Interesting shockwave signals were recorded at I57US (33.60585°N, 116.4532°W), an infrasound station of the International Monitoring System (IMS) operated by the CTBTO Preparatory Commission, located near the San Diego coast.
The signal arrived at 00:12:51 UTC — approximately 5 minutes and 51 seconds after splashdown — with a back-azimuth of 223°, consistent with the capsule’s splashdown zone. The estimated source distance was 120–150 km from the station.
As the Orion capsule decelerated through the atmosphere, it reached Mach 1, generating the shockwave that propagated as infrasound and was picked up by the IMS network.
This detection adds the Orion capsule to the growing list of interplanetary reentry vehicles acoustically detected by infrasound sensors, alongside:
Infrasound monitoring is a powerful, passive tool for tracking atmospheric reentries — even those occurring hundreds of kilometers away — and contributes to both space mission science and the verification mission of the IMS network.
The map below shows the splashdown location, the I57US station position, the estimated back-azimuth, and the propagation path of the acoustic signal.
If you are interested in the infrasound data or analysis, feel free to reach out: islam.hamama@nriag.sci.eg
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