last updated: 04/02/2015
The design process for large-scale international science and engineering projects is complex, made of many milestones and key steps to ensure the project evolves in a sound manner towards a solid, reliable final design before starting construction. This page aims to provide a detailed chronology of the SKA’s design process from 2013 onwards, to be updated regularly as the project moves forward towards construction approval.
Baseline design & SKA1
The SKA’s Baseline Design document – the key document that establishes the ideal SKA configuration – was released in early 2013 and serves as the guiding document for the design work undertaken to develop the SKA, focusing on the first phase of construction of the telescope (SKA1), which represents roughly 10% of the full SKA (SKA2).
In July 2013, the Board of the SKA Organisation – representing all member countries involved in the SKA project – implemented a cost-cap of €650 million for SKA1, in order to ensure maximum support for the project from the member countries while still doing transformational science at an affordable cost. The SKA Board passed the following resolution:
‘Following the recommendation of the Director-General of the SKA Organisation, the SKA Board has instructed the SKA Office to proceed with the design phase for SKA Phase 1 assuming a capital expenditure cost ceiling for construction of €650M. The evolution of the SKA Phase 1 project to fit within this cost ceiling will be guided both during the design phase and construction by scientific and engineering assessments of the baseline design undertaken by the SKA Office in collaboration with the community and SKA’s advisory bodies including the Science and Engineering Advisory Committee (SEAC). This decision is consistent with the primary objective of building an exciting, next-generation telescope capable of transformational science.’
This decision called for a re-scoping (or re-baselining) of the project to fit within the allocated envelope (see re-baselining process paragraph below), to be conducted in parallel to the on-going detailed design process of the SKA.
Start of the detailed design phase
Funded by each of the SKA Organisation’s Members and some non-Members, in November 2013, eleven consortia, consisting of over 500 top engineers and scientists from 100 companies & research institutions around the world, were established and started to work on the preliminary design of the SKA. Each consortium was tasked with designing a specific element of the telescope (see work packages section of the website) as defined by the Baseline Design document. The total amount to be invested by all the Members and partners in this design phase is estimated at €150 million.
The consortia were asked to deliver a ‘cost package’ for each element of work by September 2014. This provides a basis for exploration of an acceptable selection of options for the design of SKA1 whose cost will fit inside the cost cap.
The science case for the SKA was drafted back in 2004 so it became important to update it by taking into account the latest discoveries in the field and how these pave the way towards the SKA. To help with this enterprise and with a view of involving as large a community as possible, the SKA Organisation organised in June 2014 the Advancing Astrophysics with the SKA conference in Sicily. The conference gathered over 250 scientists from 15 countries to present their work on how the SKA will help their research and what it will be able to achieve. The scientists are now busy drafting their papers to be included in the updated SKA science case, scheduled to be published in 2015. Most of the papers are being released online on the astro-ph arxiv in the lead up to the publication.
In July, the SKA Organisation Board approved a process for developing and testing a list of high-priority science objectives for SKA1, to guide the SKA Organisation in the development of re-baselining options (see re-baselining process paragraph below). The Science Working Groups (SWGs) that represent the various science communities interested in the SKA science were requested to submit their highest ranked science objectives to the SKA Office science team, who undertook an assessment of each of these objectives against a set of criteria (examples are the scientific impact or the importance of the radio contribution).The outcome of the assessment process was reviewed by two independent bodies: the 16-member ad-hoc Science Review Panel (SRP), and the Science and Engineering Advisory Committee (SEAC), resulting in a list of high-priority science objectives. The results were then presented to the SKA Board of Directors in October.
Preliminary Design Reviews
The Preliminary Design Reviews (PDR) started in December of 2014. Each consortium was asked to deliver their detailed design proposal for their respective ‘element’ of the SKA to the SKA Office for review. The SKA, assisted by panels of experts from a range of organisations, has the critical role of thoroughly reviewing all the documentation received from the consortia. PDR panels are taking place at the SKA Office between December 2014 and February 2015 and the final outcomes of these meetings will then feed back to the design activities undertaken by the consortia towards a final design. The individual PDRs will then be followed by a general systems review around April 2015.
Re-scoping is often required as an engineering exercise in major international projects as they move towards realisation (examples are the ESO’s Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA)); it comes as the detailed design process reveals the true cost of engineering concepts and the core science drivers, and where this exceeds the likely available cost envelope from the funders. In the case of the SKA this is termed re-baselining because the end result is a new baseline design. In effect, it is an evolution of the original baseline design whose end goal is to define the best possible instrument that can be built with the funding available while still achieving priority science goals.
In September 2014 the SKA Organisation organised an all-hands Engineering Meeting, one of the aims of which was to brainstorm on re-baselining options with the engineering community. In dedicated workshops, groups of colleagues involved in the SKA consortia were asked to study and suggest options they felt would save significant cost while maintaining the capability to do transformational science with SKA1.
In total, including inputs from the Engineering Meeting, over 250 re-baselining options were submitted to the SKA Office and have been thoroughly evaluated by the Office’s architecture and engineering teams. Options selected for consideration must maintain the main science objectives defined by the SKA Office science team in collaboration with the Science Working Groups.
The impact of the numerous re-baselining options under consideration on the high-priority science objectives is being studied in detail with all options being tested against the high-priority science objectives.
A large number of options have already been eliminated, some because they are unfeasible or out of scope, others because their science impact is too high or their risk is too high, etc.
The options that make it through the screening process for further investigation are packaged together to develop a series of overall options that will fit into the budget and will maintain the capability to undertake transformational science.
Science Review Panel
An initial set of these individual options was submitted by the SKA Office to the ad-hoc Science Review Panel in mid-December to assess the science impact of individual options. In January 2015, the Panel provided its assessment of the science impact of complete packages of options.
Science and Engineering Advisory Committee Meeting
In January 2015, a further review of the re-baselining options was undertaken by the Science and Engineering Advisory Committee (SEAC). The SEAC then advised the SKA Director General on the final list of recommendations to be presented to the SKA Board for the March 2015 Board meeting.
Assessment of the re-baselining process at different stages of its development by the various independent panels ensures a strong, transparent and broad-based process aiming at selecting the most productive options for the SKA within the budget.
Board review and decision
The Board of Directors of the SKA Organisation will review the re-baselining options submitted to them at their March meeting. Once a decision has been reached on the best re-baselining option, the baseline design of SKA1 will be updated to take into account the changes. Formally, the baseline design will be subject to a series of Engineering Change Proposals to implement the required changes.
In parallel, the consortia will continue refining their design proposals for each element of the SKA based on the feedback they received from the preliminary design review. They will further detail the design of each element towards a final design.
Critical Design Reviews
Critical Design Reviews (CDR) are scheduled to take place in 2016 to make sure the detailed design proposals for each of the elements are sound. These will be followed by appropriate System CDRs.
Once the critical design review has successfully taken place and the detailed design of the elements has been approved, construction of the SKA can then be approved.