LAU-65D/SGM-151 missile pod

The Missile Pod is a United Nations Space Command infantry weapon. It is a missile-launching weapon, holding up to eight small highly explosive missiles. The Missile Pod is capable of tracking down targets.

It's extreme size and weight probably means only a Spartan, Elite, Brute, or a vehicle can operate it.

Operation
The Missile Pod can carry eight rounds, equal to the Rocket Launcher but without having to be reloaded. Once picked up the player will appear in a third-person view. Due to the weapon's weight, the user will run at a slower pace, similar to using the AIE-486H Heavy Machinegun in this mode it is harder to aim.

It is the only weapon in Halo 3 that can track vehicles, taking the ability away from the M41 SSR MAV/AW Rocket Launcher from Halo 2. But the ability of tracking vehicles comes at a cost; there is little splash damage to other people.

Once the missile is fired, it will travel about 5 meters before becoming self-propelled and begin pursuing the target. This, along with the pod's ability to maintain a lock even when there's an obstacle (such as a small hill in Valhalla) between the pod and the target, means the wielder can fire at an upward angle, giving the missile enough vertical clearance to fly over the hill and into the target.

It is also effective against foot-bound stationary targets (such as an enemy sniper); the missile's high speed means that even if the target hears the missile, he or she may not be able to react in time. This is most effective at short and medium range, mostly because it is harder to see an enemy at long ranges, much less determining if one is moving. However, using it to combat moving infantry targets is inadvisable.

Trivia

 * This weapon may possibly be the M19-B SAM Missile Launcher that was used by Alpha Company and Beta Company.
 * It is aesthetically similar to the the rocket pods carried on the Russian Mi-24 "Hind" Helicopter Gunships.