Dominion Radio Astrophysical Observatory DVA-1 Reflector Development Timeline Gary Hovey NRC-HIA...

Dominion Radio Astrophysical Observatory

DVA-1 ReflectorDevelopment Timeline

Gary HoveyNRC-HIA

Dominion Radio Astrophysical Observaotry

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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 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?



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?



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.



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.



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



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.



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



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.



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.



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.



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



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



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



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



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



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



Timeline

Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2

ConceptDesign

Preliminary

Design

Detailed

Design

Fabrication

ReflectorTesting

20112010 2012

Buy Molds



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.

Dominion Radio Astrophysical Observatory DVA-1 Reflector Development Timeline Gary Hovey NRC-HIA...

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