Horizontal Integration Facility
A horizontal integration facility is a location within which the stages of a multistage rocket are brought together, before the assembled stack is rolled out to the launch pad or complex and raised into vertical position for launch.HIF elsewhere
Most Russian, Ukrainian and former Soviet launchers are integrated horizontally, including Dnepr, Proton, Rockot, Shtil' and Soyuz. New Zealand Electron launcher is also integrated horizontally and European Ariane 6 would also use HIF to integrate its rocket stack.
