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.
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.
