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The wavelength range between roughly 30 and 300 micron offers an unique window on the Universe, which has not been explored to its full potential depth due to technological and engineering limitations. This so-called “THz gap” between JWST in the mid-IR, and ALMA in the sub-mm domain, is very rich of key diagnostic lines, characteristic spectral features, and peaks in dust emission by cold and dusty objects, which can only be observed from space. The main astronomical themes address some of the most compelling questions about galaxy evolution over cosmic time and the water trail from molecular clouds to planet forming systems. In order to obtain a natural sky background limited view on this wavelength domain, a sufficiently large, and deeply cooled space telescope is required, eliminating the thermal background emission of the optics. A number of mission concepts like SAFIR, and more recently SPICA and the GEP, have been proposed and studied, but did not make it into actual implementation so far. The major challenge is to cool a large aperture telescope and instruments to about 4K, and to meet the demanding detector requirements, which demand very low NEP (of order 10-20 to 10-19 W/√Hz), sub-K cryo-coolers, and large format focal plane arrays with low-power high-multiplex advantage readout electronics. In my talk I will offer a technology push perspective on further development of such space missions. I will briefly review the core science objectives and drivers defining the strong astronomical pull and desire to have such telescope in space at some day in the future. In the context of the Astro2020 decadal survey by the USA, there are currently a number of ongoing initiatives to develop so-called far-IR probe missions. I will provide a short overview and introduction of the mission concepts known to date, and their underlying instrumental concepts, and then discuss the technological needs matching state-of-the-art enabling technology and ongoing developments at SRON. In my talk I will particularly focus on SRON’s MKID detector technology, highlighting some of our recent breakthroughs, and activities in the area of advanced optical instrumentation employing dispersive optics, including our collaboration with ASIAA.