The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of James Webb Space Telescope (JWST), as determined from six month commissioning period. We summarize spacecraft, telescope, instruments, and ground system, with an emphasis on differences pre-launch expectations. Commissioning has made clear that JWST is fully capable achieving discoveries for which it was built. Moreover, almost across board, better than expected; in most cases, will go deeper faster expected. The telescope instrument suite have demonstrated sensitivity, stability, image quality, spectral range are necessary to transform our understanding cosmos through observations spanning near-earth asteroids distant galaxies.