Solar wind particle experiment payload onboard Aditya-L1 starts operations, says ISRO

The Aditya-L1 is an ‘observatory’ or spacecraft that will monitor the Sun 24×7. This will be the first time that India will put a spacecraft on a Lagrange point – a position in space where, as per NASA, “the gravitational forces of a two-body system like the Sun and Earth produce enhanced regions of attraction and repulsion”.

There are five Lagrange points in the Sun-Earth system; India’s solar mission will be placed in a halo orbit around Lagrange point 1, or L1, which is about 1.5 million km from the Earth, according to ISRO.

L1, Aditya’s parking spot, has been housing Solar and Heliospheric Observatory, a project by America’s NASA and the European Space Agency (ESA) since 1996, reported Space.com.

The Aditya-L1 mission will carry seven payloads, out of which four will directly observe the Sun. These seven payloads or scientific instruments include Visible Emission Line Coronagraph(VELC), Solar Ultraviolet Imaging Telescope (SUIT), Solar Low Energy X-ray Spectrometer (SoLEXS), High Energy L1 Orbiting X-ray Spectrometer (HEL1OS), Aditya Solar wind Particle Experiment (ASPEX), Plasma Analyser Package For Aditya (PAPA) and Advanced Tri-axial High Resolution Digital Magnetometers.

These instruments will study the photosphere or the Sun’s visible surface; the layer above the photosphere known as the chromosphere; and the corona – the outermost part of the Sun’s atmosphere.

Objectives of Aditya-L1 mission

As per ISRO, the spacecraft will examine the dynamics of the chromosphere and corona; in-situ particle and plasma environment; the heating mechanism of the corona; magnetic field topology and magnetic field measurements in corona; temperature, velocity and density of coronal and coronal loops plasma; and development, dynamics and origin of coronal mass ejections (CMEs).

It will also study chromospheric and coronal heating, space weather, the physics of the partially ionized plasma, what leads to solar eruptive events, and how CMEs and solar flares start.

Why is studying the Sun important?

Before that, here are some facts about the centre of our solar system. The Sun, which sustains most life on Earth, is a 4.5 billion-year-old star. Located 150 million kilometres away from the Earth, the Sun’s gravity holds the solar system together. Unlike Earth, the Sun’s surface is not solid but made of “super-hot, electrically charged gas called plasma”, noted NASA.

According to the US Space Agency, “The Sun’s activity, from its powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system.”

The solar activity constitutes solar flares, CMEs or huge plasma clouds, high-speed solar wind, and solar energetic particles.