the name along with the flavor text are essentially an exaggeration saying that the launcher will deal enough death through incinerating its targets with rocket blast's that the resultant ash will "blot out the sun", in the same way that if enough volcano's erupt around the planet at the same time, the resultant ash thrown into the atmosphere could eventually block sunlight, leaving the earth to freeze. Unlike with other weapons names and flavor text's, I don't believe this weapon is referring to anything historical. Just my opinion though.