Design and Realization of the LST Main Structure for the Cherenkov Telescope Array

The LST is a 23 m diameter next-generation Cherenkov telescope for CTA, located at 2250 m altitude on La Palma, following MAGIC, H.E.S.S., and VERITAS. To enable rapid repositioning (180 degrees in 18 s) for gamma-ray burst observations, the mechanical structure was designed to be ultra-lightweight at 110 tons.

The space-frame structure consists of slender struts made of carbon fibre, aluminium (for the dish and camera mast), and steel. It is designed to withstand extreme environmental conditions at the ORM observatory, including wind speeds up to 200 km/h, uplift forces, and ice loads of up to 30 tons. The mechanical structure is led by MPP Munich together with partner institutes in France (LAPP) and Spain (IFAE).

The prototype LST-1 has been operational since 2019, and three additional LSTs are currently under construction. The design successfully meets the functional requirements for rapid slewing and the environmental challenges, supporting the Cherenkov Telescope Array's goal of observing transient gamma-ray events.