Super Telescopes
Astronomy megaprojects that attract the most attention are generally telescopes in the visible spectrum or close to it, as they generate a lot of spectacular pictures. This is, for example, true for the JWST (James Webb Space Telescope), which we analyzed in detail in a previous megaproject article.
Stars and other space objects are, however, not emitting signals only in the form of light. Another important field of astronomy is radio telescopes for detecting a different segment of the electromagnetic spectrum, radio signals.
Source: SKAO
It used to rely on ultra-large antennae, like the now defunct 305-meter-wide Arecibo observatory, which you might have seen in 1990s movies like James Bond’s GoldenEye or Contact.
Source: The Meliorist
A different technique uses a large number of smaller antennae, and aggregates the total data into one bigger picture digitally, a method called interferometry, or also sometimes aperture synthesis.
In this method, the larger the spacing between the antennas, the more resolution the final image has. This can slowly build a high-quality image even from a very faint source if given enough time.
Source: NRAO
This is the method followed by SKAO (Square Kilometre Array Observatory), a megaproject with receiving stations extending out to a distance of at least 3,000 km. When operational, SKA-Mid and SKA-Low will be the largest radio telescope array on Earth.
It should revolutionize our understanding of the Universe by giving the most detailed information ever in the radio wave spectrum.
Radio Astronomy
The first time that radio waves were detected from the sky was in 1933, by Karl Jansky at Bell Telephone Laboratories, detecting them from our Milky Way galaxy.
More analysis would go on in the following years, culminating in the 1974 Nobel Prize for Physics awarded to Sir Martin Ryle for the development of aperture synthesis (interferometry) and Antony Hewish for the discovery of pulsars (pulsars are rapidly spinning neutron stars, emitting very regular and very powerful radio pulses).
Source: Nobel Prize
Pulsars, as well as other astronomic phenomena among the most powerful and violent in the Universe, like supermassive black holes, can only be observed through radio astronomy. It can also detect neutral hydrogen, which is otherwise invisible in visible light.
Radio astronomy also has the advantage of working in all weather conditions, being unhampered by clouds in the sky or bad weather. Similarly, radio signals are not stopped by cosmic dust, allowing radio astronomy to “see” where other type of telescopes cannot.
Today, most of radio astronomy is performed with radio interferometry, notably with facilities like the 27-dish Very Large Array (VLA) in New Mexico, USA, the 66-dish Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile (currently the world’s largest radio telescope array).
Historically, radio astronomy has been closely linked to the development of many important modern technologies, including:
- The invention of WiFi.
- Magnetic resonance imaging (MRI);
- Reference systems for space navigation and GPS;
- High-precision monitoring of tectonic plate movements, important for earthquake alarms.
- Low-noise amplifiers for use in radar, telecommunications, and remote sensing;
SKAO is at its origin a project designed to try to reach through interferometry the equivalent of a one square kilometer (one million square meters, 10 million square feet) array.
This is because it was known since the 1980s that such a large array would be required for analyzing the expansion of the Universe a mere 100 million years after the Big Bang, through the study of hydrogen clouds, as well as the formation of the first galaxies 1 billion years after the Big Bang.
The core members of the project are Australia, China, Italy, the Netherlands, Portugal, South Africa, Switzerland and the UK. Other countries are either in the accession stage, with a cooperation agreement, or observers of the project, with the notable absence of the USA among the major countries.
Source: Wikipedia
A short list of 6 potential designs where chosen in 2005, and the SKA Organization would be formally created in 2011.
Source: SKAO
In 2015, a massive science book, “Advancing Astrophysics with the Square Kilometre Array,” was written. It would contain 135 chapters written by 1,213 contributors from 31 nationalities.
In 2019, the SKAO Convention was signed in Rome, formalizing the contribution and engagement taken by each country in the project.
Construction would be greenlighted in 2021. By the close of 2022, contracts worth some €500m have been awarded as the SKAO continues to progress along its ambitious construction schedule.
The initial costs were estimated at €1.8 billion in 2014. In 2021, the required budget was estimated to have grown to $3B.
2025 will see the first Key Science Planning (KSP) planning and proposals, which will determine exactly what the telescope will observe first depending on the project offered by individual scientific teams from all over the world.
Source: SKAO
From 2027 onward, the first observations will be made, and the radio telescope will be operational, the verification that all works as planned done and growing in capacity with the first observations will be done in 2029.
Source: SKAO
SKAO Design
SKAO will be distributed as 2 different telescopes on 2 different continents (South Africa for SKA-Mid and Australia for SKA-Low), with a headquarters in the UK.
Source: SKAO
The UK location is Jodrell Bank site, a UNESCO World Heritage Site for its contribution to the development of radio astronomy.
Source: SKAO
The choice of South Africa and Australia was linked to the lower radio interference in these regions (less landmass and population), especially in remote desert areas, while offering a good view of the Milky Way.
SKA-Mid
Reaching for an unprecedented scale, SKAO will include in its SKA-Mid part no less than 197 fully steerable dishes, incorporating in the new project the existing MeerKAT radio telescope, a 64 interlink antennas system in South Africa.
The existing MeerKAT radio telescope’s 13.5m-diameter dishes will be joined by the slightly larger 15m-diameter SKA dishes, all integrated into one system.
The maximum distance (or baseline) between dishes will be 150km, creating a total collecting area of 33,000 m².
Institutions in China, Australia, Canada, France, Germany, Italy, South Africa, Spain, the United Kingdom, and Sweden all contributed to the SKA-Mid design, and the various components will be manufactured all over the globe before being shipped to South Africa for assembly.
Each 22-meter-tall, 15-meter-diameter dish will be made of 66 individual panels, each of which has to be adjusted with an average surface accuracy between 0.010 and 0.030mm, to ensure a smooth collecting surface.
Source: SKAO
The 160 kg receivers transform radio waves from analog to digital, which can then be transferred through optical fiber and processed.
The choice of a 15-meter antenna was a compromise between the need for precision and high definition (smaller antennas are better) and the ability to scan large segments of the sky at once (for which larger antennas are better).
The cost constraints, the feasibility of mass producing the dishes, installation speed, maintaining low operating costs, and the ability to withstand environmental extremes like high winds or thermal stress were also all matters considered during the design of the system.
Source: SKAO
Overall, SKA-Mid will have, compared to the current best radio telescope, 4x the resolution, 5x the sensitivity, and will be able to survey the sky 60x faster.
SKA-Low
SKA-Low relies on a very different design than SKA-Mid, which is more similar to other radio telescopes using large antennas.
Instead, SKA-Low will use 131,072 log-periodic antennas spread between 512 stations. Log periodic antennas are smaller, 2-meter-tall antennas, designed to detect low-frequency radio waves.
Source: ABC
The “Christmas tree” shape of the antenna is designed so that it can detect every possible radio signal in the 50 MHz to 350 MHz frequency range. The longer signals are generally the most ancient, as they have been “stretched” by the expansion of the Universe.
The antennae themselves do not move, but a technique called “beamforming” is used to point them in the right direction, essentially detecting where a signal is coming from to amplify it.
Each antenna is connected to a smart box, converting the amplified electric signal into optical data for transfer by optical fibers to the Central Processing Facility (CPF).
Altogether, the SKA-Low antenna creates an astonishing collecting area of 419,000 m². This means that even the weakest of signals can be detected, combined, and enhanced in a way that has never been possible before.
Source: SKAO
It also gives SKA-Low a significant boost in performance compared to the similar best system currently in use, with 25% better resolution, 8x the sensitivity, and the ability to survey the sky 135x faster.
In the design of SKA-Low antennae, the necessity to mass produce them decided a lot of the options, like making them all with un-moving parts.
SKAO’s Objectives
SKAO will deploy in successive phases, as the radio telescope systems are being built.
In phase 1, it is expected to have the sensitivity required to detect up to 10,000 normal pulsars, and 1,000 millisecond pulsars (ultra-rapid and powerful pulsars) in the Milky Way. When fully deployed, it should be able to detect all the galactic pulsars emitting their signal toward Earth.
It will also provide the first detailed measurement of the so-called Cosmic Dawn, the moment and conditions when the first stars and galaxies formed, as well as the subsequent “Era of Reionisation”, more similar to the current state of the Universe.
Source: SKAO
SKAO will also be able to analyze gravitational waves, through their effects on the radio signals, complementing the LIGO gravitational wave detector.
The systems will also be able to form variable “sub-arrays”, allowing for parallel observations and experiments to run at the same, mobilizing only a part of the whole interferometry telescope.
Source: SKAO
SKAO Technological Achievements
Manufacturing & Economic Impact
On a technical level, SKAO is impressive for its scale and precision, notably with the extremely precise manufacturing required for its antenna, which has to be replicated at scale hundreds of times for SKA-Mid and hundreds of thousands of times for SKA-Low.
This has been achieved through many partnership programs with companies from the participating countries, having a strong impact on their technological abilities, as well as the local economies, for example:
Data Management
Another impact SKAO will have is in the handling of data. As the radio signal collected by the antennas is converted into digital information, it will create a flood of data requiring processing.
An average of 8 terabits per second of data will be transferred over hundreds of kilometers from the SKA-Low telescope in the Murchison outback in Australia to the processing facility in Perth. For SKA-Mid in South Africa, the data rate is even bigger, around 20 terabits per second. This is 1,000x more data than the ALMA radio telescope (the world’s largest) is currently generating.
Each of the data received by individual antennas is slightly at a different time, so they must be aligned thanks to ultra-precise atomic clocks. This requirement was so stringent that it required designing new ways to synchronize the data.
The data are then transferred to 2 supercomputers called Science Data Processors (SDPs). They each will have a processing speed of ~135 PFlops (petaflops), which was among the top 3 quickest computers on Earth in 2022.
In total, the project will archive 700 petabytes of data per year, the equivalent of the hard drives of 1.5 million normal laptops.
Most of the computing is powered by a solar plant and its associated batteries, with diesel generator backups.
Beyond SKAO Phase 1
The Next Step For SKAO
As more and more antennae get connected, the capacity of SKAO will grow, increasing in both resolution and total scanning capacity.
Source: SKAO
In the long term, SKAO is designed to keep integrating more radio telescope arrays. This should be achieved by adding more antennas in Australia, as well as new arrays in other African countries. Among the new partners considered are many of South Africa’s neighbors, including Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia.
For phase II of the project, a new volume of the “Advancing Astrophysics with the Square Kilometre Array” opus is in preparation, “Advancing Astrophysics II”.
Other Radio Telescopes
The USA is building the Next Generation Very Large Array (ngVLA), successor to the current VLA, which will be made of 25-meter dishes, spread over 5,505 miles (8,860 km) between continental USA territory, Hawaii, Puerto Rico, and Canada.
Source: ngVLA
Another plan is for NASA to build a massive radio telescope on the dark side of the Moon, a position that would shield it entirely from any interference from Earth, named the LuSEE-Night instrument (Lunar Surface Electromagnetic Experiment). Instead of a big dish, this concept will use long cables to detect radio signals.
Source: Cosmo
A much more ambitious concept, called the Lunar Crater Radio Telescope (LCRT) imagines a design using a Moon 3-5 km crater to be used as a dish, with a kilometer-long cable acting as the receiving antenna.
Source: NASA
Conclusion
SKAO results are going to be a lot less visual than from other telescopes, as it focuses on the invisible and more complex radio wave signals produced by some of the most massive objects in the Universe, like neutron stars and supermassive black holes at the centers of galaxies.
These results might, however, be as much, if not more, transformative to our understanding of the Universe than data from telescopes like the JWST. This includes the very first moment of the Universe, as well as how gravitational waves shape the Universe as we know it.
It is also a massive industrial and scientific endeavor, mobilizing thousands of the world’s best minds. As with many of the previous radio astronomy projects, the extreme technical requirement for the hardware and software used will push forward what can be done with wireless data detection, semiconductors & precision manufacturing, and data analysis.
So, without a doubt, it will be remembered as one of the most important and transformative scientific megaprojects of the early 21st century.
SKAO Related Company
AAC Clyde Space
While many companies are being involved with SKAO, for some it is a much larger deal due to the company being smaller and the project comparatively larger for them.
AAC is one of them, a Swedish company that has won in 2023 a tender for providing the radio telescope project with its key radio astronomy receivers.
The project is worth EUR12M, and the order will be delivered by the first quarter of 2027. Each receiver is over a meter across and weighs 180 kg. Omnisys will deliver 80 complete functioning and integrated receiver systems to the project. The attached digital converter will be built by Qualcomm (QCOM -1.08%).
Source: Chalmers SE
Besides radio telescope systems, the expertise of AAC is in producing and operating small satellites. The company’s focus on small satellites benefits from launch cost to orbit declining, making the launch of many small satellites more profitable, especially with the construction of satellite constellations (of which the most famous example is SpaceX’s Starlink).
AAC has its own constellation of 15 satellites, providing data like orbital imagery, ship tracking, precision farming, forestry data, etc., to its clients without them having to operate their own satellites.
The company is planning to grow this “Space Data as a Service” offer throughout the upcoming decade, adding hyperspectral data for agriculture in 2025, as well as VDES (Very High-Frequency Data Exchange System) for ship communications (with the first satellite launched in 2023).
Source: AAC
In the meantime, the company is winning contracts for building new satellites, like the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the real-time optical and quantum direct-to-earth communication ESA OPS-SAT VOLT, Scotland’s first satellite UKube-1, or the Maritime Communications Satellite Ymir-1.
As a key provider of satellite systems to Europe, the company is in a good position to benefit from the region’s goals of staying a relevant space power and develop its own satellites constellations, even if the ESA is lagging behind in reusable launchers when compared to China, SpaceX, or Rocket Lab (RKLB +1.41%) (follow the link for the dedicated Rocket Lab investment report).