Artificial Solar Eclipses: A New Frontier in Solar Research

In a groundbreaking initiative, researchers are proposing the Moon-Enabled Sun Occultation Mission (MESOM), which aims to recreate artificial solar eclipses in space. This ambitious project, presented at the Royal Astronomical Society's National Astronomy Meeting in Durham, UK, seeks to provide unprecedented insights into the Sun's atmosphere, particularly the inner solar corona, which remains largely mysterious due to the challenges of observing it from Earth.

The mission proposes deploying a mini-satellite into an orbit that aligns with the Moon's shadow approximately once every 29.6 days, mimicking the conditions of total solar eclipses. According to Dr. Nicola Baresi, co-investigator from the Surrey Space Centre, “MESOM capitalizes on the chaotic dynamics of the Sun-Earth-Moon system to reproduce total solar eclipse conditions in space, using the Moon as a natural occulter.” This innovative approach could allow the satellite to capture data for up to 48 minutes at a time — significantly longer than typical terrestrial observations, which are often hindered by atmospheric interference.

The MESOM project is a collaboration involving researchers from the Mullard Space Science Laboratory at University College London (UCL), Aberystwyth University, and the Surrey Space Centre. If approved by the European Space Agency (ESA), the mission could operate for two years, potentially yielding the equivalent of 80 Earth-based solar eclipses. This would present a unique opportunity for solar scientists to study the Sun's corona, which is critical for understanding space weather phenomena, including solar flares and coronal mass ejections.

The inner solar corona, located just above the Sun's surface, is a region that has eluded detailed study due to its transient visibility during total solar eclipses. Current missions, such as the European Space Agency's Proba-3, observe the corona from a distance of approximately 1.1 solar radii (765,000 km). In contrast, MESOM aims to reach below 1.02 solar radii (710,000 km), allowing it to approach the Sun much closer than previous missions. This proximity is expected to reveal new insights into the processes that drive solar activity.

The satellite will be equipped with a suite of advanced instruments, including a high-resolution coronal imager and a corona mass spectrometer, to analyze the composition and properties of the coronal plasma. Researchers believe that understanding the dynamics of the corona is vital for predicting and mitigating the impacts of space weather on Earth, particularly as society becomes increasingly reliant on satellite technology.

The team submitted MESOM to ESA's F-class mission call in May 2025, with expectations of a response later this year. F-class missions are designed to be smaller, quicker, and more cost-effective than larger M-class missions, with a budget cap of €205 million and a development timeline of less than eight years from selection to launch.

The implications of this mission extend beyond academic inquiry; they could significantly enhance our understanding of solar activity and its effects on Earth, reinforcing the importance of solar research in the context of global technological infrastructure and climate science. As the scientific community eagerly awaits ESA's decision, MESOM stands as a testament to the innovative spirit driving modern astronomical research.