NEW DELHI
Following the remarkable achievement of Chandrayaan-3’s recent landing on the Moon’s south pole recently, ISRO’s inaugural solar mission, Aditya L1, was launched from Sriharikota in Andhra Pradesh on Saturday at 11.50 a.m.
Before the launch, ISRO had said: “Aditya-L1, the first space-based Indian observatory to study the Sun, is getting ready for the launch. The satellite realised at the UR Rao Satellite Centre (URSC), Bengaluru has arrived at SDSC-SHAR, Sriharikota.”
About Aditiya-L1
Aditya-L1 is the first space-based observatory-class Indian solar mission to study the Sun. The spacecraft is planned to be placed in a halo orbit around the Lagrangian point1 (L1) of the Sun-Earth system, which is about 1.5 million km from the Earth.
A satellite placed in the halo orbit around the L1 point has the major advantage of continuously viewing the Sun without any occultation/eclipse. This will provide a greater advantage of observing the solar activities continuously. The spacecraft carries seven payloads to observe the photosphere, chromosphere, and the outermost layers of the Sun (the corona) using electromagnetic and particle detectors. Using the special vantage point of L1, four payloads will directly view the Sun and the remaining three payloads will carry out in-situ studies of particles and fields at the Lagrange point L1.
The suit of Aditya L1 payloads is expected to provide the most crucial information to understand the problems of coronal heating, Coronal Mass Ejection, pre-flare and flare activities, and their characteristics, dynamics of space weather, study of the propagation of particles, fields in the interplanetary medium, etc
What are Lagrange Points?
Lagrange Points are positions in space where the gravitational forces of a two-body system like the Sun and the Earth produce enhanced regions of attraction and repulsion. These can be used by spacecraft to reduce fuel consumption needed to remain in position. Lagrange points are named in honour of Italian-French mathematician Josephy-Louis Lagrange.
Before India, the countries that set off on the solar mission are:
USA: The Parker Solar Probe was launched by the National Aeronautics and Space Administration (NASA), the US space agency, in August 2018. In December 2021, Parker flew through the sun’s upper atmosphere, the corona, and sampled particles and magnetic fields there. In February 2020, NASA joined hands with the European Space Agency (ESA) and launched the Solar Orbiter to collect data to find out how the sun created and controlled the constantly changing space environment throughout the solar system. Other active solar missions by NASA are the Advanced Composition Explorer, launched in August 1997; the Solar Terrestrial Relations Observatory, launched in October 2006; the Solar Dynamics Observatory, launched in February 2010; and the Interface Region Imaging Spectrograph, launched in June 2013.
Also, in December 1995, NASA, ESA, and JAXA (the Japan Aerospace Exploration Agency) jointly launched the Solar and Heliospheric Observatory (SOHO).
Japan: JAXA, Japan’s space agency, launched its first solar observation satellite, Hinotori (ASTRO-A), in 1981. In 1991, JAXA’s other solar exploratory missions were Yohkoh (SOLAR-A); SOHO (along with NASA and ESA) in 1995; and Transient Region and Coronal Explorer (TRACE), launched with NASA in 1998. In 2006, Hinode (SOLAR-B) was launched, which was the successor to Yohkoh (SOLAR-A), the orbiting solar observatory. Japan launched it in collaboration with the US and the UK. The objective of Hinode, an observatory satellite, is to study the impact of the sun on the earth.
Europe: In October 1990, the ESA launched Ulysses to study the environment of space above and below the poles of the Sun. Other than solar missions launched in collaboration with NASA and JAXA, the ESA launched Proba-2 in October 2001. Proba-2 is the second of the Proba series, building on nearly eight years of successful Proba-1 experience, even though Proba-1 was not a solar exploratory mission.
On board Proba-2, there were four experiments, two of which were solar observation experiments. Proba stands for Project for On-Board Autonomy. Upcoming solar missions of the ESA include Proba-3, scheduled for 2024, and Smile, scheduled for 2025.
China: On 8 October 2022, the Advanced Space-based Solar Observatory (ASO-S) was successfully launched by the National Space Science Centre, Chinese Academy of Sciences (CAS).
What are the major objectives of the mission?
l Study of Solar upper atmospheric (chromosphere and corona) dynamics.
l Study of chromospheric and coronal heating, physics of the partially ionized plasma, initiation of the coronal mass ejections, and flares
l Observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the Sun.
l Physics of solar corona and its heating mechanism.
l Diagnostics of the coronal and coronal loops plasma: Temperature, velocity and density.
l Development, dynamics, and origin of CMEs.
l Identify the sequence of processes that occur at multiple layers (chromosphere, base, and extended corona) which eventually leads to solar eruptive events.
Magnetic field topology and magnetic field measurements in the solar corona.
Drivers for space weather (origin, composition, and dynamics of solar wind.
What are the seven payloads?
The Visible Emission Line Coronagraph (VELC) will study the Corona, imaging and spectroscopy, and Coronal mass ejections.
The Solar Ultraviolet Imaging Telescope (SUIT) will focus on the Photosphere and Chromosphere imaging- narrow and broadband. It will also measure the solar irradiance variations.
The Solar Low Energy X-ray Spectrometer (SoLEXS) and High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) will study the soft and hard X-ray flares form the Sun over wide X-ray energy range.
The Aditya Solar Wind Particle Experiment (ASPEX) and Plasma Analyser Package for Aditya (PAPA) will analyse the electrons and protons in the Solar wind or particles. It will also study the energetic ions.
The Advanced Tri-axial High-Resolution Digital Magnetometers will study the interplanetary magnetic field at the L1 point.