scholarly journals Ionic Liquids as Performance Ingredients in Space Lubricants

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1013
Author(s):  
Erik Nyberg ◽  
Christoph Schneidhofer ◽  
Lucia Pisarova ◽  
Nicole Dörr ◽  
Ichiro Minami
Keyword(s):  
Ionic Liquids ◽  
Space Environment ◽  
Secondary Effects ◽  
Multifunctional Additive ◽  
Space Applications ◽  
Liquid Lubricant ◽  
Machine Elements ◽  
Effects Of Radiation ◽  
Boundary Films ◽  
Space Conditions

Low vapor pressure and several other outstanding properties make room-temperature ionic liquids attractive candidates as lubricants for machine elements in space applications. Ensuring sufficient liquid lubricant supply under space conditions is challenging, and consequently, such tribological systems may operate in boundary lubrication conditions. Under such circumstances, effective lubrication requires the formation of adsorbed or chemically reacted boundary films to prevent excessive friction and wear. In this work, we evaluated hydrocarbon-mimicking ionic liquids, designated P-SiSO, as performance ingredients in multiply alkylated cyclopentane (MAC). The tribological properties under vacuum or various atmospheres (air, nitrogen, carbon dioxide) were measured and analyzed. Thermal vacuum outgassing and electric conductivity were meas- ured to evaluate ‘MAC & P-SiSO’ compatibility to the space environment, including the secondary effects of radiation. Heritage space lubricants—MAC and perfluoroalkyl polyethers (PFPE)—were employed as references. The results corroborate the beneficial lubricating performance of incorporating P-SiSO in MAC, under vacuum as well as under various atmospheres, and demonstrates the feasibility for use as a multifunctional additive in hydrocarbon base oils, for use in space exploration applications.

scholarly journals Self-healing materials for space applications: overview of present development and major limitations

2021 ◽  
Author(s):  
Laura Pernigoni ◽  
Ugo Lafont ◽  
Antonio Mattia Grande
Keyword(s):  
Orbital Debris ◽  
Space Environment ◽  
Technological Evolution ◽  
Self Healing ◽  
Space Systems ◽  
Space Applications ◽  
Structural Fatigue ◽  
Operational Life ◽  
Technological Limitations ◽  
Human Exploration

AbstractIn the last decade, self-healing materials have become extremely appealing for the field of space applications, due to their technological evolution and the consequent possibility of designing space systems and structures able to repair autonomously after damage arising from impacts with micrometeoroids and orbital debris, from accidental contact with sharp objects, from structural fatigue or simply due to material aging. The integration of these novel materials in the design of spacecraft structures would result in increased reliability and safety leading to longer operational life and missions. Such concepts will bring a decisive boost enabling new mission scenario for the establishment of new orbital stations, settlement on the Moon and human exploration of Mars.The proposed review aims at presenting the newest and most promising self-healing materials and associated technologies for space application, along with the issues related to their current technological limitations in combination with the effect of the space environment. An introductory part about the outlooks and challenges of space exploration and the self-healing concept is followed by a brief description of the space environment and its possible effects on the performance of materials. Self-healing materials are then analysed in detail, moving from the general intrinsic and extrinsic categories down to the specific mechanisms.

Thermoelectric Applications as Related to Biomedical Engineering for Nasa Johnson Space Center

1997 ◽  
Vol 478 ◽  
Author(s):  
C. D. Kramer ◽  
P.E.
Keyword(s):  
International Space Station ◽  
Space Station ◽  
Space Environment ◽  
Space Applications ◽  
International Space ◽  
Future Technology ◽  
Technological Developments ◽  
Environment Noise ◽  
Scientific Value

AbstractThis paper presents current NASA biomedical developments and applications using thermoelectrics. Discussion will include future technology enhancements that would be most beneficial to the application of thermoelectric technology.A great deal of thermoelectric applications have focused on electronic cooling. As with all technological developments within NASA, if the application cannot be related to the average consumer, the technology will not be mass-produced and widely available to the public (a key to research and development expenditures and thermoelectric companies). Included are discussions of thermoelectric applications to cool astronauts during launch and reentry. The earth-based applications, or spin-offs, include such innovations as tank and race car driver cooling, to cooling infants with high temperatures, as well as, the prevention of hair loss during chemotherapy. In order to preserve the scientific value of metabolic samples during long-term space missions, cooling is required to enable scientific studies. Results of one such study should provide a better understanding of osteoporosis and may lead to a possible cure for the disease.In the space environment, noise has to be kept to a minimum. In long-term space applications such as the International Space Station, thermoelectric technology provides the acoustic relief and the reliability for food, as well as, scientific refrigeration/freezers. Applications and future needs are discussed as NASA moves closer to a continued space presence in Mir, International Space Station, and Lunar-Mars Exploration.

Computer Modelling of Autonomous Satellite Navigation Characteristics on Geostationary Orbit

2019 ◽  
pp. 311-338
Author(s):  
Fedir Shyshkov ◽  
Valeriy Konin
Keyword(s):  
Computer Modelling ◽  
Satellite Navigation ◽  
Research Data ◽  
Global Navigation Satellite Systems ◽  
Geostationary Orbit ◽  
Space Environment ◽  
Space Applications ◽  
Satellite Systems ◽  
Spacecraft Navigation ◽  
Global Navigation Satellite

Satellite systems are a fast-developing and broad field of study. The use of global navigation satellite systems for relatively autonomous spacecraft navigation holds a lot of interest for researchers. It is extremely expensive to research space applications as live experiments. Therefore, computer modelling comes in handy when there is a need to analyze important factors in space environment. The chapter describes the radionavigation field model that uses the off-nadir satellites. This model allows estimation of the availability and accuracy characteristics of autonomous satellite navigation in space up to the geostationary orbit in order to provide the necessary research data.

scholarly journals The Effect of POSS Type on the Shape Memory Properties of Epoxy-Based Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4203
Author(s):  
Avraham I. Bram ◽  
Irina Gouzman ◽  
Asaf Bolker ◽  
Noam Eliaz ◽  
Ronen Verker
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Space Environment ◽  
Scanning Calorimetry ◽  
Space Applications ◽  
Curing Conditions ◽  
Oligomeric Silsesquioxane

Thermally activated shape memory polymers (SMPs) can memorize a temporary shape at low temperature and return to their permanent shape at higher temperature. These materials can be used for light and compact space deployment mechanisms. The control of transition temperature and thermomechanical properties of epoxy-based SMPs can be done using functionalized polyhedral oligomeric silsesquioxane (POSS) additives, which are also known to improve the durability to atomic oxygen in the space environment. In this study, the influence of varying amounts of two types of POSS added to epoxy-based SMPs on the shape memory effect (SME) were studied. The first type contained amine groups, whereas the second type contained epoxide groups. The curing conditions were defined using differential scanning calorimetry and glass transition temperature (Tg) measurements. Thermomechanical and SME properties were characterized using dynamic mechanical analysis. It was found that SMPs containing amine-based POSS show higher Tg, better shape fixity and faster recovery speed, while SMPs containing epoxide-based POSS have higher crosslinking density and show superior thermomechanical properties above Tg. This work demonstrates how the Tg and SME of SMPs can be controlled by the type and amount of POSS in an epoxy-based SMP nanocomposite for future space applications.

PVAT - a Video Analysis Tool for Microgravity Posture Evaluation

1993 ◽  
Vol 37 (10) ◽  
pp. 749-753
Author(s):  
Mihriban Whitmore ◽  
Darlene Merced-Moore ◽  
Susan C. Adam
Keyword(s):  
Video Analysis ◽  
Body Movement ◽  
Body Part ◽  
Space Environment ◽  
Analysis Tool ◽  
Interactive Software ◽  
Space Applications ◽  
Video Footage ◽  
Input Parameters ◽  
Data Collection Technique

PVAT (Posture Video Analysis Tool) has been developed to meet the special needs of ergonomist and human factors analyst attempting to evaluate microgravity working posture from video footage. These specialists often have very little or no control over the video coverage. Moreover, the majority of Shuttle mission videos are not recorded for quantitative analysis. The purpose for developing PVAT is to provide a structured methodology in which these specialists could optimize the data collection technique. PVAT is specifically designed to document microgravity postures using videos of astronauts working in a space environment. The primary focus of PVAT is identifying the microgravity working postures and relating them to design issues in the workplace. This tool is currently an interactive software prototype written in SupercardTM. Users are provided with a set of input parameters such as: subject code, body orientation, targeted body part, camera view (given subject location), body movement, and rating level. A secondary set of inputs are also available which provides the ability to document extraneous behaviors or activities such as bending, reaching and interruptions. The tool allows for the input parameters to be customized as needed. Once the setup is defined, the user begins documenting the target posture and/or behaviors. The paper will discuss PVAT, its space applications and plans for its use.

Nanocomposites for Space Applications

2020 ◽  
pp. 191-222
Author(s):  
Rafael Vargas-Bernal ◽  
Margarita Tecpoyotl-Torres
Keyword(s):  
Electromagnetic Interference ◽  
Hybrid Nanocomposites ◽  
Space Environment ◽  
Self Healing ◽  
Two Dimensional ◽  
Space Applications ◽  
Aerospace Applications ◽  
Structural Applications ◽  
Two Dimensional Materials ◽  
Carbon Based Nanomaterials

A review on the advances achieved in the last 25 years in the development of hybrid nanocomposites based on polymer matrix for aerospace applications is presented here. The chapter analyzes the state-of-the-art strategies used in the design of materials that support the different conditions of the space environment. These materials are aimed primarily at structural applications, electromagnetic interference shielding, self-sensing, and self-healing, although they are not restricted to these applications. The introduction of metallic, ceramic, carbon-based nanomaterials such as carbon nanotubes and graphene, as well as two-dimensional materials have been used with a successful impact. Despite the significant advances that have been reached, much work must be done to achieve complete reliability for all properties required to protect the systems against the hazardous conditions found in space. Therefore, futuristic visions of the actions that must be carried out are raised in this chapter.

Performance of Elastomeric Silicones in Ablative and Space Environments

1966 ◽  
Vol 39 (4) ◽  
pp. 1247-1257 ◽  
Author(s):  
Clyde L. Whipple ◽  
John A. Thorne
Keyword(s):  
High Vacuum ◽  
Thermal Control ◽  
Heat Fluxes ◽  
Space Environment ◽  
Space Applications ◽  
Wide Range ◽  
Environmental Extremes ◽  
Temperature Ranges ◽  
Space Environments ◽  
Thermal Control Coatings

Abstract Elastomeric silicones are among the best materials available for many ablative and space applications. In ablative applications, these materials protect launching equipment, safeguard various parts of vehicles and spacecraft during flight, and shield re-entering spacecraft. Generally, elastomeric silicones are used where ablative conditions involve low to moderate heat fluxes and shear forces. Ablative characteristics of materials can vary widely depending on polymer type, fillers, and applications techniques, and no one elastomeric silicone will perform in a wide range of ablative missions. A good knowledge of the ablative characteristics of silicone materials is required to select the best candidates for a given application. In the space environment, silicones are often used for seals, thermal control coatings, potting materials, and other applications because they perform well over wide temperature ranges, and because they are inherently stable to high-vacuum and ultraviolet conditions. Data given in this paper illustrate that silicones show little weight loss or loss of properties on exposure to space environmental extremes. Furthermore, these losses can be made almost negligible by proper conditioning of the finished elastomer.

Space Environment Effect on Fluorinated Polymers

2003 ◽  
Vol 792 ◽  
Author(s):  
M. Chipara ◽  
D. L. Edwards ◽  
J. Zaleski ◽  
B. Hoang ◽  
B. Przewoski ◽  
...  
Keyword(s):  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Fluorinated Polymers ◽  
Space Applications ◽  
Environment Effect ◽  
Low Altitude ◽  
Low Earth Orbits ◽  
Degradation Of Materials ◽  
Earth Orbits

ABSTRACTThe effects of the space environment on polytetrafluorethylene and some fluorinated polymers, copolymers, and blends are critically reviewed. It is shown that in low altitude orbits such as Low Earth Orbit and Geostationary Orbit the presence of both ionizing radiation and atomic oxygen triggers a synergetic degradation of materials based on fluorinated polymers. The behavior is due to the lability of the in-chain alkyl radical to oxygen attack. It is concluded that fluorinated polymers should not be used as materials for space applications, as long as the mission implies low Earth orbits.

scholarly journals Large angle flexure pivot development for future science payloads for space applications

2019 ◽  
Vol 304 ◽  
pp. 07016 ◽  
Author(s):  
Peter Spanoudakis ◽  
Lionel Kiener ◽  
Florent Cosandier ◽  
Philippe Schwab ◽  
Laurent Giriens ◽  
...  
Keyword(s):  
Random Vibration ◽  
Performance Test ◽  
Test Bench ◽  
Large Angle ◽  
Lateral Shift ◽  
Space Environment ◽  
Small Displacement ◽  
Component Level ◽  
Space Applications ◽  
Future Science

An innovative design of a Large Angle Flexure Pivot (LAFP) is described. It combines the advantages of flexure mechanisms while surpassing one of their few flaws, small displacement strokes. The LAFP design exceeds these angular limitations to reach a deflection of 180° (±90°). The centre shifts laterally by less than ±35 μm throughout the full rotation range. The LAFP is meant to be mounted in pairs, coaxially and with the payload between them. The intended application of the LAFP is to angularly guide an optical component in a space environment for future science missions operating in a cryogenic environment. A dedicated performance test bench was developed and manufactured to test the pivot characteristics notably the lateral shift using Eddy current sensors. The test bench incorporates a representative dummy payload for mass and inertia. Extensive FEM analysis has been performed to validate the design at component level and further analysis with the pivots mounted with a representative payload on a test bench for random vibration, shock and thermal cycling environment. The second test bench for the vibration and shock tests has been manufactured incorporating a simplified launch locking device. The performance tests have confirmed a lateral shift of less than ±35 μm over an angular range of ±90°. The pivots have been successfully tested and survived vibration loads for high level sine at 24 g and random vibration at 12 grms in all three directions.

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