80 likes | 184 Views
EUSO U.S. Phase A Trade & Manufacturing Studies Plan. Perform a trade study on the lens materials and select the prime candidate for the conceptual design. The following parameters should be considered in the trade study: a. Optical performance i. D n/ D T ii. D n/ Dl (dispersion)
E N D
EUSO U.S. Phase A Trade & Manufacturing Studies Plan • Perform a trade study on the lens materials and select the prime candidate for the conceptual design. The following parameters should be considered in the trade study: • a. Optical performance • i. Dn/DT • ii. Dn/Dl (dispersion) • iii. Transmission in UV • b. Mechanical Properties • i. Density • ii. Coefficient of Thermal expansion • iii. Yield tensile strength • iv. Ultimate tensile strength • v. Thermal conductivity • vi. Young’s modulus of elasticity • vii. Glass transition temperature • viii. Effect of temperature on mechanical properties
EUSO U.S. Phase A Trade & Manufacturing Studies Plan • c. Cost • d. Lead time (commercial availability) • e. Machineability • i. Direct turn small (8 inch) samples of all materials to determine machineability. The difference of direct turning PMMA vs. other materials – so we can argue in the CSR that we did it with PMMA and we know what is involved in doing it for the prime candidate. • ii. Mold one petal from each material to determine molding characteristics. • iii. Metrology – measure lens material samples (direct turn and molded) • 1. surface roughness • 2. scattering • 3. groove geometry • 4. transmission • f. Space Environment Effects (SEE) • i. Shrinkage • ii. Surface compaction • iii. Change in index of refraction with radiation exposure • g. Technical risk
Refractive Index (Measured) PMMA 1.6 MX004 (TPX) 1.55 RT-31(TPX) Refractive Index TPX-W(yellow) 1.5 1.45 1.4 300 400 500 600 700 800 900 1000 Wavelength (nm) Material Properties
EUSO U.S. Phase A Trade & Manufacturing Studies Plan • 2. Perform a trade study on the lens design and select the prime candidate for the conceptual design. The following issues should be considered: • a. Lens material • b. Frame material • c. Metering structure • d. Minimize amount of segmentation to cut down obscuration • e. Minimize the overall mass of the subsystem • f. Subsystem I/F to the telescope structure (must be worked with Alenia)
10 mm 15 mm Rings 6 mm 10 mm 50 mm Ring and Rib Detail 20 mm Strut Detail Struts and Cross braces Ribs • Mass of each Fresnel Lenses: • 20 mm PMMA 125 kg • 20 mm TPX 90 kg • 3 support rings, 24 ribs/lens, 20% Contingency 90 kg • Mass of Optical Structure • 12 metering struts with 11 cross braces, 20% Contingency • Graphite Fiber Re-enforced Polymer 60 kg • 20 mm CYTOP 215 kg • 20 mm Zenox 105 kg Preliminary Metering Structure Mass Estimate PMMA, f1.25, 20 mm thick design
EUSO U.S. Phase A Trade & Manufacturing Studies Plan • 3. Perform a trade study on the lens manufacturing techniques and select the prime candidate for the conceptual design. The following techniques/issues should be considered: • a. Molding • How are the molds made? - ELID or cut on a Diamond Turning machine. • See 1.e above. Mold samples to characterize each material. • Mold entire lens • Center section • 1. monolithic or segmented mold • Petals – Size of petals??? • b. Direct turning – • i. See 1.e above. Cut samples to characterize Moore performance • 1. Tool speed • 2. Feed rate • Options for the production of large pieces of 1.5 m to 2.5 m using resources other than SOMTC (Livermore, Oak Ridge, Stewart Films) • Combination – Direct turn center and mold petals • Slumping of plastic
UAH 20 cm RIKEN 40 cm SOMTC 90 cm DIRECT TURNING SOMTC 1.5 m Flat Mold RIKEN Petal Mold RIKEN Molded Segment MOLDING
EUSO U.S. Phase A Trade & Manufacturing Studies Plan • 4. Manufacture lens segment test articles in PMMA by direct turning and molding techniques. The Following tasks will be accomplished: • a. Make 1 meter plano-convex single sided center piece by direct turning a PMMA blank • b. Mold 5 ea. segments of the first ring by pressing the mold into PMMA blanks. • c. Make 1 ea. center piece frame and 3 ea. frame segments to hold the first ring pieces (include all attachment hardware for integrating the pieces together –include a stand to hold the partial optic?) • d. Integrate the pieces into a single unit. • e. Test the partial optic • i. Surface roughness (molded and turned) • ii. Repeatability • iii. Conformance to prescription/specification • iv. Alignment after launch (vibration?)