I begin with the sad news of which I am sure you are now all aware, the unexpected passing of the Chair of the SKA Board, Professor Giovanni (Nanni) Bignami. Nanni and I were travelling to Madrid on 24th May, to meet with a senior Spanish government official about the SKA; Nanni tragically died soon after arriving at the hotel on that afternoon. Alistair McPherson, Luca Stringhetti and I, representing the SKA project, attended an event at the Milan Museum of Science and Industry a week later, which was a celebration of Nanni’s life; more than 500 people were present. I had known but not fully appreciated, the massive amount of work that Nanni did in bringing science to the public, through television, books, articles and newspapers; but this was brought out well at the event.
An excellent obituary of Nanni was recently published in Nature Astronomy.
Those of you who follow the SKA closely, and that must be all of those who read this eNews, will be aware of the huge efforts across the project, from staff in the SKA office, the design consortia and the science community, to identify possible cost-saving options for SKA Phase 1.
Before delving into the Cost Control Project, I am pleased to note that the work on reducing the estimates for the cost of construction of the design baseline of SKA-1 continue to bear fruit. The June 2017 figures, through continuing maturity of processes and updated estimates from industry, now stand at €806M, a reduction of €22M from the February numbers.
As indicated in the previous eNews, we have had, since November 2016, a specific ‘Cost Control Project (CCP)’ that has been studying possible cost-saving options. I won’t repeat the whole story here, but suffice to say, the options proposed have been submitted to detailed scientific scrutiny, by the SKA’s Science Working Groups, by the Science and Engineering Advisory Committee (SEAC) and, for three specific issues, by dedicated external Science Assessment Teams.
In addition, in the spirit of attempting to identify potential cost savings, several design changes were proposed. The most significant of these was a proposal to change the beam-forming architecture on SKA1-low in Western Australia from a digital system to one that uses analogue beam-forming, a development of that used on LOFAR and the MWA. A highly-experienced and external group of experts participated in what we call a Resolution Team (RT) to evaluate the pros and cons of such a design change. The RT provided a deep and thorough analysis of the problem and concluded that the digital beam-forming solution was preferred for SKA1-low. That decision was therefore taken and the design team is continuing its work on the digital systems.
The culmination of all this work was a report to the SKA Board at its meeting in Den Haag, NL on 18-19 July. The report was very well received. Below, I provide an extract from the ‘Notes from the Chair’, which summarise the conclusions of the Board on the CCP.
The Board meeting itself was chaired by Lars Börjesson of Chalmers University in Sweden, who is the Swedish voting Director and vice-Chair of the Board. The Board has formed a search committee to identify and appoint a new Board Chair.
A key outcome on the matter of the CCP was the adoption of the concept of a ‘deployment baseline’, which is defined in the text below:
The Board acknowledged the excellent work undertaken as part of the Cost Control Project (CCP), initiated at the November 2016 meeting (BD-22), in bringing the cost of the SKA1 Design Baseline down. The Design Baseline, set in March 2015, remains the long-term ambition of the SKA1 project and the focus of the design consortia as they progress their work towards the Critical Design Reviews.
The CCP has identified a route for delivering two transformational telescopes within the set cost cap of €674M (2016 euros). The Board approved the definition of a ‘Deployment Baseline’, corresponding to the telescopes currently deliverable at that funding level. The Deployment Baseline takes advantage of the scalable nature of interferometers.
The current deployment baseline is set out in the table below. This has been defined following an analysis from the SKA Office in collaboration with the engineering design consortia and in consultation with the science community. The Board now looks to the science community, and particularly to the SKA Science and Engineering Advisory Committee, to regularly review the deployment baseline to confirm its ability to deliver transformational science.
The Board agreed to wrap up the Cost Control Project as a separate project. However, it challenges the SKA Office and consortia to continue reducing project construction and operations costs as a high priority, while maintaining the project’s intent to deliver the world’s best radio telescopes.
The Board is confident that the project is now in a position to transition the SKA Organisation to formal intergovernmental status.
The current deployment baseline, compared to the design baseline, is:
|Design Baseline||Deployment Baseline|
|Max. Baseline||150 km||120 km|
|Band 1 Feeds||133||130|
|Band 2 Feeds||133||130|
|Band 5 Feeds||133||67|
|Pulsar Search (PSS)||500 nodes||375 nodes|
|Max. Baseline||65 km||40 km|
|Pulsar Search||167 nodes||125 nodes|
|Compute Power||260 PFLOPs||50 PFLOPs|
Note: The Board has taken note of recent science advice on the maximum baseline length of the SKA-low configuration and looks forward to further advice on this issue.
‘The final Deployment Baseline of SKA-1 shall be defined in the Construction Proposal. It will include as much of the Design Baseline as can be afforded at that time. The current deployment baseline is formulated on the assumption that €674M (2016 Euros) will be available. Scientific assessment of the current deployment baseline demonstrates that the SKA Observatory will deliver transformational science capabilities. Re-instatement of the omitted capabilities, up to the full restoration of the Design Baseline, is planned, either during or after the construction phase, should additional funding become available.’
All involved in this work should be proud of their efforts and pleased that we have identified a route by which the SKA can move to CDR and, following approval by the future SKA Observatory Council, to construction.
I hope you enjoy reading further on progress within the SKA project.
Professor Philip Diamond, SKA Organisation Director-General.
16th August 2017