Document Type

Article

Journal/Book Title/Conference

Journal of Spacecraft and Rockets

Volume

63

Issue

3

Publisher

American Institute of Aeronautics and Astronautics

Publication Date

12-16-2025

Journal Article Version

Accepted Manuscript

First Page

1

Last Page

27

Abstract

Optical emission spectroscopy (OES) measurements of the reentry shock layer can provide invaluable information about the dynamic aerothermal chemistry during atmospheric reentry and yield critical data needed to improve fluid dynamics modeling of reentry systems. On 28 February 2025, the Air Force Research Laboratory successfully executed the Optical Sensing of Plasmas in the ReEntry Environment (OSPREE) experiment using Varda Space Industries’ W-2 hypersonic test-bed vehicle, obtaining in situ shock-layer radiative emission measurements during reentry from an altitude of 105 km down through 50 km, encompassing a range of Mach numbers between 29.5 and 15.0. We present a summary of the reconstructed trajectory and the optical emission spectra obtained during flight, noting key emissions pointing to evolving shock-layer thermochemistry and interactions between the flowfield and vehicle thermal protection system. Temporal evolution of the spectral radiance of key molecules (CN, C2, CH) and atoms (O, O+, N, and H) is analyzed across the flight trajectory. Rotational and vibrational temperatures from spectral fits are computed to provide thermometric measurements of the shock layer over time.

Download

Share

COinS