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Abstract: The Radio Aurora Explorer (RAX) is a triple CubeSat that launched on November 19, 2010. RAX was designed to study plasma irregularities in the polar lower ionosphere (80–300km), and is the first CubeSat mission funded by the United States National Science Foundation. The scientific mission requires attitude knowledge within 5° (), and a custom attitude determination subsystem was developed for the mission. The subsystem utilizes rate gyros, magnetometers, coarse sun sensors, and an extended Kalman filter, and was designed to be a simple, low cost solution to meet the attitude determination requirements. In this paper, we describe the design, implementation, and testing of the RAX attitude determination subsystem, including derivation of the determination requirements, sensor selection, the integrated hardware design, pre-flight sensor calibration, and attitude estimation algorithms. The paper is meant to serve as a resource for others in the small satellite and nanosatellite communities, as well as a critical reference for those analyzing RAX data. Lessons learned from the design and performance of the RAX determination subsystem will be used in future designs of attitude determination systems for small satellites and similar platforms, such as high altitude balloons and autonomous aerial vehicles. [Copyright &y& Elsevier]

Abstract: The Space Environment Viability of Organics (SEVO) experiment is one of two scientific payloads aboard the triple-cube satellite Organism/ORganic Exposure to Orbital Stresses (O/OREOS). O/OREOS is the first technology demonstration mission of the NASA Astrobiology Small Payloads Program. The 1-kg, 1000-cm3 SEVO cube is investigating the chemical evolution of organic materials in interstellar space and planetary environments by exposing organic molecules under controlled conditions directly to the low-Earth orbit (LEO) particle and electromagnetic radiation environment. O/OREOS was launched on November 19, 2010 into a 650-km, 72°-inclination orbit and has a nominal operational lifetime of six months. Four classes of organic compounds, namely an amino acid, a quinone, a polycyclic aromatic hydrocarbon (PAH), and a metallo-porphyrin are being studied. Initial reaction conditions were established by hermetically sealing the thin-film organic samples in self-contained micro-environments. Chemical changes in the samples caused by direct exposure to LEO radiation and by interactions with the irradiated microenvironments are monitored in situ by ultraviolet/visible/near-infrared (UV/VIS/NIR) absorption spectroscopy using a novel compact fixed-grating CCD spectrometer with the Sun as its light source. The goals of the O/OREOS mission include: (1) demonstrating key small satellite technologies that can enable future low-cost astrobiology experiments, (2) deploying a miniature UV/VIS/NIR spectrometer suitable for in-situ astrobiology and other scientific investigations, (3) testing the capability to establish a variety of experimental reaction conditions to enable the study of astrobiological processes on small satellites, and (4) measuring the chemical evolution of organic molecules in LEO under conditions that can be extrapolated to interstellar and planetary environments. In this paper, the science and technology development of the SEVO instrument payload and its measurements are described. [Copyright &y& Elsevier]

Abstract: In the early to mid-2000s, NASA made substantial progress in the development of solar sail propulsion systems. Solar sail propulsion uses the solar radiation pressure exerted by the momentum transfer of reflected photons to generate a net force on a spacecraft. To date, solar sail propulsion systems were designed for large robotic spacecraft. Recently, however, NASA has been investigating the application of solar sails for small satellite propulsion. The NanoSail-D is a subscale solar sail system designed for possible small spacecraft applications. The NanoSail-D mission flew on board the ill-fated Falcon Rocket launched August 2, 2008, and due to the failure of that rocket, never achieved orbit. The NanoSail-D flight spare is ready for flight and a suitable launch arrangement is being actively pursued. This paper will present an introduction solar sail propulsion systems and an overview of the NanoSail-D spacecraft. [ABSTRACT FROM AUTHOR]