Proba-3: Unprecedented results on solar wind speed

The first results from the Proba-3 mission, published in March 2026 in The Astrophysical Journal Letters, challenge our knowledge of the Sun. The data reveal that solar wind structures within the inner corona move three to four times faster than previous scientific estimates. This major discovery highlights physical phenomena until now unknown within the solar atmosphere. Thanks to the precision of this mission, the study of these flows gains clarity and paves the way for a better understanding of space weather.

Credit: ESA/Proba-3/ASPIICS & ESA/Proba-2/SWAP (ROB), A. Debrabandere (ROB)
This image is taken from a video. The yellow portion (artificially colored) of the video highlights the Sun in ultraviolet light, as observed by the SWAP telescope aboard ESA’s Proba-2 satellite. The surrounding grayscale area is derived from data collected in visible light by the ASPIICS coronagraph aboard Proba-3.

Mission Overview: What is Proba-3?

The European Space Agency’s Proba-3 mission is a world first in technology that creates a permanent artificial solar eclipse. To achieve this, two satellites fly in ultra-precise formation, where one masks the Sun for the other at a distance of about 150 meters. The first satellite, called the occulter, blocks the direct light from the solar disk, while the second observes the Sun’s corona, its very faint outer layer. This feat requires both spacecraft to remain aligned to the nearest millimeter, as if they form a single rigid structure in space. Usually, this part of the solar atmosphere is visible only during rare natural eclipses on Earth. Successfully launched on December 4, 2024, this mission allows scientists to study solar flares on a continuous basis. This test now validates formation flight concepts for future coordinated space architectures.

The Key Tools Behind the Proba-3 Mission

The Proba-3 mission carries three main instruments, distributed between the two satellites to transform the duo into a solar observatory:

• ASPIICS: This is the primary instrument, a giant “distributed” coronagraph. A coronagraph is an optical tool that simulates an eclipse because it blocks direct sunlight. Thanks to this system, the corona becomes visible even though it is usually imperceptible due to its low brightness. The 1.4-meter occulter disk is located on one satellite, while the telescope is placed on the second, 150 meters behind. This device offers observations of the solar corona very close to the edge of the Sun with high precision.
• DARA: This radiometer measures total solar irradiance. It records the total energy from the Sun that reaches Earth for the study of its influence on the climate.
• 3DEES: This spectrometer analyzes electrons and energetic particles in the Earth’s radiation belts for the study of the space environment.

In addition, the satellites use metrology instruments (lasers, guidance cameras, and shadow sensors) for the maintenance of their alignment during observations.

Our onboard components for the Proba-3 satellites

At 3D PLUS, we are proud to support this advanced mission with our high-reliability electronic solutions:

• Memories (SDRAM, MRAM, SRAM, EEPROM): These chips manage the storage of scientific data and the backup of onboard software. The MRAM ensures data retention without power, even in high-radiation environments.
• POL Converters: These modules regulate electrical voltage locally. They provide stable power to the precision instruments to prevent any electronic interference.
• LVDS Interfaces: These components ensure the fast transfer of data flows between the cameras and the onboard computer.