A Remote Scanning Outpost, abbreviated R.S.O. and sometimes referred to as a "Remote Sensing Station", is a small space station usually placed near the edge of a UNSC-controlled system. Remote Scanning Outposts are usually manned by a small crew of Navy personnel. They scan deep space and Slipstream Space for any sign of scientific phenomena, pirates, and especially Covenant vessels. They usually carry an array of three probes, which can enter Slipspace, scan and reemerge to return their information to the outpost. The probes are referred to as Alpha, Beta and Gamma Probe, respectively.