Assuming the orbit is at 200km, these mirrors could only focus the image of the Sun on a 1.7km wide disk (that's (Sun diameter)/(Sun's distance)×(Earth distance)).

Moreover, the Sun's illuminance is about 1kW/m2 around Earth. 10000×60m2 satellite will thetefore intercept 600MW, so that's 260W/m2 on the focussed area. You're not going to burn anything with that.