[Porsche-O-Phile]

Paint weight adds up. In the earliest days of the shuttle program as some of you may remember, the ET (external fuel tank, which supported the orbiter and sat between the two solid boosters) was painted white to enhance the look of the assembly. The paint weight alone was 600 pounds - pretty significant when you're schlumping something uphill to orbital altitude / velocity. Later the "orange" tanks appeared for the remainder of the program - the untreated insulation color.

It does add up...