An object stage bearing system can include an object stage, a hollow shaft coupled to the object stage, and an in-vacuum gas bearing assembly coupled to the hollow shaft and the object stage. The in-vacuum gas bearing assembly can include a gas bearing, a scavenging groove, and a vacuum groove. The gas bearing is disposed along an inner wall of the in-vacuum gas bearing assembly and along an external wall of the hollow shaft. The scavenging groove is disposed along the inner wall such that the scavenging groove is isolated from the gas bearing. The vacuum groove is disposed along the inner wall such that the vacuum groove is isolated from the scavenging groove and the gas bearing.