Dish

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The past four months have been productive but turbulent for DISH and the next few months look likely to be similar as the Consortium Lead Organisation is changing. But more on that later …

Overview of progress

The period from March through to July have been particularly busy months with sub elements continuing to work on outstanding actions arising from the suite of DDRs that were held over the period September 16 to January 17, as well as many other tasks.

Pleasingly, the Local Monitoring and Control (LMC) and Dish Fibre Network (DFN) teams successfully closed out the LMC and the DFN DDRs respectively so DISH was able to formally realise two additional milestones. Plus, DISH will shortly claim an additional milestone for the SPF Band 2 DDR.

Dish Structure (DS) still needed to clarify certain design elements following the DS DDR in December but the MTM/JLRAT/SAM design team made good progress and unresolved details moved much closer to resolution (Figure 1). The feed indexer and feed indexer interface were further improved. CETC-54 completed the manufacture of the 66 panel moulds needed for the main reflector (Figure 2) and commenced the manufacturing of the sub-reflector moulds (Figures 3, 4). Main reflector panels are now in production (see Figure 5). The sub-reflector experimental BUS (the steel structure for verifying the sub-reflector position adjustment) has been assembled and is ready for test (Figures 6 and 7). The antenna main reflector BUS, pedestal and turn head designs are complete.

Figure 1. CAD image of SKA-P Prototype (Courtesy MT Mechatronics)

Figure 2. 66 Main Reflector Moulds Produced (Courtesy CETC-54)

Left Image Figure 3: Sub Reflector Mould Casted Mould Machining (Courtesy CETC-54). Right Image Figure 4: Sub Reflector (Courtesy CETC-54)

Figure 5: Main Reflector Panel Ribs-Painted (Courtesy CETC-54)

Figure 6. Sub-Reflector Steel Knots (Courtesy CETC-54)

Figure 7. Sub-Reflector Experimental BUS (Courtesy CETC-54)

The Single Pixel Feed (SPF) team continued work to close out the SPF B2 DDR. This DDR was passed in Nov16 and the Detailed Design Baseline has been closed out. The corresponding milestone will be claimed shortly. The Band 2 qualification model (QM) build is nearing completion as planned. Development testing commenced and the feed was started, put under vacuum and was running cold at temperatures as predicted (Figure 8a, 8b). This development work continued into July in preparation for qualification testing. A Test Readiness Review(TRR) is planned for August before formal qualification testing starts.

Figure 8a, 8b. Band 2 cryostat in test (Courtesy of EMSS)

Figure 8c, 8d. The SPF band 2 feed qualification model being tested in the EMSS Antennas RFI shielded tent. (Courtesy of EMSS)

Planning continued for the SPF B1 delta DDR which was held in late May. The band 1 team passed and are currently working to fully close-out the DDR. In the meantime, the team has commenced building their qualification model (QM).

Figure 9. First Band 1 Feed Moulded Quadrant before precision finishing (Courtesy of Miroslav Pantaleev)

In early July, the SKAO held the Band 5 PDR (feeds and digitisers) at Oxford University. The Band 5 team achieved a partial pass with a delta PDR required on the cryostat. The panel review was robust, identified the main issues, and the recommendations are a pragmatic way forward. This is a great result given the Oxford team started much later than others. In parallel, the digitiser team (SPFRx) continued preparations for the delta SPFRx DDR (Bands 1 and 2) which is currently scheduled for the end of July.

FIGURE 10: Band 3,4,5 – Descriptive View (Courtesy of Prof Angela Taylor)

With the DDRs substantially complete, the System Engineering team was able to refocus their efforts on their evaluation of the impact of SKAO revisions to Level 1 Requirements. A large effort was spent in March analysing the impact of the L1 requirements change from Rev7 to Rev10 on the Dish and its subsystems. ECP-DSH-170001 was registered to manage the transition process. All requirements that impacted on DISH were identified, clarifications were sought from the SKAO and the sub-elements were asked for impact feedback. DISH documentation is in the process of being updated, with the aim of completing the updates by end of July.

CSIRO announces intention to withdraw as Dish Consortium Lead Organisation

The Australian government announced in late May that it would cease to fund the Dish Management resource, leaving CSIRO with little option but to withdraw as Dish Consortium Lead Organisation and from Dish Consortium Management.

At the time of writing, the Dish Consortium Board and SKAO are considering proposals from organisations interested in replacing CSIRO. However, and as many readers will know, the Dish Consortium Leader, Roger Franzen, has departed already so a new Leader will need to be chosen soon. At this time, Susan Stopford remains both the Dish Project Manager and Consortium Officer, but this will likely change in the near future. Watch this space!

June Costing Updates

Despite the leadership disruption, May was also the time in which all consortia were again asked to review and update their construction and operation cost estimates for the SKAO. Despite a range of small variations, the net cost result for DISH was a small overall reduction. In preparation for the June costing updates, DISH convened for a cost harmonisation workshop in Cape Town, South Africa in late March so all sub element leads could cross check any assumptions in their own costings and, importantly for the group and project, collectively identify any gaps in the aggregated DISH estimate. Learnings from this workshop were applied to the June cost updates.

SKA Engineering Meeting 2017, Rotterdam & DISH F2F All Hands Meeting, Dwingeloo

June commenced with the Dish All Hands Engineering Meeting at ASTRON in Dwingeloo, followed immediately by the SKA All Hands Engineering Meeting in Rotterdam.

The primary purpose of the DISH meeting was to focus on I&V planning, and preparations and requirements for CDR. The two day meeting was attended by over 40 people currently working on DISH. Sincere thanks must be given to ASTRON for providing DISH facilities and support in Dwingeloo.

Schedule remains a concern to the consortium and the SKAO but note that Dish is manufacturing a full first of type system that will require, in aggregate, nearly €10M just for tooling and fabrication.

Figure 11. DISH All Hands Meeting, ASTRON, Dwingeloo, Jun 17. Photo courtesy of ASTRON

In Rotterdam, the Consortium Leader’s meeting paid thanks to the departing Dish Management Team. During the plenary presentations, the Dish Consortium Leader (Roger Franzen) and the Dish Project Manager (Susan Stopford) shared the presentation of Dish progress since October 2016 in Stellenbosch, in South Africa. The progress is, indeed, amazing and it is a huge credit to all the Dish Consortium sub-element teams that not only does Dish have one of (if not the) most developed designs in the SKA but importantly, it is now under full prototype manufacture.

Goodbye

So now it is time to say farewell. Whilst I expect to remain on this project for a while yet assisting the Board Chair and to wrap-up at the CSIRO end, I think that this will likely be my last eNews submission on behalf of the Dish Consortium. Therefore, I would like to take this opportunity to thank everyone involved in the Dish Consortium, but in particular Roger Franzen, as well as those at the SKAO, for their assistance and support during my tenure as Dish Project Manager. It has been an absolute pleasure working with you and on this exciting project.

Susan Stopford, Dish Project Manager & Consortium Officer, CSIRO


Report provided by Susan Stopford, DISH consortium