ISRO's Aditya-L1 mission explained: India's first dedicated scientific effort to study sun with VELC payload

The Visible Emission Line Coronagraph (VELC), which was recently given to the Indian Space Research Organization (ISRO) by the Indian Institute of Astrophysics (IIA), will be carried on the Aditya-L1 spacecraft. The IIA's Centre for Research and Education in Science and Technology (CREST) campus in Hoskote built the VELC, which will be the largest payload to be carried on the Aditya-L1. VELC integration with the Aditya-L1 spacecraft will now be done by ISRO after further testing.

Aditya-L1 is India's first specifically designed solar research mission. With the VELC as its only payload, the mission—originally known as Aditya-1—was intended to be put into an 800km low-Earth orbit as a 400kg class satellite. The mission was later given the name Aditya-L1, and it will be placed in a halo orbit around the sun-earth system's first Lagrangian Point (L1). The sun may be seen constantly from this position, 1.5 million kilometers away from Earth, without any occultation or eclipses.

The Aditya-L1 satellite carries  six additional payloads, including a magnetometer, the solar ultraviolet imaging telescope (SUIT), the Aditya Solar Wind Particle Experiment (ASPEX), the Plasma Analyser Package for Aditya (PAPA), the Solar Low Energy X-ray Spectrometer (SoLEXS), the High Energy L1 Orbiting X-ray Spectrometer (HEL1OS), and the Solar Low Energy X-ray. By conducting comprehensive remote and on-site observations of the sun, these payloads enable expanded science scope and objectives.

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Aditya-internal L1's occulted solar coronagraph, known as the VELC payload, enables the simultaneous operation of spectro-polarimetry, imaging, and spectroscopy channels close to the solar limb. This is crucial for determining the solar corona's magnetic field as well as for researching the dynamics of the solar corona, the origins of coronal mass ejections, and its diagnostic parameters.

The mission is most likely planned for April or May of this year. The Aditya-L1 mission will significantly advance our knowledge of the sun and its effects on the Earth and represents a huge step forward for India in the fields of space science and solar research.