The ground-based Stage-4 Cosmic Microwave Background Experiment (CMB-S4) is a forefront scientific endeavor aimed at mapping the cosmic microwave background (CMB) with unprecedented sensitivity. The cosmic microwave background is the afterglow of the Big Bang and provides crucial insights into the origin and evolution of the universe. CMB-S4 will enhance our understanding of the universe's history, from the highest energy density at the moment of the Big Bang to the formation and evolution of cosmic structures up to the present day.

CMB-S4 is a collaborative effort proposed to be jointly pursued by the U.S. Department of Energy, the National Science Foundation, and international partners. CMB-S4 will deploy the largest arrays of superconducting microwave detectors ever built. The receiver cryostats will be integrated into three different types of highly optimized survey telescopes.

The paper briefly describes the main elements of the proposed CMB-S4 construction project and the key technologies required to build the survey telescopes. The CMB-S4 project management organization is designed as a unified single project integrating the complex organization and support from the two funding agencies. A possible project schedule is introduced, which maps out mass-producing large quantities of superconducting detector wafers, superconducting readout electronics, and testing of final focus module assemblies.