| Authors : | Karthic Kumar, Jayakumar PS, Ananthu C M, Arun Kumar, Jeevan, Surojit Kumar Roy, Prasad N, Viswanatha N, Sudarshan, Prasanna Deshmukh, Nikhil Naik, Varun Saraswat, Karthikeyan SR, Ravishankar, Shivaprakash, Ferris Antony, Vijay |
| Abstract : | India as a member partner of the consortium of countries like the USA, Canada, Japan &
China, is involved in the development of a Thirty Meter Telescope (TMT) and is responsible
for the realization of certain very important subassemblies for TMT apart from the cash
contribution. India’s in-kind contribution to the TMT project includes Primary Mirror
Segment polishing (84), Manufacture and Assembly of Segment Support Assemblies (580),
Actuators (1535), Edge Sensors (3284), Software development for the observatory and
design and development of science instruments.
This paper describes the different aspects and challenges of realizing Segment Support
Assembly (SSA), which supports the Primary mirror segments. The SSA is a flexures-based
whiffle tree mechanism that can support the Mirror segment and correct the tip-tilt and
aspherical aberrations caused due to various environmental conditions including gravity
effects.
TMT Primary Mirror (M1) is composed of 492 hexagonal aspheric segments equipped with
Segment Support assembly (SSA), Each TMT SSA consists of around 500 individual precision
components of tolerance as low as 5 micrometers, and Component size ranges from 4.5 mm
to 1200mm manufactured using various grades and tempers of Aluminium, Stainless Steel,
Copper, Aluminium Nickel bronze, Manganese Bronze, Invar, Brass, Titanium, etc.
Manufacturing included precision machining, and TIG welding, along with special secondary
processes such as Anodization, Gold Chemical Conversion, passivation, Dicronite coating,
and BR127 application. All the manufactured parts were thoroughly inspected by the
Vendor and ITCC, identified (India TMT Co-ordination Center) Third Party Inspectors. After
manufacturing and Inspection, these parts are assembled using a meticulously worked-out
assembly procedure to ensure desired functionality and performance. |
