Dominion Radio Astrophysical Observatory
DVA-1 ReflectorDevelopment Timeline
Gary HoveyNRC-HIA
Dominion Radio Astrophysical Observaotry
DVA-1 Reflector Development TimelineG. Hovey
2 of 20DVA-1 Meeting Washington15 April 2010
Contents
• Reflector Project Scope
• Project Phases and Milestones
• Key Objectives, Outcomes and Issues by Phase
• Conclusions
DVA-1 Reflector Development TimelineG. Hovey
3 of 20DVA-1 Meeting Washington15 April 2010
DVA-1 Reflector Project Scope
What are the DVA-1 Goals Pertaining to the Reflector?• Performance Requirement
– Reflecting surface that meets maintains it shape over specified operating conditions (wind, temp, gravity).
• Cost Requirement– Demonstrate its affordable and has superior cost/performance.– Prototype can be built with available budget and meet
performance requirement.• Schedule Requirement
– Built within the timeframe of PrepSKA?– Built within the timeframe agreed upon in advance?– Built roughly within the timeframe agreed upon?
DVA-1 Reflector Development TimelineG. Hovey
4 of 20DVA-1 Meeting Washington15 April 2010
Scope Issues
• Budget, resources and schedule are limited.
• Requirements are in conflict and need to be prioritized.
• What are we designing for?– Schedule?
• Which schedule? SKA, Hard or soft deadline?
– Cost?– Performance?
DVA-1 Reflector Development TimelineG. Hovey
5 of 20DVA-1 Meeting Washington15 April 2010
Proposed Reflector Scope Requirements
Requirements in Priority
1. Performance: Must meet SKA performance specifications
2. Cost: Must be within DVA-1 budget and demonstrate SKA cost/performance
3. Schedule: Must be adapted to fit performance and cost requirements.
DVA-1 Reflector Development TimelineG. Hovey
6 of 20DVA-1 Meeting Washington15 April 2010
Proposed Responsibilities and Tasks
What does the reflector work include?
• Reflector performance and cost key drivers.
• Reflector performance and schedule dependent strongly (mainly/mostly) on back-up structure and feed.
• Propose reflector consists of: Surface, backup structure, feed & sub-reflector support. These need to be considered together as an integrated whole.
• Reflector Interfaces: indexer/receiver box, sub-reflector and turret frame.
DVA-1 Reflector Development TimelineG. Hovey
7 of 20DVA-1 Meeting Washington15 April 2010
Key Reflector Requirements/Specifications
• Performance– Reflector shape and feed/sub-reflector support specs– Dynamic tolerances specs as function wind, gravity and
temperature.– Mount interface specs.
• Cost– Available budget – Available infrastructure– Available resources and definition of project scope
• Schedule– Clear goals and deliverables with achievable deadlines
• These need clarity to make progress
DVA-1 Reflector Development TimelineG. Hovey
8 of 20DVA-1 Meeting Washington15 April 2010
Proposed Reflector Project Phases
• Four Phase Project– Concept Design Phase -> Concept Design Review– Preliminary Design Phase -> Preliminary Design Review– Detailed Design Phase -> Critical Design Review– Fabrication Phase -> Fabrication Acceptance– Test Phase -> Project Complete
• Clear specifications, objectives and deliverables for each phase are needed to ensure performance, cost and schedule requirements.
DVA-1 Reflector Development TimelineG. Hovey
9 of 20DVA-1 Meeting Washington15 April 2010
Reflector Concept Design Phase
• Objective: Define project based on feasible design concepts.
• Duration: 2-3 months once requirements/specifications set.
• Outcomes– Concept design
• Based mainly on estimation, calculation and simulation• Feasible design that meets overall performance, cost and
schedule requirements• Risk items identified
– Baseline project plan including:• Initial WBS, costs and schedule• Risks: technical, cost, schedule• Plan to address risks
DVA-1 Reflector Development TimelineG. Hovey
10 of 20DVA-1 Meeting Washington15 April 2010
Key Concept Design Issues
• Need to define surface shape specifications– What diameter: 12m or 15m? At CoDR? Now??– What antenna pattern? What is optimized?
• Aeff • Aeff/Tsys • Near and far sidelobe response• Symmetry, stability, uniformity
– Need to understand calibration, imaging and computing impact• Select or defer backup structure approach to prelim design?• To what extent are PAFs considered?• Need clarity on design goals: Performance, budget, schedule?• Need clarity on available budget and constraints.• CoDR can’t be done without these issues resolved.
DVA-1 Reflector Development TimelineG. Hovey
11 of 20DVA-1 Meeting Washington15 April 2010
Reflector Preliminary Design Phase
• Objectives – Sketched out design in non-risk areas– Detailed design/studies in riskier areas
• Duration: 2-3 months once CoDR complete• Outcomes needed
– Preliminary design • Materials selected and their performance known• Risk items addressed• Based on calculation, simulation and measurement• Technical risk low
– Updated project plan• Schedule and cost risk quantified• Detailed design plan well defined• Fabrication and test plan well understood.
DVA-1 Reflector Development TimelineG. Hovey
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Reflector Preliminary Design Activities
• Material studies/testing
• Finalize composite materials
• Select/refine backing structure
• Refine feed support
• Possibly, procure mold(s) as soon as surface defined.
DVA-1 Reflector Development TimelineG. Hovey
13 of 20DVA-1 Meeting Washington15 April 2010
Reflector Detailed Design Phase
• Goal: Fully specify design, as well as, fabrication and test plans
• Time needed: 4-6 months once PDR complete.
• Outcomes needed– Fully specified design. – Risks low: Costs, schedule well determined.– Detailed fabrication and acceptance plan(s)
• Activities, WBS, deliverables, costs and schedule
– Detailed test plan
DVA-1 Reflector Development TimelineG. Hovey
14 of 20DVA-1 Meeting Washington15 April 2010
Detailed Design Issues
• This is mainly a fill in the blanks phase.
• To what extend do we validate dynamics (wind, temp, resonance)? Schedule vs cost risk
• How much design margin is carried?– Material cost vs performance and schedule risk
• Can molds be ordered before CDR? Schedule vs cost risk
DVA-1 Reflector Development TimelineG. Hovey
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Reflector Fabrication Phase
• Objectives: fabricate/assemble reflector, back-up structure, feed/sub support.
• Duration: 6-9 months (not including setup/procurement)
• Outcomes– Sub-assembly fabrication and acceptance complete
• Reflector surface• Backup structure• Feed/sub support
– Assembly complete and ready for test on mount
DVA-1 Reflector Development TimelineG. Hovey
16 of 20DVA-1 Meeting Washington15 April 2010
Fabrication Phase: Issues
• Lead time for procurement of materials
• Lead time for preparing site for fabrication
• What facilities on-site can be used?
• Site regulation and procedure issues
• Schedule and cost overheads due to the location
• Costs magnified if project delayed
• Clean-up costs
DVA-1 Reflector Development TimelineG. Hovey
17 of 20DVA-1 Meeting Washington15 April 2010
Reflector Test Phase
• Objectives: Determine reflector assembly performance
• Duration: 2-4 months
• Outcomes• Reflector metrology tests
– Over gravity, temp, wind
• Simulated antenna pattern response• Measured antenna pattern and holography measurements
DVA-1 Reflector Development TimelineG. Hovey
18 of 20DVA-1 Meeting Washington15 April 2010
Reflector Test Phase Issues
• Separating dynamic reflector performance from the mount.
• Testing over temperature extremes difficult
• Testing over wind conditions/requirements difficult
• Schedule and cost overheads due to the location
DVA-1 Reflector Development TimelineG. Hovey
19 of 20DVA-1 Meeting Washington15 April 2010
Timeline
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2
ConceptDesign
Preliminary
Design
Detailed
Design
Fabrication
ReflectorTesting
20112010 2012
Buy Molds
DVA-1 Reflector Development TimelineG. Hovey
20 of 20DVA-1 Meeting Washington15 April 2010
Conclusions
• Reflector project reasonably complex.
• Need to better define scope and responsibilities
• Number of requirements/issues need to be address/resolved.
• Project plan, design phases and reviews needed
• These would inform key decisions.