b'Aerospace | Engineer Innovationfacilities (sometimes over 1,000 cubic meters to accommodate large spacecraft) are filled with gaseous nitrogen which has a lower sound absorption coefficient than air. The noise is generated by modulators connected to horns placed in the chamber; the result is a noise level that can reach over 150 decibels (dB). In these facilities, engineers simulate the noise field that excites the satellite in the fairing of the launcher. In addition to its extensive offering formulti-channel data acquisition, Simcenter offers a comprehensive solution to control acoustic signals in the reverberant room.Acoustic testing in reverberant rooms is a safe, reliable and accurate testing method, while at the same time extremely costly and time-consuming. Satellite subsystems such as antennas or reflectors are also tested according to this method, often in medium-sized reverberant rooms.Over the past 15 years, the U.S. space industry has been trying alternative testing methods. Research projects evaluate methods that offer a more economical option as well as more flexibility to perform the tests away from sparse and costly-to-operate facilities. A Direct Field Acoustic eXcitation (DFAX) method, also named DFAT in the U.S., has been developed and is partly used today for qualification of North American satellites. DFAX has lower running costs and initial investment and offers the technical benefit of considerably shorter ramp-up time to level or better controllability in the lower frequency range of 20 hertz to 60 hertz (Hz). 13'