Gray Team

Gray Team is the mysterious designation for the team of three Spartan-IIs that were said to be "on battlefields too distant to be easily recalled" in Halo: The Fall of Reach. The team was further identified to have been "on a mission far outside the confines of UNSC space, now missing for over a year"

Nothing is known about the three Spartans. It is possible that their story will be told in upcoming Halo novels, or could possibly be part of Spartan Group Omega in Halo Wars.