At the time of the Challenger Disaster I was working on the West Coast Shuttle Project, and the week before the disaster, the Safety Director there resigned saying that he would not be part of an endeavor that would inevitably get people killed. Sadly, he was too prophetic. The whole Shuttle program was riddled with problems caused mostly by schedules and egos.
The whole Shuttle program was riddled with problems caused mostly by schedules and egos.
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...and an intrinsically flawed design that placed the shuttle alongside the main fuel tank of the main booster and the two solid propellent boosters. This created two potential fatal flaws, each of which caused the catastrophic failure on two of the shuttles.
In earlier designs like Saturn or Atlas, the crew capsule sat atop the boosters and the capsule included a launch escape system (LES) which could propel the capsule up and away from a failing or exploding booster. The challenger took the brunt of the explosion of the two solid booster engines.
The main fuel tank on a liquid propelled rocket inevitably sheds ice buildup on launch as water freezes out on the surface due to the chilled liquid rocket propellent. When the capsule rides atop the booster, the ice falls harmlessly. In the case of the later Columbia shuttle disaster, chunks of ice fractured or damaged the heat absorbing tiles on the bottom of the shuttle. There was enough damage that a hole in the shielding allowed the superheated air of reentry to penetrate the hull destroying the shuttle.