Aditya-L1: the First Indian Solar Probe in Space
 

The space probe Aditya-L1 is the first space observatory of the Indian Space Research Organization (ISRO) to study the Sun. After its launch into space in September 2023, it took up its current observation position in January 2024: at a distance of about 1.5 million kilometers from Earth, Aditya-L1 orbits around the Lagrangian point L1, the Sun-facing equilibrium point between the Sun and Earth. From here, the probe has an uninterrupted view of our star.

Equipped with seven scientific instruments, Aditya-L1 collects data on solar activity and the impact of this activity on space weather and space climate. These data can help to understand how radiation and mass eruptions occur on the Sun, how the Sun heats its outer atmosphere, the corona, to unimaginable temperatures of sometimes more than a million degrees, how it accelerates the solar wind into space, and how intensity fluctuations in the Sun's ultraviolet radiation affect Earth.

Three of the seven measuring instruments are in situ instruments. They measure the particles and magnetic fields of the solar wind flowing around the spacecraft. The other four instruments look at the Sun’s visible surface (photosphere) and the solar atmosphere above it (chromosphere and corona). Aditya-L1 is the first spacecraft to produce a spatial image of the solar disk in the near ultraviolet range, enabling it to see into the lower chromosphere.

The Max Planck Institute for Solar System Research (MPS) is involved in the Solar Ultraviolet Imaging Telescope (SUIT) on Aditya-L1. The instrument images the photosphere and chromosphere in the near ultraviolet light at wavelengths between 200 and 400 nanometers and is equipped with eleven filters (eight narrow-band and three broadband). This way, SUIT can look into individual layers of the solar atmosphere and record intensity fluctuations in the ultraviolet radiation that play a crucial role in the ozone balance in the Earth's atmosphere.

Based on an original concept by the MPS, SUIT was developed and built entirely at the Inter-University Centre for Astronomy and Astrophysics in Prune, India.