The heating environment during Martian atmospheric descent

It has been shown that a vehicle with a lift/drag ratio of 2.3 entering the Martian atmosphere at parabolic speed of 5 km/sec, or from a low orbit at 3.5 km/sec, has a very large landing footprint. At the 5-km/sec entry speed, the trajectory exhibits large skipping motions; however, a lateral range of up to 3300 km is attainable. The entries from low satellite orbit yield a gliding lateral range of 2500 km. The distances correspond to latitude changes of 57 and 42 deg, respectively. The high-speed, skipping entries were accompanied by the most intense heating. The peak stagnation point convective rates varied from 59 W/sq cm to 88 W/sq cm for partially and fully catalytic walls, respectively; the corresponding equilibrium wall temperatures were 1900 K and 2100 K. The peak heating at a wing leading-edge point reached 50 W/sq cm because of the presence of a transitional boundary layer. The lower-speed, gliding entries experienced much milder heating with a peak stagnation point rate of about 14 W/sq cm, resulting in a wall temperature near 1300 K. However, the longer duration of the gliding entries resulted in comparable heat loads for both entry speeds. The highest heat loads approached values experienced by the Shuttle orbiter stagnation point during a typical entry.