This should definitely be conduction  The energy transfers from the gas after the shock layer into the heat shield via convection  Then the energy travels via conduction throughout the vehicle and into the payload  This remark is also noted as citation needed  Im not going to add a citation mostly because I dont feel motivated enough to look up the source but any text book on heat transfer or reference on the science of convection and conduction heat transfer would suffice  Its not very advanced and so is readily available