After the loss of the shuttle Columbia on February 1, 2003 there were several reports of possible lightning strikes as the cause of the shuttle failure. Analysis of the infrasound records taken at the ground helped dispel these notions. In this talk I will review some of the interesting properties of acoustic propagation in the atmosphere and discuss the interpretation of the infrasound records obtained. As a result of the studies undertaken during the analysis of the shuttle signals an experimental program has been initiated to study the infrasound signals produced by explosives released at various altitudes. I will summarize the current state of planning of these experiments.