When an aircraft of any kind goes faster than the speed of sound, it creates a sonic boom -- a noise that's the result of pressure waves on the plane's nose and tail. People on the ground can not only hear a sonic boom, they feel it as well.
NASA believes it might be possible to reintroduce supersonic jet travel without so much noise, like what was possible with the Concorde. As part of this goal, it's conducting research in a specially designed room to see just what kind of jet noise people would be willing to put up with.
NASA detailed the program in the below video, released Tuesday.
"What we're interested in is making a model of how to predict how annoyed people are going to be by different sonic boom sounds," Jonathan Rathsam says in the video. Rathsam is an aerospace technologist at NASA's Langley Research Center in Virginia where the sonic boom room is housed.
The room itself is set up to resemble a corner room in an ordinary house -- with some extraordinary enhancements. For starters, there are 52 subwoofers and 52 mid-range loudspeakers built into the walls that mimic the sound of the jets. Some of those sounds are taken from actual field recordings, while others are simulated.
The other distinguishing feature of the room is that test subjects sit in raised Adirondack chairs rather than on cushy sofas or easy chairs. These chairs don't have any padding and are able to transmit vibrations from shakers mounted below them to the people sitting in them.
In the study detailed in the new video, 33 people were asked to come to the room to experience a range of sounds and rate their level of annoyance with each.
"The goal is to build aircraft with sonic booms that are so quiet that they're acceptable," Rathsam says, adding somewhat mysteriously that "that appears to be within our capabilities."
While military jets can regularly exceed the speed of sound, the Concorde and a Russian airliner known as the Tupolev Tu-144, were the only commercial planes to do so. The Concorde was able to make the trip from New York to London in about 3.5 hours while traveling at twice the speed of sound (about 344 meters per second or 1128 feet per second in dry air).
Supersonic jets are currently banned over land. If NASA is able to create one that could go as fast as the Concorde without scaring the bejesus out of everyone on the ground, a similar flight time from New York to San Francisco might just be on the horizon.