Cutting-edge engineering for the world’s largest radio telescope€¦ · reflector for the 18m x...

Cutting-edge engineering for the world’s largest radio telescope

SKAO

Approaching a technological challenge on the scale of the SKA is formidable... while building on 60 years of radio-astronomy developments, the huge increase in scale from existing facilities demands a revolutionary break from traditional radio telescope design and radical developments in processing, computer speeds and the supporting technological infrastructure.

To answer this challenge the SKA has been broken down into various elements that will form the final SKA telescope. Each element is managed by an international consortium comprising world leading experts in their fields.

The SKA Office, staffed with engineering domain experts, systems engineers, scientists and managers, centralises the project management and system design.

The design work was awarded through the SKA Office to these Consortia, made up of over 100 of some of the world’s top research institutions and companies, drawn primarily from the SKA Member countries but also beyond.

Following the delivery of a detailed design package in 2016, in 2018 nine consortia are having their Critical Design Reviews (CDR) to deliver the final design documentation to prepare a construction proposal for government approval. The other three consortia are part of the SKA’s Advanced Instrumentation Programme, which develops future instrumention for the SKA.

The 2018 SKA CalenDaR aims to recognise the immense work conducted by these hundreds of dedicated engineers and project managers from around the world over the past five years. Without their crucial work, the SKA’s ambitious science programme would not be possible. As you browse through the calendar, we hope you will get a feel for the breadth and truly global nature of the work that has gone on. We wish you all an excellent and successful year 2018!

SKA Organisation

Cutting-edge engineering for the world’s largest radio telescope

SKAO

January 2018

May 2018

September 2018

February 2018

June 2018

October 2018

March 2018

July 2018

November 2018

April 2018

August 2018

December 2018

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22 23 24 25 26 Australia National Day

Date of the founding of Sydney, the first European settlement in Australia, 1788.

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JANUARY2018

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Infrastructure – laying the foundationsAfter conducting geological surveys to identify a suitable location, in June 2017 the infrastructure team from SARAO poured the concrete foundation – using 120m3 of concrete – for the first SKA prototype dish at the South African SKA site in the Karoo. The foundation comprises eight 750mm diameter piles, driven to about 10.5m below the natural ground level and a 7m diameter, 1.5m deep reinforced pile cap/base where the dish prototype will be installed. Pull tests were subsequently conducted to test the stability of the foundation. In total, 133 such foundations will have to be poured in Phase 1 of construction to accommodate the SKA dishes.

The Infrastructure element covers both the Infrastructure in Africa and in Australia. It includes all work undertaken to deploy and be able to operate the SKA in both countries. Infrastructure includes roads, buildings, power generation and distribution, reticulation, vehicles, cranes and specialist equipment needed for maintenance that are not included in the supply of the other elements. The INFRA SA Consortium is led and managed by SKA South Africa (now integrated into the South African Radio Astronomy Observatory, SARAO) Infrastructure team, which has previously worked on the infrastructure for both the KAT7 and MeerKAT telescopes.


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5 6 New Zealand National Day Waitangi

Day, signing of the Treaty of Waitangi in 1840.

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FEBRUARY2018

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the moulds & panels Pictured here are the 66 moulds used to manufacture the 66 panels of the main reflector for the 18m x 15m SKA dish prototype, at the CETC54 factory in Shijiazhuang, China. In 2017, CETC54 produced the moulds and the panels, ready for first assembly of a full prototype in China and shipment and installation of another one at the South African SKA site in 2018. Each panel has a unique shape to create the exact curvature it needs for its position on the reflector. In front, a panel’s backup structure can be seen as the panel is fitted on the mould.

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The Dish element of the SKA is probably what most people think of as a radio telescope. The international Consortium is responsible for the design and verification of the antenna structure, optics, feed suites, receivers, and all supporting systems and infrastructure ahead of the production of the 133 SKA-mid dishes in Phase 1 of construction of the SKA. The selected design for the SKA dish is a German / Chinese collaboration between MT Mechatronics and CETC54. The consortium is led by CETC54 in China.


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MARCH2018

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Infrastructure – solar power to study the starsPower is a huge challenge for the SKA, with power-hungry distributed infrastructure located in very remote areas, and the two SKA sites aim to keep their carbon footprint to a minimum. Whilst in South Africa the core of the SKA site will be able to tap into local grid power, in Australia all the electrical power must be produced on site.

Pictured here is the newly built power station at the Murchison Radio-astronomy Observatory (MRO) in Western Australia, which is home to two SKA precursors (ASKAP and the MWA) and the future site for SKA1-low. The power station consists of a 1.85 MW solar array, a lithium-ion battery that can store 2.6 MWh, and four diesel generators. It is the first hybrid-renewable facility to power a remote astronomical observatory. It was built by Australian companies Horizon Power and Energy Made Clean (EMC) in partnership with CSIRO, Australia’s national science agency, which owns and operates the MRO.

CSIRO modelling indicates that using this photovoltaic system and storage battery saves 650,000 – 840,000 litres of diesel a year and cuts carbon dioxide emissions by 1,700 – 2,200 tonnes a year.

What makes this power station unique is the RFI shielding designed by CSIRO and EMC. The shielding keeps electromagnetic interference to levels that don’t harm the radio astronomy observations. It is a world first and will be crucial for SKA1-low, which will be powered by a similar renewable generation system.

In addition, because the SKA1-Low antennas will be spread over a distance of some 65 km, the outer stations may be equipped with their own local solar power stations.

The Infrastructure element covers both the Infrastructure in Africa and in Australia. It includes all work undertaken to deploy and be able to operate the SKA in both countries. Infrastructure includes roads, buildings, power generation and distribution, reticulation, vehicles, cranes and specialist equipment needed for maintenance that are not included in the supply of the other elements. The INFRA AU Consortium is led and managed by CSIRO in Australia.

APRIL2018


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The Netherlands National Day King’s Day, King Willem-Alexander’s birthday.

South Africa National Day First democratic general election in 1994.

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Antennas – deployment in the Outback Aerial view of the partially completed Aperture Array Verification System 1 (AAVS1) main station and its 256 antennas for the SKA-low telescope at the Murchison Radio astronomy Observatory in Western Australia. An international team with engineers from the UK, the Netherlands, Malta, Italy and Australia undertook its installation on site in 2017.

All field components are clearly visible, showing the antennas mounted on their concrete bases in the lower half. The white top-node, hosting the low-noise amplifiers and Radio-Frequency over Fibre (RFoF), can be found at the upper part of the antennas. The black hybrid cables seen weaving between the antennas host 2 copper wires to transfer DC power to the antenna electronics. They also host the fibre optic cable to transfer the two polarizations to the processing system. The Antenna and Power Interface Unit (APIU) can be seen in the middle of the station. It is connected to mains power, as well as fibre optic cable to transport the RFoF-signal to the Central Processing Facility a few kilometres away.

The Low-Frequency Aperture Array (LFAA) element is the set of antennas, on board amplifiers and local processing required for the SKA-low telescope, representing over 130,000 low frequency antennas covering the 50 MHz to 350 MHz frequency range to be installed at the Australian SKA site in Western Australia. LFAA includes the design of the local station signal processing and hardware required to combine the antennas and the transport of antenna data to the station processing, called the Antenna Array Verification System 1 or AAVS1. The consortium is led by ASTRON in the Netherlands.


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MAY2018

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Signal processing – liquid cooling & ultra-fast optical connectivityClose up of the liquid-cooled Gemini LRU Central Signal Processor board for the SKA1-low telescope, ready for post-assembly testing at ASTRON in the Netherlands. The board is a collaboration between CSIRO in Australia, ASTRON in the Netherlands and Auckland University of Technology in New Zealand. At the heart of it is a Field-Programmable Gate Array or FPGA, DDR4 memory and 1.3 Tbit/s of optical input and outputs. When fully powered, SKA1-low’s Correlator and Beamformer will require 288 such boards. The central processing facilities (one for each telescope) are where the signals from the antennas – flowing in at ~8 Tbit/s – will be combined together using FPGAs and GPUs and where data starts to becomes information. With 65,000 different frequency channels for each of the SKA’s ~130,000 antennas and ~200 dishes, the SKA’s CSP will produce up to 8 billion data streams.

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The Central Signal Processor or CSP is the central processing “brain” of the SKA. It converts digitised astronomical signals detected by SKA receivers into the vital information needed by the Science Data Processor to make detailed images of deep space astronomical phenomena that the SKA is observing. It will also design a “non-image processor” in order to facilitate the most comprehensive and ambitious survey yet to find new pulsars and precisely time known pulsars. The lead organisation of the Consortium is the National Research Council of Canada (NRC).


1 2 Italy National Day

Festa della Repubblica, Italy is made a republic in 1946; death of Giuseppe Garibaldi in 1882

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Election of Gustav Vasa as King of Sweden in 1523; adoption of the constitutions of 1809 and 1974

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JUNE2018

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Data processing – scaling up to tackle the Big Data challengePictured here is the Performance Prototyping Platform for the SKA Science Data Processor at the University of Cambridge, UK, used to verify the SDP architecture. Designing the SDP is a huge challenge with the two SKA telescopes expected to work day and night all year round, producing around 8 Tbit/s of data each that will need to be processed in near real-time. All together, the two SKA Science Data Processors will require about 250 PFLOPS, representing two and a half times the current fastest supercomputer in the world, Sunway TaihuLight in China. They will produce an expected 300 PB of science data products, to be delivered to an international alliance of regional centres around the globe for further processing.

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The Science Data Processor (SDP) element will focus on the design of the computing hardware platforms, software, and algorithms needed to process science data from the correlator or non-imaging processor into science data products. The Science Data Processor will have to manage the vast amounts of data being generated by the telescopes. From spectral and continuum sky surveys, to more targeted observations of objects both near and far, the SDP will ingest the data, and move it through data reduction pipelines at staggering speeds, to then form data packages which will then be passed to the scientists, and in almost realtime, make decisions about noise that is not part of those delicate radio signals. The consortium is led by the University of Cambridge in the UK.

JULY2018


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Canada National Day

Creation of a federal Canada from three British Dominions in 1867.

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The Telescope Manager element includes all hardware and software necessary to control the telescope and associated infrastructure. The TM includes the co-ordination of the systems at observatory level and the software necessary for scheduling the telescope operations. It also includes the central monitoring of key performance metrics and the provision of central co-ordination of safety signals generated by Elements of the SKA. The consortium is led by the National Centre for Radio Astrophysics in India.

Software – creating the SKA’s nervous systemThe control room of the Giant Metrewave Radio Telescope in Khodad, Maharashtra, India and close-ups of two of the computer screens used to operate and monitor the telescope. As an SKA pathfinder instrument, GMRT is used to provide valuable input into the SKA design. In particular, the National Centre for Radio Astrophysics (NCRA) located in Pune and which operates it, designed the Telescope Manager for the instrument and is leading the design of the SKA’s TM, based on their experience with the SKA pathfinder.

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AUGUST2018

Signal & data transport – precision timing While optical fibres are incredibly stable and suited to transport data, mechanical stresses and thermal changes do affect the fibre, degrading the stability of the transmitted signals over long distances.

The long distances between the SKA antennas means radio waves from the sky reach each antenna at different times. With eventually thousands of antennas spread over continental scales and therefore thousands of kilometres of fibre, one of the most complex technical challenges for the SKA to function properly is to make sure the signals from the antennas are aligned with extreme precision to be successfully combined by the SKA’s supercomputers.

To achieve this level of precision or “coherence” across the array, the SKA requires a synchronisation distribution system that supresses these fibre fluctuations in real time.

Pictured is one of two synchronisation systems developed for the SKA. This optical fibre-based synchronisation distribution system was designed by a team from the International Centre for Radio Astronomy Research (ICRAR) in Perth for the SKA-mid dishes in South Africa. Another system has been designed by Tsinghua University in Beijing for the SKA-low antennas in Australia.

The Sub-Rack enclosure is used to hold 16 of the 197 Transmitter Modules for the SKA-mid phase synchronisation system. One prototype Transmitter Module is shown partly extended from the front of the enclosure, revealing details of the system’s critical fibre-optic components.

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India National Day Independence from the British Empire in 1947.

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Signal and data transport is the backbone of the SKA telescope. The Signal and Data Transport (SaDT) Consortium is responsible for the design of three data transport networks. These include the Digital Data Backhaul (DDBH) that transports signals from the radio telescopes to the Central Signal Processor (CSP), and data products from the CSP to the Science Data Processor (SDP) and from the SDP to the regional SKA Data Centres. The consortium is led by the University of Manchester in the UK.

SEPTEMBER 2018


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Integration – fitting the pieces of the puzzle togetherA major part of AIV’s work is to plan the integration of the 64-dish MeerKAT array into the SKA1-mid telescope to supplement the 133 SKA dishes and create a 197-dish array. With the installation of all MeerKAT dishes on site in the Karoo in South Africa completed in 2017 and the start of SKA construction drawing closer, this work is starting to come into focus. Integrating 13m diameter dishes equipped with their own instrumention with 15m diameter dishes with their own, different instrumentation and all the associated software and infrastructure is no small feat and the engineers of AIV are working hard to make sure the documentation detailing the interface between these different pieces, where one stops and where one begins and how they fit together – from bolts, power all the way to software coding – is a perfect, seamless match.

The Assembly Integration and Verification (AIV) element includes the planning for all activities at the remote sites that are necessary to incorporate the elements of the SKA into existing infrastructures whether these be precursors or new components of the SKA. In particular, this includes integrating the 64-dish MeerKAT array into the SKA1-mid telescope in South Africa. The consortium is led by the South African Radio Astronomy Observatory, SARAO.

OCTOBER2018


1 China National Day

Proclamation of the People’s Republic of China in 1949.

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R&D – radio cameras for radio astronomy Phased Array Feeds or PAFS for radio astronomy is an active area of research conducted by a number of leading science institutions and universities around the world and new approaches continue to emerge.

A recent innovation in PAF design is CSIRO’s ‘rocket’ PAF prototype seen here being lifted onto the Parkes telescope in Australia. The excellent wide band (3:1) and low noise performance of the array was demonstrated showing this as a promising design for future cryogenic and room temperature receivers.

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Phased array feeds (PAFs) are radiotelescope receivers which house hundreds of detectors that enable astronomers to perform multidirectional searches of the sky simultaneously. They increase the field of view of traditional ‘dish’ radiotelescopes by typically 40 times.APERTIF on the Westerbork Synthesis Radio Telescope (WSRT), Australian SKA Pathfinder (ASKAP) telescope and the Effelsberg 100m radiotelescope, amongst others, are proving the value of PAF technology for the next generation of radio astronomy instruments.

The SKA inspired much of the early radio astronomy PAF research and the technology continues to develop. The SKA PAF led by CSIRO in Australia is leading the coordination of these developments for the SKA as part of the SKA’s Advanced Instrumentation Programme (AIP), which develops new and potentially high-gain technology for use on the SKA.


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R&D – aperture arrays for wideband frequency coveragePictured here is a Front-End solution for the Mid-Frequency Aperture Array based on a Crossed Octagonal Ring Antenna array under development at the University of Manchester. It is being measured in the large anechoic chamber at Leonardo MW in Edinburgh, UK. Anechoic (non-echoing) chambers are designed to completely absorb reflections of either sound or electromagnetic waves. Here it is used to check the performance of the instrument’s design.

The Mid-Frequency Aperture Array (MFAA) element of the SKA, part of the SKA Advanced Instrumentation Programme, includes the activities necessary for the development of a set of antennas, on board amplifiers and local processing for possible deployment in the second phase of construction of the SKA. MFAA would cover a wide-range of radio frequencies from 400 MHz upwards. One of the key science goals for these telescopes is their planned mission to measure the effects of dark energy on the Universe, as well as doing high speed surveys for pulsars and other radio transient events. The consortium is led by ASTRON in the Netherlands.


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R&D – receivers for wideband frequency coveragePictured here is a feed horn receiver for the SKA Dish – designed and manufactured at Onsala Space Observatory, Sweden – undergoing beam pattern measurements tests to check its performance in the anechoic chamber at Yebes observatory in Spain as part of the European Commission-funded FP7 RadioNet programme. This wideband feed covers the 4.6 to 24 GHz frequency band and is equipped with cryogenic low-noise amplifiers designed and fabricated at Low Noise Factory, Gothenburg, Sweden.

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The Wide-Band Signle Pixel Feed (WBSPF) consortium designs and prototypes two wide band feeds for the SKA Dish as part of the SKA’s Advanced Instrumentation Programme. Specifically, WBSPF seeks to greatly expand the frequency range covered by radio astronomy receiver systems. One of the bands covers the Baseline design bands 3 and 4 and the other one extends the frequency coverage of SKA up to 24 GHz. The consortium is led by Onsala Space Observatory in Sweden and includes universities and companies from Sweden.

SKA Engineering Meetings

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SKAO

SKA OrganisationJodrell Bank Lower Withington Macclesfield Cheshire SK11 9DLUnited Kingdom+44 (0)161 306 9600www.skatelescope.org

Square Kilometre Array

@SKA_telescope



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Cutting-edge engineering for the world’s largest radio telescope€¦ · reflector for the 18m x...

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