HV on PCB High voltage on printed circuit boards

Although High Voltage Technology is a niche marked in space business, it is very important since it enables highly-efficient RF amplification with TWTAs, a significant payload element for a telecom spacecraft, as well highly-efficient generation of thrust per electric propulsion. Further, various scientific instruments rely on high voltage. 
Pending on the equipment use, in space environment (and on the way there), voltages above 200V have to be considered as high voltage (see RD 3). 

Communication TWTAs usually require voltages in the range of 4kV - 7kV, while most electric propulsion thrusters are fed with 300V … 2.000V, pending on the thruster technology.

A comparison of standards for HV on PCB designs either did not exist jet or differ in the distance / material thickness rules (see chapter 4). Further, the parameters and sources, how the rules (if existing) were determined are not available.
Heritage and current designs either avoid high voltage on PCBs or are based on qualified heritage designs, where the true margin for lifetime until electrical breakdown is not known.

All together shows the urgent need for research in this field: Determination of design rules for HV-PCBs for different space-environment compatible coating-, potting-and PCB-substrate-materials, based on lifetime measurements under known parameters enables better prediction of design durability.