Design and development of a deployable self-inflating adaptive membrane

Space structures nowadays are often designed to serve just one objective during their mission life, examples include truss structures that are used as support structures, solar sails for propulsion or antennas for communication. Each and every single one of these structures is optimized to serve just their distinct purpose and are more or less useless for the rest of the mission and therefore dead weight. By developing a smart structure that can change its shape and therefore adapt to different mission requirements in a single structure, the flexibility of the spacecraft can be increased by greatly decreasing the mass of the entire system. This paper will introduce such an adaptive structure called the Self-inflating Adaptive Membrane (SAM) concept which is being developed at the Advanced Space Concepts Laboratory of the University of Strathclyde. An idea presented in this paper is to adapt these basic changeable elements from nature’s heliotropism. Heliotropism describes a movement of a plant towards the sun during a day; the movement is initiated by turgor pressure change between adjacent cells. The shape change of the global structure can be significant by adding up these local changes induced by local elements, for example the cell’s length. To imitate the turgor pressure change between the motor cells in plants to space structures, piezoelectric micro pumps are added between two neighboring cells. A passive inflation technique is used for deploying the membrane at its destination in space. The trapped air in the spheres will inflate the spheres when subjected to vacuum, therefore no pump or secondary active deployment methods are needed. The paper will present the idea behind the adaption of nature’s heliotropism principle to space structures. The feasibility of the residual air inflation method is verified by LS-DYNA simulations and prototype bench tests under vacuum conditions. Additionally, manufacturing techniques and folding patterns are presented to optimize the actual bench test structure and to minimize the required storage volume. It is shown that through a bio-inspired concept, a high ratio of adaptability of the membrane can be obtained. The paper concludes with the design of a technology demonstrator for a sounding rocket experiment to be launched in March 2013 from the Swedish launch side Esrange

Experimental methods using force application of a single boom for a 500-m²-class solar sail

Solar sailing missions rely on deployable systems for large area-to-mass ratios once in space, while still being small enough for launcher envelopes in the stowed configuration. Many of these deployable systems feature booms that are flattened and subsequently coiled onto a spool / hub. As part of a collaborative deployable space structures research effort between the National Aeronautics and Space Administration (NASA) and German Aerospace Center (DLR), a boom deployment system for a future 500 m² solar sail has been developed. To achieve the respective solar sail size goal, 16.5-m-long booms produced by NASA were integrated into a DLR-designed deployer mechanism. This considerable size, as well as the lightweight construction of the booms and respective deployable systems makes testing on the ground a significant challenge. Some systems for gravity compensation as well as vertical testing to minimize the influence of gravity have been used in the past. However, an uncertainty factor remains towards the behaviour in the space environment. The focus of this paper is the load application testing of the integrated boomdeployment mechanism system under microgravity condition, as well as a comparison to vertical testing under gravity. Testing in microgravity was performed during a parabolic flight test inside an aircraft and it included stowage and full deployment of a single boom along the longitudinal axis of the aircraft. The load application was split into two categories: static testing, which induced a linear force ramp to the static boom for either compression or compression-bending; and dynamic testing, which applied a constant force to a boom during extension provided by the deployer mechanism. Both types of tests were performed multiple times at two distinct lengths of the boom, fully deployed (12.76 m) and ~28.6 % deployed (3.65 m). More parameters that are vital to the test philosophy are the angles of attack in the force application and the highest force applied. The data acquisition used for the applied load and deflection measurements of the boom is also presented

Questions of fairness and anti-doping in US cycling: The contrasting experiences of professionals and amateurs

The focus of researchers, media and policy on doping in cycling is often limited to the professional level of the sport. However, anti-doping test results since 2001 demonstrate that banned substances are also used by US cyclists at lower levels of the sport, necessitating a broader view of the patterns and motivations of substance use within the sport. In this article, we describe and explain the doping culture that has emerged in domestic US cycling among amateur and semi-professionals. Through analysis of records from sports governing bodies and journalistic reports, we assess the range of violation types and discuss the detection and punishing of riders who were not proven to have intended to cheat but became "collateral damage" in the war on doping. We argue that the phenomenon of doping is more complex than what has been shown to occur in elite sport, as it includes a wider variety of behaviours, situations and motivations. We develop fresh insights by examining cases where doping has been accidental, intrinsically motivated, non-performance enhancing or the result of prescribed medical treatments banned by anti-doping authorities. Such trends call into question the fairness of anti-doping measures, and we discuss the possibility of developing localised solutions to testing and sanctioning amateur athletes

Moderne Diesel-Einspritztechnik

Paper presented at TU Muenchen, February 16, 1984Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

FULL SCALE FLAT FLOOR TESTING OF A 500-M²-CLASS SOLAR SAIL DEPLOYER

Solar sailing missions rely on deployable systems for large area to mass ratios once in space, while still being small enough for launcher envelopes in the stowed configuration. Many of these deployable systems feature booms that are flattened and subsequently coiled onto a spool/hub. As part of a collaborative deployable space structures research effort of NASA and DLR, a boom deployment mechanism for a future 500 m² solar sail has been developed since 2017. To achieve the respective solar sail size goal, 16.5 m long booms produced by NASA were integrated into a DLR-designed deployer. This considerable size, as well as the lightweight construction of the booms and respective deployable systems makes ground testing a significant challenge. Some systems for gravity compensation and boom alignment will be presented in the paper. However, the main focus is the functional flat floor testing of the integrated boom-deployment mechanism system, as well as its challenges. The testing performed includes full deployment as well as stowage of the booms. Both have been performed multiple times. The latter is one of the key parameters determining packaging efficiency, which in turn confirms design assumptions. During system development, small scale tests and models have been used in preparation of flat floor testing of the 33 m span cross of the full-scale booms and deployment mechanism. Hence a small chapter is also devoted to analysing the differences in behaviour between small- and full-scale deployment systems. More parameters that are vital to design decisions have been determined this way, such as driving belt force or hub brake torque. This paper also focuses on development goals and needs for future steps to achieve higher levels of technology readiness, such as the balancing of driving motor force, synchronisation of its transmission and the countering hub brake torque

Testing of the Deorbitsail drag sail subsystem

Deorbitsail is a 3U Cubesat project that will launch, deploy, and support a large drag sail deorbiting payload. The flight payload sail system will deploy to 5 by 5 meters, increasing the frontal area of the spacecraft dramatically. A series of 4-by-4-meter sail deployments has been performed with a prototype of the proposed system. The prototype system tests included partial deployments in environmental chambers and full-scale deployment at ambient lab conditions. Design changes arising from testing of the sail system prototype are described in this paper. Engineering model construction is underway and the Deorbitsail launch will be in 2014. Deorbitsail is a European Commission 7th Framework Programme project with nine partner organizations. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved

Testing of the Deorbitsail drag sail subsystem

Deorbitsail is a 3U Cubesat project that will launch, deploy, and support a large drag sail deorbiting payload. The flight payload sail system will deploy to 5 by 5 meters, increasing the frontal area of the spacecraft dramatically. A series of 4-by-4-meter sail deployments has been performed with a prototype of the proposed system. The prototype system tests included partial deployments in environmental chambers and full-scale deployment at ambient lab conditions. Design changes arising from testing of the sail system prototype are described in this paper. Engineering model construction is underway and the Deorbitsail launch will be in 2014. Deorbitsail is a European Commission 7th Framework Programme project with nine partner organizations. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved