We all know the NASA method of re-entry Big shower of sparks and that's the scientists on the ground.

However, given a vehicle of 40,000 LB or 20,000Kg
travelling at say 3 miles per second at 200 miles above earth.

Now descend, trailing a parachute 600 feet in diameter or 282,000 square feet in cross-sectional area. Parachute is opened while in zero gravity by using small inflated rubber tubing annular rings in the rim of the chute.

Given at some point the density of atmosphere rises from zero to say 0.002 kg/m3

Given that drag coefficient is 0.7 for a parachute which eventually drags/spills out as it progressively collects molecules of air as it descends.

Best result I can figure is a terminal velocity of 116 m/sec

So is the math wrong or what ? If the chute fills progressively from an empty vacuum into thicker and thicker air, there should be no sudden explosive fill so no destructive force and I guess more and more drag and decelleration as it falls...

see calculator at http://www.calctool.org/CALC/eng/aerospace/terminal

Comments please.