Ordnance pod

Ordnance pods, formally referred to as Materiel Acquisition Pods (MAP), are rearmament capsules frequently used to rearm UNSC ground units in hazardous combat situations. Launched from the air or suborbital positions, they are deployed to provide weapons and equipment for UNSC forces deep behind enemy lines or outside the range of a forward operating base.

Description
A resupply canister is a long, oblong capsule, typically painted in olive green drab or gray. In the interior is a stiff blue or black/gray foam that encapsulates a firearm, typically an M7 submachine gun, BR55 battle rifle, M90 shotgun, SRS99C-S2 AM sniper rifle, MA5C assault rifle, or M41 rocket launcher. Most pods are saved for heavy ordnance and munitions, or long-range equipment. Upon impact, a gas-pressured release system pops off a set of panels on the upper surfaces of the capsule, revealing a partial profile of the weapon within.

D77-TC Pelican dropships may carry six resupply canisters on their tail assemblies and eject them in sequence, allowing the capsules to air-drop to the ground and implant themselves firmly into the ground, similar to the ODST Human Entry Vehicle. Ordnance pods can also be deployed by GA-TL1 Longswords.

Types of resupply canisters
There are several types of ordnance pods. Some of the most prominent include the Type-B Capsule, and the Type-C Capsule. The Type-B Capsule, which has a length of 2.76 meters (9.06 feet), was used in Halo 2, and the Type-C Capsule was used in Halo 3. The difference between Type-B's and Type-C's is that Type-B's lack the rounded part on top, the flashing red light, and the pop off protection panel. There is also a more streamlined variant of resupply canister that is commonly dropped by Longswords to deliver ordnance to ground forces.

M2859 Materiel Acquisition Pod
The M2859 Materiel Acquisition Pod is a type of ordnance pod developed by Misriah Armory and commonly employed in the years following the Human-Covenant War. The M2859 pod is equipped with a short-range thruster on top for acceleration during deployment. The hatches are secured in to the extremely durable casing by a pressurized locking mechanism and magnetic latches on the sides. On its underside, the pod features a weighted anchor and a tapered nose, allowing it to breach most types of terrain and remain upright. The pod is 242.1 centimeters (95.3in) tall, 82.5 cm (32.5in) wide on one side and 83.5 cm (32.9in) on the other.

War Games exercises train Spartan-IV personnel to summon these pods in the battlefield to a maximum efficiency.

In-game
Ordnance pods also appear by default on the multiplayer level High Ground and on Valhalla, having been dropped by Victor 398 before crash landing. In Forge, players can spawn the pods, but not delete opened ones. If one is spawned couple feet off the ground, the panel comes off but will spawn a full capsule.

Trivia

 * In the Halo 2 level Delta Halo it is possible to move these weapon capsules after they have been deployed by a Pelican by pushing them with a Scorpion or Type-26 Wraith.
 * These pods can kill the player in Halo 2 if one stands right under them when they are dropped.
 * In Halo: Reach during the start of Firefight matches, a Longsword can be seen dropping ordnance pods that resembles a resupply canister (they usually contain heavy weapons).
 * In Halo 3 via Forge, players can embed them into the ground, creating vehicle barriers.

List of appearances

 * Halo 2
 * Halo 3
 * Halo: Reach
 * Halo 4
 * Spartan Ops
 * Halo 2: Anniversary