You're Ops 51 or higher and already running the V'Ger Challenge Track and Challenge Refinery loop. The Signal Observatory is a station building whose entire purpose is to make that loop pay off faster -- it boosts Challenge Track rewards, Challenge Refinery payouts, and late-game FKR (Federation/Klingon/Romulan) progression. Unlike an Outpost Control Center or an alliance-owned structure, it's alliance-independent: it's yours alone, no coordination required.
The Observatory becomes available the moment you hit Ops 51 -- no alliance ownership, no event participation, nothing else gating it. From there it's a standard late-game progression building with 80 levels, upgraded the same way as any other late-game structure: resources and time, no special unlock chain.
The Observatory's payoff isn't smooth -- it lands in steps, at levels 20, 30, 40, 60, 70, and 75. Hitting one of those levels increases your Challenge Credit payouts and your FKR Credit exchange rewards, grants a one-time bonus bundle through the Challenge Refinery, and permanently raises what you get every time the Challenge Track resets. If you're deciding whether to push the Observatory now or later, those six thresholds are the actual milestones worth timing your upgrades around, not just "more levels are always better."
Separately from the six reward-tier levels above, every 10 building levels hands you a milestone Gift containing shards of the Prototype Tech Neural Neutralizer, Veil Warp Tolls, and other V'Ger progression materials -- so the Observatory keeps paying out steadily even between the bigger jumps. At Ops 71 specifically, it unlocks the Daily V'Ger Bounty Challenge for free, worth 50 Challenge Track Points a day, that you'd otherwise have to buy as a contract from the Store.
On top of the Challenge-Track economy, upgrading the Observatory grants permanent buffs: increased base damage against V'Ger hostiles specifically, increased critical damage against non-Armada hostiles for G5+ FKR ships, increased Isolytic Defense against other players for G5+ FKR ships, and better cost efficiency on G7 Uncommon station materials. These stack with whatever your ships and officers are already providing -- the Observatory is a station-wide multiplier, not a ship upgrade.
Combine the Observatory with the USS Excelsior's V'Ger Challenge Sweep research and you can clear multiple V'Ger daily challenges in one pass while maximizing Challenge Track points, Challenge Credits, and FKR Credit gains -- the two are built to complement each other, not compete for the same slot. None of this is strictly mandatory: you can progress through V'Ger content without the Observatory. But it noticeably speeds up that progression, cuts down how much you need to buy from the Store, and improves your long-run reward efficiency the longer you're active in V'Ger and FKR content.