Aditya-L1 Mission: Exploring the Sun

• India's first space-based solar mission, Aditya-L1, launched September 2, 2023 by ISRO.
• Orbit: halo orbit around the Sun-Earth Lagrange point 1 (L1).
• Provides uninterrupted view of the Sun, overcoming limitations of Low Earth Orbits.
• Facilitates India to establish its own solar observatory in space.
• Places ISRO in an elite space club with NASA and ESA
• Studying Sun's magnetic behavior is crucial for advancing space weather prediction, securing technological assets, and unraveling stellar evolution.
• The Aditya-L1 mission signifies India's study into solar uncertainties.

Solar Space Programs of Other Countries

• Helios 2 Solar Probe (1976): NASA and West Germany collab; approached within 43 million km of the Sun.
• Advanced Composition Explorer (ACE) NASA (1997): Analyzes solar wind and cosmic rays.
• NASA's Parker Solar Probe (2018): Tracks energy and heat movement through Sun’s corona.
• Component of NASA's 'Living with a Star' initiative.
• Solar Orbiter (2020): Joint project between ESA and NASA; gathers heliophysics data.
• Questions include how the Sun generates and manages the space environment.
• International 'Living with a Star' initiative with Solar Dynamics Observatory and Parker Solar Probe.
• Includes other Active Sun-Monitoring Spacecraft: Interface Region Imaging Spectrograph (IRIS) (NASA-2013), WIND (NASA-1994), Hinode (JAXA-2006), Solar Terrestrial Relations Observatory (STEREO) (NASA-2006).

Major Science Objectives of Aditya L1 Mission

• Understanding Coronal Heating and Solar Wind Acceleration.
• Understanding Coronal Mass Ejection (CME), solar flares, and near-earth space weather.
• Understanding solar atmosphere coupling and dynamics.
• Understanding solar wind distribution and temperature anisotropy ("unequal in different directions").
• Launched via PSLV XL launch vehicle from Sriharikota.
• Carries payloads to examine the Sun's properties.

Aditya-L1: Payloads and Objectives

• Remote Sensing Payloads: Measures Sun's emissions (light, UV, X-rays) to study outer layers and solar phenomena remotely.

• Visible Emission Line Coronagraph (VELC): Studies solar corona; observes coronal mass ejections.

• Solar Ultraviolet Imaging Telescope (SUIT): Captures solar Photosphere and Chromosphere images in near Ultraviolet (UV).

• Measures solar irradiance variations in near UV.

• Solar Low Energy X-ray Spectrometer (SOLEXS): Soft X-ray spectrometer; studies solar X-ray flares in wide range.

• High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): Hard X-ray spectrometer; investigates solar X-ray flares in wide range.

• In Situ Payloads: Measures real-time environment around spacecraft (solar wind properties, magnetic fields).

• Aditya Solar Wind Particle Experiment (ASPEX): Studies solar wind and energetic ions; analyzes their energy distribution.

• Plasma Analyzer Package for Aditya (PAPA): Gathers data on plasma characteristics and composition.

• Provides insights into solar wind interactions with the environment.

• Advanced Tri-axial High-Resolution Digital Magnetometers (MAG): Measures low-intensity interplanetary magnetic field in space.

• Has Magnetic Sensors: One at boom tip (6m deployable), other in boom middle (3m from spacecraft).

Why L1: Lagrangian Points

• These points are positions in space where the gravitational forces of two large orbiting bodies produce regions of equilibrium.
• L1, L2, and L3 lie along the line connecting the two masses
• L1 point of Earth-Sun system provides uninterrupted Sun view; SOHO space telescope is located here.
• L2 is ideal as spacecraft can communicate with Earth, harness solar power, and have clear view of deep space.
• The James Webb Space Telescope resides at L2 point.
• L1, L2, and L3 points are unstable; L3 is less useful (hidden behind the sun).
• L4 and L5 form corners of equilateral triangles (stable); objects orbiting here are called Trojans.
• Stability and gravitational forces make Lagrange points valuable for clear space views from astronomy telescopes.

Earth's Additional Moons

• Earth has three moons total, with 2 'moons' made entirely of dust.
• In the 1950s, Kordylewski searched two Lagrange points L4 and L5 where he found the first glimpse of the two dust clouds.
• The first glimpse of the clouds was seen only in 1961 by Polish astronomer Kazimierz Kordylewski.
• When sunlight hits the dust particles, they glow very faintly.

Lagrangian Point 1 and its Importance

• L1 is gravitationally stable point where Sun's and Earth's gravity balance.
• Located 1.5 million km from Earth towards the Sun, providing uninterrupted Sun view without eclipses.
• It can also be identified as allowing the tracking of solar storms heading towards Earth.
• Maintaining position requires little fuel.
• L1 provides an early vantage point to observe coronal mass ejections and solar flares before they affect Earth.
• The Solar and Heliospheric Observatory (SOHO) is already at L1.

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

• Phase 1: Earth-Bound Orbits and Maneuvers
• Aditya-L1 enters Earth-bound orbits for 16 days, undergoing 5 maneuvers to gain velocity.
• Phase 2: Trans-Lagrangian Insertion and Trajectory: After Earth-bound orbits, undergoes a Trans-Lagrangian insertion maneuver to achieve 110 day trajectory towards L1 Lagrange point.
  • Continuous adjustments ensure path.
• Phase 3: L1 Orbit and Mission Operations
• Upon arrival at L1 Lagrange point, Aditya-L1 performs a maneuver to bind itself to an orbit around L1 (halo orbit).
• The satellite spends its entire mission orbiting around L1 in an irregularly shaped orbit.

What is Halo Orbit?

• The spacecraft moves in circular path due to interaction between gravitational pull of two planetary bodies and accelerations.

Uniqueness of the Aditya L1 Mission

• It is India's first solar mission stationed at L1 (1.5 million km from Earth).
• Carries seven scientific payloads, which combine remote sensing with observation tools
• Example: Visible Emission Line Coronagraph (VELC)offers detailed imaging of the solar corona.
• Example: Plasma Analyzer Package for Aditya (PAPA) and Magnetometer study solar wind.

Real-Time Space Weather Monitoring

• Emphasizes real-time monitoring of space weather events, such as Coronal Mass Ejections (CMEs).

Affordability and Accessibility

• It is able to achieve scientific goals in a cost effective manner
• Cost-effective approach makes Aditya L1 a pioneering mission for countries with smaller space budgets.

India's Indigenous Contribution

• Marks unique milestone as indigenous effort to join global solar research alongside NASA and ESA.

Future Solar Exploration

• Aditya-L1 cements India's position as major spacefaring nation.
• Also lays foundation for the country to become global hub for solar system science.
• Opens doors for studying the intriguing solar poles.

Way Forward

• Missions should be directed towards the L5 for studying the Earth-directed CME events and assessing the space weather more accurately.
• To know more about the various solar processes, there should be missions to study the sun's polar regions also, despite the technological challenges of the spacecraft.

James Webb Space Telescope (JWST)

• It launched on December 25, 2021, as premier space-based observatory.
• Designed to observe the universe primarily in the infrared spectrum.
• Researchers, as part of the James Web Space Telescope (JWST) UNCOVER program, finds a clue about the end of 'dark ages' in early universe.

Background of JWST

• Began in 1996 as NASA, ESA, and CSA collaboration.
• Serves as next–generation telescope after the Hubble Space Telescope, with focus on infrared astronomy.

Key Features

• Infrared optimization for observation.
• Equipped with a large 6.5-meter diameter mirror.
• The primary mirror comprises 18 hexagonal, gold-coated beryllium segments.
• Five layered sunshield blocks solar light.
• Operates from orbit around the Sun-Earth L2 point.
• Uses passive cooling system to reach temperatures as low as 40 Kelvin (-233°C).
• Capable of observing wavelengths from 0.6 to 28 micrometers.

Objectives

• Looks for galaxies that formed just after the Big Bang.
• Determines galaxy evolution from their creation to the present.
• Examines star creation stages till the formation of planetary systems.
• Investigates potential for life by measuring physical & chemical features.

Significance

• Advances astrophysical knowledge.
• Studies exoplanets, including their atmospheres and potential for habitability.
• Promotes international collaboration in science and education.

Key Observations

• Galaxy cluster: A galaxy cluster that first formed 4.6 billion years ago, offering a glimpse into the early universe.
• Deepest infrared image: Showcasing some of the oldest and most distant galaxies ever observed by scientists.
• It also identifies six 'Monster' galaxies

Webb vs Hubble

• JWST is Primarily infrared, with some capability in the visible and near-infrared wavelength range, while Hubble is Primarily visible, ultraviolet, and near infrared
• JWST has 6.5 meters (primary mirror) while Hubble only has 2.4 meters (primary mirror)
• JWST is located at the L2 Lagrange point (1.5 million km from Earth) while Hubble is in Low Earth Orbit (approximately 560 km above Earth)
• JWST Equipped with a five-layer sunshield to protect it from the Sun's heat and light, Hubble does not have a sunshield
• JWST is Excellent for observing infrared sources and focuses on distant galaxies, star-forming regions and Hubble Observes a wide range of astronomical objects and phenomena across various wavelengths
• JWST is Not designed for in-orbit repair while Hubble is Designed for in-orbit servicing and repair

This lesson explores the Aditya-L1 mission, India's first solar mission. It covers the mission's objectives, such as studying solar magnetic behavior and its impact on Earth's weather. It also discusses the spacecraft's placement in a halo orbit around the Sun-Earth L1 point and its various instruments.