Xenonauts Wiki

In-Game Briefing[]

Art by Henry Ponciano

Our installation (Base name) is under attack by (Alien Race Name). The alien vessel has survived our anti-air defences and alien troops have been detected entering our maintenance tunnels. All non-military personnel have been evacuated to the emergency bunker beneath the base Command Centre. All military personnel in the base are preparing to repel the invaders.

The alien objective will be our Command Center, as this contains the base reactor. It must be protected at all costs, as if destroyed the resulting explosion will annihilate our installation. However, remember that you are fighting within a Xenonaut installation - inflicting heavy damage on our structures will knock them out of action until our maintenance crews can repair them

The loss of one of our installations to alien attack could be catastrophic for the Xenonauts. It must not be allowed to happen. Good luck, commander.


  1. Eliminate all Alien forces
  2. Defend the Command Center from destruction.


A Base Defence mission is triggered when an Alien Base Attack mission is able to locate a Xenonaut's base. These missions are generated when a region of the world is doing very well in shooting down UFOs.

The player is charged with defending the base from the Alien attackers at all costs. If the Aliens kill all defending personnel or destroy the Command Center then the Base is destroyed. To win the Xenonauts must kill all attacking Alien forces within the base. Commanders should take care to the use of explosives as heavily damaging rooms will destroy them, forcing commanders to rebuild or repair them at a later date.

The Aliens enter the base via Alien Breaching Pods which are forced into the base at random locations and deposit the Alien forces into the base. Aliens tend to appear at the extremities of the base however.

Even if a bases air defences did not shoot down the attacking UFO, every successful hit will reduce the number of alien attackers assaulting the base.

While the game recommends you avoid causing collateral damage, there is currently no penalty to using explosive weapons in your base. Other than the Command Center, you won't lose any structures by using them.

During a defense mission only 16 xenonauts can be brought to defend during the mission.