Space inflatable/rigidizable structures technology
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space inflatable rigidizable structures technology↗
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Deep Space Habitat Primary Structure - A Comparison between Metallic, Inflatable, and Composite Materials
This paper presents a comprehensive trade study comparing metallic, inflatable, and composite primary structure materials for a Mars Transit Habitat module. The study evaluates the impact of these materials on the overall mass, outfitting, and mission complexity of the habitat. The results show that the composite module outperforms the other options in terms of minimum mass, being 33% lighter than the metallic configurations and 41% lighter than the inflatable option. The study highlights the potential of composite habitats for future space missions and emphasizes the need for further development and testing to increase the Technology Readiness Level.
Matthew T. Ziglar↗
Inflatable Hangar for Assembly of Large Structures in Space
The NASA Human Space Flight program is interested in projects where humans, beyond low-Earth orbit (LEO), can make an important and unique contribution that cannot be reasonably accomplished purely by robotic means, and is commensurate with the effort and cost associated with human spaceflight. Robotic space telescope missions have been conceived and launched as completed assemblies (e.g., Hubble) or as jack-in-the-box one-time deployments (e.g., James Webb). If it were possible to assemble components of a very large telescope from one or two launches into a telescope that was vastly greater in light-gathering power and resolution, that would constitute a breakthrough. Large telescopes on Earth, like all one-off precision assembly tasks, are done by humans. Humans in shirtsleeves (or cleanroom bunny suits) can perform tasks of remarkable dexterity and precision. Unfortunately, astronauts in pressure suits cannot perform such dexterous and precise tasks because of the limitations of the pressurized gloves. If a large, inflatable hangar were placed in high orbit, along with all the components needed for a large assembly such as a large telescope, then humans in bunny suits could perform the same sorts of extremely precise and dexterous assembly that they could be expected to perform on Earth. Calculations show that such an inflatable hangar, and the necessary gas to make it safe to occupy by shirtsleeves humans wearing oxygen masks, fits within the mass and volume limitations of the proposed "Space Launch System" heavy-lift rocket. A second launch could bring up all the components of an approximately 100-meter-diameter or larger telescope. A large [200 ft (approximately 61 m) in diameter] inflated fabric sphere (or hangar) would contain four humans in bunny suits. The sphere would contain sufficient atmospheric pressure so that spacesuits would not be necessary [about 3.2 psi (approximately 22 kPa)]. The humans would require only oxygen masks and small backpacks similar to SCUBA tanks. The oxygen content of the gas would be about 35%, low enough to reduce fire risk but high enough to sustain life in the event of a failure of an oxygen mask. The bunnysuited astronauts could ride on long "cherry-picker" robots with foot restraints somewhat similar to the arm on the International Space Station. Other astronauts would maneuver freely with small propeller fans on their backpacks to provide thrust in the zero-g environment.
Wilcox, Brian H.↗
Thermal distortion analyses of a three-meter inflatable reflectarray antenna
Gossamer space structures are relatively large, flimsy, and lightweight. As a result, they are more easily affected or degraded by space thermal environments compared to other space structures. This study examines the structural integrity of a three-meeter Ka-band inltable/self-rigidizable reflectarray antenna under space thermal environments.
thermal inflatable temperature buckling boom anten↗
Dynamic analysis of stability and deployment of inflatable shell structures Final report
Dynamic analysis of stability and deployment of inflatable shell structures for space vehicle antennas and gravity-gradient damper booms
Falgout, T. E.↗
Effect of Urea Links in the Backbone of Polyimide Aerogels
Flexible, conformal polyimide aerogels with low density, good mechanical properties and high surface areas have attracted much attention for many potential applications such as lightweight antenna substrates, insulating materials for launch vehicles, inflatable structures, aircraft or space suits. Development and improvements to fabrication of polyimide aerogel thin films have been reported over the last decade to meet the needs of many of these applications. However, most starting materials are expensive. In this research, we utilized commercially available, low cost monomers including 4,4’-bis(4-aminophenoxy)propane (BAPP) and 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (BTDA), and 4,4-methylene diphenyl di-isocyanate (MDI) in fabricating polyimide (PI) and polyimide-urea (PIU), which were then cross-linked with 1,3,5-tris(4-aminophenoxy)benzene (TAB). It was found that the addition of MDI into the PI chains not only maintained the flexibility of the aerogel films, but also enhanced the film casting, allowing the production on pilot scale. With the capability in producing robust films at affordable cost, application of the PIU aerogel films can be expanded to terrestrial goods such as winter clothing, or pipe wrapping, etc. In addition, the presence of only a small addition of the urea links in the polyimide chains in PIU aerogels led to lower shrinkage when compared to the corresponding PI aerogels, leading to lower density
Baochau N. Nguyen↗
Meeting the Grand Challenge of Protecting Astronauts Health: Electrostatic Active Space Radiation Shielding for Deep Space Missions
This report describes the research completed during 2011 for the NASA Innovative Advanced Concepts (NIAC) project. The research is motivated by the desire to safely send humans in deep space missions and to keep radiation exposures within permitted limits. To this end current material shielding, developed for low earth orbit missions, is not a viable option due to payload and cost penalties. The active radiation shielding is the path forward for such missions. To achieve active space radiation shielding innovative large lightweight gossamer space structures are used. The goal is to deflect enough positive ions without attracting negatively charged plasma and to investigate if a charged Gossamer structure can perform charge deflections without significant structural instabilities occurring. In this study different innovative configurations are explored to design an optimum active shielding. In addition, to establish technological feasibility experiments are performed with up to 10kV of membrane charging, and an electron flux source with up to 5keV of energy and 5mA of current. While these charge flux energy levels are much less than those encountered in space, the fundamental coupled interaction of charged Gossamer structures with the ambient charge flux can be experimentally investigated. Of interest are, will the EIMS remain inflated during the charge deflections, and are there visible charge flux interactions. Aluminum coated Mylar membrane prototype structures are created to test their inflation capability using electrostatic charging. To simulate the charge flux, a 5keV electron emitter is utilized. The remaining charge flux at the end of the test chamber is measured with a Faraday cup mounted on a movable boom. A range of experiments with this electron emitter and detector were performed within a 30x60cm vacuum chamber with vacuum environment capability of 10-7 Torr. Experiments are performed with the charge flux aimed at the electrostatically inflated membrane structure (EIMS) in both charged and uncharged configurations. The amount of charge shielding behind and around the EIMS was studied for different combinations of membrane structure voltages and electron energies. Both passive and active shielding were observed, with active shielding capable of deflecting nearly all incoming electrons. The pattern of charge distribution around the structure was studied as well as the stability of the structures in the charge flow. The charge deflection experiments illustrate that the EIMS remain inflated during charge deflection, but will experience small amplitude oscillations. Investigations were performed to determine a potential cause of the vibrations. It is postulated these vibrations are due to the charge flux causing local membrane charge distribution changes. As the membrane structure inflation pressure is changed, the shape responds, and causes the observed sustained vibration. Having identified this phenomenon is important when considering electrostatically inflated membrane structures (EIMS) in a space environment. Additionally, this project included a study of membrane material impacts, specifically the impact of membrane thickness. Extremely thin materials presented new challenges with vacuum preparation techniques and rapid charging. The thinner and lighter membrane materials were successfully inflated using electrostatic forces in a vacuum chamber. However, care must be taken when varying the potentials of such lighter structures as the currents can cause local heating and melting of the very thin membranes. Lastly, a preliminary analysis is performed to study rough order of magnitude power requirements for using EIMS for radiation shielding. The EIMS power requirement becomes increasingly more challenging as the spacecraft voltage is increased. As a result, the emphasis is on the deflection of charges away from the spacecraft rather than totally stopping them. This significantly alleviates the initial power requirements. With modest technological development(s) active shielding is emerging to be a viable option.
Radiation↗
Dynamic Testing of an Inflatable Structure Under Thermal Vacuum Conditions
The Marshall Space Flight Center's Space Transportation Programs Office is responsible for the development and demonstration of advanced launch vehicle and propulsion technologies. One of these advanced propulsion concepts being pursued is solar thermal propulsion. This concept employs a concentrated beam of sunlight to heat a working fluid within a solar thermal engine. Expansion of the fluid would provide thrust at an increased specific impulse. One way to concentrate the sun's light to a specific point in the engine cavity is to use a fresnel lens that is supported by an inflatable structure. Such propulsion systems could provide an inexpensive way of transferring and maintaining satellites to upper stage orbit trajectories. This paper describes the test hardware, procedures, and non-contacting measurement methodologies used to determine the modal characteristics of an inflatable concentrator under the thermal-vacuum conditions of space. These characteristics were necessary to identify for validation of a finite element model to be used for developing the spacecraft's pointing and control system.
Engberg, Robert↗
Development of a three-meter Ka-band reflectarray antenna
With the development of inflatable technologies, inflatable structures used as large space antennas are becoming very possible for near term space missions. This paper discusses the development of an inflatable/self-rigidizable structure for a three-meter Ka-band reflectarray antenna.
inflatable gossamer reflectarray antenna self rigi↗
Design of a Microgravity Hybrid Inflatable Airlock
Spacewalks, or extra-vehicular activities (EVAs), are a critical component of human space exploration for science activities and habitat construction and maintenance. For NASA's proposed lunar Gateway system, an airlock module is required for vehicle maintenance, repair, and exploration. Traditional airlock structures are fully metallic, with two chambers, known as an equipment lock and a crew lock. The larger volume, called the equipment lock, serves as the storage, logistics and electronics area, while the smaller volume, called the crew lock, serves as the volume to transition from the vacuum of space to the pressurized cabin. A traditional metallic structure design offers mass efficiency for these elements, but cannot offer volume efficiency. The potential to use an inflatable fabric pressure shell supplemented by a metallic support structure allows for efficiency in both mass and volume. Inflatable structures are being used for human habitable space modules, starting with the Bigelow Expandable Activities Module on the International Space Station. They are high-strength fabric-based structures that are compactly stowed for launch and then, once in space, they are expanded and rigidized with internal pressure. They provide significant launch volume savings over metallic structures. For Gateway, a hybrid airlock design is proposed with both metallic and inflatable structural elements, taking advantage of each material's capabilities. A metallic equipment lock serves as both a docking node and provides pressurized volume for pre-EVA activities including pre-breathe and suit donning/doffing. A rigid equipment lock offers stowage space during launch for integrated hardware and suits. Adding an integrated inflatable crew lock provides the volume required for EVAs with minimal use of launch volume. Using dual inflatable crew locks provides redundancy and the capability to move large pieces of equipment into and out of the vehicle for repair and maintenance. The inflatable crew lock is deflated and packaged in the launch shroud and expanded after installation on the Gateway. This packing capability allows additional volume to be added to the equipment lock and fully utilize the capability of the launch vehicle. This report outlines the work completed to design, analyze, and test the systems of a microgravity airlock with inflatable crew locks. In detail, it includes launch vehicles, structural sizing of the metallic equipment lock, the fabric layers of the inflatable crew lock, the internal structure of the crew lock, the space suit interface elements, the crew restraint system, the hatches and pass-throughs, the material and thermal elements, and the crew operations for the usage of the system. This paper is meant to offer a reference design for a hybrid microgravity airlock design for deep space human exploration.
Litteken, Douglas↗
Design of a Microgravity Hybrid Inflatable Airlock
Spacewalks, or extra-vehicular activities (EVAs), are a critical component of human space exploration for science activities and habitat construction and maintenance. For NASA's proposed lunar Gateway system, an airlock module is required for vehicle maintenance, repair, and exploration. Traditional airlock structures are fully metallic, with two chambers, known as an equipment lock and a crew lock. The larger volume, called the equipment lock, serves as the storage, logistics and electronics area, while the smaller volume, called the crew lock, serves as the volume to transition from the vacuum of space to the pressurized cabin. A traditional metallic structure design offers mass efficiency for these elements, but cannot offer volume efficiency. The potential to use an inflatable fabric pressure shell supplemented by a metallic support structure allows for efficiency in both mass and volume. Inflatable structures are being used for human habitable space modules, starting with the Bigelow Expandable Activities Module on the International Space Station. They are high-strength fabric-based structures that are compactly stowed for launch and then, once in space, they are expanded and rigidized with internal pressure. They provide significant launch volume savings over metallic structures. For Gateway, a hybrid airlock design is proposed with both metallic and inflatable structural elements, taking advantage of each material's capabilities. A metallic equipment lock serves as both a docking node and provides pressurized volume for pre-EVA activities including pre-breathe and suit donning/doffing. A rigid equipment lock offers stowage space during launch for integrated hardware and suits. Adding an integrated inflatable crew lock provides the volume required for EVAs with minimal use of launch volume. Using dual inflatable crew locks provides redundancy and the capability to move large pieces of equipment into and out of the vehicle for repair and maintenance. The inflatable crew lock is deflated and packaged in the launch shroud and expanded after installation on the Gateway. This packing capability allows additional volume to be added to the equipment lock and fully utilize the capability of the launch vehicle. This report outlines the work completed to design, analyze, and test the systems of a microgravity airlock with inflatable crew locks. In detail, it includes launch vehicles, structural sizing of the metallic equipment lock, the fabric layers of the inflatable crew lock, the internal structure of the crew lock, the space suit interface elements, the crew restraint system, the hatches and pass-throughs, the material and thermal elements, and the crew operations for the usage of the system. This paper is meant to offer a reference design for a hybrid microgravity airlock design for deep space human exploration.
Litteken, Douglas↗
Test and Analysis of an Inflatable Parabolic Dish Antenna
NASA is developing ultra-lightweight structures technology for large communication antennas for application to space missions. With these goals in mind, SRS Technologies has been funded by NASA Glenn Research Center (GRC) to undertake the development of a subscale ultra-thin membrane inflatable antenna for deep-space applications. One of the research goals is to develop approaches for prediction of the radio frequency and structural characteristics of inflatable and rigidizable membrane antenna structures. GRC has teamed with NASA Langley Research Center (LaRC) to evaluate inflatable and rigidizable antenna concepts for potential space missions. GRC has completed tests to evaluate RF performance, while LaRC completed structural tests and analysis to evaluate the static shape and structural dynamic responses of a laboratory model of a 0.3 meter antenna. This paper presents the details of the tests and analysis completed to evaluate the radio frequency and structural characteristics of the antenna.
Gaspar, james L.↗
Laser-Induced Fluorescence Photogrammetry for Dynamic Characterization of Transparent and Aluminized Membrane Structures
Photogrammetry has proven to be a valuable tool for static and dynamic profiling of membrane based inflatable and ultra-lightweight space structures. However, the traditional photogrammetric targeting techniques used for solid structures, such as attached retro-reflective targets and white-light dot projection, have some disadvantages and are not ideally suited for measuring highly transparent or reflective membrane structures. In this paper, we describe a new laser-induced fluorescence based target generation technique that is more suitable for these types of structures. We also present several examples of non-contact non-invasive photogrammetric measurements of laser-dye doped polymers, including the dynamic measurement and modal analysis of a 1m-by-1m aluminized solar sail style membrane.
Dorrington, Adrian A.↗
Expandable and modular structures technology for support on manned missions.
Expandable and modular structures for support on manned space missions, reviewing inflatable, chemically rigidizable, unfurlable and elastic recovery structures
EXPANDABLE STRUCTURE↗
Expandable and modular structures technology for support of manned missions.
Expandable and modular structures for support on manned space missions, reviewing inflatable, chemically rigidizable, unfurlable and elastic recovery structures
Forbes, F. W.↗
Space Radiation Effects in Inflatable and Composite Habitat Materials
This Year 2 project provides much needed risk reduction data to assess solar particle event (SPE) and galactic cosmic ray (GCR) space radiation damage in existing and emerging materials used in manned low-earth orbit, lunar, interplanetary, and Martian surface missions. More specifically, long duration (up to 50 years) space radiation damage is quantified for materials used in inflatable structures (1st priority), and habitable composite structures and space suits materials (2nd priority). The data collected has relevance for nonmetallic materials (polymers and composites) used in NASA missions where long duration reliability is needed in continuous or intermittent radiation fluxes.
Waller, Jess↗
The Development of Large Inflatable Antenna for Deep-Space Communications
NASA/JPL's deep-space exploration program has been placing emphasis on reducing the mass and stowage volume of its spacecraft's high-gain and large-aperture antennas. To achieve these goals, the concept of deployable flat reflectarray antenna using an inflatable/thin-membrane structure was introduced at JPL several years ago. A reflectarray is a flat array antenna space-fed by a low-gain feed located at its focal point in a fashion similar to that of a parabolic reflector. The ref1ectarray's elements, using microstrip technology, can be printed onto a flat thin-membrane surface and are each uniquely designed to compensate for the different phase delays due to different path lengths from the feed. Although the reflectarray suffers from limited bandwidth (typically < 10%), it offers a more reliably deployed and maintained flat "natural" surface. A recent hardware development at JPL has demonstrated that a 0.2mm rms surface tolerance (l/50th of a wavelength) was achieved on a 3-meter Ka-band inflatable reflectarray. Another recent development, to combat the reflectarray's narrow band characteristic, demonstrated that dual-band performance, such as X- and Ka-bands, with an aperture efficiency of above 50 percent is achievable by the reflectarray antenna. To mechanically deploy the antenna, the reflectarray's thin membrane aperture surface is supported, tensioned and deployed by an inflatable tubular structure. There are several critical elements and challenging issues associated with the inflatable tube structure. First, the inflatable tube must be made rigidizable so that, once the tube is fully deployed in space, it rigidizes itself and the inflation system is no longer needed. In addition, if the tube is penetrated by small space debris, the tube will maintain its rigidity and not cause deformation to the antenna structure. To support large apertures (e.g. 10m or beyond) without causing any buckling to the small-diameter inflatable tube during vibration, the tube, in addition to rigidization, is also reinforced by circumferential thin blades, as well as axial blades. Second, a controlled deployment mechanism, such as by using Velcro strips, must also be implemented into the system so that, for very large structures, the long inflatable tubes can be deployed in a time-controlled fashion and not get tangled with each other. Third, the thermal analysis is another critical element and must be performed for the tube design in order to assure that the inflated tube, under extreme space thermal conditions, will not deform significantly. Finally, the dynamic vibration analysis must also be performed on the inflatable structure. This will investigate the response of the structure due to excitation introduced by the spacecraft maneuvering and thus determine any necessary damping. Several reflectarray antennas have been developed at JPL to demonstrate the technology. These include an earlier 1-meter X-band inflatable reflectarray, a 3-meter Ka-band inflatable reflectarray, a half-meter dual-band (X and Ka) reflectarray, and the current on-going 10-meter inflatable structure development. The detailed RF and mechanical descriptions of these antennas, as well as their performances, will be presented during the conference.
inflatable antenna↗
Wireless Sensing Opportunities for Aerospace Applications
Wireless sensors and sensor networks is an emerging technology area with many applications within the aerospace industry. Integrated vehicle health monitoring (IVHM) of aerospace vehicles is needed to ensure the safety of the crew and the vehicle, yet often high costs, weight, size and other constraints prevent the incorporation of instrumentation onto spacecraft. This paper presents a few of the areas such as IVHM, where new wireless sensing technology is needed on both existing vehicles as well as future spacecraft. From ground tests to inflatable structures to the International Space Station, many applications could receive benefits from small, low power, wireless sensors. This paper also highlights some of the challenges that need to overcome when implementing wireless sensor networks for aerospace vehicles.
Wilson, William↗