Cosmonaut

Cosmonauts (コスモノーツ Kosumonōtsu) are a new enemy type introduced in Earth Defense Force 5, and like the Colonists fill the role of the Hectors from Earth Defense Force 2017 and 2025. They are encountered towards the middle of the campaign, and represent a distinct step up in difficulty.

Description
Cosmonauts are a powerful enemy type that resemble the classic "grey" aliens. They are the second wave of giant soldiers deployed by the Primers in their invasion of Earth, the first being the frog human-like Colonists.

Like the Colonists, Cosmonauts are typically deployed into battle by Landing Ships. It is likely that the Cosmonauts are members of the very alien race behind the Primer invasion of Earth. Cosmonauts wear armored spacesuits that give them the appearance of a robot upon first glance, however their spacesuits can be damaged and destroyed by gunfire. Their armor is divided into ten distinct pieces which receive damage separately, and they cannot be killed while their armor is intact. They will always take at least two hits to kill no matter how powerful the weapon used against them, since a hit that destroys a piece of their armor will not "overflow" damage to the body part underneath. This even applies to weapons capable of piercing multiple enemies. The sole exception is punches from Gigantic Unloader Barga, which will destroy the armor and damage the Cosmonaut in a single blow. Weapons that score multiple hits with the same shot such as Dispersal Mortars can also destroy the armor and hit the Colonist underneath with one shot.

Their armor applies "weight" to them, and as more of it is destroyed, the Cosmonaut will gradually speed up: when "naked," they are extremely fast and agile, to the point it can be quite tricky to land hits on them consistently.

Their armor parts are not all of the same strength: on normal, the head armor has 400HP, the torso 300HP, and the limb parts (two per limb) 100HP. Underneath, the head has 300HP, the torso 400HP, and the limbs 50HP (limbs have two sub-sections, upper and lower, each with 50HP). The creature will die if it receives an aggregate total of 400HP in damage across all parts of its body or its head is destroyed: this total is not restored when the creature regenerates a destroyed limb. The heavily armored variant has increased durability, a two-layer armor scheme, and also takes no damage to its main HP pool from hits to its limbs, meaning the player can only deal meaningful damage to it by attacking the head or torso.

Like Colonists, Cosmonauts' limbs can be severed once they are exposed, leaving them crawling on the ground or unable to fire their weapons. However, if they are left alone for enough time, they will regenerate severed limbs. Cosmonauts are highly intelligent and will communicate and coordinate with other Cosmonauts and Colonists, making them very challenging in groups.

Like Colonists, they can perform evasive rolls, take cover behind buildings, and will sometimes climb on top of smaller structures to get a better line of sight. Their AI is similar to the Colonist AI in that they can lose track of the player character and if they do, will search the last place they were seen: they also share the same quirk that if they have previously seen a character operating a vehicle and do not see them exit it, they will continue to act as if the empty vehicle is occupied.

One of the best ways to combat them is to use rapid-fire, high-damage weapons, as they are just as vulnerable to stunlock as Colonists. The Wing Diver's Rapiers or the Air Raider's Minigun strikes, for example, will tear through their armor while leaving them very little ability to respond. They are particularly weak to Rapiers since at extremely close range they cannot actually point their large weapon close enough to themselves to hit the Wing Diver: since their weapons lack any penetration ability, the Wing Diver can use the body of a Cosmonaut she is attacking to protect herself from shots fired by its companions.

They are also weak against enemies on top of buildings, since only one Cosmonaut variant can destroy structures. Several of the Wing Diver's orb weapons are very effective against them in this state, particularly the homing Gleipnir and the downward-firing Heaven's Gate if the player can get the hang of throwing it properly, as they will tend to crowd around on one side of the structure if they are alerted.

On Hard and below they are also surprisingly vulnerable to the second model of the Ranger's Air Tortoise, particularly when not aggro'd, since it allows the Ranger to throw out enough damage to kill a Cosmonaut without actually alerting them until the first missile impact occurs. Their habit of hiding behind structures very much works against them when dealing with this weapon, as it results in long periods of them standing still.

NPCs will always mark their shots to a Cosmonaut's torso, so it can be a good idea to destroy the chest armor to assist them.

There are two major variants of Cosmonaut:

Standard
The most common variant of the Cosmonaut, equipped with the standard single-layer armored spacesuit. The basic type carry a gun known as the Ether Rifle. This rifle fires dense 15-round bursts of projectiles, and is significantly more accurate than the Ether Gun carried by the Colonist Infantry.

Less commonly, Cosmonauts can be equipped with a powerful shotgun called a Rupture Gun, the same type of gun wielded by the corresponding Colonist variant. A Cosmonaut's Rupture gun is half as powerful as a Colonist's per-shot due to firing 20 pellets instead of 40 with the same damage, but the shot is more focused and a Cosmonaut can fire 15 shots in a row between "reloading" pauses rather than 2. It should be noted that if the Cosmonaut flinches the game will "forget" its current ammo count and reset it to 15, which can be very dangerous at close range.

The least common weapon for basic Cosmonauts is a high-powered long-range laser cannon known as the Raster Cannon: this is easily recognised by being carried on their shoulder instead of in their hands. It possesses a range ten times greater than the Ether Rifle, and is extremely accurate at long distance. It fires a continuous beam that deals constant damage in a similar manner to the green beams of the Outpost Base, and can very quickly chew through the health of anything the Cosmonaut has a line of sight to. The impact also creates a blinding burst of light that makes it difficult to target the Cosmonaut effectively. The Raster Cannon fires a continuous beam for three seconds, after which there is a five-second "cooldown" time before the Colonist can use it again. As with the flinch-reloading of shotgun Cosmonauts, if a Cosmonaut with a Raster Cannon flinches during their weapon's cooldown time, they will immediately be able to fire it again on recovery.

Heavy
Heavy Cosmonauts are effectively a Mutant form of the Cosmonaut with an additional layer of armor over their spacesuit's exterior: this is 50-100% tougher than the regular plating for the same area. However, their heavier armor makes them able to move only about half as quickly as normal Cosmonauts. As with regular Cosmonauts, their armor has "weight" and if all of their exterior plating is destroyed they will move as fast as a normal Cosmonaut. Heavy Cosmonauts are much more aggressive than standard Cosmonauts and will generally not take cover or perform evasive rolls, preferring to charge head-on and attack from as close a range as possible. Because most of their weapons have a spin-up time, they can be prevented from firing if the player is able to make them flinch, as this resets the spin-up animation.

Their most common armament is a Heavy Ether Gun, a more powerful version of the Ether Rifle that functions like a Gatling gun. They fire in a 150-round burst that lasts for five seconds, after which they have a cooldown of around 10 seconds. Their weapon also requires a roughly 3 second spin-up before the Cosmonaut can actually fire.

A less common weapon for Heavies is an explosive launcher known as the Wrecking Launcher. The Wrecking Launcher fires from a port on the tip that opens and closes: its shots consist of bursts of five unguided rockets, which are fairly slow and rather weak in terms of damage. As with other enemy missile weapons, the shots from the Wrecking Launcher cannot be redirected by a Fencer's Deflector, but reflecting them does prevent them from dealing damage to the Fencer or his allies. They are the only Cosmonaut variant able to destroy buildings with their weapons.

Towards the end of the campaign, Heavies are also encountered with their equivalent of the Rupture Gun: in their case the weapon is not a shotgun but an extremely powerful and deceptively long-ranged flamethrower. This weapon is particularly dangerous if most of the Heavy's armor has been destroyed. Like the Heavy Ether Gun, there is a "spin up" animation on the flamethrower's barrel before it actually starts to fire. The flames themselves have a similar blinding effect to the Raster Cannon: it is very important to get a feel for where the Cosmonaut is in relation to the jet of flames when it fires, as blind counter-fire can be necessary in order to make them flinch and cease firing.

In DLC 2's missions Heavies can sometimes be found wielding one of two variants of the Raster Cannon: either a long-range type that fires a purple beam with a 3-second duration but only a 5-second cooldown, or a red type which is half as powerful but fires for twice as long, and has a 10-second cooldown. This variant is more accurate and has better tracking than the standard Raster Cannon, making it very difficult to evade. A couple of Heavy Colonists with Raster Cannons will also appear in mission 100 on Hardest and Inferno difficulties.

Trivia

 * Cosmonaut (космона́вт) is the Russian equivalent of "astronaut."