How does that work? You need a combined reflective area equivalent to the amount of radiative power you want block. So let's say that you want to block just 0.001% of the Sun's incident power on Earth. According to my calculations, that represents a total reflective area of approximately 1275 km^2. And those have to be directly in between the Sun and Earth at any given time. If you're on an orbit around Earth, the best that you'll get is in the LEO, where only half of those satellites will be in that condition on average at any given time. So, how many satellites (of any size class) will you need for that?