NCSOFT and Carbine Studios have a detailed article on the new 20-player raid that will arrive with the INVASION: Nexus update.
Initialization Core Y-83 will not requirement the completion of a regular attunement process and will offer a bite-sized raid that could be done in less than half an hour.
It will have 2 difficulty levels and a boatload of rewards for players completing the raid.
More info about this is available on the WildStar site.