1. Roger Boisjoly
Roger Boisjoly wrote a memo about the limitations of the O-rings used in the Challenger space shuttle assembly. Though he managed to convince to set up an investigating committee to look into his concerns, it had no power, funding, and backing. Realizing it, he further raised his fears but fell into deaf ears. The blatant ignorance by the authorities caused the explosion of the shuttle, killing all its seven crew.