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Full-Text Articles in Physics
The Space Survivability Test Chamber, Katie Gamaunt, Heather Tippets, Alex Souvall, Ben Russon, Jr Dennison
The Space Survivability Test Chamber, Katie Gamaunt, Heather Tippets, Alex Souvall, Ben Russon, Jr Dennison
Posters
The Space Survivability Test chamber is a new ground-based research instrument being used for accelerated testing of environment-induced modifications of diverse samples. The chamber simulates space environment conditions, including neutral gas atmospheres and vacuum (<10-5 Pa) environments, temperature (~100 K to >450 K), ionizing radiation, electron fluxes (<10 eV to ~2½ MeV), and vacuum ultraviolet through mid-infrared photon fluxes. This versatile test chamber is well-suited for cost-effective testing of complete systems up to the size (< 20 cm dia.) of a 1U CubeSat, smaller components or electronics, and individual material samples. Multiple in-flux or in-situ space survivability and radiation exposure tests can be performed simultaneously, as well as extensive before and after ex-situ tests. Currently the chamber is performing a series of radiation experiments using a Sr90 beta radiation source which approximately mimics the geostationary high energy electron spectra at ~4-10X accelerated …
Density Of State Models Of Steady-State Temperature Dependent Radiation Induced Conductivity, Jodie Corbridge Gillespie, Jr Dennison
Density Of State Models Of Steady-State Temperature Dependent Radiation Induced Conductivity, Jodie Corbridge Gillespie, Jr Dennison
Posters
Radiation induced conductivity (RIC) occurs when incident radiation deposits energy and excites electrons into the conduction band of insulators. The magnitude of the enhanced conductivity is dependent on a number of factors including temperature and the spatial- and energy-dependence and occupation of the material’s distribution of localized trap states within the band gap—or density of states (DOS). Expressions are developed for steady-state RIC over an extended temperature range, based on DOS models for highly disordered insulating materials. A general discussion of the DOS of disordered materials can be given using two simple distributions: one that monotonically decreases below the band …
Properties Of Spacecraft Materials Exposed To Ionizing Radiation, Alex Souvall, Gregory Wilson, Katie Gamaunt, Ben Russon, Heather Tippets, Jr Dennison
Properties Of Spacecraft Materials Exposed To Ionizing Radiation, Alex Souvall, Gregory Wilson, Katie Gamaunt, Ben Russon, Heather Tippets, Jr Dennison
Posters
The effects of ionizing radiation damage on the various properties of spacecraft materials resulting from exposure in the Space Survivability Testing chamber (SST) are being studied with both ex situ and in situ tests. The SST is a ground based test facility designed to mimic low earth orbit (LEO), and geosynchronous orbit to test potential environmental-induced modifications to small satellites , and materials. Tests described here expose spacecraft materials to a Sr90 ionizing beta radiation source at room temperature and in high vacuum. Ex situ optical transmission/reflectivity measurements glass samples will monitor optical darkening. Properties of polymeric samples will …
Dependence Of Electrostatic Field Strength On Voltage Ramp Rates For Spacecraft Material, Krysta Moser, Allen Andersen, Jr Dennison
Dependence Of Electrostatic Field Strength On Voltage Ramp Rates For Spacecraft Material, Krysta Moser, Allen Andersen, Jr Dennison
Posters
Previous tests done by the USU Materials Physics Group (MPG) using our electrostatic discharge (ESD) custom vacuum chamber have found that, for the polymeric materials polyimide and low density polyethylene (LDPE), the electrostatic field strength at breakdown depends on the voltage ramp rate applied across the materials. At ramp rates an order of magnitude lower than the maximum recommended rate of 500 V/s, the breakdown electrostatic field strength was also found to be significantly lower. The data from these tests were compared to a microscopic mean field theory for dielectric breakdown in highly disordered insulating materials. We present new ramp …
Measurement Of Effects Of Long Term Ionizing Radiation On High Efficiency Solar Arrays, Ben Russon, Heather Tippets, Gregory Wilson, Katie Gamaunt, Alex Souvall, Jr Dennison
Measurement Of Effects Of Long Term Ionizing Radiation On High Efficiency Solar Arrays, Ben Russon, Heather Tippets, Gregory Wilson, Katie Gamaunt, Alex Souvall, Jr Dennison
Posters
Degradation of power output efficiency for high-efficiency multilayer solar arrays due to ionizing radiation is measured using the Space Survivability Test chamber. Exposure to ionizing radiation disrupts the crystalline structure and can reduce solar array power output to the point that it no longer provides adequate output capacity. This can be a significant concern, particularly in the harsh environment of space where radiation dose rate is significantly higher and replacing components is often impossible. Ionizing radiation is simulated in a controlled environment to allow measurement and characterization of the power output of solar arrays, using a 100 mCi encapsulated Sr90 …