Aditya-L1, India's first space-based observatory to study the sun, is set to undergo a crucial manoeuvre on Saturday at 4pm as it heads to Lagrange point 1 (L1) of the sun-earth system.
The spacecraft will be placed in its final destination, a halo orbit around the L1 point. This point is around 1.5 million km from our planet.
Why is today's manoeuvre crucial?
An observatory in a halo orbit around the L1 point has the advantage of continuously viewing the sun without any eclipses.
"This manoeuvre (at around 4 pm on Saturday) will bind the Aditya-L1 to a halo orbit around L1. If we don't do this, there is a possibility that it will continue its journey, maybe towards the Sun," an ISRO official told PTI.
Aditya-L1 127-day timeline
September 2, 2023: Aditya-L1 launched from the Satish Dhawan Space Centre, Sriharikota.
September 3, 2023: First earth-bound manoeuvre places Aditya-L1 in 245 x 22,459km orbit.
September 5, 2023: The spacecraft enters 282x40,225km orbit in second earth-bound manoeuvre.
September 10, 2023: Third earth-bound manoeuvres successfully puts the spacecraft in 296x71,767km orbit.
September 18, 2023: In the fourth and last earth-bound manoeuvre, the satellite enters 256x1,21,973km orbit; the space observatory starts gathering scientific data.
September 19, 2023: Aditya-L1 starts moving towards the L1 point.
September 25, 2023: An assessment of space situation around L1 point.
September 30, 2023: Aditya-L1 escapes the earth's sphere of influence.
November 7: The first high-energy x-ray glimpse of solar flares captured by HELIOS.
December 1, 2023: Solar wind Ion Spectrometer (SWIS) in the Aditya Solar wind Particle Experiment (ASPEX) payload begins operating.
December 8, 2023: The SUIT payload captures sun's full-disk images in near ultraviolet wavelengths.
January 6, 2024: Aditya-L1 set to enter its final orbit.
What are Aditya-L1 mission objectives?
According to ISRO, Aditya-L1 will conduct the following studies:
Study of solar upper atmospheric (chromosphere and corona) dynamics.
Study of chromospheric and coronal heating, physics of the partially ionized plasma, initiation of the coronal mass ejections, and flares
Observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the sun.
Physics of solar corona and its heating mechanism.
Diagnostics of the coronal and coronal loops plasma: Temperature, velocity and density.
Development, dynamics and origin of CMEs.
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 payloads Aditya-L1 mission will be carrying?
The mission will carry seven scientific payloads for the study, which will observe the photosphere, chromosphere and the corona of the sun using electromagnetic and particle and magnetic field detectors.
Four of the seven payloads are remote sensing and can directly view the sun. The remaining three payloads carry out in-situ studies of particles and fields at L1, thus providing important scientific studies of the propagatory effect of solar dynamics in the interplanetary medium.
What is the cost of Aditya L1 mission?
ISRO has not revealed the final figures yet. The total cost of Aditya-L1 solar mission is estimated to be around Rs 400 crore, as per reports. In 2019, the Centre sanctioned around Rs 378 crore for the mission.
-- with inputs from agencies