We demonstrated a fiber-based approach for obtaining optical spectra of a glowing bow shock in a high-enthalpy air flow. The work was performed in a ground test with the NASA Ames Aerodynamic Heating Facility (AHF) that is used for atmospheric reentry simulation. The method uses a commercial fiber optic that is embedded in the nose of an ablating bluntbody model and provides a line-of-sight view in the streamwise direction -directly upstream into the hot post-shock gas flow. Both phenolic impregnated carbon ablator (PICA) and phenolic carbon (PhenCarb 28) materials were used as thermal protection systems. Results show that the fibers survive the intense heat and operate sufficiently well during the first several seconds of a typical AHF run (20 MJ/kg). This approach allowed the acquisition of optical spectra, enabling a Boltzmann-based electronic excitation temperature measurement from Cu atom impurities (averaged over a line-of-sight through the gas cap, with a 0.04 sec integration time). Nomenclature I. Backgroundadiometry and spectroradiometry instrumentation for measuring bow shock emission ahead of blunt-body atmospheric entry vehicles was successfully demonstrated in well-known NASA flight experiments in the 1960s as part of the Apollo program. In the Fire I and Fire II flight tests, 1, 2 each entry vehicle had a stacked series of three "clean" beryllium forebody heat shields, two of which were jettisoned successively during reentry. Each heat shield had its own fused quartz window at the stagnation point that provided viewing of the bow shock. The total 1 AST, Flight Systems Remote Sensing Branch, B1202/MS 468 2

An existing Magnetic Suspension and Balance System (MSBS) has been restored to operation in a small (octagonal test section, 6-inches across flats) low-speed wind tunnel as the first phase of a project to develop new dynamic test capabilities for planetary entry capsules at supersonic speeds. The MSBS and associated wind tunnel were originally designed and built at MIT and were subsequently relocated to NASA Langley Research Center. NASA ceased operations of the system in the late 1990s and it was transferred to Old Dominion University where it had been mothballed until the present work started in 2015. All-new position sensor electronics, electromagnet power supplies, digital controller, and other hardware have been developed, leading to more efficient and reliable operation. Important features of the new hardware will be briefly described. Wind tunnel testing has commenced, focusing first on static aerodynamics of re-entry capsule shapes. Some preliminary results will be reviewed, including comparison to reference data. The proposed extension to dynamic stability testing, using a variety of free-to-pitch approaches will be described. Finally, the preliminary design of the all-new Phase II (supersonic) system will be briefly outlined. NomenclatureBx,y,z Magnetic flux density in the x, y and z directions (Tesla) Bxx Gradient of flux density in the axial (tunnel flow) direction d Capsule diameter CD Drag coefficient, Fx/(qs) Fx Force in the x direction ""⃗ Magnetization vector (A/m) Mx,y,z Components of the magnetization vector along the x, y and z axes q Dynamic pressure Red Reynolds number based on model diameter: density*velocity*diameter/(kinematic viscosity) S Reference area (area of circle with diameter of wind tunnel model) "⃗ Torque vector Tx,y,z Torque components about the x, y and z axes x,y,z Tunnel axes: +x = upstream, +y = right when looking upstream, +z = down

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