India’s first space-based observatory to study the Sun, Aditya-L1, is headed to the Lagrangian 1 (L1) point as ISRO carried out the Trans-Lagrangian 1 Insertion (TL1I) manoeuvre in the early hours of 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. L1 is about 1.5 million km from the Earth and the distance of L1 from Earth is approximately 1% of the Earth-Sun distance.

“Off to Sun-Earth L1 point! The Trans-Lagrangean Point 1 Insertion (TL1I) maneuvre is performed successfully. The spacecraft is now on a trajectory that will take it to the Sun-Earth L1 point. It will be injected into an orbit around L1 through a maneuver after about 110 days. This is the fifth consecutive time ISRO has successfully transferred an object on a trajectory toward another celestial body or location in space,” ISRO posted on X.

Aditya-L1 was launched on September 2 by the Polar Satellite Launch Vehicle (PSLV) from the Satish Dhawan Space Centre in Sriharikota.

Following the launch, Aditya-L1 carried out four earth-bound manoeuvres between September 3 and September 15.

Aditya-L1, which is dedicated to the comprehensive study of the Sun, has seven payloads. Five payloads were developed by ISRO and two by Indian academic institutes in collaboration with the space agency.

Upon arrival at the L1 point in January 2024, another manoeuvre will be performed which will bind Aditya-L1 to an orbit around L1. The satellite will spend its mission life orbiting around L1 in an irregularly shaped orbit in a plane roughly perpendicular to the line joining the Earth and the Sun.

Aditya-L1 has a mission life of five years during which its payloads are expected to provide the most crucial information to understand the problem of coronal heating; coronal mass ejection; pre-flare and flare activities and their characteristics; dynamics of space weather; and propagation of particles and fields.

Scientific data collection has started: ISRO

ISRO on September 18 announced that the Supra Thermal and Energetic Particle Spectrometer (STEPS) instrument, a part of the Aditya Solar Wind Particle EXperiment (ASPEX) payload, has begun the collection of scientific data.

STEPS comprises six sensors, each observing in different directions and measuring supra-thermal and energetic ions ranging from 20 keV/nucleon to 5 MeV/nucleon, in addition to electrons exceeding 1 MeV. These measurements are conducted using low and high-energy particle spectrometers. The data collected during Earth’s orbits helps scientists to analyse the behaviour of particles surrounding the Earth, especially in the presence of the magnetic field of Earth.

“STEPS was activated on September 10, 2023, at a distance greater than 50,000 km from Earth. This distance is equivalent to more than 8 times the Earth’s radius, placing it well beyond Earth’s radiation belt region. After completing the necessary instrument health checks, data collection continued until the spacecraft had moved farther than 50,000 km from Earth,” the space agency said.

It added that each unit of STEPS is operating within normal parameters.

“A figure displays measurements depicting variations in the energetic particle environment within Earth’s magnetosphere, collected by one of the units. These STEPS measurements will persist during the cruise phase of the Aditya-L1 mission as it progresses toward the Sun-Earth L1 point. They will continue once the spacecraft is positioned in its intended orbit. Data collected around L1 would provide insights into the origin, acceleration, and anisotropy of solar wind and space weather phenomena,” ISRO said.

STEPS was developed by the Physical Research Laboratory (PRL) with support from the Space Application Centre (SAC) in Ahmedabad.

In a significant leap for the country’s space exploration endeavours, the Indian Space Research Organisation (ISRO) on Saturday successfully launched its maiden solar mission, Aditya-L1, carrying seven payloads for a detailed study of the sun.

India’s first solar space observatory mission was launched on the Polar Satellite Launch Vehicle (PSLV) XL from the Satish Dhawan Space Centre in Sriharikota at 11.50 am. The separation of Aditya-L1 and its injection into an elliptical orbit around the Earth were successful and took about 63 minutes.

Several politicians across party lines congratulated ISRO on the successful launch of the mission and its importance for science and humanity.

President Droupadi Murmu celebrated the significant milestone as a “historic feat,” underscoring its contribution to expanding our understanding of outer space. She conveyed her sincere congratulations to the dedicated ISRO scientists and engineers for their outstanding achievement and offered her utmost support for the mission’s prosperous outcome.

“The launch of Aditya-L1, India’s first solar mission, is a landmark achievement that takes India’s indigenous space programme to a new trajectory. It will help us better understand space and celestial phenomena. I congratulate the scientists and engineers at ISRO for this exceptional feat. My best wishes for the success of the mission,” President Murumu said.

The launch of Aditya-L1, India’s first solar mission, is a landmark achievement that takes India’s indigenous space programme to a new trajectory. It will help us better understand space and celestial phenomena. I congratulate the scientists and engineers at @isro for this…

— President of India (@rashtrapatibhvn) September 2, 2023

Appreciating the hardworking scientists responsible for this extraordinary accomplishment in India’s space exploration journey, Prime Minister Narendra Modi conveyed his confidence in India’s continued efforts to enhance our “understanding of the universe for the welfare of entire humanity.”

“After the success of Chandrayaan-3, India continues its space journey. Congratulations to our scientists and engineers at ISRO for the successful launch of India’s first Solar Mission, Aditya -L1. Our tireless scientific efforts will continue in order to develop a better understanding of the universe for the welfare of entire humanity,” PM Modi said.

After the success of Chandrayaan-3, India continues its space journey.

Congratulations to our scientists and engineers at @isro for the successful launch of India’s first Solar Mission, Aditya -L1.

Our tireless scientific efforts will continue in order to develop better…

— Narendra Modi (@narendramodi) September 2, 2023

The main opposition party in the Indian parliament, Congress, hailed the launch of Aditya-L1 as a “stupendous achievement” for India, as it shared a timeline of the mission from its conceptualization for understanding the “continuity in the ISRO saga”.

In a post in Hindi on X, the Congress said ISRO has given many opportunities to the country to be proud.

“After Chandrayaan-3, ISRO has again raised the nation’s prestige by successfully launching Aditya L-1,” the party said.

ISRO ने देश को गौरवान्वित होने के अनेक मौके दिए हैं।

चंद्रयान-3 के बाद ISRO ने आदित्य L-1 को सफलतापूर्वक लॉन्च कर फिर से देश का मान बढ़ाया है।

देश के वैज्ञानिकों की इस अभूतपूर्व उपलब्धि पर समस्त कांग्रेस परिवार को गर्व है। ISRO की पूरी टीम को शुभकामनाएं।

जय हिंद pic.twitter.com/xzyKgwxQsh

— Congress (@INCIndia) September 2, 2023

The entire Congress family is proud of this unprecedented achievement of the country’s scientists, it said.  Best wishes to the entire ISRO team, the party added.

In a post on X, Congress general secretary Jairam Ramesh said, “Today’s launch of Aditya-L1 is another stupendous achievement of ISRO and for India!” “While saluting ISRO once again, it is worthwhile recalling the recent timeline for Aditya-L1 to understand the continuity in the ISRO saga,” he said.

Today’s launch of Aditya-L1 is another stupendous achievement of ISRO and for India!

While saluting ISRO once again, it is worthwhile recalling the recent timeline for Aditya-L1 to understand the continuity in the ISRO saga.

2006: Scientists with the Astronomical Society of…

— Jairam Ramesh (@Jairam_Ramesh) September 2, 2023

According to ISRO, Aditya-L1 is the first space-based observatory to study the Sun. The spacecraft, after travelling about 1.5 million km from the Earth over 125 days, is expected to be placed in a Halo orbit around the Lagrangian point L1 which is considered closest to the Sun.

(With inputs from agencies)