#02 2018
News
SARAO celebrates the successful completion of the SKA Telescope Manager Critical Design Review
The General Assembly of the International Astronomical Union to be hosted on African soil for the first time in 2024
US Embassy members visit Losberg and Carnarvon
European Union delegation visits SARAO Cape Town office
First cohort of SARAO-sponsored Northern Cape matrics progressing well at university
2017 SARAO bursary beneficiaries progress to second year of tertiary studies
Students from African countries complete third HartRAO AVN training school
Outreach
MeerLICHT telescope inaugurated
SARAO hosts Minister Kubayi-Ngubane and members of Parliamentary Portfolio Committee at Losberg
SARAO hosts Community Information sessions in the Northern Cape
South Africa’s initialling of the SKA Convention and Protocol texts takes place in Rome, Italy
Astronomy in South Africa is profiled at the IAU GA 2018 in Vienna
SARAO staff member leads 2018 NRAO NINE Program
Chinese Vice Minister for Science and Technology visits SARAO offices
Ghana and South Africa celebrate first success of African network of telescopes
Servitude establishment program
Latest developments on the land acquisitions programme
SARAO Human Capital Development Programme – Creating excellence in radio astronomy
SARAO Tech News
Ghana marks first spot on the AVN
Standing on the shoulders of giants: a South African’s contribution to global radio astronomy
HERA: Building to view the past
Across the Globe
SKA prototype dish assembled for the first time
First SKA-Low Prototype Station completed on site
SKA precursor upgrade makes telescope 10 times more powerful
Paving the way towards the SKA: astronomers detect signal from the first stars
Spain joins the SKA Organisation
New platform to showcase SKA’s major engineering progress
SKA treaty open for initialling
SARAO Science Engagement
RD9 Solutions: Introduction to Robotics
DST Mini Science Forum ignites conversations about big science
SARAO participates in Science Centre World Summit 2017
SARAO participates in third Science Forum South Africa
SARAO/SKA SA hosts DST Mini Science Forum in Northern Cape
Scifest Africa 2018
SARAO and Oculus announce partnership
SARAO wins Best Workshop prize at Scifest Africa 2018
NASA Electrical Engineer visits schools in Sutherland
SARAO participates in Public Communication of Science and Technology Conference in Dunedin, New Zealand
Participants graduate from Phase 1 of MAPPP NINE
SKA AVN MAPPP NINE Development Lab
MAPPP NINE expands to SKA AVN
IAU CAP 2018
SARAO participates in EuroScience Open Forum 2018 in Toulouse, France
National Science Week 2018
SARAO hosts 2018 SAASTA National Schools Debates Competition in the Northern Cape and North West
SARAO Big Data Africa School 2018 kicks off
Carnarvon High School teams through to National Competition of World Robot Olympiad 2018
SARAO Big Data Africa School 2018 ends on high note for African students
SARAO People
SARAO staffers shine at INCOSE SA 2018 conference
Five SARAO electrician trade artisan students attend media training in Carnarvon
SARAO Junior engineer wins Best Poster Presentation at UCT Engineering Research Expo
Dr Bonita de Swardt presents at plenary session at Grand Challenges Partners meeting in Kenya
SARAO bursary holder wins first prize in AT-RASC student paper competition
Dr Aletha de Witt elected to the IAU commission on astrometry
Dr Rob Adam inducted as a Fellow of the South African Academy of Engineering
SARAO bursary funded students selected for 2018/19 CSIRO scholarship
Junior Science Process Developer wins Thomson Reuters Award
Brendan Swarts – Electrician Artisan student
Morgan Daba – Electrician Artisan student
Marthinus Steyn – Telescope Operator
Griet Tobias – Housekeeper
Jan Mouers – General Worker
Mathakane Molewa – HERA Construction Supervisor
Malissa Pietersen – Procurement Officer (Site)
Lourencia Lyon – HERA General Worker
Peter van Wyngaarden – HERA General Worker
Bradwin Vermeulen – HERA General Worker
Tyrone Adams – HERA General Worker
Levurd Vaarland – HERA General Worker
R. Sean Oliphant – Mathematics teacher at Carnarvon High School
Ghana marks first spot on the AVN
SARAO News #02 2018
The African VLBI Network (AVN) is an ambitious project by the SARAO team of scientists and engineers to have a Very Long Baseline Interferometer (VLBI) across the African continent. The SKA AVN partners of South Africa are: Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia, and Zambia.
The first of these countries to complete the conversion of a communications antenna into a functioning radio telescope is Ghana with its Kutunse Space Station. The journey to the 2017 launch has seen a lot of engineering prowess and skills enrichment for the country.
Before refurbishment
The Ghana Intelsat Satellite Earth Station at Kutunse is situated at an elevation of 70 metres above sea level. Kutunse is a suburb located about 25 kilometres north-west of the national capital, Accra. The station hosts three antennas of diameters 32 metres, 16 metres and 9 metres.
The station was commissioned on 12 August 1981, and was operated by the Ghana Telecommunications Corporation until 3 July 3 2008, when Ghana Vodafone took over as major shareholder with a 70% share of the station.
The Ghanaian government has warmly embraced the prospect of radio astronomy in the country and this is demonstrated through its radio astronomy development plan. This plan was incorporated in the Ghana Science, Technology and Innovation Policy, and the Science, Technology and Innovation Development Plan 2011-2015 (GPDP15).
As an SKA Africa partner country, Ghana welcomed and collaborated with the SKA SA/HartRAO group to access the radio astronomy potential of the redundant satellite communication antennas at Kutunse. The SKA-SA/HartRAO team assessed the suitability of the 32 metre Beam Waveguide antenna and the Kutunse control station for radio astronomy through two successive working visits in March and May 2011.
The state of conversion so far
In January 2011, the Ghanaian government established the Ghana Space Science and Technology Institute (GSSTI) under the Ministry of Environment, Science, Technology and Innovation (MESTI), as per the agenda planned by the GPDP15. This meant that from that time, converting the antenna for all radio astronomy, space science and emerging related technologies programmes could finally begin.
A special team of scientists and engineers from SKA SA/HartRAO and GSSTI started on the conversion work on the antenna in earnest, following the negotiations that eventually lead to the official handing over of the station from Vodafone to the Ghanaian state. Now, besides the astronomy instrumentation upgrade needed for the conversion, the state of the antenna needed some refurbishment before it would be radio-astronomy ready.
The areas on the antenna that needed major rehabilitative work included:
- replacing the corroded sub-reflector quadrupod support legs
- replacing the azimuth and elevation angle resolvers with more accurate angle encoders
- covering the beam waveguide aperture with a safety net
- replacing some rusty hardware on the antenna structure
- replacing azimuth and elevation limit switches
- flushing and greasing the gearbox systems
- Installing the elevation and azimuth gearbox oil temperature sensors
- repainting the whole antenna structure
- re-engineering the automatic control/rotation system to a state of the art digital servo control system.
The team responsible for control and monitoring in the antenna completely rewired the antenna including the control room equipment.
The engineering team found that that long non-operational antenna had gone off-centre so they had to correct it by elevating the 220 tonne structure and re-centring it before settling it back down on the track. In 2015 the team replaced a rusted out bump stop by designing and fabricating the structure out of two tonnes of steel in South Africa, and shipping it back to Ghana where it was hoisted using hired cranes on the Kutunse site.
In April 2016, the team elected to replace the corroded sub-reflector quadrupod support legs. After much deliberation, they decided to fabricate the structure in Ghana by making use of the workshop facilities and personnel of the Ghana Atomic Energy Commission (GAEC). The process started with the certification of 2 Ghanaian welders to American Welding Standard (AWS) welding. The locally procured raw material was certificated to requirements in South African laboratories.
As part of the fabrication process, the engineers started by rolling 32 tube sections and welding eight of them together to make the four tube masts of 15 metre length. They 100% x-ray inspected each of the welds using the GAEC’s Non Destructive Test (NDT) facility to ensure conformance to the AWS welding requirements. This whole process spanned four months and in the time the rusted, old quadropod was replaced with the new one using cranes on site.
The Cape Town based team designed, built and commissioned a new motion control system based on the KAT-7 telescope architecture.
Moog, a German-based engineering firm that specialises in motion control technologies, supplied the motion controller equipment used in the new motion control system for the antenna which was designed by the Cape Town team. A specialised test rig was designed and built in Cape Town to allow integration and testing of the new control system before deploying it to the Ghana site.
Using the test rig, the team then simulated the antenna so that all the control functions could be verified. Thus, the team was then able to successfully rotate the antenna in Ghana for the very first time in September 2016.
Salvatore Gioio, an Radio Frequency engineer at SKA SA, designed a new radio astronomy receiver, which would plug into the existing horn of the antenna. From measurements taken on site in Ghana, the team fabricated the receiver in South Africa and then shipped by air to Ghana.
SKA SA electronics engineer Glen Taylor worked on the control model in Cape Town. He was responsible for the system level controllers at the Ghana station, where he also developed the analogue and I/O modules.
The conversion and refurbishment of the Kutunse station ran parallel with the refurbishment of local skills sets with the local human capital development (HCD) to produce the needed manpower.
A team of graduates from the GSSTI also completed six months of rigorous training with the South African AVN team at SKA SA and HartRAO.
The science requirements
Once completed, the newly refurbished radio telescope, will have dual functions: to form part of the African VLBI Network and also operate as a single-dish radio telescope. To meet both these needs, each function has its own set of required capabilities that the station has to satisfy.
For the single-dish component, the C- and L-band receivers will be fitted for Phase-2 operations. This will allow the antenna to do: radio continuum flux measurements (with a wideband multi-channel radiometer); pulsar observations (with a wideband multi-channel pulsar timer); and emission lines spectroscopy (with a narrowband multi-channel spectrometer).
For the VLBI component, the station requires capacity for: mapping interstellar masers in star-forming regions in the Milky Way; determining the distances to star-forming regions in the Milky Way through methanol maser parallax measurements; using trigonometric parallax measurements to determine accurate pulsar distances as well as pulsar proper motions; imaging active galactic nuclei (AGN); and other important functionalities.
The commissioning phase
For the commissioning phase, the engineering part of the SKA-SA/HartRAO working on the Kutunse station have taken a backseat to allow the scientists to find the nuances of the radio telescope and find out what the instrument can and cannot do.
The team has successfully commissioned the control and monitoring system, which is now fully functional. The current commissioning phase at the station in Ghana has been set up to understand the nuances of the newly converted radio telescope and so far. Results indicate that all is working as well as it should.
The team then tested how the antenna behaves during the process of blind tracking, and looked at the condition of the antenna beam, and how it is affected by factors such as gravity as the antenna rotates. The team has checked the effect of radio-frequency interference (RFI), and checked for any eccentricity problems in the rotation of the antenna.
Now they are testing all the systems at the station, which will be followed by the second round where the infrastructure controller will be integrated into the system. The Environmental Monitoring System is slated to be part of the system before the end of February, which is key as it provides weather information to MET 4 standard to assist with the pointing of the antenna.
The team used the existing telecommunication feed horn in the frequency range 3.8 – 6.4 GHz (C-band) for phase 1. For the actual science observations (Phase-2), the team will fit it with uncooled 5 GHz and 6.7 GHz (C-band) receivers and follow that up with a 1.4 – 1.7 GHz or wider L-band receiver, for which extra funding will be needed.
Future receiver developments could include replacing the original C-band feed horn with a wider band design covering more VLBI bands, introducing cryogenic receivers for improved sensitivity and adding more frequency bands.
For the time being, the whole system seems to be stable but the science processing team continues to test the performance of the station to better understand the nuances of the system.
Read more about Ghana’s science commissioning
Big Data Attendees at the one-day work session which was held on 11 July 2017 at the Ministry of Environment, Science, Technology and Innovation in Ghana to kick off the High Performance Computing training programme in Ghana.
Members of the nine SKA African partner countries concluded the Fourth Ministerial Meeting on the SKA in Accra, Ghana by signing a memorandum of understanding to collaborate on radio astronomy.
Minister of Science and Technology Naledi Pandor watches on as the President of the Republic of Ghana, His Excellency Nana Addo Dankwa Akufo-Addo cuts the ribbon at the launch of the Ghana Radio Astronomy Observatory.
Media coverage
The launch of the Ghana Radio Astronomy Observatory was covered 119 times in the media between 23 and 25 August 2017:
In Ghana: 24 times
In South Africa: 36 times
In other African countries: 8 times
Internationally: 51 times
The value of these placements is R6 983 234.17.
Last Updated on November 19, 2018
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