Why in news?

• The Indian Space Research Organisation (ISRO) successfully launched the observatory that will study the Sun from 1.5 million kilometres away.
  • It is the space organisation's maiden expedition to study the Sun.
  • It is also ISRO’s second astronomy observatory-class mission after AstroSat (2015).
• It took nearly 63 minutes for one of the heaviest configurations of the PSLV to place the spacecraft in a precise elliptical orbit of nearly 235 km x 19,500 km.

What’s in today’s article?

• Aditya L1 Mission
• Why is Aditya-L1 important?

Aditya L1 Mission

• About
  • 
  • Launched by the PSLV-C57, Aditya-L1 mission aims to study prospects of Sun.
    • The solar probe was carried into space by the Polar Satellite Launch Vehicle (PSLV) in ‘XL’ configuration.
  • This mission is India's solar mission where the spacecraft will be placed in a halo orbit around the Lagrange point 1 (L1) of the Sun-Earth system.
    • The Lagrange point as defined by NASA refers to positions in space where 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 -L1, L2, L3, L4, and L5.
    • Placing the satellite in a halo orbit around L1 of the Sun-Earth system enables continuous viewing of the Sun without any eclipses or obstructions.
  • The mission will span five years and carry seven specialised payloads designed to observe various aspects of solar activity.
• Trajectory followed
  • 
  • The PSLV initially placed the Aditya L-1 in a lower Earth orbit.
  • Subsequently, the spacecraft’s orbit around the Earth will be raised multiple times before it is put on a path to a halo orbit around the L1 Lagrange point.
    • A spacecraft can orbit about an unstable Lagrange point with a minimum use of thrusters for stationkeeping.
    • Such an orbit is known as a halo orbit as it appears as an ellipse floating over the plane
    • A halo orbit, however, isnot the usual orbit because the unstable Lagrange point doesn’t exert any attractive force on its own.
  • The spacecraft will finally be stationed in a halo orbit around the Lagrange point 1 (L1) of the Sun-Earth system, which is about 1.5 million km from the Earth.
  • The Aditya L-1 will cover its journey to the L1 point in about four months.
• Objectives of the Aditya L-1
  • To expand our knowledge of the Sun, and how its radiation, heat, flow of particles, and magnetic fields affect us;
  • To study the upper atmospheric layers of the Sun called chromosphere and corona;
    • While the corona is the outermost layer, the chromosphere is just below it.
  • To examine coronal mass ejections (CMEs), which are large expulsions of plasma and magnetic fields from the Sun’s corona;
  • To analyse the corona’s magnetic field and the driver of the space weather;
  • To understand why the Sun’s not-so-bright corona is a million degree Celsius hot when the temperature on the surface of the Sun is just about 5,500 degree Celsius;
  • To help scientists know the reasons behind the acceleration of particles on the Sun, which leads to the solar wind — the constant flow of particles from the Sun;
• Payloads
  • The spacecraft carries seven payloads. Out of these, 4 will be the remote sensing payloads which will study the sun and remaining 3 will be the payloads to study the L1 in situ.
• Remote sensing payloads which will study the sun:
  • Visible Emission Line Coronagraph (VELC) for corona/imaging and spectroscopy;
  • Solar Ultraviolet Imaging Telescope (SUIT) for photosphere and chromosphere imaging;
  • Solar Low Energy X-ray Spectrometer (SoLEXS), which is a soft X-ray spectrometer for Sun-as-a-star observation; and
  • High Energy L1 Orbiting X-ray Spectrometer (HEL1OS), which is a Hard X-ray spectrometer for Sun-as-a-star observation
• The payloads to study the L1 in situ
  • Aditya Solar wind Particle Experiment (ASPEX), for solar wind/particle analyzer protons and heavier ions with directions;
  • Plasma Analyser Package For Aditya (PAPA), for solar wind/particle analyzer electrons and heavier ions with directions; and
  • Advanced Tri-axial High Resolution Digital Magnetometers for in situ magnetic field study.

Why is Aditya-L1 important?

• India in the big league
  • It is the first space-based Indian mission to study the Sun.
  • So far, only two other space agencies have had their spacecraft reach L1 or the Lagrange point: USA's National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA).
• Need to study sun from space
  • Studying the Sun from space is essential because the Sun emits various forms of radiation, energetic particles, and magnetic fields in all wavelengths.
  • Earth's atmosphere and magnetic field act as protective shields against harmful solar radiation, making space-based observations crucial for comprehensive understanding.
• Understanding space weather
  • Every planet, including Earth and the exoplanets beyond the Solar System, evolves — and this evolution is governed by its parent star.
  • The solar weather and environment affect the weather of the entire system.
  • Variations in this weather can change the orbits of satellites or shorten their lives, interfere with or damage onboard electronics, and cause power blackouts and other disturbances on Earth.
  • Knowledge of solar events is key to understanding space weather.