Impact of Space Junk

What is the impact of space debris on the Earth's atmosphere?
OPINION Physics Today (May 21, 2009)

Space.com: There is growing appreciation that outer space has become a trash bin, with the Earth encircled by dead or dying spacecraft, along with menacing bits of orbital clutter — some of which burns up in the planet's atmosphere.

PHOTO: depiction of tracked space debris, not to scale (ESA/AP)

But there is another line of research that needs exploring: The overall impact of human-made orbital debris, solid and liquid propellant discharges, and other space age substance abuse that winds up in a high-speed dive through Earth's atmosphere.

There's a convenient toss-away line that is in vogue: that such space refuse simply "burns up" — a kind of out of sight, out of mind declaration.

What chemistry is involved given the high heating during reentry of space leftovers made of tungsten, beryllium, aluminum, and lots of composite materials? The impact of these materials on Earth's atmosphere — top to bottom — would seem worthy of investigation. Source