Power Suit

A Chozo Power Suit is a suit of powered armor designed by the Chozo. This term applies to two things: Samus's basic suit without any upgrades, and her suit as a whole regardless of its current upgrade level. This is likely because the word "Power Suit" is short for powered armorsuit. A Chozo known as Dryn was apparently instrumental in the development of the technology, and Mother Brain claims to be the creator of Samus' original Power Suit. Two specific models are well-known: the first is a suit given to Samus in her teenage years by the Chozo who raised her (seen in Metroid Zero Mission). This suit was lost to her as a result of a Pirate attack during this game's events, however, and was soon replaced with an enhanced Power Suit, featuring slight physical differences. Presumably this second Power Suit is an ancient model, given its depiction in Chozo prophetic murals and its compatibility with some of the oldest Chozo-produced upgrades such as the Space Jump, Plasma Beam and Gravity Suit.

Samus’s Power Suit comes with a standard Power Beam and allows her to survive underwater and in outer space, and to resist Space Pirate poison. Its basic functions are not always sufficient for a busy warrior, however, so the Chozo used a modular construction allowing the suit to be outfitted with a wide variety of weapons systems and special armor. The Chozo themselves left many such tools on various planets they inhabited, including the Varia and Gravity Suit upgrades. The Luminoth, another ancient race technologically equivalent to the Chozo, were able to produce modifications compatible with the Power Suit including the Dark Suit and the Light Suit. A considerable amount of the suit is biological, which resulted in Phazon corruption following Samus’s encounter with the Omega Pirate. Exposure to the large quantity of unrefined Phazon ore caused a kind of ‘mutation’, rendering the suit impervious to radiation from Blue Phazon, and allowing Samus to fire the devastating Phazon Beam under certain conditions.

While active, the Power Suit bonds with Samus biologically, and cannot be taken off without her cooperation. It has been observed on many occasions that the method Samus uses to remove the Power Suit is to have it dematerialize with a bright flash. When the suit is inactive, Samus is able to retain the upgrades within herself until it becomes active again (observed in the events of Metroid Zero Mission.) But it has also been observed that she can have it materialize at will, (seen several times taking place in the Metroid Zero Mission Manga, once at the beginning of Metroid Prime 3: Corruption  and at the start of Metroid: Other M) suggesting that this suit is not meant to be dismantled to be removed like regular armor, and that it's somehow put on or taken off by using an energy-to-matter reaction. When this is not possible to do, the Galactic Federation has been able to modify it while she is unconscious. In the first instance of this, they added PED functionality to take advantage of a Phazon infection in her bloodstream. Later, the weaker Fusion Suit is built on the remains of Samus’s Power Suit after large portions were surgically removed due to X infestation.

Official Metroid Prime website
"Weapon effect: N/A

Weapon range: Unlimited

Weapon potential: Medium

''Samus Aran's Power Suit provides life support functions, and is well shielded from attack. The modular nature of the Power Suit allows for the addition of weapons, visors and other gear as needed. The Power Suit's shielding loses energy with each hit, but can be replenished by collecting energy upgrades. The origin of this suit is the subject of much speculation."''

Super Smash Bros. Brawl Trophy
"Samus in the basic version of the legendary Power Suit, made for her by the Chozo race. Samus is most often seen at the beginning of each game in this suit. The normal Power Suit has the lowest level of protective power and features no additional functions. She can use the cannon on her right arm for power shots and build up her arsenal through item pickups."

NES Metroid

GCN Metroid Prime

Sticker

 * Samus - Metroid [Specials: Indirect] Attack +15 (Samus, Zero Suit Samus)

Metroid: Other M Art Folio - Power Suit Samus
"My Power Suit is my greatest weapon. Designed by the Chozo, it boosts all of my natural athletic abilities while providing an array of defensive and offensive attributes. Boasting full armor capable of sustaining ballistic damage, life-support systems, my upgradable Arm Cannon, and Morph Ball capabilities, it truly is a part of me."

Metroid: Other M manual
"The Power Suit that Samus is wearing will acquire new features as you progress through the game."

Trivia

 * In the commercial for the original Metroid, Samus's suit can be seen giving off a cloud of steam, possibly implying that it produced large amounts of heat. However, this was probably for dramatic effect.
 * The Power Suit is apparently able to assimilate almost any technological upgrade into its system, regardless of the upgrade's origins. This is shown when Samus acquires the Hazard Shield and Nova Beam, both of which are of Space Pirate design. Oddly, however, the suit was originally unable to assimilate the Plasma Beam, Gravity Suit, and Space Jump upgrades in Metroid: Zero Mission, despite the fact that they were of Chozo origins. This might be because they were ancient and possibly forgotten devices incompatible with the newer Chozo suits or simply designed to only be compatible with the suit obtained in Chozodia. It is also likely that her power suit was a older design and not compatable with the three, newer upgrades.
 * The suit alters Samus's physical strength allowing her to do things she couldn't do without her suit. (see Power Suit Mechanics)
 * The Power Suit acts as a second skin. As seen in the opening scene in Metroid Prime 3: Corruption, she can control when she puts on the suit internally.
 * While Samus worked as a Galactic Federation Police Officer, she had a symbol on the left shoulder of her Power Suit. It looked like a spiraling galaxy, likely a Federation mark.
 * A small feature of the Power Suit is a glowing green (or blue) "L" shape on the left chest plate. In Metroid Prime, the shape points outward, rather than inward, like in other games.
 * Weavel is also stated to possess a Power Suit.
 * In an interview with Yoshio Sakamoto about the Ruins Test, it is revealed that Samus needs an immense amount of mental concentration in order to operate her Power Suit.
 * In Metroid Zero Mission, Samus manually removed her own Power Suit after escaping the exploding Tourian, in a belief that the mission was over. However, Space Pirates ambushed her and succeeded in forcing her to crash land her back on Zebes, ultimately disabling her ability to re-summon her Power Suit. However, she obtains a new suit after defeating the Ruins Test.
 * In Super Metroid and Metroid: Other M, the Power Suit has a yellow coloration with the large shoulders of the Varia Suit. However, in Super Metroid, the front-facing sprite used in elevators and save points has flat shoulders.
 * The suit's shape in Metroid: Other M could be explained by the fact that Samus already has the Varia Suit, but does not have authorization to use it yet. The 'non-legendary' flat-shouldered suit also appears in a flashback.
 * In Metroid Prime and Metroid Prime Pinball, the Power Suit speaks at certain points, the former depending on the version. In the Japanese, European and Australian versions of Prime, such cases include when the Ventilation Shaft fills with gas (the suit says "Poison gas detected"), when engaging a horde of enemies that causes the doors to lock, and when Samus' abilities are lost (the suit will list each item that Samus has lost) at the beginning of the game. Cases in Pinball include when a Jackpot is scored. In Pinball, the suit voice is provided by Lorelei King.
 * In Metroid Prime, the Suit's components malfunctioned after Samus was caught in an explosion in the Frigate Orpheon. This is the only time that Samus' suit has malfunctioned, although Samus loses her suit upgrades after her suit takes damage on numerous other occasions, possibly due to malfunctions similar to this. However, this is the only time whe Samus's suit has malfunctioned from an ordinary explosion, instead of special circumstances or enemies.
 * The following Power-ups were lost in the malfunction: Charge Beam, Missiles, Morph Ball, Varia Suit, and Grapple Beam.
 * In Metroid Prime, the shoulders of the normal Power Suit seem to stretch all the way to Samus's shoulders, while in the other Metroid games, they "fan" up and extend (in height) past Samus's head.
 * In Metroid Prime 2: Echoes, numerous Ing stole many major portions of her Power Suit, leaving only the Varia Suit upgrade and the Charge Beam intact. It is unknown how the Ing managed to acquire the suit pieces.
 * The following Power-ups were stolen: Missiles, Space Jump Boots, Morph Ball Bombs, Boost Ball, Spider Ball, Grapple Beam and Power Bombs.
 * In Metroid: Other M, the Power Suit starts deteriorating under shock of Ridley's appearance. It deteriorates yet again prior to being shot by Adam. This could be because in an interview, the creator of Metroid stated that it takes Samus a large amount of concentration to use the Power Suit.
 * In most recent Metroid games, such as Metroid Fusion, Metroid Prime, Metroid Prime 2: Echoes, and Metroid: Other M, the reason for why Samus Aran starts off with most of her upgrades missing is explained. The only exception in the past was Metroid II: Return of Samus, where Samus started off with Missiles, the Morph Ball, and Bombs. The recent installation, Metroid Prime 3: Corruption, also follows the same method as Metroid II (excluding the missiles).
 * Currently, Super Metroid is the only game in which Samus starts off with not a single upgrade in her possession, and no explanation is given.
 * It is also worthy to note in Super Metroid that when Samus is giving the story about when she delivered the Baby to the Ceres Station, she is wearing her Power Suit when shaking the old man's hand in the cut-scene.
 * Other than the Diffusion Beam and the Seeker Missiles, Samus has all her upgrades in Metroid: Other M and only uses them when authorized to.
 * In Metroid Prime, the Power Suit was modeled and skinned by Gene Kohler.