When watching space rocket launches on TV, we generally do not hear sonic booms when the rockets break the sound barrier due to a few reasons:
Sound Propagation: Sound requires a medium, such as air or water, to propagate. In the vacuum of space, there is no air or any other medium to transmit sound waves. Therefore, even if the rockets create sonic booms, we would not be able to hear them because there is no medium for the sound to travel through.
Microphones and Audio Recording: The audio that accompanies space rocket launches on TV broadcasts is typically captured using microphones placed near the launch site or on the ground. These microphones are designed to pick up sounds within the atmosphere, where sound waves can propagate. Since sonic booms occur at high altitudes, well above the ground level where the microphones are located, they may not be picked up by the microphones or captured in the audio recording.
Delayed Broadcast: In many cases, the audio and video feeds of space rocket launches on TV broadcasts are not transmitted in real-time. There is often a delay between the actual event and its broadcast on television. Therefore, even if sonic booms were produced during the launch, the audio may be edited or omitted from the broadcast for various reasons.
It's worth noting that sonic booms are indeed generated by rockets and aircraft when they surpass the speed of sound within Earth's atmosphere. However, due to the factors mentioned above, we typically do not hear these sonic booms when watching space rocket launches on TV.