Accident waiting to happen

This worries me a great deal. I'm no Rocket Scientist, but it seems an awful lot like the problems on the space shuttle that caused the Columbia disaster have not been solved at all.

The only thing anyone really knows for sure about the Columbia accident was that the shuttle systems were functioning normally up until the point where mission control lost contact with the crew as they re-entered the atmosphere. What happens from that point forward is that the shuttle must maintain a specific angle throughout re-entry so that the protective tiles on it's underbelly prevent the ship from burning up. The problem that started this whole disaster happened after that point.

The tiles have been a source of problems for years. Even the first space shuttle mission astronauts reported missing tiles that they could see visually were missing from protected areas of the shuttle. The risk is that crucial areas of the space shuttle underbelly could become exposed without protection to the large temperatures of re-entry. NASA whenever it would receive these reports made the determination that the risk was an acceptable one and the crew made re-entry and nothing happened each time.

However, two things bothered me about the results of the accident review board. They found evidence that foam from the external fuel tank of the shuttle fell and hit the wing of he shuttle. But that doesn't neccessarily mean that it knocked off tiles off the wing. For all we know the shuttle instrumentation may have had some sort of fatal flaw that made the shuttle loose control in re-entry.

This is not a new problem, footage of foam hitting the wing can also be found on other previous misions. Those crews made it home safely. Did they even ask the question was there any tile damage found in the locations of the foam impacts shown in the footage on those missions? You need to prove your theories after all. If they didn't that means the review board really doesn't have conclusive evidence of anything.

Second let's suppose that the foam was infact the cause of the disaster. The most important thing an Engineer can do when tackling a problem is ask the question "why?" five times. The shuttle burned up on re-entry. Why? Because tiles were missing from the wing. Why? Because frequently tiles will fall off from the wing from vibrations or falling foam or other causes. Why? Because the space shuttle was designed to ride not on the top of the launch system but in-line with it causing it to be the target of debry from the external fuel tank, and SRB's. Why? The wings need protection for re-entry, so these specific tiles were chosen. Why? So that they could removed when they got worn and replaced because the space shuttle was designed to be a reusable system.

And hence the true problem with the space shuttle. Originally the first space re-entry systems built by NASA were what they call ablative heat shields. These were shields that could never be used again. The tiles on the space shuttle were designed to be used over and over and were split into tile segments. Each segment is attached to the wing. This was supposed to be cheaper, but I have little doubt that this new system is more expensive than the old throw away one.

The basic problem of the tiles falling off the wing for a variety of causes has not been solved.

This could happen again.

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