Movement Patterns of Carabid Beetles Between Heterogenous Crop and Noncrop Habitats

Habitats adjacent to crop fields can increase natural enemy populations by providing additional food, shelter and overwintering sites. While many studies have focused on the role of non-crop borders for supporting natural enemies, here we investigate the influence of adjacent crop habitats as well. We monitored the movement of carabid beetles (Coleoptera: Carabidae) between wheat fields and adjacent crop and non-crop habitats using bi-directional pitfall traps. We found greater movement of carabids from corn into wheat fields than from forest and soybean, with intermediate levels of movement from roadside vegetation. Additionally, significantly more carabids were captured moving into corn from wheat than into any other habitat. We also found that carabid community assemblages at habitat borders were different from those in the interior of wheat fields. Our findings suggest that agricultural ecosystems composed of a variety of both non- crop and crop habitats are necessary to maintain carabid abundance and diversity

The Space Survivability Test Chamber

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 (\u3c10-5 Pa) environments, temperature (~100 K to \u3e450 K), ionizing radiation, electron fluxes (\u3c10 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 (\u3c 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 rates. These measurements will serve to forecast sample radiation damage, predict lifetimes of electronics, and substantiate the ability of the chamber to mimic space environments. Specific tests include: modified efficiency of solar arrays; single event upsets and failure of commercial off-the shelf microcontrollers, memory, and sensors; structural damage and modifications of mechanical and electrical properties; changes in electron transport and arcing of materials; and modification of optical properties of glasses and polymeric materials

The Space Survivability Test Chamber

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 (\u3c10-5 Pa) environments, temperature (~100 K to \u3e450 K), ionizing radiation, electron fluxes (\u3c10 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 (\u3c 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 rates. These measurements will serve to forecast sample radiation damage, predict lifetimes of electronics, and substantiate the ability of the chamber to mimic space environments. Specific tests include: modified efficiency of solar arrays; single event upsets and failure of commercial off-the shelf microcontrollers, memory, and sensors; structural damage and modifications of mechanical and electrical properties; changes in electron transport and arcing of materials; and modification of optical properties of glasses and polymeric materials

Properties of Spacecraft Materials Exposed to Ionizing Radiation

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 be measured before and after SST exposure as well as a comparative study of SST ground-based tests to space flown samples. These include materials from the MISSE and PrintSat missions. The MISSE mission studied the effects of prolonged exposure to the LEO space environment properties of common spacecraft materials. PrintSat is a 3D printed CubeSat built by students at Montana State University constructed of WindForm, a nano-carbon-impregnated plastic; it will use on-board sensors to observe mechanical and electrical space-induced changes of WindForm. By comparison of ground-based tests in the SST to the results of these in-flight tests, the ability of the chamber to mimic the space environment and predict potential radiation damage effects will be quantified

Measurement of Effects of Long Term Ionizing Radiation on High Efficiency Solar Arrays

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 beta radiation source which produces a high energy spectrum similar to the geosynchronous space environment at more than 10X intensity for accelerated testing. The total ionizing dose is measured by a radiation sensitive diode and can be controlled by varying both the exposure time and distance to the source. Controlled temperature conditions are monitored with thermocouples. The critical measurement of power output is made through IV curves, using a standard solar light source (Class AAA Solar Simulator). IV curves can be monitored in situ, allowing for characterization with respect to total ionizing dose. More extensive IV response curves as a function of temperature and incident UV flux can be completed ex situ before and after SST exposure