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Fuel slosh testing for spin-stabilized spacecraft and stages

Harrison Drop Test
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The drop test, as developed by Jon Harrison at Applied Dynamics Laboratories, involves building a dynamically scaled model of the full-size spacecraft, spinning the model and dropping it 30 feet into a catch box, recording nutational data as it falls. The nutation time constant for the model is computed and scaled back to the spacecraft. 

Advantages
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All of the relevant dimensionless parameters associated with fuel slosh can be very closely matched between the model and the full-scale spacecraft — the shape and locations of the propellant tanks, the mass, center-of-mass location and inertias of the vehicle, the Reynolds number of the fuids and the Froude number, which is essentially infinite during the freefall portion of the test.

Services
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Develop and test scale model to determine the effects of fuel slosh on spin-stabilized spacecraft and stages. Design and test tank baffles to suppress fuel-slosh effects. Provide a dedicated drop tower facility for microgravity experiments. Test and analyze propellant-migration induced instability for inertia ratios greater than unity (the wobble-amplification problem).

Banner Photo: Launch of NASA's Pluto New Horizons, an ADL project. New Horizons explored the outer edges of our solar system. Photo: Launch Photography. Used with permission