This Standard defines the technical requirements and quality assurance provisions for the assembly and mounting of highreliability, radiofrequency (RF) coaxialcable interconnections for use as transmission lines in spacecraft and associated equipment. In general, these assemblies are designed for lowloss, stable operation from the relatively low frequencies through the higher frequencies in the microwave regions. These transmissionline cables should not be confused with lowfrequency cables with conductive sheaths (usually copper braid), which are used in applications where shielding of the centre conductors from the surrounding electrical ambient is required. The interconnection of those shielded cables, not covered by the present standard, is covered in ECSS-Q-ST-70-08. This standard may be tailored for the specific characteristics and constrains of a space project in conformance with ECSS-S-ST-00.