While I was drinking my third cup of coffee this morning, I noticed some traffic on Twitter from people talking about their memories of the day the Space Shuttle Challenger blew up. Here’s mine.

I was working as the Chief Engineer of a company that built equipment used to transmit high-quality audio over satellite and cable systems. Analog stereo audio for television was just being rolled out, and we were developing equipment to allow stereo satellite audio feeds to be used with cable TV systems. In order to prevent interference, it was necessary to synchronized the audio subcarrier with the video’s horizontal sync signal. Because CNN’s signal was generally clean and usually available 24/7, we used it in our lab as generic video signal for testing.

On the morning of 28 January, 1986, I was setting up our prototype stereo generator for a test, and I looked up at the lab video monitor to verify we had a video feed. I saw the shuttle engines lighting up on the pad, and I went back to finishing my test setup. Then a puff of smoke on the video monitor caught my eye. I looked directly at the monitor and saw that something was wrong, so I turned up the audio on the CNN feed. It didn’t take long listening to the confusion to realize what had happened, and I went out break the news to my coworkers.