Gold rings circle and encapsulate the desolate moonscape – lavish architecture signifying the Orokin mastery over all things natural and technological during their reign. The opalescent halls stitching together what the enemy destroyed have been vacated since that era came to an end.
Lua is the Earth's moon, accessible as a planet in the Star Chart. Once the seat of the Orokin Empire's power during their reign, it is now shattered and broken, scarred by the Old War. Recent events have led to the reemergence of this lost celestial body, and now its fragmented remains are fought over by the Grineer and the Corpus.
Lua can only be unlocked after a player completes The Second Dreamquest. Both Grineer and Corpus contest possession of the moon, leading to Lua being the only other planet, besides Mars, that has Crossfire missions.
Sentient units can be found and fought on this moon. Combat against them revolves around their ability to adapt themselves to the damage dealt by the player's weapons and abilities, requiring Tenno to have multiple types of damage (both physical and elemental) in their loadouts.
Corrupted Wardens can be found in "Lua Rescue" missions.
If someone hasn't completed The Second Dream and tries to access any mission on Lua (via taxi or otherwise), they will be prompted to complete it before continuing and will be kicked from the party. Other party members who qualify will still be able to run the mission.
Before Update: Specters of the Rail, Lua was the name of a node on Earth, and the Orokin Moon missions introduced in Update 18.0 were considered Earth nodes. Specters of the Rail update subsequently moved the Orokin Moon missions to its own location, with the Lua node being renamed Cervantes as its previous name was then used for the new star chart location.
The name Lua for the Earth's Moon was foreshadowed by dialogue in The Second Dream, named as the place where the "rejects were consigned", likely referring to the Tenno.
Lua ties with the Orokin Derelict for the least amount of nodes of all the planets in the Origin System. While Lua's post-Orokin dimensions are unclear, the Moon is larger than Phobos, Ceres, Europa, Pluto, Sedna, and Eris.
Lua also refers to lightweight multi-paradigm programming language designed primarily for embedded systems and clients. It is cross-platform, since it is written in ANSI C, and has a relatively simple C API.