The Payload Operations Control Center (POCC) at Marshall Space Flight Center (MSFC) in Huntsville, Alabama, is the ground control center for Spacelab missions. Real-time data from the experiments aboard the shuttle are relayed via the Tracking and Data Relay Satellite (TDRS) and a domestic communications satellite to the POCC. The POCC also receives live audio and video from the shuttle, and it can uplink voice and commands to the shuttle through mission control at Johnson Spaceflight Center (JSC) in Houston. Within the POCC these data and communication lines are distributed over an internal network to individual experimenters' stations in the facility. Each station has access to the POCC internal communications loops, video displays, displays of shuttle ground tracks and times of AOS/LOS (acquisition and loss of signal from the shuttle), and terminals connected to the POCC Peripheral Processor system and the POCC VAX cluster. All positions in the HUT area of the POCC also have terminal connections to the HUT ground support equipment (GSE) computers which process the HUT HRM data.
The POCC Peripheral Processor system is a cluster of MicroVAX 2's which access the POCC database. The PP's can create customized displays of data in the database stored from the telemetry transmitted by the Spacelab EC, or uplink commands and data to the shuttle.
The POCC VAX cluster supports software comprising the Operations Management Information System (OMIS), an electronic database/bulletin board/memo system. OMIS is used to request, manage and track most requests that affect mission operations during the flight. For example, all changes to the science timeline are initiated by submitting electronic Replanning Requests (RR's) at least 24 hours in advance of the desired change. Changes to operations on shorter timescales are managed by Operation Change Requests, or OCR's. The system is cumbersome, slow, and frustrating to use, but it provides a good record, and it sure beats paper.