An infrasound source analysis of the OSIRIS-REx sample return capsule hypersonic re-entry

Area of Science:

• Acoustics
• Aerospace Engineering
• Planetary Science

Background:

• Hypersonic re-entry of space capsules offers unique opportunities to study sonic boom phenomena.
• The OSIRIS-REx mission provided well-characterized projectile dimensions for atmospheric re-entry analysis.
• Understanding sonic boom sources is crucial for designing future sample return missions.

Purpose of the Study:

• To test and validate different sonic boom source models using data from the OSIRIS-REx capsule's atmospheric re-entry.
• To estimate the emission locations of infrasound signals generated during re-entry.
• To compare the predictive accuracy of various sonic boom theories against recorded acoustic data.

Main Methods:

• Deployment of six infrasound microphones to record signals during re-entry.
• Utilizing geometric acoustics approximation with various atmospheric profiles to estimate signal emission locations.
• Analysis of acoustic overpressure and signal duration using Whitham's theory, Carlson's method, and a drag-dominated hypersonic model.
• Propagation modeling using an inviscid Burgers's equation solver.

Main Results:

• Estimated emission locations along the predicted flight path with associated uncertainty.
• Compared predictions from three sonic boom models against recorded infrasound data.
• Identified the drag-dominated source model, when coupled with inviscid Burgers's equation, as providing an excellent match to the observed data.

Conclusions:

• The drag-dominated source model shows high fidelity for predicting sonic booms from hypersonic re-entries.
• Infrasound data from the OSIRIS-REx re-entry validates atmospheric acoustic propagation models.
• Findings will enhance future sample return mission planning and improve understanding of high-altitude infrasonic sources.