I was stationed at Brookley AFB in Mobile,Alabama at that time. It was common for T-38 aircraft piloted by astronauts to stop at Brookley enroute from Houston to Cape Canaveral. I assisted the Sargeant (who was a forecaster) who gave these three astronauts their enroute weather briefing from Brookley to Canaveral. I was a weather observer. All three came into BaseOps and the weather office for their clearance and weather briefing. We were shocked and saddened when we heard of this sad event. Sad indeed. More on reddit.com

Spaceflight will never tolerate carelessness, incapacity, and neglect. Somewhere, somehow, we screwed up. It could have been in design, build, or test. Whatever it was, we should have caught it. We were too gung ho about the schedule and we locked out all of the problems we saw each day in our work. Every element of the program was in trouble and so were we. The simulators were not working, Mission Control was behind in virtually every area, and the flight and test procedures changed daily. Nothing we did had any shelf life. Not one of us stood up and said, 'Dammit, stop!' I don't know what Thompson's committee will find as the cause, but I know what I find. We are the cause! We were not ready! We did not do our job. We were rolling the dice, hoping that things would come together by launch day, when in our hearts we knew it would take a miracle. We were pushing the schedule and betting that the Cape would slip before we did. From this day forward, Flight Control will be known by two words: 'Tough' and 'Competent.' Tough means we are forever accountable for what we do or what we fail to do. We will never again compromise our responsibilities. Every time we walk into Mission Control we will know what we stand for. Competent means we will never take anything for granted. We will never be found short in our knowledge and in our skills. Mission Control will be perfect. When you leave this meeting today you will go to your office and the first thing you will do there is to write 'Tough and Competent' on your blackboards. It will never be erased. Each day when you enter the room these words will remind you of the price paid by Grissom, White, and Chaffee. These words are the price of admission to the ranks of Mission Control Gene Kranz - NASA Flight Director More on reddit.com

For those who don't know, Apollo 1 was to be the first manned mission of the Apollo program. It was intended to reach low Earth orbit, but it never got off the ground. During a launch rehearsal, an electrical fire broke out in the cabin, and the craft's door was stuck, as there was too much air pressure in the cabin compared to outside. All three crew members died. Manned missions were put on hold for 20 months to address the safety issues that led to the tragedy, and their next attempt at a manned launch, Apollo 7, was a success. More on reddit.com

Just as important as the positive result of getting to the Moon was avoiding the negative result: having had to perfect the spacecraft to the point where it never suffered catastrophic failures in deep space. It's actually quite amazing that all fatal accidents so far have occurred in phases of flight where accident investigation had something to work with later on. Losing all telemetry from a spacecraft on its way to the Moon and never hearing from it again would likely have wrecked the whole space program on a level we can't really appreciate today. More on reddit.com