Discovery in space question

[Quiggers]

I find things that go into space fascinating and I have a serious question, which is probably bizarre, but it something I don't know, so fellow LRs...:

Space shuttles return to earth filthy. See the photo attached and there's Discovery in space, equally filthy. When they're launched they're pristine, so how come they get so covered in dust? Is our pollution really that bad and that high up? Or does all that come from the blast of the solid rocket bosters prior to launch?

Any ideas or expert opinions?

Cheers, GQ

[dobbo]

The tiles are burnt on re entry into the atmosphere, I have heard that it costs more to re tile a shuttle after it's been used than it is to actually build a new one.

[one_iota]

Not satisfied we are also turning near space into a dumping ground as we have done in Antarctica

Satelites damaged by human faeces ejected from the space station

Just google "Space Debris"