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Description
Uranus and Neptune, known collectively as the Ice Giants, are the only two planets in the solar system that are yet to be explored with a dedicated mission. Planetary entry probe missions to the Ice Giants were proposed in 2010 by NASA and ESA which prompted a resurgence of interest in experimental simulation of the aeroheating environment that would be encountered by such a spacecraft. The Oxford T6 Stalker tunnel is the only facility in Europe capable of replicating the high speeds required for Ice Giant entry and is therefore a key stepping stone on the path to realising the goal of an Ice Giant mission.
Although significant progress in Gas Giant entry research has been made in the last ten years, many studies have neglected the influence of trace components such as CH4 on the aeroheating environment. Such trace components are negligible for Jupiter and Saturn, but may exist in much greater quantities on Uranus and Neptune - CH4 is what is believed to give the Ice Giants their distinctive blue colour.
In the present work, a 1:10 scaled model of the Galileo probe has been tested at Ice Giant entry conditions. Conditions for nominal composition (85%H215%He), Stalker substituted, and nominal composition with methane (0.5% and 5% CH4) gas mixtures have been developed and validated for use with a new expansion nozzle via a pitot rake survey. Test flows with flight equivalent velocities greater than 22 km/s have been produced with test times on the order of 30 𝜇𝑠. Heat flux into the model for the developed conditions has been inferred from temperature measurements with a series of coaxial thermocouples. High speed video has been captured to allow for measurement of the shock standoff distance during the test time.
This work provides the first ever experimental dataset for Ice Giant entry conditions with CH4 addition and demonstrates a unique capability to simulate Ice Giant entry conditions in Europe.
Summary
A 1:10 scaled model of the Galileo probe has been tested at Ice Giant entry conditions. Conditions for nominal composition (85%H215%He), Stalker substituted, and nominal composition with methane (0.5% and 5% CH4) gas mixtures have been developed and validated for use with a new expansion nozzle via a pitot rake survey. Test flows with flight equivalent velocities greater than 22 km/s have been produced with test times on the order of 30 𝜇𝑠.
