Using MapReduce to improve the power generation of the International Space Station
William R. Marchetto · PhDT · 2014
The International Space Station (ISS) spends approximately 98% of its time in orbits that experience Earth eclipse. Since the station's solar arrays produce no power when in Earth's shadow, the total power generated decreases substantially, lowering the power budget available to experimental payloads. Therefore, increasing the power output during these eclipsed orbits would be of great benefit to the space station's scientific endeavors. ? The ISS's current solar array configuration tracks the Sun throughout each orbit, keeping each of its 16 solar panels perpendicular to the Sun at all times. While this is the optimal orientation for solar panels with unobstructed views of the Sun, the space station's solar arrays experience shadowing from the spacecraft's structure as well as from the other solar panels. Deviating from the Sun?tracking scheme at strategic points in certain orbits can provide an increase in power output. ? The goal of this research was to provide a programmatic solution that increases the power generation capabilities of the ISS in orbits experiencing Earth?eclipse without requiring any physical modifications to the space station's structure. To achieve this goal, a simulator was developed to model the ISS?Earth?Sun environment and calculate the power output of the station's solar arrays based on each panel's orientation and shadowing. Many combinations of array configurations were analyzed, taking into account the physical constraints of the gimbals responsible for rotating the solar panels. ? The power output of the ISS was improved for the subset of Earth?eclipsed orbits that experience a high degree of shadowing from the station's structure, resulting in an average energy increase of 1.08 kWh per orbit. The power gains were achieved by quickly rotating the solar arrays through the points in each orbit that experienced the highest degree of shadowing.