The 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 to the required rate 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. Accuracy Verified Flight data have demonstrated the validity of the Harrison Drop Test: Ford Aerospace (1983), Hughes Aircraft (1984), RCA (1984), British Aerospace (1985), NASA Goddard (1992), Martin Marietta (1993) and Lockheed Martin (1996) spacecraft data compared favorably with test data developed for those spacecraft designs. Flight data obtained from Mars Global Surveyor (1996) verified test results to within 0.2% error. All tested spacecraft successfully performed the spin-stabilized maneuvers during flight. Solutions Found When testing revealed unacceptable time constants, Dr. Harrison helped develop and test the design and/or mission changes that would result in acceptable results. Descriptions of photos (above, left to right), all ADL projects: Launch of the Pluto New Horizons spacecraft Delta II rocket ready for launch of the Deep Impact spacecraft Artist rendering of the Mars Global Surveyor spacecraft Jupiter and one of its moons (viewed by the New Horizons spacecraft) Photo credits: LaunchPhotography.com NASA http://www.launchphotography.comshapeimage_1_link_0
Applied Dynamics Laboratories provides fuel-slosh testing and services for spin-stabilized spacecraft and stages.