NASA resisted the urge to launch STS-122 with less than well understood Engine Cut Off sensor anomalies last week. Was this the right thing to do? I think so, it showed courage and good engineering sense to delay the launch and figure out the root cause of the erratic sensor readings.
There are those who argue that we really don't need the ECO sensors in the Space Shuttle system. These sensors shut the main engines down if they detect an impending fuel depletion before planned Main Engine Cutoff (MECO). If the main engines were not cut off and allowed to run the fuel tanks dry, an explosion would almost certainly result, with a catastrophic loss of vehicle and crew. The argument is that the burn and fuel loading calculations are precise enough that such a situation could not happen realistically.
On the other hand, we have data that appear to indicate that we have come close to such events in the past.
In light of this uncertainty, I think NASA made the right call. What do you think?