Tmt comp background

Summit Facilities and Enclosure

Summit Facilities

Models for TMT operations have been developed and the conventional facilities have been designed in-line with the operations models. Conventional facilities include all of the pumps, compressors, refrigeration systems, power conditioning and control, computer facilities, offices, kitchens, workshops, optics facilites, lab space, restrooms, etc. that are needed to support TMT on-site operations. The most efficient and minimal facilites have been developed so that the facility footprint, excavations and entire construction sequence are minimized and the maximum amount of work is done off-site.

The summit facility supports telescope and instrument operations, control room functions, staff summit support, mirror handling, stripping, cleaning, storage and recoating, basic engineering and technical activities and other elements of operation that must be carried out close to the telescope.

The Summit Facilities planned at the Maunakea site.

The Summit Facilities planned at the Maunakea site.


The TMT enclosure has several key functions. By day, it must protect observatory systems, facilitate a broad range of maintenance activities, including providing cranes for lifting, and keep the telescope temperature near the expected night time temperature. By night, it must shield the telescope from wind buffeting while allowing enough airflow to keep the interior structures in thermal equilibrium with the outside air to limit image degradation due to air turbulence in the enclosure. The control of the enclosure is coordinated with other observatory systems (such as the Telescope Structure) by the Telescope Controls System (TCS).

TMT has selected an innovative, structurally efficient calotte enclosure design that, by its spherical shape and circular “shutter” aperture, fulfills key functional requirements with lower mass (and hence lower cost) than possible for previous enclosure designs.Further information about the Final Design Phase of the Enclosure (completed in mid-2018) can be found in the Associate Project Manager Blog.

TMT Enclosure Exploded View

Exploded view of the TMT Enclosure

Enclosure design by Dynamic Structures

Enclosure design by Dynamic Structures. 

Computational Fluid Dynamics thermal modeling of the TMT enclosure

Computational Fluid Dynamics thermal modeling of the TMT enclosure

Artist impression of the TMT Observatory at sunset
Cross sectional view of TMT

Cross sectional view of TMT enclosure revealing the observatory structure and components.