Pasadena, CA – TMT’s telescope structure subsystem (STR) recently completed two successful Production Readiness Reviews (PRR2 and PRR3) to assess the availability of adequate resources and planning for production, and later for assembly, integration and verification. The STR’s design and future fabrication are activities led by NAOJ and their prime contractor Mitsubishi Electric Corporation (MELCO) in Japan.
The TMT Telescope is an altitude over azimuth design with a single azimuth track (horizontal rotation) and two large elevation journals (vertical rotation). TMT’s STR will securely hold all TMT mirrors precisely in place under any circumstances and support all science instruments. It will also enable precise pointing and tracking of any objects in the night sky and keep all mechanical and optical components aligned to achieve the best possible observations.
While PRR2 dealt with the elevation and azimuth structures of the telescope (the main moving parts of the telescope and weigh about 2000 metric tons), the PRR3 review focused on the Nasmyth platforms (3rd floor level which give access to the laser guide star facility plus the cryogenic platform and the large 4th floor level where all science instruments are seated).
TMT’s large STR serves as the framework of the telescope and thus interfaces with all telescope mounted instrumentation, optics, software, and control subsystems. The verification of the STR interfaces with all other subsystems, and production drawings and documentation were carried out by TMT Systems Engineering (SE) and Quality Assurance & Safety teams.
"NAOJ and MELCO teams in Japan have been working very hard with TMT’s System Engineering team on the telescope structure development and updating the TMT Interface Control Document product to make sure the project is ready for these readiness reviews,” said Mike Sheehan, Chair of the review and group leader for TMT Enclosure.
A significant part of TMT’s design and construction is provided by in-kind contributions led by TMT-Japan which has been involved in the project since the beginning. TMT partners in Japan have retained the proficiency and intellectual property developed over many years by MELCO with a high level of expertise in building telescopes.
Successfully passing these reviews is an important step forward, not only validating the production readiness of the TMT structure itself but also for the TMT Project and TMT partners. “TIO is grateful for NAOJ's support of the telescope structure work and progress made by MELCO to achieve these major STR PRRs 2 & 3 milestones,” expressed Kyle Kinoshita, leader of the STR group at the project office. “Working with MELCO is a huge asset for the TMT Project.”
As Masahiro Sugimoto, NAOJ STR group leader, noted in his debriefing remarks, “the scope of these PRRs encompass the majority of the main structure elements and completing this work achieves a significant STR and TMT milestone.”
“Thank you to the TMT STR Design and SE Teams, Review Panel and Observers for their intense efforts to prepare for, and successfully conduct STR PRRs 2 and 3,” said Fengchuan Liu, TMT Project Manager. “Also, a special acknowledgement to the Review Panel who performed a thorough and objective evaluation of all review materials and provided the Design Team and TIO helpful recommendations!”