A hermetically sealed electronic package may include a thermal panel having a panel interior surface and a panel exterior surface with electronic device(s) in thermal communication with the panel interior surface. An enclosure, isolating environmental communication from internal electronic devices and modules, may be coupled to the thermal panel, and the enclosure may have an enclosure interior surface and an enclosure exterior surface. A plurality of electrical feedthroughs may be coupled to the package enclosure for signal and data transmission, and the conducting pin(s) in every electrical feedthrough may be bonded by a hydrophobic sealing material for harsh environmental electrical signal, data and power transmission. The ratio of sealing length over sealing bead diameter in the electrical feedthrough subassembly may have a preferred value from 2 to 3; and the ratio of the sealing bead diameter over pin diameter in the electrical feedthrough subassembly may have a preferred value from 1.5 to 2.0, where a preferred thermal stress resistance could be designed for making highly hermetic sealed electronic package.