On July 4, 1997, after traveling close to 500 million km, the Pathfinder spacecraft successfully completed entry, descent, and landing at Mars. In the present paper, the focus is on the hypersonic rarefied portion of Pathfinder's atmospheric entry where the synergy of flight measurements, aerodynamic calculations, and atmospheric modeling tools are used to extract Pathfinder's attitude and the freestream density. Accuracy of the capsule aerodynamics directly impacts the inferred atmospheric properties extracted from deceleration measurements made by on-board accelerometers. The range of rarefaction considered in this study extends from the free molecular to continuum conditions and angles of attack from O to 30 deg. The aerodynamic computations are made with free-molecular and direct simulation Monte Carlo codes. The calculations show that Pathfinder is statically unstable for much of the transitional rarefied regime. Due to the relatively modest forces and the gyroscopic motion of the spacecraft, the angle of attack excursions were less than 5 deg as inferred from force measurements for the rarefied portion of entry and approached a nominal zero degree trim angle near hypersonic continuum conditions.


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    Title :

    Mars Pathfider Rarefied Aerodynamics: Computations and Measurements


    Contributors:

    Conference:

    Aerospace Science Meeting and Exhibit ; 1998 ; Reno, NV, United States


    Publication date :

    1998-01-01


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English


    Keywords :


    Mars Pathfinder Rarefied Aerodynamics: Computations and Measurements

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    Mars Pathfinder Rarefied Aerodynamics: Computations and Measurements

    James N. Moss / Robert C. Blanchard / Richard G. Wilmoth et al. | AIAA | 1999


    Mars Pathfider Rarefied Aerodynamics: Computations and Measurements

    J. N. Moss / R. C. Blanchard / R. G. Wilmoth et al. | NTIS | 1998


    Mars Pathfinder rarefied aerodynamics - Computations and measurements

    Moss, James / Blanchard, Robert / Wilmoth, Richard et al. | AIAA | 1998