Warrant Officer Shiela Polaski was a blonde-haired UNSC Warrant Officer assigned to the 23rd Naval Air Squadron in 2552. She was stationed aboard the UNSC Pillar of Autumn as a Pelican pilot. When that vessel fled the Battle of Reach, crash landing on Installation 04, Polaski survived.
She was never mentioned during The Battle of Installation 04 but was among the handful of survivors who fled in a Pelican when the Halo was destroyed. She, Lieutenant Elias Haverson, Staff Sergeant Avery Johnson, and Corporal Locklear hid in the debris field until they met with John-117 and Cortana in their Longsword fighter. Despite the harrowing experience of Installation 04, she was relatively levelheaded. At some point, Locklear developed a crush on her. She apparently returned his feelings.
She helped the Chief capture the Covenant flagship Ascendant Justice. She then learned to pilot its Covenant Dropships, and when they returned to Reach, she piloted the ship to the surface so they could locate the SPARTAN-IIs who had survived the fall of Reach.
When they returned to the Ascendant Justice and were caught in an anomalous Slipspace bubble, Polaski volunteered to pilot the Spartans outside the vessel to conduct extra-vehicular repairs. She was killed along with Anton-044 and Li-008 when a renegade charge of plasma flash-vaporized the dropship's cockpit.
Halo: First Strike, page 43