The Horizons content - essentially add-on DownLoad Content - was released as a series of updates over the last, nearly 2 years now. FD sold these updates as a "season", so we got them when they were "ready" (for some often dubious values of "ready"). Planetary landings are kinda self-explanatory, the engineers was a very popularHi,
... ... ...What Is Elite Dangerous: Horizons - Season Pass...? What's A Season Pass...?
And What Are those Planetary Landings, The Engineers, Guardians, The Commanders, The Return...?
update that allows us to modify ship modules to increase perfomance, the Guardians included the Ship Launched Fighters, passenger missions and some odd (non-thargoid?) alien bases, the Commanders was the multi-crew and the commander creator. The Return (or 2.4) is currently ongoing and includes the Thargoids content (and apparently some new ships - still to come). Well that's the general gist of it anyway. If you buy Horizons season pass now, you'd get all the DLC in one go (upto where 2.4 is now anyway).
... ... ...What Is Elite Dangerous: Horizons - Season Pass...? What's A Season Pass...?
And What Are those Planetary Landings, The Engineers, Guardians, The Commanders, The Return...?
I'll assume you've currently only got the Elite: Dangerous base game.
So Horizons is the name given to another season of content (Elite is under constant development) that was/is being released for the game over the course of a couple of years. I think the original plan was that there would be another "season" of content after Horizons which Frontier would again charge for but they've since changed the payment model and next years series of updates (called "Beyond") will be free for everyone who bought Horizons.
So Horizons began with planetary landings. This allows you to land your ship on millions of procedurally generated non-atmospheric planets and moons and drive around the surface of these worlds in a Surface Reconnaissance Vehicle. For me this one feature was/is easily worth the entire price of the Horizons season. Beyond that Horizons also includes Engineers (npc characters with bases down on various planet surfaces who can tune the performance of your ship in exchange for various data and materials), guardians (a name for one of the updates which covers both the appearance of ancient alien surface structures belonging to "The Guardians" but also to the introduction of ship launched fighters and hireable npc crew), The Commanders (the introduction of a multi-crew feature which allows players to operate either a gunnery role or else fly a ship launched fighter for another players ship) and The Return (which is the ongoing series of updates featuring the return of the alien species known as the Thargoids.
Given that the price of Horizons also now extends to include the next series of "Beyond" updates I would personally throughly recommend getting it (assuming you like Elite: Dangerous).
The next thing on your wishlist?
Posts above, explain it well. o7
Posts above, explain it well. o7