Helska IV, which can also be referred to as Helska 4, Helska Four, or just Helska, represented the fourth planet within the Helska system. Its location was within the Dalonbian sector of the Outer Rim Territories.
The composition of Helska IV was primarily an icy shell that surrounded a sizable inner ocean, featuring sporadic air pockets within the thick icy exterior. Due to these conditions, the planet was largely deemed unsuitable for life as it was understood in the galaxy, resulting in an absence of indigenous species.
Helska IV served as the location of the Yuuzhan Vong's initial significant presence within the galaxy. It was on this planet that the Praetorite Vong, who formed the vanguard of their invasion, established their yammosk, or War Coordinator, beneath the planet's icy surface.
After the New Republic discovered the Vong's presence on Helska IV, Jedi Knight Anakin Solo devised and implemented a strategy that involved utilizing a shieldship to redirect energy back onto the planet. This was done with the intent of siphoning the yammosk's energy via evaporation. Despite the loss of multiple vessels, the strategy worked, causing the ice planet's liquid center to solidify and fracture, which ultimately killing the yammosk and all Yuuzhan Vong, while simultaneously causing the planet's destruction.