[Porsche-O-Phile]

Way faster than 4,000 fps in orbit - orbital velocity is about 17,500 mph (or 25,670 fps). You're right though - it would slow down a lot on its way back through the lower atmosphere although still be going at a pretty good clip when it slammed into the ground (or someone's shoulder). Obviously different pieces will have different terminal velocities hence the "debris field" created.

The Shuttle has (had) to do a lot of maneuvering/S-turns on the way back in order to slow down in roughly 1/2 an orbit. This thing is just going to free-fall right on in without the benefit of any such deliberate aerodynamic braking/speed bleed-off techniques, so I wouldn't be at all surprised if some pieces don't end up lasering into the ground at very high speeds and others just kind of go "thunk" without any major drama due to low(er) terminal Vs.

Should be interesting. I hope it ends up being observable as it comes in and doesn't just go "splash" without anyone getting to see anything.