Yesterday wasn't the first time we have heard sonic booms in central Florida since the Space Shuttle stopped flying, but it was the first time we have heard sonic booms because of something that launch ed off of Launch Complex 39A (where the Apollo moon mission were launched from and it was also one of the Space Shuttle launch pads).
When the Space Shuttle's returned to Earth they would glide back unpowered and land like an airplane. But even though they were flying like an airplane, they were still bleeding off a lot of speed because they had just returned from space. During their descent through the atmosphere they would slow down but even as they would approach the Space Coast they would still be flying faster than the speed of sound...hence the sonic booms. For those of us that followed the Space Shuttle mission closely we would all breathe a sigh of relief when we heard those sonic booms because it meant our astronauts were almost home.
Fast forward a few years and the sonic booms were heard once again, but this time it was because of the Falcon 9 first stage flying back. SpaceX is trying to make as much of their Falcon 9 rocket as reusable as possible, so they after they launch the rocket and the 1st stage is jettisoned from the rocket the 1st stage flies back to the launch site so it can be used again. The 1st stage is also flying faster than the speed of sound, so we again hear sonic booms on the Space Coast.