At the end of October 2018 the SKA SDP Consortium submitted its Critical Design Review (CDR) documentation pack. Contained in this were the formal deliverables of the design consortium covering all aspects of the SDP architecture, system engineering and programmatics (the documents are available here). The documents were received by the CDR reviewers (consisting of 3 external members and 20 internal to SKAO) who proceeded to generate clarification questions, requests and notes in the form of observations (called OARs after the Observation Action Register approach commonly used for them). Where possible these were addressed via communication exchanges in JIRA OAR tickets.
From 15th to 19th January 2019 members of the SDP Consortium then visited the SKAO HQ at Jodrell Bank (see Figure 1), where direct discussions took place in the new SKAO Council Chamber (see Figure 2), to further explore the architecture and identify risks as part of an SEI Architecture Tradeoff Analysis Method (ATAM).
Figure 1: The Lovell telescope as seen behind the new SKA HQ building just before day 3 of the SDP CDR got underway on Thursday 17th January 2019.
24 scenarios were identified and then prioritised in terms of business impact and architectural complexity, with those scoring highly in both areas worked through first. The exercise led to the identification of a number of risk themes and specific areas where it was deemed useful if more work could be done (either before the SDP Consortium ends in March 2019 or during a new phase of work called ‘bridging’) or an explanation provided in the documents. In total 10 recommendations were made by the panel and these included:
Further work being undertaken on the interface between the SDP and SKA Regional Centres;
Updating the Construction Plan with staff ramp-up in bridging and the incorporation of more end-to-end testing milestones;
Giving further consideration to staff needed to advance and tailor algorithms during construction;
And, advancing work on areas identified as “SKA Common”, that is software shared with other parts of the system.
Further information on the process used for the CDR, the observations and panel recommendations can be found in the CDR Panel Report which has been uploaded to this website here.
Figure 2: Discussions taking place as part of the SDP CDR in the new SKAO Council Chamber at the SKA HQ in Jodrell Bank, UK.
We are pleased to report that the panel recommended SDP CDR outcome “pass, with some actions to address” has today been endorsed by the SKA Director General and Programme Director. As a consequence the SDP Consortium is now undertaking its final work sprint before ending its activities in March 2019. From that point on there will be a transition of effort from the design consortium phase into a new set of activities falling under the title of “bridging”. These set out to support the system level CDR (due late 2019) and then to advance aspects of the design and supporting processes to begin construction in 2021/22.