Development of a Ground Based Atomic Oxygen and Vacuum Ultraviolet Radiation Simulation Apparatus

Glicklin, Max Jay

doi:10.15368/theses.2012.116

Cited by 6 publications

(37 citation statements)

References 17 publications

(38 reference statements)

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“…Neutral molecules can also condense on material surfaces of a spacecraft; this can result in the degradation of thermal properties, solar array efficiencies, and optical sensors. [12] Plasma is present across all orbital regimes. Plasma is formed when an electron is hit with enough energy to escape the nucleus that it is electrically attracted to.…”

Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

“…Outgassing results for three tested materials subjected to outgassing in Micro-VCM, Simple schematic of capacitively coupled plasma system. [12] . shield.…”

Section: List Of Tablesmentioning

confidence: 99%

“…There are several modes of arcing, including electrostatic discharge, dielectric breakdown, metallization melt, bulk breakdown, surface breakdown, and induced currents. [12] Arcing can severely damage electronics onboard a spacecraft by inducing unwanted current through the components. [16] Other than arcing, plasma is also a concern for spacecraft because it can impede communications, distort navigation data, damage surface materials, and create plasma wakes that affect the performance of nearby spacecraft.…”

Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

“…Collisions with particulates can be catastrophic; particulates with such high kinetic energies can damage and destroy spacecraft surfaces and components. [12] Collisions are also a huge concern for any mission involving sending humans to space; collisions that create holes in spacesuits, shuttles, or capsules can subject humans to a depressurized environment and are very dangerous. [31] While it is clear that each specific environment poses a plethora of threats to spacecraft exposed to them, it is not enough to analyze the effects of each environment separately.…”

Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

“…This means that while it is very important to consider the effects of AO throughout the LEO regime, AO effects become less consequential as altitudes approach 800 km and higher; at higher orbits, AO effects are negligible and do not need to be considered. [12] Figure 1. Number density of atmospheric constituents relative to altitude based on the NRLMSISE model.…”

Section: Atomic Oxygenmentioning

confidence: 99%

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The Effects of Atomic Oxygen on the Outgassing Properties of Spacecraft Materials

Gurnee¹

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The space environment contains many harsh characteristics that are harmful to spacecraft and threaten the success of space missions. Atomic oxygen (AO) and outgassing are among the chief concerns that spacecraft engineers must design for in order to ensure the safety of a spacecraft. AO is monatomic oxygen (O1) that is created when Ultraviolet (UV) radiation photochemically disassociates diatomic oxygen (O2) in space. AO is the dominant atmospheric constituent between 175 and 600 km, and is a great concern in low earth orbits. Orbital AO has an average impact energy of 4.5 ± 1 eV with orbiting spacecraft and is also very reactive; this makes AO very corrosive to spacecraft materials. Outgassing is the process by which trapped and adsorbed gases are expelled from materials. The high temperatures and low pressure of the spacecraft environment exacerbate the process of outgassing. Outgassing is problematic for spacecraft because outgassed material can condense on sensitive surfaces such as optical and thermal surfaces, or the material can create clouds that impede sensors ability to observe their target. While it has been shown that many aspects of the spacecraft environment act synergistically together to further degrade spacecraft performance, there is very little information and data available on the interactions between AO and outgassing. Cal Poly's Space Environments Lab is equipped with an AO simulation vacuum chamber (MAX) and an outgas testing chamber (Micro-VCM) which is capable of testing materials for total mass loss (TML) and collected volatile condensable mass (CVCM) outgassing values. MAX and Micro-VCM were used in tandem to test different spacecraft materials in order to determine if AO exposure had any effect on the respective materials TML and CVCM values. Prior to conducting testing, Micro-VCM was refurbished and validated since it was recently donated to Cal Poly and was not in working order upon arrival. Three Sheldahl materials were tested: aluminum coated 1.0 mil Kapton tape, 2.0 mil Kapton film coated with ITO on one side and aluminum on the other, and 2.0 Kapton film coated with aluminum. The materials were exposed to an average AO fluence of 1.33 ± 0.130 × 10 21 atoms/cm 2 for AO testing. The TML and CVCM results from four of the six tests did not show any significant changes between AO samples and control samples, partially due to large error bars that stem from using a semi-microbalance instead of a full microbalance. However, the AO exposed ITO-Kapton-Al did show an increase in TML from -0.03 ± 0.09% to 0.19 ± 0.08% for one procedure, while the aluminum Kapton tape CVCM decreased from 0.81 ± 0.12% to 0.63 ± 0.12% for another procedure. These results show that two materials exhibited a change in their outgassing properties after AO exposure. More testing on the subject is warranted and should be conducted in order to collect more data points and begin defining trend lines that can further describe the effects of AO on outgassing.iv ACKNOWLEDGMENTS

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Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

“…Outgassing results for three tested materials subjected to outgassing in Micro-VCM, Simple schematic of capacitively coupled plasma system. [12] . shield.…”

Section: List Of Tablesmentioning

confidence: 99%

Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

Section: Spacecraft Environments Backgroundmentioning

confidence: 99%

Section: Atomic Oxygenmentioning

confidence: 99%

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The Effects of Atomic Oxygen on the Outgassing Properties of Spacecraft Materials

Gurnee¹

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Effects of space environmental exposure on photoemission yield of polyimide

Miyahara

Khan

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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Effects of Atomic Oxygen on the Vacuum-Induced Mass Loss Properties of a Variety of Spacecraft Materials

Harty¹

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The space environment influences spacecraft design and material selection in many ways. Two aspects of the space environment that were of interest for this research are the vacuum and atomic oxygen (AO) environments. This project used the outgassing testing chamber and the AO chamber in the Cal Poly Space Environments lab to test multiple common spacecraft materials and determine whether AO affects the outgassing properties of those materials. This research has relevant applications in the

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Development of a Ground Based Atomic Oxygen and Vacuum Ultraviolet Radiation Simulation Apparatus

Cited by 6 publications

References 17 publications

The Effects of Atomic Oxygen on the Outgassing Properties of Spacecraft Materials

The Effects of Atomic Oxygen on the Outgassing Properties of Spacecraft Materials

Effects of space environmental exposure on photoemission yield of polyimide

Effects of Atomic Oxygen on the Vacuum-Induced Mass Loss Properties of a Variety of Spacecraft Materials

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