NASA Bids Farewell to the Mission Operations Computer

From the beginning of the Mission Control Center in Houston, we have relied upon 'centralized' ground based computers to process and display telemetry, format commands, and perform trajectory processing. This has always been done with a IBM style mainframe computer starting with five IBM 7094's in the Gemini program. They were replaced with IBM 360/75's for Apollo, IBM 3081/3084's during the middle part of the Shuttle era and IBM ESA 9000's in the recent Shuttle era. These were known as the Mission Operations Computer (MOC).

Over the last several years, various functions of the MOC have been offloaded to the new 'distributed' architecture in the MCC. This started with various Telemetry Processing and Display functions as the new DEC/Alpha workstations gave flight controllers the capability to better format telemetry from the spacecraft and organize it into a much more concise, human interface. During a transition period that lasted several years, flight controllers could pull telemetry data from the MOC or directly off the MCC distributed network.

A few years ago, a "Command Server" capability was established, using MCC workstations to perform the Command authentication and control functions of the MOC. Although this had some interesting times during it's testing and first year of operations, it has turned into a very stable platform. The command functions on the MOC have not been used for nearly two years.

The only remaining function on the MOC was trajectory processing. This has always been the most CPU-intensive function and several attempts to port this function to a workstation/server environment, starting back in the late 1980's, were unsuccessful. Over the past few years a new effort has been made leading to what is now known as the "Trajectory Server". Extensive testing, along with lessons learned from previous attempts, have demonstrated these systems to be very robust.

Shortly after launch on STS-110, we transitioned support from the MOC to the Trajectory Server, which supported all orbit and entry phases of the mission without significant anomalies. STS-111 was supported from ascent through entry on the Trajectory Servers as well - again without any significant issues. In both cases, the MOC was available as a backup in the event of a problem.

The plan was to continue supporting the next two missions (STS-107 and STS-113) with the MOC as a backup, then decommission it by the end of the fiscal year (September 30). Due to the mission delays that have pushed the next flight into the next fiscal year, along with the unqualified success of the Trajectory Server on two flights, as well as many simulations and tests, the decision was made to accelerate the schedule to decommission the MOC.

This afternoon, in the large computer room on the first floor of the MCC that has been the home of the MOC from the early 1960's, a large crowd of Flight Controllers, Flight Directors, Engineers, Technicians, and management witnessed the final power down of the MOC. Missing from this event, unfortunately, were the computer operators and supervisors responsible for actually running the MOC.

They were laid off two weeks ago.


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