looking at it more plainly the satellite only has 18 m^2 reflective surface are so if it hypothetically could perfectly reflect it to earth it could at most add equalient of that in solar energy as harvested electricity that would mean at best added 3.6kW meaning at $40/MWH it would generate about $3.5/day so it would take 235 years to pay itself back, almost a millenia if it only helps 6h/day