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WUSAT-SOLSPEC experiment

WUSAT (Engineering CubeSat)

The original Engineering project was to design a CubeSat. The CubeSat, a standardised satellite in the form of a 10cm cube usually with a weight under 1.33kg, is intended to make space technology accessible and affordable by scaling down the size and the costs of satellite technology by several orders of magnitude, made possible by standardisation of components and advances in microelectronics. Whereas a traditional, large satellite would weigh thousands of kilograms and cost in the order of hundreds of millions of pounds, getting a CubeSat into orbit may be carried out for well under £100 000. CubeSats that are to be launched using a standard deployer are generally standardised according to the CubeSat Design Specification that is produced and revised by the CubeSat Program at California Polytechnic (Cal Poly).

While the majority of CubeSat applications carried out so far or proposed for the future have been based around sending the satellites into Low Earth Orbit (LEO), either on solo missions or as larger constellations or clusters, there is also the possibility of using them to look at the middle atmosphere (50-100km above the Earth’s surface), beyond the reach of weather balloons or LEO satellites. This can be achieved by releasing the CubeSat and allowing it to fall through this range of altitudes.

SOLSPEC (Physics Payload)

The idea for the solar spectroscopy payload came from Professor Don Pollacco and his team in the University of Warwcik Physics department. The equipment to perform the experiment was then developed and designed by the WUSAT team and integrated into the CubeSat design.

The principle of spectroscopy is the subdivision of the electromagnetic spectrum through dispersion into wavelengths. Analysing spectra during the descent of a CubeSat can provide information about the nature of the atmosphere; Sodium and O2 gases emit wavelengths that form distinct spectra, and therefore the proportion of the atmosphere that is composed from these gases can be calculated. As the composition of the Earth’s atmosphere is known, the intensity data collected for these specified wavelength ranges can then be calibrated to the presence of these gases, and applied to other atmospheres using the length of atmosphere – the “atmospheric path length” – that light has travelled through to get to the CubeSat. Spectroscopy can be performed by splitting light into different wavelengths with prisms or diffraction gratings, or replacing this with photodiodes that each detect only a narrow band of wavelengths.