All rights reserved © AEM - ALMA EUROPEAN CONSORTIUM All rights reserved Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 1 Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas CFRP status at PM#6

All rights reserved © AEM - ALMA EUROPEAN CONSORTIUM All rights reserved Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2  CFRP (Prepreg)  AEM problematic Avoid any monopolistic position wrt to the procurement of the raw material Each resin type is the property of the “prepreger” Optimisation of both BUS and CABIN imposed to be able to manufacture them using as well an oven as an autoclave curing. This is linked to the choice of the manufacturer.  AEM approach Consideration of different prepregers offering resin similar to the prototype one (in terms of hydric, thermal… properties). Consideration of different manufacturers ( according to their capabilities/competencies).  Prepreger choice will be confirmed shortly.  Manufacturer of the equipped cabin is on going.  CONCLUSION The majority of the preliminary qualifications for the prepregers examined by AEM are done. AEM selected the resins of prepregers that satisfy the requirements of the construction of the BUS and CABIN Some additional qualification test shall be defined if needed without impact on the planning

All rights reserved © AEM - ALMA EUROPEAN CONSORTIUM All rights reserved Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3  CFRP (Prepreg)  Resin selection Potential impacts of resin change : –Thermo-hygro elastic properties of laminates –ILSS Thermo-hygro elastic characterization of selected resin (including the prototype’s as reference)  All the selected resin show equivalent properties ( , ,  m/m), leading to no difference in antenna behaviour. ILSS tested with T700 fabric : same conclusion. CONCLUSION OF ELEMENTARY TESTS ON RESIN AND LAMINATES : ALL THE SELECTED RESINS ARE EQUIVALENT

All rights reserved © AEM - ALMA EUROPEAN CONSORTIUM All rights reserved Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4  CFRP (Prepreg)  Process choice Oven curing might lead to slight redesign of items and manufacturing process optimisation (oven are generally bigger than autoclaves, allowing to cure bigger parts with less junctions) Oven curing instead of autoclave could theoretically have an impact on: –Void ratio –Fiber volumic ratio, directly connected to the mass of the final laminate –ILSS (needed for local design) –Compression strength Elementary tests have been performed on laminates, with the selected resins, K63712 pitch fiber and oven curing : Properties remain in the range of the reference ones. Selected resins are autoclave (BUS) and oven (CABIN) compatible CONCLUSION : THE SELECTED RESINS CAN BE CURED IN OVEN OR AUTOCLAVE WITH NO IMPACT ON ANTENNA PROPERTIES

All rights reserved © AEM - ALMA EUROPEAN CONSORTIUM All rights reserved Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5  CFRP (Prepreg)  CFRP qualification Once the prepreg is selected, final process optimisation will be done (curing cycles for oven and autoclave, bagging material, scale effect, compactions,…) Representative samples (layup, thickness, process, size, outer plies, …) will be manufactured by the parts manufacturer. Testing before and after ageing will be performed, according to “CFRP qualification plan”, to be agreed between consortium members.