Models Dropped From High-Altitude Balloons Record Sound Levels

Swedish aerospace company SSC has developed and conducted an advanced stratospheric balloon experiment to measure sonic booms on behalf of the Japanese space organization JAXA. The experiment was performed during two balloon flights with a first flight on May 7 and the second on May 16. The two drop tests were performed from Esrange Space Center, SSC's operational base for launch services.

Dr. Kenji Yoshida, Project Manager of D-SEND Project Team, said the tests appear to have resulted in good data. "We are happy to state that the performance of these complicated tests went according to plan," says Mr. Mikael Toyra, Project Manager at Esrange Space Center. "Each gondola released two heavy drop models in quick succession, making SSC the first to drop such heavy objects from a single balloon in sequence."

The D-SEND#1 experiment demonstrates a reduced sonic boom for aircraft with a non-conventional shape by releasing drop models from a high altitude (20-30 km) so that they reach supersonic speeds and produce sonic booms. The drop models include electronics that measure their motion, while a microphone system at lower altitudes (0-1 km) records the sonic booms.

SSC's engineers developed the balloon gondola and four drop models according to JAXA's specifications. Three of the drop bodies were equipped with an inertial measurement system and onboard telemetry system that downlinked real time data to the customer. JAXA used their own developed recording system on ground with microphones in the field.

FMI: www.sscspace.com