US Technology Development Project for the SKAJim 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 ProjectPreliminary 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+ GHzThree frequency bands:

• Low: 70 – 300 MHz dipole array• Mid: 0.3 – 10 GHz dipole arrays + dishes• High: up to 35 GHz dishes

Three construction phases:• Phase 1: Low and mid: start ~ 2013, ~10% of mid• Phase 2: Finish low and mid by end of decade• Phase 3: 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. Antennas, Feeds and Receivers

2. Calibration and Processing

3. Cost Function Analysis

4. SKA Design Project

5. SKA Research Associateship

6. TDP Management

7. US SKA Consortium Participant Costs

AWG

CPGAthol Kemball et al.

Many in the US consider the timeline to be unrealistic. But … something will be built next decade (2010-2020)

Why Technology Options are Neededvs. 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)

ReferencesInternational SKA Project

• http://www.skatelescope.org• Relevant documents:

– 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• http://www.astro.cornell.edu/SKATDP• Relevant document: TDP Project Execution Plan

(not yet available on the web)

“PrepSKA”

“TDP”

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