Scientific commissioning of the James Webb Space Telescope

The long-awaited launch of the James Webb Space Telescope on December 25, 2021, initiated a complex commissioning campaign which successfully brought the observatory to readiness for carrying out its scientific observing program by early July, 2022. Commissioning began by bringing online the various spacecraft systems and executing a series of mission-critical deployments. The next few months involved a complex interplay of cooling toward the final cryogenic operating temperatures of the telescope and instruments, aligning the segmented, deployable telescope, bringing online Webb's four scientific instruments (plus Fine Guidance Sensors), and beginning the process of preparing their many powerful observing modes for scientific use. We provide an overview of the process and timeline for executing the commissioning campaign and then focus on its final stages: for each instrument, acquiring the numerous pieces of performance data and carrying out the operational verifications that ultimately led to confirmation of each observing mode's readiness for scientific operations.