By Julie Cooper

Each month in “Slice of History” we’ll be featuring a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Anechoic Chamber — Photograph Number 383-5765Ac

This aerodynamic noise facility, also called an anechoic chamber, was used to study the noise generating mechanisms in supersonic and subsonic jets in the early 1970s. It was housed at NASA’s Jet Propulsion Laboratory in building 57 (which no longer exists) located next door to the wind tunnel that was in building 79 at the time. The large round opening in the wall is an exhaust silencer inlet. Standing next to it is Paul Massier, co-author of a technical report about this chamber. On the right is a support structure for microphones. Fiberglass wedge blocks cover the ceiling and walls, which were mostly reinforced concrete. Spaces were left open to allow for observation windows and instruments to record test data. There were also openings in the walls that allowed air to flow into the chamber to replace the air forced out during tests.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.