ODST armor
From Halopedia, the Halo wiki
The Body Suit is the fully-sealed combat armor worn exclusively by the Orbital Drop Shock Trooper (ODST) special-operators of the UNSC Marine Corps.
Description
The helmet of the suit has a dark purple protective plate with matte black armor surrounding it. The suit itself is black around the torso with a black and Grey camouflage pattern around the legs. The boots and gloves are also black. There are a total of six pouches on the waist, with four smaller pouches on the chest and two holster-style pouches on each side of the hip. The back serves as a makeshift backpack and can hold the optional oxygen gear. Below the backpack, there is a sheath that can hold a Combat Knife. A red patch signifies squad leaders. The ODST's blood type is shown on the patch.
History
Not much is known about the history, development, or implementation of the Body Suit. It is known that the SPARTAN-IIs, used the Body Suit before they got their MJOLNIR Armor. The ODST Armor has come in several designs since its first iteration. The current ODST Armor is an offshoot of the MJOLNIR Armor, using CTC's and HUD Communications Systems from the MJOLNIR program to give more situational awareness to the wearer. The suit was recently upgraded with added protection, endurance, and agility.
It was then used on Delta Halo, during the events of Halo 2. It proved effective on the most part, absorbing the shock for most of the ODSTs inside the HEVs. Others; however, died on impact upon hitting the Halo's surface, though this was mainly from drowning after crashing in a lake or hitting a vertical surface, like the wall of a canyon. The suits could take a bit more damage than a normal, standard issue Marine combat ensemble, and much more than the ODST ballistic armor used on Alpha Halo.
By the events of Halo 3, however, the body suit became much more powerful, suggesting that in between Halo 2 and Halo 3, the technology was enhanced sufficiently, or that the ODSTs have switched their armor to a more reliable suit. The ODSTs using this armor helped The Master Chief, The Arbiter, and the rest of the Separatist-UNSC forces to rout Covenant ground forces on the Ark. With the mentioning of a technological advance one should remember, when having read the book, Ghosts of Onyx that the SPARTAN, Kelly-087 sees the SPI Armor, and remarks on having to remember seeing ODSTs expermenting with a type of camaflouge armor that the SPARTAN-III generation wears.
The ODST's weapons have always been simple. Their signature weapon is the Battle Rifle and their second signature weapon is the Sniper Rifle. Although they have been known to wield the SMG in Halo 2, the ODSTs appear to mostly use medium to long ranged weapons.
Systems
The Body Suit has cooling and heating units that mask the infrared signature of the wearer, as well as creating a comfortable environment. The body armor, boots and gloves are fully encased and airtight, making them operable in a vacuum for up to fifteen minutes when equipped with an additional oxygen tank. The helmet has encrypted communications gear and a HUD, along with thermal and motion detectors giving the user an advantage over the standard Marines.
Advantages
The Body Suit is lightweight and offers protection in hard vacuum. It supplies more armor protection than standard Marine armor, and contains a enhanced communications suite. Along with the protection and communications gear, the Body Suit provides increased agility and maneuverability not afforded by standard Marine Armor. The Body Suit's helmet can withstand several head shots from head shot capable weapons. The armor's black coloring gives wearers an advantage at night and in space, as well as providing a psychological advantage over foes.
Disadvantages
Unfortunately, the suit's general complexity leads to complications. Over prolonged periods of time the suit will become very uncomfortable to wear, and it is tricky to repair in the field. It's effectiveness is decreased in desert or arctic environments where harsh light and sparsity of dark colors make its black camouflage useless. It is more suited for nighttime, urban, and forest operations, which fortunately the ODSTs have seen plenty of.
MJOLNIR ODST Helmet
The MJOLNIR ODST helmet in Halo 3, is derived from the technology utilized in MJOLNIR armor. It is attained and unlocked by the Spartan Graduate Achievement, or getting 5 XP in Matchmaking. At one point in development the ODST helmet had an antenna on its back (See "Halo 3: PAX 2007 Omegathon Round 2 Cam Gameplay", the antenna can be glimpsed for a brief moment when the player dies). The visor on the regular ODST helmets are blue, while the Spartan MJOLNIR ODST helmet has an orange visor.