Jonathan S Cheatwood | Search NASA

NASA NTRSDate not supplied

Mars Sample Return Earth Entry System Woven Roughness Mach 6 Aeroheating Test

The Mars Sample Return Earth Entry System is the first entry vehicle designed for a NASA flagship mission to utilize a woven thermal protection system as well as a 52.5 degree sphere cone forebody geometry. As a result, no heritage aeroheating experimental data set exists to compare with computational predictions. In order to obtain a set of validation data for computational models, an extensive wind tunnel test campaign was funded by the Mars Sample Return Earth Entry System project. The first entry in the test campaign was completed in April of 2023, which was an investigation of turbulent heating augmentation due to woven thermal protection system roughness on the 52.5 degree Mars Sample Return - Earth Entry System vehicle forebody geometry. This test entry produced the first ever experimental aeroheating data on a 52.5 degree sphere-cone geometry as well as the first NASA experimental aeroheating data on a woven surface roughness pattern. Data obtained from this test campaign is being directly leveraged to support the NASA flight program, as experimental results are being utilized to validate the computational models which characterize the aeroheating environment that the vehicle experiences and predict turbulent surface heating levels and margins across the woven surface.

Jonathan S Cheatwood↗

NASA NTRSDate not supplied

Progress on Quantitative Infrared Thermography at the NASA Langley Aerothermodynamic Laboratory

A quantitative infrared thermography technique is being developed for accurate and high-resolution measurements of surface temperature and heat flux in the hypersonic wind tunnels at NASA Langley Research Center. A hemisphere test campaign was carried out in the Langley Aerothermodynamic Laboratory 20-Inch Mach 6 Air Tunnel to assess the current performance of the technique and to identify remaining challenges. Measurements were obtained for three different model materials over a range of freestream Reynolds numbers. The raw infrared images were converted to temperature via a radiometric calibration of the camera sensor. Corrections were made for losses due to test article emissivity and window transmissivity. A preliminary uncertainty analysis yielded an estimated accuracy within 4 K at moderate viewing angles, similar to that of a standard thermocouple. Surface heat flux was obtained from the measured surface temperatures via a finite-difference solution of the one-dimensional heat equation that modeled thermal variation of the material properties. Comparisons of the measured heating to both computational and theoretical predictions demonstrated agreement within the expected uncertainty of the technique. The heat transfer measurement near the stagnation point was found to be highly sensitive to the test article emissivity, which establishes the need for improved characterization of the wind tunnel model materials for high temperature applications.

infrared thermography↗

NASA NTRSDate not supplied

NASA LaRC Hypersonic Experimental Aerothermodynamic Capabilities and Recent Contributions

A review is presented of recent research, development, testing and evaluation aerothermodynamic activities that have been conducted at the NASA Langley Research Center in the Langley Aerothermodynamics Laboratory. An overview of the test facilities, model development and fabrication capabilities, and instrumentation and measurement techniques employed in this work is provided. Contributions to hypersonic flight and planetary exploration programs are detailed, as are fundamental research and development activities. Wind tunnel investigations are described that supported flight programs for NASA and Commercial Crew external partners. Collaborations between NASA projects and academia are also highlighted in this overview of recent wind tunnel experiments.

hypersonic↗

NASA NTRSDate not supplied

NASA Langley Hypersonic Experimental Aerothermodynamic Capabilities and Recent Contributions

A review is presented of recent research, development, testing and evaluation aerothermodynamic activities that have been conducted at the NASA Langley Research Center in the Langley Aerothermodynamics Laboratory. An overview of the test facilities, model development and fabrication capabilities, and instrumentation and measurement techniques employed in this work is provided. Contributions to hypersonic flight and planetary exploration programs are detailed, as are fundamental research and development activities. Wind tunnel investigations are described that supported flight programs for NASA and Commercial Crew external partners. Collaborations between NASA projects and academia are also highlighted in this overview of recent wind tunnel experiments.

hypersonic↗

NASA NTRSDate not supplied

Aeroheating Testing of the Mars Sample Return Earth Entry System with Surface Roughness

The Mars Sample Return Earth Entry System is a mission concept which would be the first NASA entry vehicle to utilize a woven thermal protection system as well as a 52.5 degree sphere-cone forebody geometry. Due to its novel design, historic experimental data sets were insufficient to validate the models used to characterize the expected aerothermal environment. A wind tunnel test campaign was funded by the Mars Sample Return Earth Entry System project in the NASA Langley 20-Inch Mach 6 Air Tunnel in order to obtain validation data. The December 2023 test entry of this campaign sought to obtain thermographic data to capture the impact of supersonic flow near woven surface roughness elements on convective heating augmentation, which was the largest remaining uncertainty in aerothermal design of the Earth Entry System. Data obtained were in family with prior results obtained on identical woven patterns without supersonic flow present at roughness elements, and it was found that this presence of supersonic flow did not have a noticeable effect on surface convective heating augmentation. Data were directly leveraged to support the NASA Mars Sample Return flight program and this data set is valuable for validating computational solutions on roughness-resolved grids.

Mars Sample Return↗