Aditya-L1 Mission

• The first space-based Indian mission to study the Sun will be called Aditya L1.
• The spacecraft will be positioned in a halo orbit around the Sun-Earth system's Lagrange point 1, or L1, which is located approximately 1.5 million kilometres from Earth.

About the mission:

• The Indian Institute of Astrophysics recently handed over the primary payload Visible Line Emission Coronagraph (VELC) for Aditya-L1 to the Indian Space Research Organisation (ISRO).
• ISRO will launch the Aditya-L1 mission to place the satellite in the L1 orbit for solar research.
• Of the seven payloads/telescopes that will be launched on Aditya-L1, the VELC is both the largest and one of the most technically difficult.
• The Polar Satellite Launch Vehicle (PSLV), which will carry 7 payloads (instruments) on board, will launch Aditya L1.
• The spacecraft is equipped with seven payloads that use electromagnetic, particle, and magnetic field detectors to study the photosphere, chromosphere, and the Sun's outermost layers (the corona).
• Four payloads use the unique vantage point L1 to observe the Sun directly, while the remaining three payloads conduct in-situ particle and field studies at the Lagrange point L1. This allows for significant scientific research on the propagation of solar dynamics in the interplanetary medium.

The 7 payloads include:

• VELC
• Solar Ultraviolet Imaging Telescope (SUIT)
• Solar Low Energy X-ray Spectrometer (SoLEXS)
• Aditya Solar wind Particle Experiment (ASPEX)
• High Energy L1 Orbiting X-ray Spectrometer (HEL1OS)
• Plasma Analyser Package for Aditya (PAPA)
• Advanced Tri-axial High Resolution Digital Magnetometers.

Aditya-L1 is the second space-based project of India, following the successful launch of AstroSat in 2015.

• The first dedicated Indian astronomy mission, AstroSat, was launched by ISRO in 2015 with the goal of simultaneously studying celestial sources in the X-ray, optical, and UV spectral bands.

The following are the main goals of the Aditya-L1 mission:

• Study of the dynamics of the solar upper atmosphere (chromosphere and corona).
• Study of flares, coronal mass ejections, partial ionisation of the plasma, and chromospheric and solar heating
• Watch the in-situ particle and plasma environment that the Sun provides, since this information will be used to investigate particle dynamics.
• Physics of solar corona and its heating mechanism.
• coronal and coronal loops plasma diagnostics: velocity, density, and temperature.
• CME evolution, dynamics, and genesis.
• Determine the series of events that take place at various layers (chromosphere, base, and extended corona) and ultimately result in solar eruptive events.
• Magnetic field measurements and field topologies in the solar corona.
• Space weather triggers (solar wind origin, composition, and dynamics)

What is L1?

• L1 stands for Lagrangian/Lagrange Point 1, one of the five places in the Earth-Sun system's orbital plane.
• Lagrange Points are locations in space where heightened zones of attraction and repulsion are produced by the gravitational forces of a two-body system, such as the Sun and Earth.
• These can be employed by spacecraft to lower the amount of fuel needed to stay in place.
• The main benefit of having a satellite in the halo orbit around the L1 is that it can continuously see the Sun without being blocked by clouds or experiencing eclipses.
• The Solar and Heliospheric Observatory Satellite (SOHO), a project of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) is located at the L1 point.

What are Lagrangian points?

• In the three-dimensional space surrounding two massive entities in orbit around one another, there are five Lagrangian points, denoted by the letters L1 through L5.
• L1, L2, and L3 are unstable equilibrium locations, which means that an object placed there won't stay there without ongoing propulsion. They are situated on a line that connects the two enormous bodies.
• L4 and L5, on the other hand, are stable equilibrium points, which means an object placed there will remain in that position without propulsion. They are situated at the third corners of a tetrahedron formed by the two massive bodies and their barycenter.

Why was Aditya 1 Mission renamed to Aditya L1 Mission by ISRO?

• The Aditya-1 mission was intended to simply observe the sun's corona. In solar physics, the cause of Corona heating up to such high temperatures is still a mystery.
• The satellite was launched on the Aditya-1 mission into an 800 km low earth orbit. Later, ISRO intended to orbit the satellite around the Lagrangian Point in a halo (L1). 1.5 million km separate Earth from L1.
• The benefit of uninterrupted, continuous observation of the Sun is offered at this site. As a result, the mission was changed to the Aditya L1 mission.

What are the Other Sun-Directed Missions?

NASA’s Parker Solar Probe:

• The purpose of NASA's Parker Solar Probe is to track the flow of heat and energy through the solar corona and to investigate what causes the solar wind to speed up.
• It's a component of NASA's "Living with a Star" programme, which investigates several facets of the Sun-Earth system.

Helios 2 Solar Probe:

• The earlier Helios 2 solar probe, a collaboration between NASA and the West German space agency, came within 43 million kilometres of the Sun's surface in 1976.
• The ESA (European space agency ) and NASA will work together on the Solar Orbiter project to gather the information that will assist scientists in better understanding how the Sun shapes and regulates the solar system's dynamic space environment.