Fleet Detection
This page explores how players discover incoming fleets, what determines how early a threat is visible, and how sensor range can be extended through research and infrastructure.
It does not describe final game behavior. It captures the current direction and unresolved design choices.
Goal
The goal is a detection model that:
- gives defenders a meaningful window to react to incoming attacks
- makes sensor investment a genuine strategic choice rather than an obvious upgrade
- creates an information asymmetry that attackers can exploit and defenders can reduce
- supports espionage and stealth mechanics as natural extensions
Core Problem
If attackers are always visible the moment they leave their home colony, war becomes a pure numbers game — the defender always has full information and can always respond optimally. If attackers are never visible until they arrive, defense becomes impossible and the game favors pure offense.
The right model gives the defender an information advantage in their own territory, while giving the attacker tools to reduce or eliminate that advantage.
Working Direction: Home System Visibility + Extended Sensor Range
Default visibility
A player with a colony inside a system can see all fleet activity within that system. This is passive — no investment required. Any fleet that enters the system is immediately visible to all players holding territory there.
This means:
- an attacker is always detected the moment they enter the defender's system
- the defender knows the fleet composition, size, and trajectory
- the alert window is determined by how long it takes the fleet to travel from the system edge to the colony
The alert window in the home system is the baseline. It may be enough to recall a nearby fleet or send an alliance message, but probably not enough to bring in distant reinforcements.
Extended sensor range
Players can extend their detection range beyond their home system through research and structures. Extended sensors detect incoming fleets while they are still in transit — before they enter the target system.
This widens the alert window significantly. A player who detects a fleet two systems away has hours more to respond than one who detects it at the system boundary.
Extended detection does not reveal everything. A sensor extended one system out detects that a fleet is moving toward the player's territory — but may not reveal full fleet composition, only approximate size and heading.
Investment options (working directions):
| Investment type | Effect |
|---|---|
| Sensor research (tech tree) | Extends detection range by system hops |
| Early warning station (structure) | Provides extended detection for the colony it is built at |
| Sensor relay network | Alliance-level infrastructure — shares detection data across multiple colonies |
The Alert Window Is the Core Tension
The gap between "fleet detected" and "fleet arrives" is where all defender decisions happen:
- Should I recall my fleet from its current operation?
- Should I alert my alliance?
- Should I spend stockpiled resources on construction before they can be stolen?
- Is the incoming fleet a raid or a siege — and does my defense match the threat?
A longer alert window does not guarantee a better defense. It only means more time to make decisions. A defender who makes no decision in that window gains nothing from the extended detection.
Stealth as a Counter
If sensor range can be extended, stealth technology is a natural counter. A fleet equipped with stealth systems reduces its sensor signature, shrinking the effective detection range of the defender's sensors.
A cloaked corvette fleet might not be detected until it enters the home system — removing most of the defender's reaction window and arriving almost without warning.
Stealth likely requires investment to unlock and may impose penalties (speed reduction, reduced combat effectiveness) to prevent it from being universally optimal.
Strategic Value of Sensor-Rich Colonies
A colony with extended sensors provides early warning not just for itself, but potentially for allies in the surrounding region. A sensor-rich colony on the frontier of an empire functions as a watchtower — valuable beyond its production output.
This makes sensor investment a collective benefit in alliances. A member who invests heavily in detection infrastructure provides strategic value to the whole group. It also makes sensor-rich colonies a priority target: destroying or blockading a watchtower colony degrades an empire's early warning capability.
Open Questions
- How is detection range measured — system hops, or a continuous distance metric?
- Does extended detection reveal fleet composition, or only presence and approximate size?
- Can a fleet choose to move slowly to reduce its sensor signature, or is stealth purely a tech investment?
- Should there be counter-intelligence mechanics — false fleet movements designed to provoke a reaction?
- How does detection interact with neutral systems — can a player place sensor relays in unclaimed space?
- Is there a maximum possible detection range, or can it be extended indefinitely through investment?