ADITYA-L1 MISSION

Description

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Context:

ISRO is planning to launch the Aditya-L1 mission by June or July this year.

About Aditya L-1:

Aditya-L1 is a spacecraft mission to study the Sun.
It will be built in collaboration between the Indian Space Research Organisation (ISRO) and various Indian research institutes.
It is planned to be launched on the It is India's first solar mission.

Objective of Aditya L-1 Mission:

To research the Sun’s corona (Visible and Near infrared rays), photosphere (soft and hard X-ray), chromosphere (Ultra Violet rays), solar emissions, solar winds and flares, and Coronal Mass Ejections (CMEs), as well as conduct round-the-clock imaging of the Sun.
- Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun’s corona.

Placing of the Spacecraft

The Aditya-L1 mission will be inserted in a halo orbitaround the L1 point, which is about 1.5 million km from Earth.

Lagrange Points – Spots beyond the High Earth Orbits

Other orbital “sweet spots,” just beyond high Earth orbit, are the Lagrange points. At the Lagrange points, the pull of gravity from the Earth cancels out the pull of gravity from the Sun. Anything placed at these points will feel equally pulled toward the Earth and the Sun and will revolve with the Earth around the Sun.

Of the five Lagrange points in the Sun-Earth system, only the last two, called L4 and L5, are stable. A satellite at the other three points is like a ball balanced at the peak of a steep hill: any slight perturbation will push the satellite out of the Lagrange point like the ball rolling down the hill. Satellites at these three points need constant adjustments to stay balanced and in place.

L-1

The first Lagrange point is located between the Earth and the Sun, giving satellites at this point a constant view of the Sun. The Solar and Heliospheric Observatory (SOHO), a NASA and European Space Agency satellite which is tasked to monitor the Sun, orbits the first Lagrange point, about 1.5 million kilometers away from Earth.

L-2

The second Lagrange point is about the same distance from the Earth, but is located behind the Earth. Earth is always between the second Lagrange point and the Sun. Since the Sun and Earth are in a single line, satellites at this location only need one heat shield to block heat and light from the Sun and Earth. It is a good location for space telescopes.

L-3

The third Lagrange point is opposite the Earth on the other side of the Sun so that the Sun is always between it and Earth. A satellite in this position would not be able to communicate with Earth. The extremely stable fourth and fifth Lagrange points are in Earth’s orbital path around the Sun, 60 degrees ahead of and behind Earth.

Lagrange points are special locations where a satellite will stay stationary relative to the Earth as the satellite and the Earth revolve around the Sun. L1 and L2 are positioned above the day and night sides of the Earth, respectively. L3 is on the other side of the Sun, opposite the Earth. L4 and L5 are 60° ahead and behind the Earth in the same orbit.

Read about orbits: https://www.iasgyan.in/blogs/types-of-orbits-explained

Payloads:

The 1,500 kg satellite carries seven science payloads with diverse objectives.
Payload is the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight.
Depending on the nature of the flight or mission, the payload of a vehicle may include cargo, passengers, flight crew, munitions, scientific instruments or experiments, or other equipment.

The complete list of payloads, their science objective and lead institute for developing the payload is provided below:

Visible Emission Line Coronagraph (VELC): To study the diagnostic parameters of solar corona and dynamics and origin of Coronal Mass Ejections, magnetic field measurement of solar corona.
Solar Ultraviolet Imaging Telescope (SUIT): To image the spatially resolved Solar Photosphere and Chromosphere in near Ultraviolet (200-400 nm) and measure solar irradiance variations.
Aditya Solar wind Particle Experiment (ASPEX): To study the variation of solar wind properties as well as its distribution and spectral characteristics.
Plasma Analyser Package for Aditya (PAPA): To understand the composition of solar wind and its energy distribution
Solar Low Energy X-ray Spectrometer (SoLEXS): To monitor the X-ray flares for studying the heating mechanism of the solar corona .
High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): To observe the dynamic events in the solar corona and provide an estimate of the energy used to accelerate the particles during the eruptive events.
Magnetometer: To measure the magnitude and nature of the Interplanetary Magnetic Field.

Significance:

The Sun, which controls the atmosphere of all planets in the Solar System, shows many variations in its radiations due to the activities in it. Hence, understanding these variations can provide clues on the origin of life, the atmosphere of exoplanets and insights into plasma—the state of matter abundant in the Universe.
The Aditya-L1 project will enable a comprehensive understanding of the dynamical processes of the sun and address some of the outstanding problems in solar physics.
Right now, no solar mission can measure the magnetic field of the Sun's corona as it is only observable during the eclipse. With Aditya, we can now collect this information in real-time.