'Halo' Sun: Aditya L1 to be injected into final orbit on January 6

From L1, the 1,475 kilogram Aditya-L1 satellite will conduct scientific experiments to better understand the Sun.

India’s first mission to study the Sun, Aditya L1, would be injected into its final orbit on January 6 evening.

According to The Indian Space Research Organization (ISRO), the satellite, which will reach its destination orbit on January 6 at 4 pm, will get into the “halo orbit” around Lagrange Point 1 (L1), one of the five spots in the moving Sun-Earth system. The gravitational effects of the two bodies roughly balance each other here.

In its 126-day journey that began on September 2 last year, Aditya L1 traversed about 3.7 million kilometers as it went about a circuitous route to reach its "karambhoomi" or "land of action".

Aditya L1's home is in a halo-shaped orbit, 1.5 million kilometers away from Earth. The orbit is closer to the Sun than the Earth. However, it is still far away, since the Sun is some 150 million kilometers away from the Earth.  “Aditya L1 will make it to a halo orbit around the L1 point. As the Earth moves around the Sun, the L1 point will also move. So does the halo orbit,” Annapurni Subramaniam, director, the Indian Institute of Astrophysics, Bengaluru, told Indian Express.

According to experts, getting into this orbit is quite challenging. “This manoeuvre is critical. It involves the firing of thrusters in order to change the speed and trajectory of the spacecraft. If the intended orbit is missed in the first attempt, there would be multiple subsequent corrections and thruster firings required,” Dibyendu Nandi, solar physicist and Chair, Space Weather and Monitoring Committee, Aditya L1 mission, told Indian Express.

From L1, the 1,475 kilogram Aditya-L1 satellite will conduct scientific experiments to better understand the Sun. "The Indian solar observatory will have an uninterrupted and continuous view of the Sun and will help us understand space weather. It will act like a forecasting and warning platform for solar storms," Nigar Shaji, the Project Director for Aditya-L1 satellite at the U R Rao Satellite Center, Bengaluru told NDTV.

A solar storm is a large-scale magnetic eruption on the Sun. According to ISRO chairman, S Somanath, since Aditya-L1 will observe the Sun continuously, it can warn of imminent solar electro-magnetic effects on Earth.

"This will help continue normal operations by operating them in safe modes, till the solar storm passes by," Somanath told NDTV.

He said India owns assets worth over Rs 50,000 crore in space including over 50 operational satellites that need to be protected against the effects of the Sun.

Aditya-L1 is equipped with seven scientific payloads. These are all developed indigenously by ISRO and national research laboratories. These payloads are specifically designed to observe the photosphere, chromosphere, and the outermost layers of the Sun (the corona) using electromagnetic particle and magnetic field detectors.

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Major objectives of Aditya-L1 mission

-Studying the solar upper atmospheric (chromosphere and corona) dynamics

- Studying the chromospheric and coronal heating, the physics of the partially ionized plasma, the initiation of the coronal mass ejections, and flares

-Observing the in-situ particle and plasma environment, providing data for the study of particle dynamics from the Sun

-Studying the physics of solar corona and its heating mechanism

-Diagnostics of the coronal and coronal loops plasma: Temperature, velocity and density

-Studying the origin, composition and dynamics of solar wind, the drivers for space weather