https://www.polygon.com/2018/5/2/17311504/destiny-2-spire-of-stars-raid-lair-launch-date

In an information round-up about its upcoming Destiny 2 expansion, Warmind, Bungie announced that the game’s next raid lair challenge will go live for players on Friday, May 11 at 10 AM PT. Players who purchase the Warmind expansion will have three days to prepare themselves for Bungie’s latest challenge.

Spire of Stairs will be Destiny 2’s second raid lair, following Eater of Worlds, which launched only days after the Curse of Osiris expansion. Raid lairs are a new concept introduced in Destiny 2 that involve players tackling smaller raids and a single boss encounter within the same location as the larger raid.