Fig.2.5 is a bad reflection of temperature distribution for any re-entry
vehicle. The reason for this outcome is associated with electric
circuit. Instead of current flowing through the graphite heat shield, it
flows through tungsten because tungsten is a better electrical conductor
than graphite. This leaves the heat shield with little or no flow of
current. Zero current results in zero heat flux according to Eq.1.1.
Further improvement of the model in Fig.2.4 results in Fig.2.6 where the
idea is to have tungsten fins up to half of the heat shield diameter.