Sub-millimeter and far-infrared technology in the Herschel Space Observatory and beyond

The electromagnetic spectrum at wavelengths longer than 50 microns (∼6 THz), contains approximately half the total power emitted in the Universe since the big bang. Additionally, the spectral region also contains the boundary between the dust being optically thick and optically thin, as well as numerous transitions of atoms and molecules which can be used to study the physical, chemical and structural details of the interstellar medium. The majority of this spectral region is completely obscured from the surface of the Earth, due to absorption of water vapor in the atmosphere. The space environment offers a unique opportunity to observe the far infrared sky without atmospheric opacity or excess thermal emission. The Herschel Space Observatory is the first major facility operating in the far infrared. The Herschel instruments and their technology and optimization are presented along with a brief outline of the future developments needed in far infrared space sensors for astrophysics.