Overview and Status of the Giant Magellan Telescope Project

The Giant Magellan Telescope is proceeding with design, fabrication, and site construction. Of the seven 8.4 m diameter mirror segments required for the primary mirror, two have been completed and placed in storage, a third has been polished to specification, three more have been cast and are in various stages of fabrication, and glass is in hand to cast the final segment. The telescope structure is nearing final design review and the start of fabrication. Residence buildings and other facilities needed to support construction at the Las Campanas site in Chile are complete. Hard rock excavation of the foundations for the enclosure and telescope pier is complete. The enclosure is in final design. The first off-axis adaptive secondary mirror is being fabricated, and a primary mirror cell has been fabricated and is under test. Two adaptive optics and phasing testbeds are being fabricated for risk reduction testing and component qualification. Our fabrication and construction schedule is being revised in response to evolving programmatic factors, including the US-ELT initiative, which received the top ranking in the National Academies' ASTRO2020 Decadal Survey.