Not all designs can be used to achieve a good re-entry temperature
distribution field. Very large cold region always results with a
considerable larger contacting surface area at the graphite/tungsten
junction thus making tungsten to act as a heat sink to the heat shield.
Further simulation results in section 3 show the limit to which the
diameter of tungsten rod can be increased in order not to unnecessarily
create cooler surface temperatures at the stagnation region.