Structural assembly demonstration experiment, phase 1

2012

Research Area Spacecraft Materials and Systems The In-SPACE Soldering Experiment (ISSI) is another payload that was rapidly developed after the Columbia accident to provide a lowmass experiment using hardware already on board station. It was designed to promote understanding of joining techniques, shape equilibrium, wetting phenomena, and micro-structural development in space. Its primary objective was to better understand the effects and consequences of soldering in a microgravity environment such as that found on ISS. In Earth's gravity, soldering has a defined behavior and is reliant on gravity and convection to assist in solidification, joint shape, integrity, and microstructure. Unfortunately, on Earth detrimental gas bubbles (void spaces) are still found in the solder joint and at contact surfaces. These voids reduce the thermal and electrical conductivity and provide sites for crack initiation. Bubbles have less chance to escape in the reduced-gravity environment of space and, therefore, are likely to be more of a problem. To better understand this potential problem, a systematic series of soldering samples was designed to investigate and understand porosity development, surface wetting, and equilibrium shape formation. After the samples were heated on orbit, they were returned to Earth for property testing and metallographic examination. 1 1 3 B RESULTS Five soldering sessions resulted in 86 samples. Experiment samples were returned to the investigator team in late 2005, and were evaluated both nondestructively and then destructively.

2004

The purpose of this research was to validate the structural integrity of the Rigidizable Inflatable GetAway Special Experiment (RIGEX) and make appropriate improvements to the design, motivated by static and dynamic analysis results. RIGEX is designed to advance the use of rigidizable inflatable structures in the space environment by providing three sets of on-orbit test data on the structural characteristics of three thermoplastic composite tubes. This thesis discusses the RIGEX structural analysis. The term structural analysis refers to the development of a detailed finite element model and the tests for which the model was used. The finite element model provided an acceptable estimation of RIGEX's natural frequencies, the structural integrity of the fastener system, the maximum stress seen by the aluminum primary structure, and the maximum possible displacements at various locations around the RIGEX structure for various load conditions. These three analyses motivated numerous design changes, which are discussed in detail in this thesis. The analysis process was repeated following each design change until all structural integrity and design criteria were met. In addition to the structural analysis and associated design changes, this thesis presents the as built RIGEX drawing package and wiring schematic. The results presented in this thesis are the first step towards passing the structural integrity requirements set forth by the National Aeronautics and Space Administration (NASA) for manned spaceflight. Recommendations of appropriate construction and testing techniques to ensure the actual structure matches the computer model are discussed. v Acknowledgments I would like to express my sincere appreciation to my thesis advisor, Dr. Richard Cobb, for his support and guidance for the RIGEX project. I would also like to thank Major Eric Swenson for shining some light on finite element analysis. Additionally, the RIGEX project would not be possible without the ongoing support of Mr. Wilbur Lacy and Mr. Jay Anderson. Their insights into laboratory work have kept the RIGEX team safe and successful during all varieties of tests. To the folks at the AFIT shop, especially Jason Vangel, thanks for facilitating countless changes to the RIGEX design. The drawings presented in this thesis really are the final versions, I promise. Thanks also go to past RIGEX researchers, Jeremy Goodwin and Sarah Helms, for taking the time to answer endless questions and facilitate a smooth transition to the new RIGEX team. Mr. Carson Taylor and Mr. Scott Ritterhouse of the Space Test Program are invaluable to the RIGEX program. They offer wisdom beyond their years in mechanical and electrical systems, and with their continued assistance, the RIGEX program is bound to succeed. Finally, I'd like to thank my family and friends for their valuable support and encouragement.

Concepts for the operation of two fluid experiments in the mid-deck region of the STS were developed Based upon these concepts a preliminary design for each experiment is made. The two experiments are the Surface Tension Induced Convection experiment and the Free Surface Phenomena experiment. The mid-deck lockers of the STS are described and the requirements for operating an experiment in this region are described. For each locker the experiment design uses a two locker volume with an experiment unique structure as a housing. For the Surface Tension Induced Convection experiment a manual mode is developed. The fluid is maintained in an accumulator pre-flight. To begin the experiment a pressurized gas drives the fluid 'i nto the experiment conta i ner. The fluid is an inert silicone oil and the container material is selected to be compatable. A wound wire heater is located axisymmetrically above the fluid. The heater is designed to deliver three wattages to a spot on tne fluid surface. These wattages vary from 1-15 watts. The fluid flow is observed through the motion of particles in the fluid. The experiment container is illuminated by a 5 mw HeiNe laser. Scattered light is recorded on the film plane of a 35mm camera. The free surface phenomena experiment consists of a trapezoidal cell which is filled from the bottom The fluid is photographed at high speed using a 35mm camera which incorporated the entire cell 'Iength in the field of view. The assembly can incorporate four cells in one flight. For each experiment an electronics block diagram is provided. A control panel concept is given also for the surface tension induced convection. Both experiments are within the mid-deck locker weight and c-g 1 imits. 17. Key Words (Suggested by Author(s', 18. Distribution St.tamant mid-deck experiments Unclassified-Unlimited 'Iow gravity fluid behavior surface tension induced convection free surface phenomena low gravity research 19. Security Clallif. (olthitreport, 120. Security elllsif.

Advances in Space Research, 1991

The Liquid Structure Facility (L.S.F.) is presently developed under ESA contract. This instrument will allow to perform a wide range of fluid science experiments taking use of the determination of the velocities, temperatures concentrations and also the interface shape deformations. This facility will be activated automatically or by telescience, or manually by the crew.

2000

The software disk accompanying this book and all material contained on it is supplied without any warranty of any kind. The use of registered names, trademarks etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore free for general use. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made.

33rd Structures, Structural Dynamics and Materials Conference, 1992

An analytic and experimental study of gravity and suspension influences on space structural test articles is presented. A modular test article including deployable, erectable, and rotary modules was assembled in three one-and twodimensional structures. The two deployable modules utilized cable diagonal bracing rather than rigid cross members; within a bay of one of the deployable modules, the cable preload was adjustable. A friction lock was used on the alpha joint to either allow or prohibit rotary motion. Suspension systems with plunge fundamentals of 1, 2, and 5 Hz were used for ground testing to evaluate the influences of suspension stiffness. Assembly a n d reassembly testing was performed, as was testing on two separate shipsets a t two test sites. Trends and statistical variances in modal parameters are presented as a function of force amplitude, joint preload, reassembly, shipset and suspension. Linear finite element modeling of each structure provided analytical results for 0-g unsuspended and 1-g suspended models, which are correlated with the analytical model.

2018

This paper presents an overview of the development and qualification test campaign for the primary structure of the European Service Module of ORION, the NASA spacecraft which will serve the future human exploration missions to the Moon, Mars and beyond. Under an agreement between NASA and ESA, the ORION will be powered by a European Service Module (ESM), providing also water and oxygen for astronauts' life sustainability. The development and qualification of the European Service Module (ESM) is under ESA responsibility with Airbus Defence and Space as the prime contractor. Thales Alenia Space Italia is responsible for design development, manufacturing, assembly and qualification of the Structure subsystem. The European Service Module, installed onto the launch adapter, shall support the crew module with its adapter and a launch abort system. It shall sustain:-A combination of global and local launch loads during lift off and ascent phases-On orbit loads induced by engine firing for orbital transfers and attitude control. The ESM structure is based on a core made of Composite Fiber Reinforced Polymer (CFRP) sandwich panels complemented by aluminium alloy platforms, longerons and secondary structures. A development campaign has been implemented in order to define and validate composite parts' strength allowable values for design: coupon tests at material level, test at component level up to breadboards tests performed on main structural components (composite to metallic joints, and at panels' discontinuities). An incremental approach as defined in [1] has been followed. A qualification static test campaign at primary structure assembly level has been implemented in order to validate the design against static stiffness and ultimate strength as well as to correlate the structural Finite Element Model (FEM) used for sizing and confirm the margins of safety. The tests have been performed successfully by Thales Alenia Space Italia (TAS-I) on two flight representative structural models (STA1, STA2), in Turin facilities (Italy) between August 2015 and March 2017, with engineering support of technical representatives from Airbus, ESA, NASA and LMCO. The main development and qualification test activities and associated results are presented and discussed in the paper

1990

The Department of Defense (DOD) Space Test Program (STP), a tri-service activity under the executive management of the Air Force, is chartered and funded to provide spaceflight oppor tunities for DOD research experiments and agencies that are not authorized their own means of spaceflight. In its 25 years of ex istence, the program has flown over 170 experiments on over 50 missions. Experiment sponsors include the Navy, Army, Air Force, DARPA, DNA, NSA, NASA, and other government agencies.

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Structural Health Monitoring, 2012

The paper presents the design, development, and assembly of Structural Health Monitoring (SHM) experiments intended to be launch in space on a sub-orbital rocket flight as well as a high altitude balloon flight. The experiments designed investigate the use of both piezoelectric sensing hardware in a wave propagation experiment and piezoelectric wafer active sensors (PWAS) in an electromechanical impedance experiment as active elements of spacecraft SHM systems. The list of PWAS experiments includes a bolted-joint test and an experiment to monitor PWAS condition during spaceflight. Electromechanical impedances of piezoelectric sensors will be recorded in-flight at varying input frequencies using an onboard data acquisition system. The wave propagation experiment will utilize the sensing hardware of the Metis Design MD7 Digital SHM system. The payload will employ a triggering system that will begin experiment data acquisition upon sufficient saturation of g-loading. The experiment designs must be able to withstand the harsh environment of space, intense vibrations from the rocket launch, and large shock loading upon re-entry. The paper discusses issues encountered during design, development, and assembly of the payload and aspects central to successful demonstration of the SHM system during both the sub-orbital space flight and balloon launch.

2001

Robert W. Moses*, James Van Laak†, Spencer L. Johnson‡, Trina M. Chytka§, Ruth M. Amundsen**, John T. Dorsey††, William R. Doggett‡‡ NASA Langley Research Center, Hampton, VA 23681 ... John D. Reeves§§ National Institute of Aerospace, Hampton, VA ...