scholarly journals Low Earth Orbital Atomic Oxygen Interactions with Spacecraft Materials

2004 ◽  
Vol 851 ◽  
Author(s):  
Bruce A. Banks ◽  
Kim K. de Groh ◽  
Sharon K. Miller
Keyword(s):  
Atomic Oxygen ◽  
Protective Coatings ◽  
Low Earth Orbit ◽  
Oxidation Products ◽  
Textured Surfaces ◽  
Aluminum Coatings ◽  
Volatile Oxidation Products ◽  
Residual Atmosphere ◽  
The Impact ◽  
Atomic Oxygen Erosion

ABSTRACTAtomic oxygen, formed in Earth's thermosphere, interacts readily with many materials on spacecraft flying in low Earth orbit (LEO). All hydrocarbon based polymers and graphite are easily oxidized upon the impact of ∼4.5 eV atomic oxygen as the spacecraft ram into the residual atmosphere. The resulting interactions can change the morphology and reduce the thickness of these materials. Directed atomic oxygen erosion will result in the development of textured surfaces on all materials with volatile oxidation products. Examples from space flight samples are provided. As a result of the erosive properties of atomic oxygen on polymers and composites, protective coatings have been developed and are used to increase the functional life of polymer films and composites that are exposed to the LEO environment. The atomic oxygen erosion yields for actual and predicted LEO exposure of numerous materials are presented. Results of in-space exposure of vacuum deposited aluminum protective coatings on polyimide Kapton indicate high rates of degradation are associated with aluminum coatings on both surfaces of the Kapton. Computational modeling predictions indicate that less trapping of the atomic oxygen occurs, with less resulting damage, if only the space-exposed surface is coated with vapor deposited aluminum rather than having both surfaces coated.

Monte Carlo Modeling of Atomic Oxygen Interaction with Protected Polymers for Projection of Materials Durability in Low Earth Orbit

1992 ◽  
Vol 278 ◽  
Author(s):  
Bruce A. Banks ◽  
Bruce M. Auer ◽  
Sharon K. Rutledge ◽  
Linda Gebauer ◽  
Edward A. Sechkar
Keyword(s):  
Monte Carlo ◽  
Atomic Oxygen ◽  
Protective Coatings ◽  
Polymeric Materials ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Textured Surfaces ◽  
Photovoltaic Array ◽  
Defect Sites ◽  
Oxygen Interaction

AbstractAtomic oxygen in low Earth orbit (LEO) readily attacks and oxidizes exposed spacecraft polymeric materials such as polyimide Kapton photovoltaic array blankets. The application of thin film silicon dioxide protective coatings can greatly extend the useful life of such materials in LEO. A Monte Carlo computational model has been developed which simulates atomic oxygen interaction with polymeric and protective coating materials for both ground laboratory and in-space experiments, allowing the determination of the geometrical shape of atomic oxygen attack of protected polymeric materials at defect sites in protective coatings. Modeling of attack of unprotected carbon-carbon composite materials predicts textured surfaces suitable for high emittance radiators. Results for fiberglass composites indicate loss of the matrix polymer leading to friable fibers. The computational modeling to project in-space performance based on ground laboratory testing predicts mass loss per fluence in space to be approximately one third that observed in plasma ashers.

Leveling Coatings for Reducing Atomic Oxygen Defect Density in Graphite Fiber-Epoxy Composites

1994 ◽  
Vol 37 (3) ◽  
pp. 26-31
Author(s):  
D. Jaworske ◽  
K. de Groh ◽  
G. Podojil ◽  
T. McCollum ◽  
J. Anzic
Keyword(s):  
Atomic Oxygen ◽  
Defect Density ◽  
Protective Coatings ◽  
Protective Layer ◽  
Oxide Coating ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Protective Oxide ◽  
Low Viscosity ◽  
Defect Sites

Pinholes or other defect sites in a protective oxide coating provide pathways for atomic oxygen in low-Earth orbit to reach underlying material. Onc concept for enhancing the lifetime of materials in low-Earth orbit is to apply a leveling coating to the material prior to applying any reflective and protective coatings. Using a surface-tension-leveling coating concept, a low-viscosity epoxy was applied to the surface of several composite coupons. A protective layer of 1000 Å of SiO2 was deposited on top of the leveling coating, and the coupons were exposed to an atomic oxygen environment in a plasma asher. Pinhole populations per unit area were estimated by counting the number of undercut sites observed by scanning electron microscopy. Defect density values of 180,000 defects/cm2 were reduced to about 1000 defects/cm2 as a result of the applied leveling coating. These improvements occur at a mass penalty of about 2.5 mg/cm2.

Volume Diffusion of Atomic Oxygen in α-SiO2 Protective Coating

2000 ◽  
Vol 12 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Masahito Tagawa ◽  
Kumiko Yokota ◽  
Nobuo Ohmae ◽  
Hiroshi Kinoshita
Keyword(s):  
Protective Coating ◽  
Photoelectron Spectroscopy ◽  
Atomic Oxygen ◽  
Diffusion Length ◽  
Volume Diffusion ◽  
Protective Coatings ◽  
Oxide Thickness ◽  
Low Earth Orbit ◽  
Minimum Thickness ◽  
Increasing Temperature

The minimum thickness for an amorphous silicon dioxide (α-SiO2) protective coating required to prevent volume diffusion of atomic oxygen in a low Earth orbit (LEO) was evaluated by measuring the oxide thickness formed on Si(001) wafers in a hyperthermal atomic oxygen beam. The thickness of oxide film was measured by x-ray photoelectron spectroscopy. The diffusion length of atomic oxygen in α-SiO2 at temperatures between 297 K and 493 K, where exterior surfaces of a spacecraft may be heated in LEO, shows temperature and flux dependences, i.e. the diffusion length of atomic oxygen increases with increasing temperature and beam flux. It was also demonstrated that the atomic oxygen fluence is not a primary factor of the diffusion length since the oxide growth obeys a parabolic law. The ground-based testing condition to evaluate performances of protective coatings are also discussed, based on the experimental data obtained in the experiments.

Improved atomic oxygen erosion resistance of the carbon fibre–epoxy interface with polyhedral oligomeric silsesquioxane

2020 ◽  
Vol 32 (6) ◽  
pp. 681-692 ◽  
Author(s):  
Dan Zhao ◽  
Jinmei He ◽  
Nan Zheng ◽  
Yudong Huang
Keyword(s):  
Carbon Fibre ◽  
Photoelectron Spectroscopy ◽  
Atomic Oxygen ◽  
Erosion Resistance ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Low Earth Orbit ◽  
Siloxane Oligomers ◽  
Interlaminar Shear ◽  
Oligomeric Silsesquioxane ◽  
Atomic Oxygen Erosion

Polyhedral oligomeric silsesquioxane (POSS) was grafted onto the surface of carbon fibres (CFs) to fabricate carbon fibre/epoxy (CF/EP) composites with improved interlaminar shear strength (ILSS) and atomic oxygen (AO) erosion resistance. POSS-CF was prepared by reacting amine groups on the pretreated CF surface with the POSS to form a continuous uniform layer of siloxane oligomers. X-Ray photoelectron spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy demonstrated that POSS was successfully grafted onto the CF surface. The ILSS and AO erosion resistance of the POSS-treated CFs and CF-EP interface were improved because a SiO2 passivation layer formed with AO exposure, especially with POSS-EP0409. This is an effective solution for enhancing the interfacial bonding force and interfacial AO erosion resistance for the low-Earth orbit environment.

Effects of atomic oxygen on epoxy-based shape memory polymer in low earth orbit

2017 ◽  
Vol 29 (6) ◽  
pp. 1081-1087 ◽  
Author(s):  
Qiao Tan ◽  
Fengfeng Li ◽  
Liwu Liu ◽  
Hetao Chu ◽  
Yanju Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Atomic Oxygen ◽  
Shape Memory Polymer ◽  
Mechanical Tests ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Oxygen Exposure ◽  
Static Mechanical ◽  
Atomic Oxygen Erosion ◽  
Atomic Oxygen Exposure

Atomic oxygen is a dominant component of the low earth orbit and can erode most spacecraft polymeric material. In this article, the atomic oxygen erosion resistance tests of an epoxy-based shape memory polymer are carried out in a ground-based atomic oxygen simulator with a vacuum space chamber. The samples, before and after the atomic oxygen exposure, are compared in appearance, surface morphology, mass, main component, dynamical and static mechanical properties, and shape memory properties. The atomic oxygen exposure causes oxidization reaction of the material, which leads to surface roughen and mass loss, while the shape memory polymer main components remain same. The results of dynamical and static mechanical tests indicate that the atomic oxygen exposure has little effect on the storage modulus and glassy transition temperature (Tg), whereas the elongation, elastic modulus, tensile strength, and yield strength decrease since the atomic oxygen exposure gives rise to tiny cracks. The shape memory property has rarely changed since the atomic oxygen erosion is mainly located near the surface of the sample.

Atomic Oxygen Resistant Films for Multi-Layer Insulation

2000 ◽  
Vol 12 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Peter Schuler ◽  
H Bob Mojazza ◽  
Ross Haghighat
Keyword(s):  
Atomic Oxygen ◽  
Vacuum Ultraviolet ◽  
Thermal Control ◽  
Radiation Stability ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Advanced Materials ◽  
Validation Tests ◽  
Atomic Oxygen Erosion

A series of advanced polymer films from Triton Systems is being developed to meet the challenges of harsh space environmental effects, lighter weight requirements and superior thermal control performance demands. With support from NASA, Triton Systems Inc has developed advanced new materials for thermal control films with exceptional properties and durability in the space environment. These films known as TOR™ and TOR-LM™ are amber coloured, mechanically sound, produced in continuous rolls and have undergone substantial ground-based simulation and confirming space validation tests. These films are highly resistant to atomic oxygen erosion, and have excellent vacuum ultraviolet radiation stability in ground-based simulation tests. Two applications for these films include large inflatable structures that are either deployed in low earth orbit (LEO) or travel through a LEO orbit into higher orbits, and as outer metallized layers in multi-layer insulation (MLI) blankets. This paper discusses the processing of these advanced materials into thin films, metallization of the films and characterization of their environmental durability as well as other physical, optical, thermal and mechanical properties.

scholarly journals The Effect of Low Earth Orbit Atomic Oxygen Exposure on Phenylphosphine Oxide-Containing Polymers

2000 ◽  
Vol 12 (1) ◽  
pp. 43-52 ◽  
Author(s):  
John W Connell
Keyword(s):  
Thin Film ◽  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Earth Orbit ◽  
Cooperative Effort ◽  
Flight Experiment ◽  
Oxygen Exposure ◽  
Atomic Oxygen Exposure ◽  
Phenylphosphine Oxide

Thin films of phenylphosphine oxide-containing polymers were exposed to low Earth orbit aboard a space shuttle flight (STS-85) as part of flight experiment designated Evaluation of Space Environment and Effects on Materials (ESEM). This flight experiment was a cooperative effort between the NASA Langley Research Center (LaRC) and the National Space Development Agency of Japan (NASDA). The thin-film samples described herein were part of an atomic oxygen exposure (AOE) experiment and were exposed to primarily atomic oxygen (∼1×1019 atoms cm−2). The thin-film samples consisted of three phosphine oxide-containing polymers (arylene ether, benzimidazole and imide). Based on post-flight analyses using atomic force microscopy, x-ray photo-electron spectroscopy and weight loss data, it was found that the exposure of these materials to atomic oxygen (AO) produces a phosphorus oxide layer on the surface of the samples. Earlier work has shown that this layer provides a barrier towards further attack by AO. Consequently, these materials do not exhibit linear erosion rates which is in contrast with most organic polymers. Qualitatively, the results obtained from these analyses compare favourably with those obtained from samples exposed to AO and/or an oxygen plasma in ground-based exposure experiments. The results of the low Earth orbit AO exposure on these materials will be compared with those of ground-based exposure to AO.

Sign in / Sign up

Export Citation Format

Share Document