Espionage

Espionage is sending Hermes Class Probes to somebody else's planet or moon to see what is sitting there. The probes fly out, take a look, fly home, and a report lands in your Messages. How much of that report you can actually read depends on your Espionage Tech level, their Espionage Tech level, and how many probes you sent.

Probing before you attack is not optional at the top end of the game. A fleet sent blind into a planet with a full defense grid is a fleet you are not getting back.

What you need

Espionage Tech 2 and Jet Drive 3 to unlock the Hermes.
A Shipyard at level 3, and 1,000 crystal per probe.
A free fleet slot. Espionage holds the slot for the whole round trip, out and back. Your slot count is A.I. Tech level plus one.
The probes have to be sitting on the planet you launch from. The spy button will not appear on a planet with no probes on it.

Sending probes

There are three ways to launch a spy run.

From the Galaxy screen. The eye icon in the Actions column sends probes at that row. This is how most spying gets done.

From the Fleets screen. Pick Espionage as the mission, pick the destination, and the ship list filters down to probes only. Nothing else can ride along on an espionage mission.

From the Oracle. Scan results have their own eye icon, so you can spy straight off a scan. The probes launch from the moon the Oracle is on, so they have to be stationed there.

Probes are the fastest thing in the game. Inside your own system they land in about twenty seconds. The far side of the map is still only a minute or two, and Jet Drive levels barely move that number. Fuel barely registers. A short run costs a single hydrogen, and even a long one across galaxies is a few dozen.

Quick Espionage

Settings has a Quick Espionage box. Set it to a number and the eye icon stops opening the fleet screen and just fires that many probes from your current planet in one click. Set it to 0 to turn it off and go back to the normal dispatch page.

Reading the report

The report arrives as a system message under the Espionage filter in your inbox. The header tells you the target, the owner, the chance the target had of shooting your probes down, and whether your probes are on the way home or gone.

Five things are worth knowing about the numbers in there:

The resources are what you could take, not what they own. The figures are already reduced by the target's Resource Den. Whatever the Den hides never shows up in a report at all.
The Fleet section includes borrowed ships. Anything parked there by Group Defend is counted with the owner's own ships, so the fleet you see is the fleet you would actually fight.
Buildings are per planet, technologies are per account. Probing one colony tells you the owner's research levels everywhere.
The report is a snapshot. It is true at the moment the probes arrived and nothing more. Anyone can move a fleet in the minute after you read it.
You get the report even when the probes die. Losing the probes costs you the ships, not the intel.

At the bottom of the report are buttons for Attack, Espionage, Harvest, Simulate and Copy. Simulate loads the fleet and defenses straight into the Calculator so you can work out what it would take to break them without retyping anything.

How much of the report you see

Each report gets an espionage number. Work out the gap between your Espionage Tech and theirs, then:

If your level is equal or higher: espionage number = probes sent + gap²
If their level is higher: espionage number = probes sent - gap², and it never drops below zero

That number decides which sections unlock:

Espionage number	What the report shows
0 or more	Resources
2 or more	+ Fleet
3 or more	+ Defenses
5 or more	+ Buildings
7 or more	+ Technologies

Anything you did not earn reads "Espionage level too low to gather this intelligence".

Two things fall out of the maths. Against someone on your own tech level, the espionage number is just the probe count, so seven probes buys you the whole report. Against someone two levels above you, four probes are swallowed by the gap before you learn anything, and against someone three levels above you it is nine, so small runs come home with nothing but their resources.

Counterespionage

Probes can be shot down on arrival. The chance is worked out from the tech gap, the number of probes you sent, and the number of ships sitting on the target:

chance = F x (probes)^1/3 x (ships in orbit)^1/3

where F comes from their Espionage Tech minus yours:

Their level minus yours	F
-2 or lower	0
-1	0.5
0	1
1	2
2 or more	gap²

Points that matter in practice:

No ships home, no risk. If the target has nothing in orbit the chance is zero, whatever the tech gap. Fleet saved planets can be probed for free.
Two levels ahead and you are untouchable. Once your Espionage Tech is two or more above theirs, F is 0 and your probes always come home.
More probes means more risk. Probe count is in both formulas, so a fat probe run buys you detail and pays for it in survival odds. Sending 8 probes at a planet with 700 ships on an even tech gap is about an 18% chance of losing the lot.
Group Defend ships count. Ships lent to the target by their alliance make your probes easier to kill.
Dead probes leave debris. 30% of what they cost turns into a debris field over the target, and the target can harvest it.

Shadow Probes

The Shadow Probe is the paid version. It costs 20,000 Credits in the Shipyard, or it can come out of a Lucky Draw, and it builds instantly.

It returns the entire report no matter what the tech levels are.
Counterespionage does not apply. It cannot be shot down.
The target gets no Espionage Detected message, and an incoming fleet made only of Shadow Probes does not appear on their screen at all.
It is single use. It does not come home.

Use them for the shot you cannot afford to telegraph, like the last look before a fleet crash.

When you are the one being probed

Every ordinary probe run sends you an Espionage Detected message naming the player and the coordinates they launched from. It arrives whether their report was any good or not.
Inbound probes show on your Overview alongside inbound attacks, so you get a few seconds of warning.
Espionage Tech is a defensive stat too. On an incoming attack, level 2 shows you the total ship count, level 4 shows you which ship types are coming, and level 8 shows you exactly how many of each.
Keeping ships at home is the only thing that kills probes. An empty planet cannot fight back.
You cannot start Vacation Mode while probes are on the way in.
Being probed a lot usually means somebody is measuring you for an attack. It is a good moment to check your defenses or fleet save.

Who you cannot probe

Yourself. Your own planets are not valid targets.
Players on Vacation Mode. Probes already in the air when they leave still land, but you cannot launch a new run at them.
Players in Diplomacy Mode. Works both ways. You cannot spy them, and you cannot spy anyone while your own diplomacy is on.
Players in PVE Mode. Also both ways. NPCs are still fair game.
Players under Newbie Protection, or too far from you in rank. Spying is gated by the same rank rules as attacking.
A Hephaestus platform that is moving. Probes sent at one that relocates find empty space and come home with a Target Not Found report.

The status letters in the Galaxy view tell you which of these is in the way before you waste a launch.

Probing NPCs

NPC encounters have no Espionage Tech at all. Two things follow. From Espionage Tech 2 upwards they can never shoot your probes down, and from Espionage Tech 3 upwards a single probe already returns the full report. One Hermes is enough to size up any encounter, and NPC probing is never blocked by bashing limits.

Tips

Probe again right before you launch, not just when you pick the target. Fleets move.
Send enough probes to clear the threshold you actually need. Defenses at 3 is usually the number that decides whether an attack goes ahead.
Espionage never counts against bashing limits, so you can probe the same planet as often as you like.
A Hermes carries no cargo you can use. The five units of hold are for fuel, and probes cannot plunder.
Hermes probes are not useless in a fight. Nothing in the defense grid has rapid fire against them, so they make cheap fodder against a planet that is heavy on defenses and light on ships. Every warship has rapid fire against them, though.
Keep a stack of probes on each forward colony. The spy button only works from a planet that has them.