shuttle deficiencies

The enginenerds(sic) at NASA know exactly what the problem is with the main fuel tank insulation flaking off. They decided some years ago to apply the insulation in a more environmentally friendly manner, changing the way it had been done and worked before. This change has brought death to astronauts and grounded the shuttle fleet. It has been part of engineering tradeoffs that began with the design of the shuttle in the seventies that forced crews to rely on just one, passive, system of heat shielding, rather than a redundant system involving both active and passive heat control. The attempt to save money in the design, and help the environment in the upgrades, has doomed the shuttle.