Lambda Paz (also known as Pentarus 3B) was a moon of Pentarus III. Class M, its surface was a desert with an average temperature of 55 °Celsius. In 2367, the mining shuttle Nenebek, carrying Captain Jean-Luc Picard and Wesley Crusher to negotiations on Pentarus V, crash landed on Lambda Paz after suffering a thruster failure.
Picard and Crusher, along with shuttle captain Dirgo, sought shelter in a nearby cave that contained a fountain of water. However, the water was protected by a force field and a sentry that first injured Picard, and then killed Dirgo when they attempted to access the water. Crusher eventually found a way to deactivate the fountain's defenses using a modified tricorder, sustaining Picard's life long enough for them to be rescued by the USS Enterprise-D. (TNG: "Final Mission")