System Architecture for a CubeSat DTE Laser Communication System

Small satellites and CubeSats are playing an increasingly larger role in technology demonstrations, research, and obtaining data for commercial use from space. As these use cases and applications for CubeSats increase and expand the need to get fast, secure and reliable access to the data gathered by the payloads on these spacecraft also increases. To support these developments AAC Hyperion together with TNO has developed a down-to-earth laser communication module for small satellites and CubeSats with a downlink capability of 1 Gbit/s, namely CubeCAT. One of the challenges that needed to be solved to ensure success was how to deal with the pointing of the unit both for up-link and down-link purposes. Once this could be achieved the next challenge was the stability of the pointing mechanism since the pointing accuracy and stability of the laser link directly affect the link budget and achievable data rate. In other words rejection of mechanical vibrations and other disturbances. The goal of the development project was to develop such a system with a form factor and mass suitable for implementation on CubeSats. This meant that a maximum volume of 1U was set as a requirement and a maximum mass of \u3c2 kg

Common ragweed (Ambrosia artemisiifolia L.): allergenicity and molecular characterization of pollen after plant exposure to elevated NO2

Ragweed pollen is the main cause of allergenic diseases in Northern America and the weed has become a spreading neophyte in Europe. Climate change and air pollution is speculated to affect the allergenic potential of pollen. The objective of this study was to investigate the effects of NO2 , a major air pollutant, under controlled conditions, on the allergenicity of ragweed pollen. Ragweed was exposed to different levels of NO2 throughout the entire growing season, and its pollen further analysed. Spectroscopic analysis showed increased outer cell wall polymers and decreased amounts of pectin. Proteome studies using 2D-difference gel electrophoresis and liquid chromatography-tandem mass spectrometry indicated increased amounts of several Amb a 1 isoforms and of another allergen with great homology to enolase Hev b 9 from rubber tree. Analysis of protein S-nitrosylation identified nitrosylated proteins in pollen from both conditions, including Amb a 1 isoforms. However, elevated NO2 significantly enhanced the overall nitrosylation. Finally, we demonstrated increased overall pollen allergenicity by immunoblotting using ragweed antisera, showing a significantly higher allergenicity for Amb a 1. The data highlight a direct influence of elevated NO2 on the increased allergenicity of ragweed pollen and a direct correlation with an increased risk for human health