To understand the composition of regolith on distant bodies it is important to make quantitative measurement of its composition. However, many instruments on board space missions can only make qualitative measurements. The SOil Preparation SYStem (SOPSYS) designed for the Phobos-grunt mission in 2011 was a unique spacecraft subsystem that can grind, sieve, transport and measure samples of regolith in the absence of gravity. Its mission was to produce a compact plug of regolith sample composed of particles no larger than 1 mm for a gas analytic package. It delivers a sample with specified volume enabling a quantitative analysis of the volatiles produced at different temperatures through heating. To minimize cross contamination, SOPSYS self-cleans after each sample is delivered. The apparatus was a cooperative development between China and Russia for the Phobos-Grunt mission to the Martian moon Phobos and will be reused on the upcoming reattempt of that mission and other similar missions. The paper presents an overview of the subsystem and the results of qualification model testing. The flight unit of SOPSYS has a low mass of 622 g including control electronics and compact dimensions of 247 mm by 102 mm by 45 mm.
Multifunctional power structures (MFPS) are fully integrated subassemblies that perform both structural and power functions for spacecraft. By combining functions across subsystems into single units, mass and volume savings can be achieved. Focusing on battery-based MFPS in Earth-orbiting spacecraft, the embedded lithium ion batteries that are used have strict temperature limits, outside of which efficiency and safety is compromised. Considering the limits of the model's prediction accuracy, numerical simulation has shown that a range of Earth orbits exist where an MFPS mounted in a deployed solar array would not require the addition of further thermal control with respect to the nonmultifunctional case. The numerical simulation consisted of a lumped parameter reduction of the model to a discrete set of layers. Thermal control is required to prevent overcooling of the battery in eclipse and to extend the range of orbits where MFPS can be used. An assessment of current thermal control was performed to establish the viability of each technology, with viability defined by feasibility and the mass of the system. The use of coatings, insulation, heaters, and phase-change materials were considered. It was found that the range of viable orbits is dependent on the quantity of MFPS savings that can be sacrificed.
Multifunctional spacecraft power structures are an incorporation of energy storage and generation into structures on a spacecraft. For the mass and volume saving benefits to be realised, the technology must be shown to be viable throughout the spacecraft’s lifetime. Firstly, commercially available batteries where built into a structural panel and tested to determine the battery’s capability to withstand the manufacturing cycle and the effect upon the mechanical characteristics of the panel. Secondly, a mathematical model was created to determine the temperatures a battery would experience in various earth orbits. It was found that spacecraft in most low earth orbits will require thermal control and that the addition of a phase change material is a feasible control solution.
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