First Proba-3 Science: Surprisingly Speedy Solar Wind

Why It Matters

The discovery forces a revision of solar‑wind acceleration theories and improves space‑weather forecasting, which is critical for satellite operations and power‑grid resilience.

Key Takeaways

• Proba‑3 created 57 artificial eclipses, gathering 250 hours of corona video.
• ASPIICS observed slow solar wind blobs at 250–500 km/s, far above predictions.
• Speeds are 3‑4× higher than the expected ~100 km/s near the Sun.
• Findings challenge existing models of solar‑wind acceleration in the inner corona.
• Data set remains largely unanalyzed, opening new research on coronal heating.

Pulse Analysis

The European Space Agency’s Proba‑3 mission has turned the concept of a total solar eclipse into a repeatable laboratory in orbit. By flying two spacecraft in sub‑centimetre formation, the Occulter blocks the Sun’s disk while the Coronagraph’s ASPIICS instrument records the inner corona down to 70 000 km—ten percent of a solar radius. Since its launch in December 2024 the pair has executed more than 60 formation‑flight orbits, producing 57 artificial eclipses and over 250 hours of high‑resolution video, a dataset that dwarfs the roughly 5 000 ground‑based eclipse observations collected over the past century.

The first scientific paper from this archive reveals that slow‑wind plasma blobs travel at 250‑500 km s⁻¹ in the inner corona, three to four times faster than the ~100 km s⁻¹ speeds predicted by conventional heliophysics models. This acceleration occurs within the first few hundred thousand kilometres above the photosphere, a region previously inaccessible to optical coronagraphs such as SOHO’s LASCO or Solar Orbiter’s Metis. The result forces a reassessment of magnetic‑reconnection‑driven outflows and may improve space‑weather forecasts that rely on accurate solar‑wind input.

Because the majority of Proba‑3’s observations are still unprocessed, the mission promises a steady stream of discoveries on coronal heating, magnetic topology, and the genesis of coronal mass ejections. Open access to the ASPIICS data will enable theorists to benchmark kinetic and MHD simulations against real‑time measurements, accelerating the development of predictive models for satellite operators and power‑grid managers. Moreover, the success of formation‑flying artificial eclipses validates a cost‑effective approach that could be replicated for future heliophysics or exoplanet‑imaging missions, expanding the commercial market for precision‑flight technologies.