Another damaged heat shield

Via NYT - Inspection Finds Debris Penetrated Shuttle’s Tiles

A close-up laser inspection by astronauts on the space shuttle Endeavour revealed on Sunday that a three-and-a-half-inch gouge penetrates all the way through thermal tiles on the shuttle’s belly, and left NASA officials urgently calculating whether a spacewalk for repairs is needed.

A chunk of insulating foam ricocheted off a fuel tank and smacked the shuttle during liftoff last week, carving out the gouge.

The unevenly shaped gouge, which straddles two side-by-side heat shield tiles and the corner of a third, is 3.5 inches long and just over 2 inches wide. The inspection on Sunday showed that the damage went through the one-inch-thick thermal tiles, exposing the felt material sandwiched between the tiles and the shuttle’s aluminum frame.

Mission managers expect to decide Monday or Tuesday whether to send astronauts out to patch the gouge.

I know that the mission managers want to avoid another Columbia disaster just as much as the rest of the country does. However, I am left wondering why this is becoming a recurrent problem with the space shuttle. Is it that newer technology is not actually better technology? What is the problem? It would seem that after Columbia they would have done everything in their power to stop the insulation from flying off in the first place. Maybe it is just time for the space shuttle technology to be retired, as I believe I have heard they've considered doing soon.