NTRS1980

Uniaxial and biaxial tensioning effects on thin membrane materials

Thin laminated membranes are being considered for various surface applications on future large space structural systems. Some of the thin membranes would be stretched across or between structural members with the requirement that the membrane be maintained within specified limits of smoothness which would be dictated by the particular applications such as antenna reflector requirements. The multiaxial tensile force required to maintain the smoothness in the membrane needs to be determined for use in the structure design. Therefore, several types of thicknesses of thin membrane materials have been subjected to varied levels of uniaxial and biaxial tensile loads. During the biaxial tests, deviations of the material surface smoothness were measured by a noncontacting capacitance probe. Basic materials consisted of composites of vacuum deposited aluminum on Mylar and Kapton ranging in thickness from 0.00025 in (0.000635 cm) to 0.002 in (0.00508 cm). Some of the material was reinforced with Kevlar and Nomex scrim. The uniaxial tests determined the material elongation and tensile forces up to ultimate conditions. Biaxial tests indicated that a relatively smooth material surface could be achieved with tensile force of approximately 1 to 15 Newtons per centimeter, depending upon the material thickness and/or reinforcement.

Hinson, W. F.↗

NASA NTRS1980

Electrostatic forming

The electrostatic forming of antenna and reflector surfaces through the controlled deformation of a reflective membrane is described.

Goslee, J. W.↗