US Technology Development Project for the SKA Jim Cordes AWG Meeting 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 MHzdipole array Mid: 0.3 – 10 GHzdipole arrays + dishes High: up to 35 GHzdishes 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 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 (A e, T sys, 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 f max »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 CPG Athol Kemball et al.

TDP Antennas Working Group Jack Welch (UCB) Chair Matt Fleming (Minex/SI) Co-chair German Cortes (Cornell) Mark Gatti (JPL) Bill Imbriale (JPL) Peter Napier (NRAO) (not yet confirmed) Roger Norrod (NRAO) Roger Schultz (Schultz Associates) Sandy Weinreb (Caltech) External: –Dave de Boer (ATNF/ASKAP) –Peter Dewdney (DRAO) –Justin Jonas (MeerKAT)

TDP Calibration and Processing Group Athol Kemball (UI, Chair) Geoff Bower (UCB) Jim Cordes (Cornell) Joe Lazio (NRL) Colin Lonsdale (MIT/Haystack) Steve Myers (NRAO) Greg Taylor (UNM)

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

Why Technology Options are Needed vs. a single solution Phasing of SKA construction Low, mid next decade ( ) 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 T sys  need more A e for science driven A e /T sys 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/m 2 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(f max, FoV, etc.) A plan for interacting with PrepSKA Deliverables Steer the SKA project

Additional Slides From “Preliminary Specifications for the SKA” v (10 December 2007)

References International SKA Project Relevant documents: –Preliminary Specifications for the Square Kilometre Array (version 2.7.2, December ) –A Preparatory Phase Proposal for the Square Kilometer Array: Annex I “Description of Work” –Memo 92: Costing Tool Description US Technology Development Project 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) to 2012 Pathfinder Projects ATA, ASKAP, MeerKAT, MWA, EVLA, LWA … Harnessing the cats: PrepSKA (EC funded umbrella project)

From PrepSKA Annex I:

Deliverables related to Antenna Costs: –Type and number of single-pixel feeds to cover the frequency bands 10:1: how many? What Tsys? 3:1: how many? What Tsys, etc. –How to accommodate phased-array feeds –LNAs: ambient or cooled: what are the projections? If cooled, what T? –Deployment scenarios in the construction phase: –One type of antenna for all phases? Vs. y –Low-f antennas first, high-f antennas later?

From PrepSKA Annex I