Aditya L1 Heads Towards Lagrange Point 1

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(Source: The Hindu, 09/20/2023)

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Why in the news?

• India's first space observatory to study the sun, Aditya L1, which was launched on September 2nd, is headed to the Lagrange Point 1 (L1) after ISRO carried out the Trans-Lagrangian 1 Insertion (TL1I) maneuver on September 19.
• The TL1I manoeuvre marks the beginning of Aditya-L1’s 110-day journey towards the L1 point which lies between the Sun-Earth line.

About the Mission

• Aditya-L1, India's space observatory, is specifically designed for solar studies. It orbits the Sun-Earth Lagrangian point L1, situated about 1.5 million kilometers from Earth.
• Launched on September 2, 2023, via ISRO's Polar Satellite Launch Vehicle (PSLV-C57) from Sriharikota's Satish Dhawan Space Centre (SDSC), Aditya-L1 marks a significant achievement in India's space exploration efforts.
• Its journey began successfully with the first Earth-bound maneuver, and two more such maneuvers are planned before it reaches its final destination, L1, in approximately 127 days.

Objective

• The primary objective of the Aditya L1 mission is to study the Sun's upper atmospheric layers, specifically the chromosphere and corona.
• The mission will also examine coronal mass ejections (CMEs), large expulsions of plasma and magnetic fields from the Sun’s corona, and analyse the corona’s magnetic field, the driver of space weather.

Payloads

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

What is L1?

• Lagrange Points are positions in space where the gravitational forces of a two-body system like the Sun and Earth produce enhanced regions of attraction and repulsion.
• The Lagrange point L1 resides roughly 1.5 million km from Earth and enables continuous solar observation through unobstructed halo orbit movement.
• There are five Lagrangian points between Earth and the Sun, where objects can maintain stable positions with minimal fuel consumption.
• These Lagrange points provide spacecraft with a valuable advantage, enabling them to conserve fuel while staying in a stable position where the gravitational forces of the Sun and Earth are precisely balanced by the necessary centripetal force.
• Aditya L1's mission aims to capitalize on this unique vantage point, offering unprecedented insights into the Sun and its activities.
• The Solar and Heliospheric Observatory (SOHO), an international solar observatory, is already located at L1, demonstrating its utility.

Lagrange Points in the Sun-Earth System

• L1: Ideal for solar observations; offers continuous Sun viewing. It is currently home to the Solar and Heliospheric Observatory Satellite (SOHO).
• L2: It is positioned directly 'behind' Earth as viewed from the Sun and is excellent for observing the larger Universe without Earth's shadow interference. The James Webb Space Telescope orbits the Sun near L2.
• L3: It is positioned opposite Earth behind the Sun; potential for observing the far side of the Sun.
• L4 and L5: Stable positions forming an equilateral triangle with Earth and Sun. Used for space observatories, especially for asteroid studies.

Aditya L1's Journey from Earth to the Lagrange Point L1

Earth-Bound Orbits and Manoeuvres

• Aditya-L1 launched and entered Earth-bound orbits for 16 days.
• During this phase, the spacecraft undergoes 5 manoeuvres to gain the necessary velocity for its journey.
• These manoeuvres are crucial for preparing Aditya-L1 for its trajectory towards the L1 Lagrange point.

Trans-Lagrangian Insertion and Trajectory (Cruise phase)

• After the Earth-bound orbits, Aditya-L1 undergoes a Trans-Lagrangian insertion manoeuvre.
• This marks the beginning of its 110-day trajectory towards the L1 Lagrange point.
• The spacecraft travels through space, following a trajectory that leads it to the L1 point.
• This phase involves continuous adjustments to ensure Aditya-L1 stays on the intended path.

L1 Orbit and Mission Operations

• After arrival at the L1 Lagrange point, Aditya-L1 performs a manoeuvre to bind itself to an orbit around L1 (halo orbit).
• L1 is a balanced gravitational location between the Earth and the Sun.
• The satellite spends its entire mission orbiting around L1 in an irregularly shaped orbit. The orbit is roughly perpendicular to the line joining the Earth and the Sun.
• During this phase, Aditya-L1 conducts its comprehensive study of the Sun, utilising its seven distinct payloads developed by ISRO and Indian academic institutes.

Importance of Lagrangian Point 1

• Uninterrupted Solar Observation: L1 enables continuous monitoring of the Sun without any hindrances such as eclipses or occultations. This uninterrupted view is invaluable for studying the Sun's activity.
• Optimal Sun Observation: Satellites stationed at L1 can consistently observe the Sun directly, unlike spacecraft in elliptical heliocentric orbits like the Parker Solar Probe. This ensures a more comprehensive and sustained examination of solar phenomena.
• Efficient Fuel Usage: Maintaining a satellite's position at L1 demands relatively small amounts of fuel. This is due to the finely balanced gravitational forces at this point, which reduce the need for constant course corrections.
• Early Warning for Space Weather: L1 serves as an early vantage point for monitoring solar events such as coronal mass ejections and solar flares before they impact Earth. This extended lead time enhances our ability to predict and prepare for space weather-related disruptions.

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FAQs

MCQs

Question: With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statement(s) is/are correct? (UPSC Prelims 2016)

1. Other than USA and Russia, India is the only country to have launched a similar observatory into space.
2. Astrosat is a 2000 kg satellite placed in an orbit at 1650 km above the surface of the Earth.

Select the correct answer using the codes given below.

(a) 1 only

(b) 2 only

(c) Both1 and 2

(d) Neither 1 nor 2

Question: NASA’s Deep Impact space mission was employed to take detailed pictures of which comet nucleus? (UPSC 2007)

(a) Halley’s Comet

(b) Hale-Bopp

(c) Hyakutake

(d) Tempel 1