A pioneering European mission has successfully engineered an artificial total eclipse in orbit, unlocking new insights into the Sun’s outer atmosphere and showcasing precision spaceflight powered by sustainable innovation.
World-First
In a world-first achievement for orbital science, the European Space Agency (ESA) has unveiled the first results from its ambitious Proba‑3 mission to create a controlled, artificial total solar eclipse in space. The breakthrough offers an unprecedented look at the Sun’s superheated outer atmosphere (the corona) while also demonstrating the practical viability of precision formation-flying spacecraft, a key enabler for sustainable and scalable space missions of the future.
How?
Proba‑3, launched on 5 December 2024 aboard a PSLV-XL rocket from India’s Satish Dhawan Space Centre, is made up of two satellites flying 150 metres apart in Earth orbit. One of the spacecraft, dubbed the Occulter, carries a 1.4-metre disc designed to block the bright central disc of the Sun, thereby mimicking the effect of the Moon during a total solar eclipse. The other, the Coronagraph, holds a specialised optical instrument called ASPIICS, built to observe the faint corona that surrounds the Sun.
“We can create our eclipse once every 19.6-hour orbit,” explained Andrei Zhukov, Principal Investigator for ASPIICS at the Royal Observatory of Belgium. “Unlike natural eclipses, which happen at most a couple of times a year and only last a few minutes, we can hold our eclipse for up to six hours.”
Why?
The Sun’s corona is a region of superheated gases that unexpectedly reach temperatures above one million degrees Celsius, which is far hotter than the visible surface of the Sun itself. This apparent paradox has puzzled scientists for decades and holds key information about solar weather, particularly the origins of powerful coronal mass ejections (CMEs) and solar winds.
These solar outbursts can create dramatic auroras but also cause serious disruption to power grids, communications, navigation systems and satellites on Earth. For example, in May 2024, a strong solar storm caused blackouts and temporarily disabled GPS in several regions. Understanding how and why these solar events happen has, therefore, become not just a matter of scientific curiosity, but one of economic and infrastructure resilience.
The Proba-3 mission was designed precisely to address this knowledge gap, by allowing scientists to observe the corona much more frequently, and in greater detail, than has ever been possible before.
The Technology
The technical achievement behind Proba-3 is pretty remarkable. For example, to maintain their alignment while orbiting Earth at speeds of around 1 kilometre per second, the two satellites must remain synchronised to within just a few millimetres. Doing so without continuous input from ground control relies on a suite of advanced guidance, navigation, and control technologies, many of which were developed by European startups and SMEs.
From Different Countries
Dutch company Lens R&D, a graduate of ESA’s Business Incubation Centre, developed the high-precision Sun-tracking sensors which allow the spacecraft to detect minute changes in the Sun’s position, essential for staying locked in alignment. Irish firm Onsemi (formerly SensL) supplied silicon photomultipliers, i.e., the extremely sensitive light detectors that monitor the shifting shadow of the Occulter on the Coronagraph to fine-tune positioning.
Also, software from Polish firm N7 Mobile, which transitioned from consumer app development to embedded systems, handles the formation control logic. This software suite coordinates the orbital choreography required to maintain the artificial eclipse while minimising reliance on ground-based commands.
“Although we are still in the commissioning phase, we have already achieved precise formation flying with unprecedented accuracy,” said Damien Galano, ESA’s Proba-3 mission manager. “This is what allowed us to capture the mission’s first images, which will no doubt be of high value to the scientific community.”
What the Images Show
The ASPIICS instrument (short for Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) was built by an industrial consortium led by the Centre Spatial de Liège in Belgium. Its design reduces the amount of stray light reaching the detector by keeping the Occulter spacecraft well ahead of the Coronagraph, something that’s physically impossible with ground-based or single-satellite coronagraphs.
The very first images processed by the ASPIICS Science Operations Centre in Belgium show the ghostly, intricate structures of the corona stretching outward from the Sun’s surface. The images are composites, created by combining multiple exposures of varying lengths to capture both faint outer loops and brighter inner details.
“The difference between these and traditional eclipse images is striking,” noted ESA project scientist Joe Zender. “ASPIICS sees deeper into the corona and for much longer periods than we ever could from Earth.”
A second instrument onboard Proba-3, the Digital Absolute Radiometer (DARA), will measure the total solar irradiance which is essentially the power output of the Sun over time. This could contribute to long-term climate modelling, space weather forecasting, and understanding solar variability.
A third device, the 3D Energetic Electron Spectrometer (3DEES), will monitor high-energy electrons in Earth’s radiation belts, which pose risks to satellites and astronauts.
Milestone in Sustainable Engineering
Beyond scientific discovery, Proba-3 is also being hailed as a milestone in sustainable space engineering. For example, by proving that precision formation flying is feasible with minimal intervention, the mission sets a precedent for future multi-satellite missions that could reduce launch mass, hardware duplication, and overall system complexity.
According to Dietmar Pilz, ESA Director of Technology, Engineering and Quality: “Many of the technologies which allowed Proba-3 to perform precise formation flying have been developed through ESA’s General Support Technology Programme, as has the mission itself. It is exciting to see these stunning images validate our technologies in what is now the world’s first precision formation flying mission.”
Formation flying has long been viewed as a promising approach to improving the modularity and upgradeability of space systems. Instead of building one large satellite to perform multiple tasks, smaller, specialised satellites can fly together in tandem, each optimised for a particular role, and coordinated by autonomous onboard software.
It’s thought this approach could dramatically reduce launch costs, simplify end-of-life decommissioning, and even allow future satellites to replace individual modules of larger systems without scrapping the whole assembly. These efficiencies all contribute to reducing the environmental impact of space operations, both in terms of material use and space debris.
Valuable For Predictive Modelling
For solar physicists, Proba-3’s ability to generate high-quality coronal data on demand opens new avenues for predictive modelling. Early observations have already fed into the development of more accurate computer models, such as ESA’s COCONUT (COroNal simUlaTion) software at KU Leuven in Belgium, which can now be adjusted using real, high-resolution data instead of extrapolated estimates.
“These observations will help refine our simulations of solar behaviour and improve our ability to forecast disruptive events,” said Jorge Amaya, ESA’s Space Weather Modelling Coordinator. “This ultimately helps industries and governments better prepare for the impact of solar activity.”
Showcases Space Tech Capability
For European space tech businesses, Proba-3 could also be seen as a showcase of regional capability. More than 40 companies from 14 countries contributed to the mission, with key roles played by Sener (Spain), GMV, Airbus Defence and Space, Redwire Space and Spacebel (Belgium). Their collaboration underscores Europe’s growing leadership in cutting-edge satellite technologies and fosters new opportunities in the global space market.
Helping Protect The Earth
For Earth itself, the implications are longer-term but just as vital. For example, better understanding the Sun means better protecting Earth’s climate, infrastructure, and communication systems from space weather threats, a growing concern in an increasingly digital and satellite-reliant world.
What Does This Mean For Your Organisation?
That same need for resilience is being felt across industries, including here in the UK. As sectors from energy to aviation to telecoms become increasingly dependent on satellites and GPS systems, the ability to monitor and predict solar weather is moving from scientific interest to operational necessity. A better understanding of solar dynamics could allow UK businesses to put stronger safeguards in place, from data backup protocols to grid protection strategies. For infrastructure operators, insurers, and digital service providers alike, that foresight could prove invaluable.
The engineering and innovation model behind Proba-3 also carries lessons for future sustainability-focused projects. For example, the involvement of multiple smaller European firms, including several startups, highlights a decentralised and collaborative approach that appears to have delivered advanced results without relying on single-use mega-systems. It’s a structure that supports technical excellence, local supply chains, and long-term adaptability. In the UK, where the space sector is looking to expand its global footprint while meeting environmental goals, this kind of scalable, formation-based architecture could be a defining direction.
For researchers, the mission offers more than just data. It demonstrates that high-risk, high-precision science is still possible with tight constraints and sustainable principles in mind. By proving that a six-hour solar eclipse can be recreated on demand from orbit, Proba-3 has not only opened a new window into solar physics, but it has also set a benchmark for how future missions might balance ambition with responsibility.