Okay, let’s think about this. According to Wiki, low earth orbital velocity is around 7,800 m/s. Kinetic energy equals 1/2 the mass times the square of the velocity, so a 40 kilogram manhole cover at 7,800 m/s has 1.22*10^9 Joules of kinetic energy. The specific heat of iron is 0.45 J/g-K. That’s enough energy to raise the temperature of 40 kg of iron 7,270 K. Iron boils at 3,134 K. I think we can put this one to bed.