New Delhi: The Indian Space Research Organisation (ISRO) has announced that the “halo-orbit insertion of its solar observatory spacecraft, Aditya-L1, was accomplished at 16:00 Hrs (approx) on January 6, 2024 (IST).”
“The final phase of the manoeuvre involved firing of control engines for a short duration,” it added.
This mission aims to observe the Sun’s corona and understand its extreme heat from a halo orbit around the first Sun-Earth Lagrange point (L1), which is located roughly 1.5 million kilometres from the Earth.
The gravitational forces between the Earth and the Sun are in broad equilibrium at this point.
While “absolute neutralisation is not achievable due to the influence of other celestial bodies such as the Moon, Mars and Venus,” the L1 point provides a reasonably stable position, said news reports.
India’s public space agency said that “the orbit of [the] Aditya-L1 spacecraft is a periodic Halo orbit which is located roughly 1.5 million km from [the] Earth on the continuously moving Sun-Earth line with an orbital period of about 177.86 earth days.”
It described this Halo orbit as “a periodic, three-dimensional orbit at L1 involving Sun, Earth and a spacecraft.”
“This specific halo orbit is selected to ensure a mission lifetime of 5 years, minimising station-keeping manoeuvres and thus fuel consumption and ensuring a continuous, unobstructed view of [the] Sun.”
ISRO chief S. Somanath told reporters, “Today’s event was only placing the Aditya-L1 in the precise Halo orbit. So it was moving towards a high orbit, but we had to do a little bit of corrections… So right now, in our calculation, it is at the right place.”
He spoke of the need to monitor it for the next few hours.
“But we are going to monitor it for the next few hours to see whether it is at the right place. Then if it is slightly drifted, we may have to do a little bit of correction. We don’t expect that to happen … Images have been already put out on the website,” he said.
President of India Droupadi Murmu applauded ISRO’s achievement.
“Congratulations to the entire Indian scientist community for the great achievement! This mission will enhance our knowledge of the Sun-Earth System and benefit the entire humanity. Significant participation of women scientists in ISRO missions takes women empowerment too onto a higher orbit.”
PM Modi said, “India creates yet another landmark. India’s first solar observatory Aditya-L1 reaches [its] destination. It is a testament to the relentless dedication of our scientists in realising among the most complex and intricate space missions.”
He said he joins “the nation in applauding this extraordinary feat. We will continue to pursue new frontiers of science for the benefit of humanity.”
Congress president Mallikarjun Kharge congratulated scientists saying “India is now proudly gazing at the sun”.
He emphasised that “India began its journey to sun in 2006, when our scientists proposed a solar observatory with a single instrument for the Sun. In July 2013, ISRO selects the seven payloads for the Aditya-L1 mission.
“This achievement is a testament to the vision, commitment and sincere efforts by our founders who made sure that India’s space research becomes a vital part of nation building and social development.”
Aditya-L1 was designed and realised at the U.R. Rao Satellite Centre in Bengaluru with participation from various ISRO centres.
The payloads onboard Aditya-L1 were developed by Indian scientific laboratories IIA, IUCA and ISRO.
One of its scientific objectives is listed as studying what drives space weather. A former ISRO scientist told the BBC that the Sun influences space weather, which in turn has ramifications for human-made infrastructure.
“Space weather plays a role in how effectively the satellites function. Solar winds or storms can affect the electronics on satellites, even knock down power grids. But there are gaps in our knowledge of space weather,” Mylswamy Annadurai, who is also known as the Moon Man of India, said.
ISRO had announced in September that Aditya had started the collection of scientific data.
The Supra Thermal & Energetic Particle Spectrometer or what is described as the STEPS instrument, is “a part of the Aditya Solar Wind Particle Experiment (ASPEX) payload, has begun the collection of scientific data”, it said on September 18, 2023.