Commonwealth Fusion Systems (CFS) has achieved a significant milestone in the construction of its SPARC demonstration reactor by installing a crucial component, the cryostat base, in Devens, Massachusetts. This 24-foot wide, 75-ton stainless steel circle forms the foundation of the tokamak, a key element in confining and compressing plasma to achieve fusion. Directed by Alex Creely, the project represents a shift towards building the actual fusion machine, signifying progress into a new phase. Supported by investors such as Bill Gates’ Breakthrough Energy Ventures, CFS is positioned as a leading contender in commercial fusion power development. The company plans to demonstrate the viability of fusion technology by producing more power than it consumes, with a commercial-scale reactor scheduled for construction outside Richmond, Virginia by 2027. The SPARC reactor, set to come online in 2027, aims to be the first tokamak to achieve net positive power generation. Unlike the Department of Energy’s National Ignition Facility, which uses lasers for fusion, CFS's tokamak employs superconducting magnets to confine plasma at 100 million degrees Celsius. The cryostat base is crucial for maintaining the necessary cryogenic conditions to operate the tokamak effectively. The installation process involved meticulous inspection and placement, with ongoing work on other major components of the tokamak. This achievement signifies a significant step towards unlocking the potential of fusion power as a clean energy source.