Mission Aditya-L1

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    In News

    • Recently, the ISRO chairman confirmed the launch of India’s first mission to study the Sun by mid of 2023.

    Key Takeaways

    • The primary payload Visible Line Emission Coronagraph (VELC) for Aditya-L1 was recently handed over to the Indian Space Research Organisation (ISRO) by the Indian Institute of Astrophysics (IIA).
    • The Aditya-L1 mission will be launched by ISRO to station the satellite into the L1 orbit to study the sun.
    • The VELC is the largest and one of the most technically challenging of the seven payloads/telescopes that will fly on Aditya-L1.
    • The difference between the Sun’s upper atmosphere’s temperature of 1,000,000 K and its lower temperature of 6,000 K is one of the most significant unresolved problems in the study of solar physics.
    • The VELC payload is expected to revolutionize solar astronomy around the world and the data is expected to answer many outstanding problems in the field.
    • Following the successful launch of AstroSat in 2015, Aditya-L1 will be the second space-based project in India.
    • AstroSat was the first dedicated Indian astronomy mission launched by ISRO in 2015 with an objective to study the celestial sources in X-ray, optical and UV spectral bands simultaneously.

    What is Aditya L1?

    • Aditya-L1 is the first space-based Indian mission to study the sun from the Lagrangian point 1 (L1) of the sun-earth system which is roughly 1.5 million kilometres from Earth.
    • The project was initially proposed as Aditya-1, a 400 kg class satellite carrying a single payload, the Visible Emission Line Coronagraph (VELC).
    • It was however renamed ‘Aditya-L1 mission’ since the satellite was positioned in the hallowed orbit of the Sun-Earth system’s Lagrangian point 1 (L1).
    • Named after one of many Sanskrit names for the Sun- Aditya- is scheduled to be launched from  Sriharikota, Andhra Pradesh using the Polar Satellite Launch Vehicle (PSLV-XL).
    • The mission has seven payloads on board to observe the photosphere, chromosphere, and the outermost layers of the sun viz.,
      • Visible Line Emission Coronagraph (VELC), 
      • Solar Ultraviolet Imaging Telescope,
      • Aditya Solar Wind Particle Experiment, 
      • Plasma Analyser Package for Aditya, 
      • Solar Low Energy X-ray Spectrometer, 
      • High Energy L1 Orbiting X-ray Spectrometer,
      • Magnetometer.
    • The mission will capture near-simultaneous photos of the many layers of the Sun’s atmosphere, revealing how energy is routed and transported from one layer to the next.

    What are Lagrangian points?

    • These are specific locations in space where the gravitational forces of two large bodies, such as the Earth and the Moon or the Earth and the Sun, balance the centrifugal force experienced by a smaller object, such as a satellite.
    • There are five Lagrangian points, labelled L1 through L5, in the three-dimensional space surrounding two large bodies in orbit around each other.
      • L1, L2, and L3 are located on a line that connects the two large bodies and are unstable equilibrium points, meaning an object placed there will not stay in that position without continuous propulsion.
      • L4 and L5, on the other hand, are located at the third corners of a tetrahedron formed by the two large bodies and their barycenter, and are stable equilibrium points, meaning an object placed there will remain in that position without propulsion.

    • These points have been used in various space missions, such as the Solar and Heliospheric Observatory (SOHO) which orbits the Sun-Earth L1 point, allowing it to have a continuous view of the Sun.

    Why is the mission important for India?

    • The payload data will help understand the effect of the Sun on the Earth and its surroundings, especially in studying the patterns and impacts of solar flares.
    • The scientific studies by the satellite will enhance our current understanding of the Solar Corona and also provide vital data for space weather studies.
    • VELC will help to observe the corona continuously and the data provided by it is expected to answer many outstanding problems in the field of solar astronomy.
    • No other solar coronagraph in space has the ability to image the solar corona as close to the solar disk as VELC which can image it as close as 1.05 times the solar radius.
    • It can also do imaging, spectroscopy, and polarimetry at the same time, and can take observations at a very high resolution (level of detail) and many times a second.

    Other Missions to the Sun

    • NASA’s Parker Solar Probe: Its aim is to trace how energy and heat move through the Sun’s corona and to study the source of the solar wind’s acceleration.
    • Helios 2 solar probe: It was a joint venture between NASA and space agency of erstwhile West Germany, went within 43 million km of the Sun’s surface in 1976.

    Source: TH