B777-200
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Communication Breakdown; Situational Awareness; Workload
ATC Issue All Types; Airspace Violation All Types
Human Factors; Staffing
When I got in on the MID; the sectors were already combined at ZZZ and there were several things to do. I stayed busy for almost an hour and a half and was just managing to keep my head above water. These sectors should not have been combined. Period. We have a 4-12 shift to keep someone at work during this time to keep the highs split out from the lows and I was told the Supervisor let them go home on leave. While working the traffic I was told by area 2 that 'ZZZ1 was open'. Unlike our area; they still had highs open; super highs open and split. So in other words; during the same busy period; they had four controllers in working the sectors adjacent mine; where I was working alone and I would argue that I had more traffic at the time.ZZZ1 was yelling over at me because I had just violated them with Aircraft X. This was truly an unsafe situation and violating ZZZ1 sector was minor compared to what could have happened. The Supervisor simply left in the middle of this after taking one handoff and telling ZZZ2 to keep the next one coming. After a recent fatality; it was discovered that the area stays busy during these hours and the 4-12 person is there to mitigate it. Why he was allowed to take leave and why the sectors were combined I do not know; but it put me in a very bad situation.The Supervisor needs to understand that just because it [is close to end of shift] we don't just combine everything up so he can leave and needs to understand the purpose of the 4-12 shift. If the area right next to us recognized the need to have 4 controllers in the sectors around me; clearly someone else recognized that this was a busy time with a high traffic load.
Center Controller reported a problem with staffing that may have led to an airspace violation and increased workload.