Squad Bravo was consisted of forty Galactic Federation Marines: thirty-nine normal Marines and one Missile Trooper. Squad Bravo was commanded by Captain A.C. Exeter. Squad Bravo was part of the GFMC Task Force Herakles.
One month prior to Samus' arrival on Aether, Squad Bravo was sent to track a Space Pirate Flagship, heading for the planet Aether, in the Dasha Reigon. Squad Bravo soon caught up to the Flagship, but the Marine's ship, the G.F.S. Tyr, was damaged, due to a severe storm, (part of the rapid unstability and dimensional flux which Aether was undergoing at the time) and they lost track of the flagship. Fortunately, they landed safely in the Temple Grounds. The G.F.S. Tyr was suffering heavy damage, and was virtually useless, other than for protection from the weather, and other natural threats. However, Squad Bravo had started to work on the ship, splitting into two groups, one for repairs on the ship, one for setting up Ops Base. According to Exeter's final report, "Each Station was doing fine, no problems. Until they appeared. All of the sudden, a Dark Portal appeared, and a large swarm of Dark Splinters emerged. There was a long fight between Squad Bravo and the Dark Splinters. In the end, however, most of the Troopers were killed, while the survivors, or the Troopers that were in the Computer Rooms, were later possessed by several Ing and turned into Dark Troopers, other than the some five that managed to reach the Pirate Labs in Agon Wastes.
Survivors (Episode of Aether only)
During Metroid Prime 2: Echoes
Samus Aran was sent, one month later, on a Search and Rescue Mission, by the Galactic Federation. She was too late, obviously. All the Troopers were either dead or possessed. Samus was still able to gather the Trooper Logs, and learn what happened. She found Exeter's final report, which gave a full video of what happened. In Echoes, Squad Bravo is the cause of Samus' arrival on Aether. Upon discovering the deceased squadron, Samus journeys to discover the murderers' identity, and remembering the dark extradimensionals which had threatened her previously on the mission, she began to piece together what had killed the Troopers. Determined to avenge their deaths, she set out to hunt down the murderers, and this led her to U-Mos and the story of the Luminoth-Ing war, which she then joined on the Luminoth's side and vanquished the Ing, thus avenging the Trooper Squad Bravo.
It is unknown what happened to the corpses of the Squad after Dark Aether collapsed, particularly those possessed, but it is likely the possessed Troopers became exorcized and simply crumpled over. Being that the Federation traveled to Aether later on and discovered Phazon there, it is likely that they retrieved all trooper bodies and brought them back to Earth, Norion or another important planet for an honored memorial service.