Japan Aerospace Exploration Agency (JAXA)
The Japan Aerospace Exploration Agency (JAXA) successfully conducted the first phase of the "Drop test for Simplified Evaluation of Non-symmetrically Distributed sonic boom*1" (D-SEND) twice on May 7 and 16, 2011 (Sweden Standard Time) at the Esrange Space Center in Sweden in cooperation with the Swedish Space Corporation (SSC). JAXA has, for the first time in the world, confirmed the validity of low sonic boom axisymmetric*2 design by a balloon drop test.
Establishing low sonic boom design technology is one of the highest priority issues for realizing silent supersonic transport. As part of silent supersonic research, JAXA is carrying out the two phased D-SEND project to validate its low sonic boom design concept and to contribute to the deliberation of international standards for sonic booms based on the acquired data.
In the first phase called D-SEND#1, two different axisymmetric bodies were dropped from a balloon, and the sonic booms, measured both in the air and on the ground, were compared with each other. Through this test, JAXA has successfully demonstrated its low sonic boom axisymmetric design concept technology which reduced the sonic boom by half.
The data obtained from the test is valuable as a reference for the validation of the sonic boom propagation analysis method and is expected to contribute to low-sonic boom studies in the future. JAXA has also established for the first time a new method of demonstrating the low sonic boom design concept in the form of a balloon drop test.
JAXA expresses our sincere gratitude to the Swedish Space Corporation and all parties that provided assistance in this demonstration test.
*1 sonic boom
A sonic boom is a kind of impulsive sound of shockwaves, similar to thunder, generated by supersonic flight
Typical axisymmetric shapes include cone, cylinder, etc.
For more details, please refer to the following website:
|Place:||Swedish Space Corporation (SSC), at Esrange Test Site (Kiruna, Sweden)|
|Role Sharing:||Measurement of sonic booms in the air and on the ground (JAXA)
Management of measurement balloon and dropping of test models (SSC)
|1st test||2nd test|
|Balloon release Time||5:44 a.m. on May 7 (12:44 JST)||5:30 a.m. on May 16 (12:30 JST)|
|Separation Time||7:02 a.m. on May 7 (14:02 JST)||7:36 a.m. on May 16 (14:36 JST)|
|Separation Altitude||about 21km||about 27km|
|Maximum Mach Number||around Mach 1.43||around Mach 1.7|
|Separation Point||around 68° 19′ (north latitude)
around 21° 29′ (east longitude)
|around 68° 04′ (north latitude)
around 21° 01′ (east longitude)
Preparation of balloon and test models
Balloon ascending into the sky