Within days of soft landing on the moon, the Indian Space Research Organization (ISRO) is now aiming for the Sun. This will be India’s first outing towards the Sun. A “celestial surya namaskar” of sorts.
ISRO has announced that its solar observatory will lift off from India’s space port Sriharikota on 2 September 2023, a little before noon, at 11.50 am. ISRO is deploying its workhorse and very reliable Polar Satellite Launch Vehicle (PSLV) for this mission.
As the Indian satellite intends to study the Sun, it is appropriately named Aditya-L1. ISRO says, “Our Sun is the nearest star and the largest object in the solar system. The estimated age of sun is about 4.5 billion years. It is a hot glowing ball of hydrogen and helium gases. The distance to the sun from the earth is about 150 million km, and it is the source of energy for our solar system. Without solar energy, life on earth as we know it cannot exist. The gravity of the sun holds all the objects of the solar system together. At the central region of the Sun, known as ‘core’, the temperature can be as high as 15 million degree Celsius. At this temperature, a process called nuclear fusion takes place in the core which powers the sun. The visible surface of the sun, known as photosphere, is relatively cool and has a temperature of about 5,500 degrees celsius.
Aditya L1 weighs nearly 1,500 kilogram and has a scientific robotic satellite to keep a continuous eye on the Sun.
This will be India’s first dedicated mission to monitor the Sun, especially to understand what happens when the Sun gets angry. The solar observatory has been made at a cost of Rs 400 crore.
“India’s Aditya L1 satellite is a space-based protector of sorts, keeping an eye on solar flares and ensuing solar storms,” explained S Somanath, Chairman, ISRO.
“Aditya L1 will look at Sun continuously, so it can forewarn us of imminent solar electro-magnetic effects on Earth and thus protect our satellites and other power electrical and communications networks from getting disrupted and help continue normal operations by operating them in the safe mode until the solar storm passes by,” he added.
All life on earth is dependent on the Sun, for solar radiation that helps plants capture carbon and glucose through photosynthesis. The Earth falls within the so-called ‘Goldilocks Zone’ – neither too near the Sun nor too far, just the right distance so that life could evolve on the planet.
In addition, the ISRO chief explains, “India has assets worth over Rs 50,000 crore in space with over 50 operational satellites in space and they need to be protected against the anger of the Sun.”
When a large solar flare erupts from the Sun, it can literally fry the electronics of the satellites. To protect them, space engineers shut down the electronics and keep them in a safe shut down state until the highly charged storm passes over.
ISRO says Aditya L1 shall be the first space-based Indian mission to study the Sun. The spacecraft shall be placed in a halo orbit around the Lagrange point 1 (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/eclipses. This will provide a greater advantage in observing solar activity and its effect on space weather in real-time.
The spacecraft carries seven payloads to observe the photosphere, chromosphere and the outermost layers of the Sun (the corona) using electromagnetic and particle and magnetic field detectors. Using the special vantage point L1, four payloads directly view the Sun and the remaining three payloads carry out in-situ studies of particles and fields at the Lagrange point L1, thus providing important scientific studies of the effect of solar dynamics in the interplanetary medium.
The scientific instruments of Aditya L1 are expected to provide 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, propagation of particle and fields etc.
The Indian space agency says in its statement that the major science objectives of Aditya-L1 mission are –
- Study solar upper atmospheric (chromosphere and corona) dynamics.
- Study chromospheric and coronal heating, the physics of the partially ionized plasma, the 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.
- Study the 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 CME (Coronal Mass Ejections).
- 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.
- The origin, composition and dynamics of solar wind, the drivers for space weather.