Mars Science Laboratory Entry Vehicle Research Articles

Inverse Estimation of the Mars Science Laboratory Entry Aeroheating and Heatshield Response

The Mars Science Laboratory entry vehicle successfully landed the Curiosity rover on the Martian surface on 5 August 2012. A phenolic impregnated carbon ablator heatshield was used to protect the spacecraft against the severe aeroheating environments of atmospheric entry. This heatshield was instrumented with a comprehensive set of pressure and temperature sensors. The objective of this paper is to perform an inverse estimation of the entry vehicle’s surface heating and heatshield material properties. The surface heating is estimated using the flight temperature data from the shallowest thermocouple. The sensitivity of the estimated surface heating profile to estimation tuning parameters, measurement errors, recession uncertainty, and material property uncertainty is investigated. A Monte Carlo analysis is conducted to quantify the uncertainty bounds associated with the nominal estimated surface heating. Additionally, a thermocouple driver approach is employed to estimate heatshield material properties using the flight data from the deeper thermocouples while applying the shallowest thermocouple temperature as the surface boundary condition.

Assessment of the Reconstructed Aerodynamics of the Mars Science Laboratory Entry Vehicle

On 5 August 2012, the Mars Science Laboratory entry vehicle successfully entered the atmosphere of Mars, flying a guided entry until parachute deploy. The Curiosity rover landed safely in Gale crater upon completion of the entry, descent, and landing sequence. Preflight aerodynamic predictions are compared with the aerodynamic performance of the entry capsule identified from onboard flight data, including inertial-measurement-unit accelerometer and rate gyro information, and heat shield surface pressure measurements. From the onboard data, static force and moment coefficients have been extracted. These data are compared with the preflight aerodynamic database. The Mars Science Laboratory flight data represent the most complete and self-consistent record of a blunt capsule entering Mars collected to date. These data enable the separation of aerodynamic performance from atmospheric conditions. The comparisons show the Mars Science Laboratory aerodynamic characteristics have been successfully identified and resolved to an accuracy better than the aerodynamic database uncertainties used in preflight simulations. A number of small anomalies have been identified and are discussed. These data will help improve aerodynamic databases for future missions and will guide computational fluid dynamics development to improve predictions.

Mars Science Laboratory Entry Atmospheric Data System Trajectory and Atmosphere Reconstruction

On 5 August 2012, the Mars Science Laboratory entry vehicle successfully entered Mars’s atmosphere and landed the Curiosity rover on its surface. The entry vehicle carried a system of heat shield instrumentation that measured the aerodynamic and aerothermal environment during entry. Included in these sensors were seven pressure transducers linked to ports across the entry vehicle forebody that recorded the local surface pressures during entry. These measured surface pressures were used to generate estimates of atmospheric quantities based on computationally modeled surface pressure distributions. Angle of attack, angle of sideslip, dynamic pressure, Mach number, atmospheric conditions, and vehicle aerodynamics were reconstructed from the measured pressures. Three data reduction algorithms using subsets of the available data were used to assess data quality and interpret the entry performance. A Kalman filter algorithm was used to combine all available data for a final, complete reconstruction. The reconstruction results indicate that the data quality was good, and aerodynamic performance was within the uncertainties of preflight models. The three independent reconstructions are in overall good agreement, with several small anomalies that were reconciled using reasonable corrections within known sources of error. The combined Kalman filter reconstruction identified winds that are reasonable compared with preflight atmospheric models.

Turbulent Aeroheating on the Mars Science Laboratory Entry Vehicle

A series of calculations are carried out for a Mars Science Laboratory entry vehicle heat shield and compared with tests carried out in the Arnold Engineering Development Center for Mach 8 and 10 and a range of Reynolds numbers. Three turbulence models are employed that are implemented in the LAURA code: the Cebeci-Smith algebraic model, the 98 Wilcox k − ω model, and the k − ζ model. In general, good agreement is indicated with turbulent predictions. Because the flow is attached, the algebraic model performs as well as other models.