STS-105 Sonic boom

STS-105 returned to Earth on August 22, 2001. The shuttle Discovery passed about 40 degrees above the Southern horizon as seen from Houston. Closest approach to Houston occurred at about 1:08 PM CDT with landing occuring at 1:23 PM CDT. Below is the path of Discovery across the Southern U.S. The image is cropped from one on the NASA spaceflight web site.

STS-105 entry groundtrack (2590 bytes)

An attempt was made to photograph the shuttle as on earlier reentries. Due to the pass occuring in daylight and the presence of a thin haze, the vehicle was not seen. Fortunately the pass was close enough that a faint sonic boom could be heard approximately 5 minutes after the closest point of the pass.

At closest approach, Discovery was 56 statute miles from the observing point. Its altitude was about 170,000 feet and it was travelling at about Mach 16. During the pass it was rolled 77 degrees to the right.

Below are sound files of the sonic boom in two formats. The quality is not great as the recording was made using a laptop computer through its built-in microphone. The whine of the hard drive is almost as loud as the sonic boom itself. Despite this, the boom on the recording is a relatively faithful reproduction of what was heard during the event.

aiff format (16,459 bytes)

wav format (16,428 bytes)

A view of the waveform is shown in the graph below. The sonic boom is located about 1 second into the plot. The trace does not show the textbook N-wave shape of the pressure fluctuation during a sonic boom. This probably has something to do with the 56 miles of atmosphere the shock waves had to traverse.


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