Figure 1. Large Heat Shield for Mars Science. It has a diameter of 4.5 meters and is the largest ever built for descending through the atmosphere of any planet [3]

From

Heat Diffusion in an Anisotropic Medium with Central Heat Source

Mohammad Sameti, Alibakhsh Kasaeian

International Journal of Partial Differential Equations and Applications. 2014, 2(2), 23-26 doi:10.12691/ijpdea-2-2-1