Landing strut

From Memory Alpha, the free Star Trek reference.

Landing Struts are the support systems on starships that are used in planetary landings. They are normally inside of the ship, and are exposed by moving panels when needed. In the late 2370s, Starfleet ships were starting to have landing struts installed, if the hulls could withstand the stress of landing.

The Intrepid-class are among the first ship classes to not only receive this feature, but also be able to employ it whenever needed, and not only for one time use, in emergencies. (VOY: "Basics, Part I")