> Kind of sad to see that computers nowadays still lack what we call common sense. I mean the machine received negative altimeter data but if it had been able to just look around, it could have seen that this data was erroneous. Hell, considering the descent profile was carefully prepared, the computer should also have noticed that it was way too early to reach the ground and should have concluded that something was wrong with the altitude measure.

Well, computer vision is a different issue. Imagine you're a human sealed inside this thing, with no vision from the outside. You reach the point when the parachute's supposed to deploy, you feel something goes wrong - there's a big force, or it's in the wrong direction. Did the parachute rip off? Did it fail? You look at your two altimeters; one says that you're 3.5km up, one says that you're at almost ground level (that it's negative is a red herring I think - the probe knows the readings might be noisy and expects to handle that). What do you do?