CCP has outlined the new Engineering Complexes (formally known as Industrial Arrays) coming in the November expansion (called Ascension).
There are plenty of pictures to check out.
The Medium is called Raitaru, Large – Azbel, and XL – Sotiyo.
They use the same anchoring process as Citadels and work in much the same way aside different bonuses. That again means I won’t use them for any sort of serious solo game play as they are not suitable for it.
They will cost less – 40% lower than Medium Citadels (~0.7B), 60% less than Large Citadels (~5.2B), and 90% less than XL Citadels (~30B), have 33% less Hit Points, and require longer vulnerability periods (9 hours for Medium, 18 Large and 36 XL).
They are a little more restrictive in what ships can dock – the Large won’t dock Capital ships (aside Freighters, Orca, Bowhead), and the XL won’t dock Supercarriers.
You gain benefits from using them out of High-Sec, from a couple percentage points for manufacturing material input to up to almost twenty percentage points for manufacturing or science job speeds. I’m not sure how this relates to the current situation with NPC stations v POS v Player Outposts.
From the December patch, depending on how the initial Engineering Complex release works out, the plan is for you to no longer be able to deploy new Outposts or Outpost upgrades. Those that already exist (plus POS) will continue to operate as they currently do.
Speaking of POS – you can plant a small POS for a bit over 100M at the moment (before fitting). It is plausible for you to anchor and remove them solo, and they provide a useful and interesting tool for solo play. So far CCP hasn’t provided anything similar in the move to Citadels.