Transcript • SKA Context • TDP work plan • Constraints and considerations for

US Technology Development Project for the SKA
Jim Cordes
AWG Meeting
13-14 March 2008, San Francisco
• SKA Context
• TDP work plan
• Constraints and considerations for
antenna development in the TDP
• Goals and outcomes of the meeting
SKA Project
Preliminary specifications (10 Dec 2007)
• Reviewed by international team (inc. US participants: B.
Clark, A. Rogers, chair)
• Response now being formulated
Frequency range: 70 MHz – 25+ GHz
Three frequency bands:
• Low: 70 – 300 MHz
• Mid: 0.3 – 10 GHz
• High: up to 35 GHz
dipole array
dipole arrays + dishes
dishes
Three construction phases:
• Phase 1:
• Phase 2:
• Phase 3:
Low and mid: start ~ 2013, ~10% of mid
Finish low and mid by end of decade
SKA high after 2020
US Technology Development Project
• NSF-funded 2007-2011 for $12M
» Includes US Contribution to the ISPO/SPDO
• Complementary to and integrated with PrepSKA
» EC-funded project 3+1 years, same time frame as TDP
• Targets areas that bear strongly on cost and basic performance
(Ae, Tsys, B, cross polarization, processing)
• Will deliver to the SKA project:
»
»
»
»
»
»
Technology options for LNSD array with single-pixel feeds
Costing of reflectors+mounts vs. D and fmax
Optical designs that include both SP + PAF options
An SKA optimized, fully outfitted antenna
Calibration and processing algorithms for LNSD arrays
Cost-modeling information
• Dual use deliverables: utility to other US projects?
» EVLA + deployment of antennas next decade
Work Breakdown Structure for the TDP
1.
2.
3.
4.
5.
6.
7.
Antennas, Feeds and Receivers
AWG
Calibration and Processing
CPG
Athol
Cost Function Analysis
Kemball
et al.
SKA Design Project
SKA Research Associateship
TDP Management
US SKA Consortium Participant Costs
Many in the US consider the timeline
to be unrealistic. But … something
will be built next decade (2010-2020)
Why Technology Options are Needed
vs. a single solution
• Phasing of SKA construction
• Low, mid next decade (2010-2020)
• High: the following decade (>2020), predominantly
• Question: what frequency boundaries are best?
• Cost:
• Default picture = build to cost:1.5B€
• Is the whole science program affordable?
• Time line: continuous build out vs. distinct construction/operations
phases?
• Science priorities:
•
•
•
•
Key science demands 0.07 – 25+ GHz
Phased construction as above  prioritization of science vs. time
Affordability may require rescoping on top of phased construction
Extreme case for SKA mid: Hydrogen only: 0.4 to 1.4 GHz
Risks/Mitigation
• If wideband feeds (10:1) don’t give low Tsys
•  need more Ae for science driven Ae/Tsys
• or use clusters of 3:1 feeds
• or descope science case to more modest frequency ranges
• If wideband feeds give insufficient polarization
performance (post-calibration)
• Ditto
• If antenna costs/m2 for mid/high-f are too high
• Rescope science case to favor lower frequencies
• or find a better design + labor plan to lower costs (outsource)
• or build the array more slowly (dN/dt)
» Build mid-f optimized antennas first
» High-f antennas later (and fewer of them to meet high-f
science goals)
Risks/Mitigation (continued)
• If funding streams are disjoint regionally
e.g.
»
»
»
»
Australia, South Africa first
Europe, Ca second
US third
Then RoW
•  construction needs to accommodate this
• Will impact science deliverables vs. time
• If calibration/processing algorithms don’t meet
the imaging dynamic range requirement
• Impact on antenna/mount design
•  antennas more expensive
• Science rescope vs. costs
• Other
TDP Deliverables (Antennas part)
• Assessment of fabrication/manufacturing options
• Comprehensive: aggregates results from
» Past and current efforts
» Outside and within the SKA project (pathfinders etc.)
• Utility for non-SKA projects as well as SKA
• Wideband feeds and receivers
• 10:1 options if competitive (TDP: four cases)
• N  3:1 if necessary
• Optimized SKA antenna outfitted with TDP feeds/rx
• Must accommodate phased-array feeds if competitive
– Developed in Australia, Netherlands, Canada, US?
• Assumes that a single antenna type = SKA solution
• Alternative: mid-f antenna + high-f antenna
AWG Goals:
• Define matrix of antenna types
– Plan for assessing costs and narrowing down the list
• Inventory of antenna development taking place around
the world
– Plan for consolidating results of the development
– Work not being done that needs to be done
• Cost curve: C(D, X)
–
–
–
–
–
What do we know now?
Where are the break points (now and after future development)
Plan for getting additional data points
Discount for large volume production?
Getting industry input (non-disclosure issues)
• TDP timeline for
– Cost function analysis
– Deliverable “SKA-TDP” antenna
Meeting Outcomes
• A work plan for addressing AWG deliverables
that can reduce costs significantly from the
current situation
•
•
•
•
What is the current best cost vs. performance?
Options on the table for reducing cost?
How to best engage industry? When?
What matrix of possibilities should we consider for
determining C(fmax, FoV, etc.)
• A plan for interacting with PrepSKA
• Deliverables
• Steer the SKA project
Additional Slides
• From “Preliminary Specifications for the
SKA” v. 2.7.2 (10 December 2007)
References
International SKA Project
• http://www.skatelescope.org
• Relevant documents:
“PrepSKA”
– Preliminary Specifications for the Square Kilometre Array
(version 2.7.2, December 10 2007)
– A Preparatory Phase Proposal for the Square Kilometer
Array: Annex I “Description of Work”
– Memo 92: Costing Tool Description
US Technology Development Project
“TDP”
• http://www.astro.cornell.edu/SKATDP
• Relevant document: TDP Project Execution Plan
(not yet available on the web)
From: “SKA
Preliminary
Specifications
for the SKA”
Components of the SKA Project
• International SKA Project Development Office
(SPDO)
• Regional Consortia (e.g. US SKA Consortium)
• Design Projects
• SKADS (EC) --- ends in 2009
• TDP (US) --- 2007 to 2012
• Pathfinder Projects
• ATA, ASKAP, MeerKAT, MWA, EVLA, LWA …
• Harnessing the cats: PrepSKA (EC funded umbrella
project)
From PrepSKA Annex I:
From PrepSKA Annex I