The Commissioning Phase of the LSST Project is the final stage in the combined NSF and DOE funded LSST construction project. The LSST commission phase is planned to start early in 2020 and be completed near the end of 2022, ending with the LSST Observatory system ready to start survey operations. Commissioning includes the assembly of the three principal subsystems (Telescope, Camera and Data Management) into the LSST Observatory System and the integration and test (AI&T) efforts as well as the science verification activities. The LSST System AI&T and Commissioning Plan is driven by a combination of engineering and scientifically oriented activities to show compliance with technical requirements and readiness to conduct science operations (acquiring data, processing data, and serving data and derived data products to users). LSST System AI&T and Commissioning will be carried out over four phases of activity: Phase-0) Pre-commissioning preparations (work breakdown structure; Phase-1) Early System AI&T with a commissioning camera (ComCam); Phase-2) Full System AI&T when the LSST Science Camera is shipped to Chile, integrated on the telescope and the data management system (DMS) is exercised with full scale data; and Phase-3) Science Validation where a series of mini-surveys are used to characterize the system with respect to the survey performance specifications in the SRD/LSR and functionality of the, leading to operations readiness. The Science Validation Phase concludes with an Operations Readiness Review (ORR).
The LSST System Assembly, Integration and Test and Commissioning effort has been planned out over several phases The first phase of commissioning under Early AI&T is designed to test and verify the system level interfaces using ComCam – a 144Mpixel imager utilizing the same control components as the full science camera. During this period, the telescope active optics system will be brought into compliance with system requirements; the scheduler will be exercised and all safety checks verified for autonomous operation; and early DM algorithm testing will be performed with on-sky data from ComCam using a commissioning computing cluster at the Base Facility.
The second phase of activities under Full System AI&T is designed to complete the technical integration of the three principal subsystems and EPO, show full compliance with system level requirements as detailed in the Observatory System Specifications and system level interface control documents, and provide full scale data for further DM/EPO software and algorithmic testing and development. System level requirements that flow directly to subsystems without any further derivation will be tested for compliance, at the subsystem level and below, under the supervision of Project Systems Engineering. This document includes the general approach and goals for these tests. It is expected that roughly four (4) months into the Full System AI&T phase the telescope and camera will be fully integrated and routinely producing science grade images over the full field of view (FOV), at which point “System First Light” will be declared. Following System First Light will be an intensive data acquisition period design to test the image processing pipelines and validate the derived science products that are to be delivered by the LSST survey.
The third and final phase of activities under Science Validation is designed to fully characterize the system performance specifications detailed in LSST System Requirements Document and the range of demonstrated performance per the LSST Science Requirements. These activities are based on the measured “On-Sky” performance and informed simulations of the LSST system.
In this paper we describe the inputs and assumptions to the commissioning plan, a summary of the activities in each phase, management strategies and expected outcomes.