Battle of Chi Ceti
From Halopedia, the Halo wiki
Template:Battle The Battle of Chi Ceti was a small engagement between UNSC and Covenant forces.
Background
En route to the Damascus Testing Facility, the UNSC Commonwealth was attacked by a Covenant frigate. The frigate successfully fended off the Covenant ship, blasting a hole in it with a MAC and then hitting it with a Shiva warhead while a squadron of Longsword fighters distracted the frigate to keep it from retreating. At the cost of the Longsword squadron and heavy damage to the Commonwealth, the Covenant ship was force to retreat to the edge of the system.
The Spartans on board then landed on Chi Ceti 4, where they donned their MJOLNIR armor for the first time.
At this point, the Covenant ship turned around and continued its attack on the system. Then John-117 decided that he and his Spartans were going to sneak aboard the ship, and blow it up from the inside.
The Spartans boarded a Pelican, and took off into space. They strapped the Pelican's ANVIL-II ASM warheads to themselves and donned thruster packs to fly through space to get aboard the Covenant ship. Only three Spartans, John-117, Kelly-087 and Sam-034 successfully landed on the ship and entered through it's hole. They reached the ship's reactor, tossed their warheads inside, and escaped.
Unfortunately, Sam got hit by plasma from a Jackal that breached his armor making it impossible for him to follow his friends out from the ship since he would die from decompression. He was forced to stay behind. He held off the Covenant while John and Kelly escaped. The warheads went off, and the Covenant ship was destroyed, taking Sam with it, He was the first Spartan to die in combat.