Mission 3: Reinforcement of the Perch

Reinforcement of the Perch is the third mission of Halo: Spartan Assault. Completing the level without any of the M9 Wolverines getting destroyed unlocks the Escort Service achievement.

Introduction
The UNSC's Research Facility Alpha was constructed at the base of an ancient Forerunner structure recently discovered by the UNSC. when it became clear the Covenant were heading for the Forerunner structure, UNSC command feared Alpha facility would be crushed.

The Covenant were relying heavily on drop ship insertion and Spartan Davis realized they would be vulnerable to focused anti-aircraft fire, so he began establishing air defenses west of Alpha facility at a location designated Glacial Perch. Unfortunately, the Covenant had identified the need to secure this area, and when Davis arrived, Glacial Perch was swarming with Grunts and Elites.

Escort the Wolverines to their defensive positions
Spartan Davis, two UNSC Marines, and two M9 Wolverines are near a small UNSC encampment, with the remains of a destroyed UNSC dropship and a Covenant mega turret nearby. In the background, Type-26 Banshees fly around the area, but are quickly destroyed by other Wolverines. A Type-52 Phantom drops off two Unggoy Minors as the convoy moves through Glacial Perch, leaving when the Spartan arrives. The Spartan and Marines quickly eliminate the two Unggoy and continue. While the convoy moves through the Perch, they encounter several more Unggoy Minors, one of which is manning a Type-29 Shade. Davis and the Marines eliminate the Unggoy and soon discover a large drop of Unggoy led by a single Sangheili Minor. While the Marines and Spartan fight the Covenant forces on the Perch, a flies overhead. After killing the Covenant forces, a Sangheili Minor leads a group of Unggoy and flanks the Wolverines from behind. The assaulting Covenant forces are quickly eliminated.

While Davis and the Marines continue through the Perch, they engage a Sangheili and several Unggoy that were dropped off by the Spirit. During the firefight, another group of Covenant forces flanks the Wolverines again and attacks from behind. After a long engagement, the Spartan and surviving Marines destroy all Covenant forces in the area. With no more Covenant personnel nearby, the remaining Wolverines are safely escorted to the edge of the Perch.

Eliminate remaining enemy opposition
The Wolverines begin firing on nearby Banshees, while two Spirits arrive at the edge of the Perch. One simply flies away, but the second one deploys a Sangheili Minor and three Unggoy Minors. The Covenant forces begin to attack Davis, the Marines, and the Wolverines, but they are quickly eliminated by the Spartan.