1. DVA1 Project Overview and Status Gary Hovey and Gordon Lacy SKA Project Office Visit DRAO 29 March 2014 NRC-Herzberg Astronomy Technology Program - Penticton

2. Rough Agenda 10:45 DVA1 technical discussions 11:45 Tour of DRAO labs AFAD, DVA1 12:15 Lunch here or OK Falls? 13:30 Tour of OK Falls 15:30 Tour of DVA1 site 16:30 Wrap up discussion in meeting room DVA1 - Performance and Status2 of 26

3. Introduction Asked to address: Status and Performance Contribution of DVA-1 for SKA −Risk retirement tool and plans Presentation Motivation and Goals Key innovations and contributions to SKA Current Status Plans 3 of 26DVA1 - Performance and Status

4. Background Began investigating composites in 2005 Built two reflectors in 2007 Started collaboration with US-TDP in 2009 −Design phase lead by US-TDP −Construction phase lead by NRC CoDR in early 2011 PDR in late 2011 CDR in mid 2012 Fabrication reflector and pedestal mid-2013 Integration underway DVA1 - Performance and Status4 of 26

5. DVA-1: Motivation and Goals Challenge: A leap in telescope sensitivity and dynamic range requires a corresponding leap in antenna technology. Goal: Investigate, develop and demonstrate innovations that improve antenna cost/performance. Lower cost through −Simplicity of design −Minimal part count −Modular design −Low labour content −Scalable to mass production −Minimal use of custom sizes and part DVA1 - Performance and Status5 of 26

6. Motivation and Goals (cont.) Improved performance through Shaped optics to maximise A eff Improved stability over all load conditions −Feed-high design lowering peak cross section to wind −Compact turning-head and mount to minimise moments −Single piece rim supported reflector immunity to translational loads distortions uniform and low order −High stiffness and low CTE using carbon fibre composites −Composite reflector with embedded metal mesh Reflectivity of Aluminium with the stiffness of carbon. Low moving mass -> superior closed loop response Design for low maintenance upkeep and burden, as well as long life and durability DVA1 - Performance and Status6 of 26

7. DVA-1: Designed for High Dynamic Range Capability High Thermal Performance Rim supported monocoque design along with very low CTE materials keeps all thermal movement both small and very uniform to minimize effect on beam pattern High Performance in Wind and Gravity Central compliant connector allows some structural sag without inducing unwanted distortion at center of dish Rim supported design keeps dish deflections to absolute minimum and concentrates any deflections at rim where effect on performance is small. Extremely deep truss back structure keeps dish shape as close to rigid as is possible. High Overall Optics Stability Secondary and feed platform support optimized to maximize stiffness using shape optimization software. Secondary and feed support tubes use zero and matched CTE carbon tubes for extremely high thermal stability. 7

8. Contribution to SKA Overall: Innovative design that has been optimised for low cost, long life and high performance. Specifically: −Modular and compact turn head and pedestal design −Low maintenance mechanical drive −Low cost foundation design −Innovative elevation jack-screw −Rotating electronics in pendent enclosure −Rim supported reflector concept −Optimised reflector and feed platform support −Optimised shaped optics −Composite reflector surfaces optimised for SKA −Verification of key estimated vs measured cost-performance metrics DVA1 - Performance and Status8 of 26

9. DVA1: Design Features The main design elements are: 15m Gregorian offset feed-high optics Unblocked aperture Large space for feeds Stiffer, lower cost than feed-low Molded single piece rim- supported composite reflectors Tubular backup structure Tubular composite feedlegs Pedestal-type mount allows small offset to elevation axis Deep truss backup structure with central pocket for pedestal mount Central compliant connector allows movement in wind without distortion

10. DVA1: Estimated Sensitivity DVA1 - Performance and Status10 of 26 DVA-1 Aeff/Tsys using Corrugated Horns Assumes 15K Receiver

11. DVA1: Estimated Performance in Wind DVA1 - Performance and Status11 of 26 Beam Pattern at 10 GHz. 25 kph Wind at 15 degree Elevation (Blue) Undistorted (Red)

12. DVA1 Predicted Temperature Stability DVA1 - Performance and Status12 of 26 Beam Pattern at 10 GHz. 25 Celsius Thermal Change (Blue) Undistorted (Red)

13. DVA1: Estimated Performance over Load Cases DVA1 - Performance and Status13 of 26 Freq Peak Scan Scan On-axis Peak Peak Beam Width Case Gain Offset Orthogonal Gain Sidelobe X-pol X Y (GHz) (dB) mdeg mdeg (dB) (dB) (dB) (deg) (deg) 10.000 63.270 0.51 0.00 63.270 20.857 41.954 0.133 0.133 Undistorted 10.000 63.253 -2.97 -0.18 63.247 20.317 42.196 0.133 0.133 Thermal 10.000 63.162 32.49 0.17 62.482 19.076 43.200 0.134 0.132 Gravity 15 degrees 10.000 63.250 12.82 0.12 63.145 20.674 42.092 0.134 0.133 Gravity 55 degrees 10.000 63.107 -9.29 0.03 63.052 19.501 41.046 0.134 0.134 Gravity 90 degrees 10.000 63.268 5.09 0.15 63.251 20.689 42.014 0.134 0.133 Wind 15 degrees 10.000 63.270 0.23 0.03 63.270 20.834 41.951 0.133 0.133 Wind 55 degrees 10.000 63.270 1.30 -0.11 63.269 20.804 41.954 0.133 0.133 Wind 90 degrees

14. DVA1 Primary Reflector Damage and Repairs Collapsed SurfaceAfter being popped out with air bags

15. DVA1 Repair Activites

16. DVA-1 Reflector Repairs

17. DVA-1 Reflector Accuracy After Repairs Post repair error = 1.0mm rms Excluding repaired areas error = 0.7mm rms Notes: 1.Errors are from ideal and include mold errors. 2.No aperture weighting used, otherwise rms error would be less.

18. DVA-1 Secondary Reflector Accuracy Un-weighted by illumination: Surface error = 0.2mm rms Weighted by illumination Surface error = 0.11mm rms

19. Improved Results: GDSatcom Secondary Reflector We have now built two sub reflectors for the GDSatcom Meerkat project RMS of reflector 0.090mm Mold RMS 0.058mm

20. DVA-1: Composite Performance 20 Structural TestComposite Design Consideration Metallic Design Consideration Creephigh static load Static StrengthMaterial properties Fatigue LifeHigh cyclic load Glass Transition Temp.Choose resin with sufficiently high value. NA Impact ResistanceEngineering requirement Galvanic CorrosionEncapsulate reflective layerPaint and primer UV, Moisture, Humidity Paint (no primer required) and resin properties Paint and Primer Reflectivity DegradationPaint (no primer required)Paint and Primer Fungus growthPaint

21. Contributions DVA1 Isn’t Making The main goal of DVA1 was to demonstrate several novel design concepts. Elements not impacting key design concepts nor not unique to DVA1 not addressed. −RFI, lightning protection, −ZA and AU safety and electrical code standards, −Optimal and adaptive drive control, −Testing with a full suite of receivers −Automated indexer DVA1 - Performance and Status21 of 26

22. Issues and Technical Risks Key retired technical (technology) risks Composite reflectors meet requirements for −Reflectivity −Mechanical and thermal properties −Surface accuracy Outstanding risks low. Mitigated by simulation/measurement and await system testing, such as −Optics design errors −Mechanical design errors −Major fabrication errors DVA1 - Performance and Status22 of 26

23. Elements Deferred/Tabled Testing with feeds <1GHz Optimised manufacturing methods, logistics and costing. Further proof related to QA, life cycle costs, reliability, durability, manufacturability. Concern: In some cases level of evidence/proof required is: −unclear, −somewhat arbitrary and −disproportionate. DVA1 - Performance and Status23 of 26

24. Project Schedule: Construction and Mechanical Test April Assemble feed and secondary support Complete drive and back-end software and test Install RFoF equipment and Ku receiver. Lift primary on tower Measure primary and tower over load cases using laser tracker, photogrammetry, and tilt meters. May Lift feed and secondary support on primary Initial measurements of DVA1 over load cases using laser tracker, photogrammetry, and tilt meters. DVA1 - Performance and Status24 of 26

25. Project Schedule: RF Testing May-June Basic motion tests Ku band establishment of initial pointing and focus and holography July-August L-band tests with MeerKat/NRC receiver Pointing tests, offset pointing performance, short term pointing jitter Calibration observations to estimate antenna parameters such as aperture and beam efficiencies, sensitivity, spillover contributions to system temperature August-October Final testing, analysis and reports DVA1 - Performance and Status25 of 26

26. 26DVA1 - Performance and Status26 Questions? Gary Hovey, Project Manager Gary.Hovey@nrc-cnrc.gc.ca 250.497.2363 Gordon Lacy, Project Engineer Gordon.Lacy@nrc-cnrc.gc.ca 250.497.2340