The Galactic Federation Special Squadron was a special team sent to SR388 in order to make sure there were no Metroids left on the planet. Shortly after, contact with the ship was lost. A search and rescue party was later sent, and then a special combat group, but none of them came back alive, although the special squadron was implied to have survived long enough to transmit information on how to kill various later stages of Metroids. Samus Aran was then sent to SR388 to exterminate the Metroids, setting in motion the events of Metroid II: Return of Samus and its remake, Metroid: Samus Returns.
Their remains are never encountered in Return of Samus, but their bodies can be seen throughout the Surface in the remake. Additionally, they also appear in the opening scenes, which show their arrival and exploration of SR388. When they first arrive, a group of Hornoads can be observing their ship as it lands. Though never explicitely revealed, it is heavily implied that the squadron was killed by a Larva Metroid: their bodies are covered in a cohesive substance commonly found near Metroids, and their remains are located on the path leading to the first Metroid encountered by Samus. One body can be found near the first Door Samus encounters, and three more corpses can be found in a camp near where the Scan Pulse is obtained. Two additional bodies are found near the dried out husk of a Hornoad, attacked and drained by the first Larva Metroid that Samus encounters, which quickly molts and becomes an Alpha Metroid.