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James Webb Space Telescope
Flight Operations

Flight operations is the near real-time activity of the STScI Science & Operations Center (S&OC) to obtain and capture the science data from JWST. It also includes monitoring and maintaining the performance of JWST so that the data returned will always be of the highest quality possible. General science observers will never have to interact with this part of the S&OC.

The Flight Operations System (FOS) is the integrated software and hardware that supports flight operations for JWST and real-time interaction with the observatory for both routine and contingency operations. All commands to the Observatory originate from the FOS, and all telemetry from the observatory flow to/through the FOS. The FOS provides real-time commanding of the observatory for communications, and as needed for commissioning and contingency operations, uplinks observation plans, scripts, and command sequences that are used to execute most observatory operations, and also uplinks flight software loads when changes to flight software are required. The FOS controls execution of the observation plan and coordinates commands and data needed to maintain the observatory, such as to maintain the orbit at L2. The FOS receives all telemetry data from the observatory, both real-time engineering data and recorded engineering and science data. The FOS monitors real-time engineering telemetry and analyzes recorded engineering telemetry to ensure health, safety, and performance of the observatory. Because the FOS is the originator of all commands to the observatory, the FOS will be a secure facility, with "hot" backups for critical systems, and provision for moving health and safety operations to a backup site if that should become necessary.

A Flight Operations Team (FOT) will operate the FOS. The FOT will plan communications contacts, execute real-time operations activities, and monitor engineering telemetry to ensure the health, safety and performance of the observatory. The FOT will be able to analyze engineering data within the FOS in order to identify and respond to trends in observatory performance. During commissioning and contingency operations, the FOS will be staffed 24 hours a day. During commissioning, the FOT will support the prime contractor in the execution of the commissioning plan, which consists of the deployment, adjustment, and checkout of observatory subsystems. This will include supporting prime contractor and STScI optics experts with analysis of wavefront sensor data and adjustment of the primary mirror. The FOS will be designed to function autonomously for relatively long periods, with the ability to detect and notify off-site personnel in the event of an anomaly. During normal operations, the FOT will staff the FOS on a single weekday shift unless problems with communications or operations arise.

The Jet Propulsion Laboratory (JPL) Deep Space Mission System (DSMS) will provide communications between the FOS and JWST, normally using the 34 meter antenna of the Deep Space Network (DSN) to provide high rate Ka-band downlink, low rate S-band downlink, and S-band command uplink. During contingency operations, the 70 meter antenna may be used for S-band communications. The DSN provides three sites, located in California, Spain and Australia, that can provide nearly continuous contact coverage during commissioning, and that meet the requirement for a combination of ground stations in Northern and Southern hemispheres to accurately determine the JWST orbit (to within 50 km). The DSN will support a command uplink rate of 16 kbps, real-time telemetry downlink rate of 40 kbps, and a high rate telemetry downlink rate of 28 mbps to downlink 232 Gbits of recorded telemetry data per day. During normal operations, the DSN will provide one 4-hour contact per day.

Once the FOS has captured the data from JWST, it will be prepared for Data Release.