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This paper provides an overview of the activities associated with the aerodynamic database which is be-

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Post ight analysis of the Mars Path nder hypersonic, continuum aerodynamic data base is presented. Measured data include accelerations along the body axis and axis normal directions. Comparisons of pre ight simulation and measurements show good agreement. The prediction of two static instabilities associated with movement o f the sonic line from the shoulder to the nose and back was con rmed by measured normal accelerations. Reconstruction of atmospheric density during entry has an uncertainty directly proportional to the uncertainty in the predicted axial coe cient. The sensitivity of the moment coe cient to freestream density, kinetic models and center-of-gravity location are examined to provide additional consistency checks of the simulation with ight data. The atmospheric density as derived from axial coe cient and measured axial accelerations falls within the range required for sonic line shift and static stability transition as independently determined from normal accelerations.

The Mars Entry Atmospheric Data System (MEADS) is being developed as part of the Mars Science Laboratory (MSL), Entry, Descent, and Landing Instrumentation (MEDLI) project. The MEADS project involves installing an array of seven pressure transducers linked to ports on the MSL forebody to record the surface pressure distribution during atmospheric entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. In particular, the quantities to be estimated from the MEADS pressure measurements include the total pressure, dynamic pressure, Mach number, angle of attack, and angle of sideslip. Secondary objectives are to estimate atmospheric winds by coupling the pressure measurements with the on-board Inertial Measurement Unit (IMU) data. This paper provides details of the algorithm development, MEADS system performance based on calibration, and uncertainty analysis for the aerodynamic and atmospheric quantities of interest. The work presented here is part of the MEDLI performance pre-flight validation and will culminate with processing flight data after Mars entry in 2012.

Computational uid dynamics tools have been used extensively in the analysis and development of the X-43A Hyper-X Research Vehicle. A signi cant element of this analysis is the prediction of integrated vehicle aeropropulsive performance, which includes an integration of aerodynamic and propulsion ow elds. The development of the Mach 7 X-43A required a pre ight assessment of longitudinal and lateral-directional aeropropulsive characteristics near the target ight-test condition. The development of this pre ight database was accomplished through extensive aerodynamic wind-tunnel testing and a combination of three-dimensional inviscid airframe calculations and cowlto-tail scramjet cycle analyses to generate longitudinal performance increments between mission sequences. These increments were measured directly and validated through tests of the Hyper-X ight engine and vehicle owpath simulator in the NASA Langley Research Center 8-Foot High Temperature Tunnel. Predictions were re ned with tip-to-tail Navier-Stokes calculations, which also provided information on scramjet exhaust plume expansion in the aftbody region. A qualitative assessment of lateral-directional stability characteristics was made through a series of tip-to-tail inviscid calculations, including a simulation of the powered scramjet ight-test condition. Additional comparisons with wind-tunnel force and moment data as well as surface pressure measurements from the Hyper-X ight engine and vehicle owpath simulator model and wind-tunnel testing were made to assess solution accuracy. Nomenclature C A = axial force coef cient C l¯= rolling moment derivative, /deg C M = pitching moment coef cient C N = normal force coef cient C n¯= yawing moment derivative, /deg C p = pressure coef cient C y¯= side force derivative, /deg X; Y; Z = spatial coordinates, m ® = angle of attack, deg