1. Goals of DVA-1 Meeting Overall goal: build an SKA antenna with SKA feeds/receivers, verify performance and fabrication/costs for the next stages of the SKA Project description and definition –purpose and scope –cost –schedule Partnership –resources (in-kind, cash) Management –as in MoU draft? Technical decisions Program/project decisions 15-16 April 2010 DVA1 Meeting at NSF1

2. Technical Decisions Required technical specifications Aperture size (12m – 15m) Optics (offset gregorian): shaping? Backup structure: spars, shell Pedestal type Feed and receiver plan –SPFs –PAFs –Indexer 15-16 April 2010 DVA1 Meeting at NSF2

3. Program/Project Decisions Management plan and MoU/LoI Schedule –milestones (TDP, PrepSKA, SKA program) –deliverables (hardware  test results, reports) Site –which facility and where on site? Testing program –single dish tests: those necessary for the costed system by end-2012 those needed for antennas program leading to the Phase-I dish array –interferometric tests not within timeline/scope of end-2012 project 15-16 April 2010 DVA1 Meeting at NSF3

4. Scope of the DVA-1 Project The first in a series of converging prototypes that will optimize performance at minimum cost (e.g. A/T per dollar + imaging performance) A primary deliverable of the US SKA TDP –optimized antenna + feeds for SKA-mid –WBSPFs and PAFs accommodated A global project but centered in North America Delivered to the project by end of 2012 (including testing) Current plan (to be agreed on): –fabrication, integration and testing at EVLA site by end of 2012 to provide input to the costed system design –single-dish tests with suite of feeds –extended testing program as needed for lead-up to Phase-I construction (with post-TDP, post-PrepSKA funding) 15-16 April 2010 DVA1 Meeting at NSF4

5. Overall Context in TDP System cost Costs that scale with N (antennas, feeds) Processing costs that scale as N 2 x number of beams Maximize A/T per antenna in a low-cost design minimizes number of antennas needed for total A/T also maximizes survey speed via the (A/T) 2 factor Target high imaging dynamic range and minimum susceptibility to RFI (clear aperture) Demonstrate imaging capability through simulation by Calibration and Processing Group et al. using as input measurements on DVA-1 15-16 April 2010 DVA1 Meeting at NSF5

6. Basic specifications Offset Gregorian optics Frequency range: 0.3 to 10 GHz (1 to 10 GHz) Aperture efficiency: >60% above 1 GHz Antenna noise temperature <10K Pointing stability: <1% gain variation @half-power point at 1.4 GHz Minimum 30 year lifetime Minimum 1 year maintenance interval (target 5 year) Design to be as close as possible to the final SKA dish design –Assessment of real performance –Good cost estimate 15-16 April 2010 DVA1 Meeting at NSF6

7. Optical design of reflectors Working plan: Dual shaped, offset reflectors with a Gregorian subreflector. Subreflector opening angle chosen to accommodate wide band feed(s). Shaped optics having very low spillover and high aperture efficiency to maximize A/T in a design intended to minimize costs Usage of available real estate for multiple feeds and a PAF; DVA-1 will include a feed indexer 15-16 April 2010 DVA1 Meeting at NSF7

8. Reflector design options Single composite shell and sparse support framing Dual shell reflector and support, composites 15-16 April 20108DVA1 Meeting at NSF

9. Feed Options to Cover 0.3 to 10 GHz (nominal) 15-16 April 2010 9DVA1 Meeting at NSF

10. Canadian CART program + TDP Work by Matt Fleming: 15-16 April 201010DVA1 Meeting at NSF

11. Issues and Decisions Diameter: 15m nominal (12m still possible as a choice) Optical design: offset Gregorian optics –rationale for shaped optics in TDP Memo (in prep) –final choice depends on assessment of imaging performance and long-term flexibility as well as optimized A/T @ minimum cost Fabrication material –dual-shell composite vs composite + metal spar structure –(segmented metal is a possible parallel approach) Full suite of TDP-developed feed antennas that cover 0.3 to 10 GHz –various combinations of WBSPFs and octave feeds –antenna will accommodate a PAF when appropriate Feed indexer included in design with deployment at appropriate phase of testing 15-16 April 2010 11DVA1 Meeting at NSF

12. Developing DVA-1 Partnership Cornell/TDP –Optical design: Baker, Cortes, Imbriale (JPL) –WBSPFs: Cortes (Cornell) Weinreb (Caltech) Welch (UCB) –Mechanical design: Fleming (Minex) –Calibration and Processing: Kemball (UIUC) et al DRAO (CART program for composite reflector) –G. Lacy (mechanical, composites) –G. Hovey –S. Dougherty SPDO –N. Roddis and P. Dewdney NRAO –Project management and integration with EVLA Australia/CASS China/JLRAT South Africa/MeerKAT Testing: –single dish tests by TDP team + other partners –array tests: in 2012+ post-preparatory/engineering design phase 15-16 April 2010 DVA1 Meeting at NSF12

13. Management of DVA-1 To be agreed upon: Project Manager Project Engineer Collaboration Board (Cornell, DRAO, NRAO, SPDO, …) –determined by groups that sign on to the project DVA-1 design reviews –coordinated with (but separate from) SPDO design reviews 15-16 April 2010 DVA1 Meeting at NSF13

14. DVA-1 Partner and Kick-off Meeting At the NSF 15-16 April 1.Project definition (Project Book) 1.purpose, baseline design 2.hardware deliverables 3.testing deliverables 4.timeline 5.cost 2.Partnership and Resources 1.collaboration agreement for core group 2.resource allocation 3.Management plan 4.WBS and task assignments 5.Detailed engineering discussions and decisions 15-16 April 2010 DVA1 Meeting at NSF14

15. DVA Context & DVP Goals P. Dewdney Apr 15, 2010

16. SPDO System Hierarchy (Part 1) 16 DVP

17. SPDO System Hierarchy (Part 2) 17

18. SPDO Process to verify performance of dishes for the Dish Array in the System Hierarchy. –Element level. Dishes equipped with well defined interfaces to other system elements: –Power –Signal transport –Monitor and Control –Other infrastructure Verified to be capable of handling all feeds and receivers needed to carry out the dish-based science. –May not be so-equipped at initial roll-out. Dish Verification Program (DVP) 18

19. SPDO Risk reduction –When built up into the SKA system, show that dishes will meet all the science requirements; –Also meet all other requirements needed to integrate into a system and operate in the field. Design, produce and test one or more SKA antennas; –with the greatest system sensitivity (A e /T sys and/or Survey Speed) per unit system cost (total cost of ownership); –As well as possible, ensure that the contribution of antenna-related systematic errors is within acceptable limits; –Designs/testing programs converging to a detailed design that is manufacturable in production quantities. Understand the costs. Converge to a production-ready, documented antenna design (production data-pack). DVP Goals 19

20. SPDO Integrated Approach 20 DVAs

21. SPDO Time Scale 21 Review dates are preliminary.

22. SPDO Time Scale 22 Review dates are preliminary.

23. End 23

24. Extra 15-16 April 2010 DVA1 Meeting at NSF24

25. Verifying dish performance Antenna and feed design parameters: –Mount type –Reflector: Size, shape, and manufacturing method –Optics –Feed and illumination –Polarization purity –Net bandwidth –Etc. Measurements on DVA-1 Overall system performance verification: –Cost per unit achieved sensitivity as a function of: Angular distance from center of main lobe: ρ Polarization: {I,Q,U,V} Frequency: ω –Feasibility: Limiting sensitivity in {I,Q,U,V} (ρ,ω) due to uncorrected systematic errors. Assessment of antenna performance vis a vis science requirements (end to end simulations) 15-16 April 2010 DVA1 Meeting at NSF

26. 15-16 April 2010DVA1 Meeting at NSF26

27. Optical design of reflectors. Dual shaped, offset reflectors with a Gregorian subreflector. Subreflector opening angle chosen to accommodate wide band feed(s). Shaped optics having very low spillover and high aperture efficiency. Incorporation of “real estate” for multiple feeds and a PAF. Light weight, optimized mechanical design Utilization of single shell reflectors as integral structural members. Inclusion of a feed indexer to mount multiple feeds. Design for low cost in mass production. Mount and test multiple feeds and receivers. Optics designed to accommodate feeds of intermediate gain which achieves a practical primary reflector size. Basic specifications: Frequency range:.3 to 10 GHz. Aperture efficiency: >60% Antenna noise temperature <10K Pointing stability: <1% gain variation @ ½ power point (1.4 GHz.) Minimum 30 year lifetime Minimum 1 year maintenance interval (target 5 year) 15-16 April 2010 DVA1 Meeting at NSF27

28. 15-16 April 2010 DVA1 Meeting at NSF28

29. Meeting Motivations and Outcomes NSF review of TDP and DVA plan forthcoming Overall timelines for SKA, TDP and PrepSKA Readiness for convergence in D&D Parallel development plan for SKA antennas –DVA-1, DVA-2 … –Large volume manufacturing options and costs conventional, composites, hydroforming SKA project decision tree over next 5yr –tradeoffs between science, costs and schedule 15-16 April 2010 DVA1 Meeting at NSF29

30. DVA-1 Project Book Purpose of DVA-1 –Relationship to DVA-2 How it fits into overall DVP activity Technical description Reflectors Backup structure Pedestal Indexer Feeds and receivers Interface to EVLA network and correlator Test site (and reflector fab) Testing plan and elements single-dish tests array tests Decommissioning of DVA-1 Detailed schedule Management Organizations, Personnel and Org chart Funding and funding profile MoA or MoU? 15-16 April 2010 DVA1 Meeting at NSF30