Fuel slosh testing for spin-stabilized spacecraft and stages
Harrison Drop Test
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.
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.
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