Alpha Laputa IV was the fourth planet in the Alpha Laputa system. This planet was inhabited by a prewarp civilization. In 2367, the USS Zhukov undertook a cultural observation mission here. (TNG: "Brothers")
This assignment of the Zhukov was not mentioned on screen, but rather was first seen on a Starship mission status chart on the bridge, then in the the observation lounge, during Star Trek: The Next Generation's run.