After landing on the Moon, India is all set to reach for the Sun. The ambitious Aditya L1 mission will be launched around 1130 hrs on September 2 from the Satish Dhawan Spaceport in Sriharikota, Andhra Pradesh by the ever dependable PSLV rocket.
The traditional/proverbial saying “ The Sun, Moon and Stars”, could well alter for the history book of the ISRO (Indian Space Research Organisation), which successfully landed on the Moon first with its Chandrayaan- mission on August 3.
We were all told during our growing up years that “You should aim for the Moon and you will at least end up with a star.” Now, with its imprint strongly getting embedded on the Moon, the ISRO Mission will embark on the four month journey of reaching one of the brightest stars in our galaxy-The Sun.
Halo Orbit
According to the ISRO, it wants to place the spacecraft in a “halo orbit around the Lagrange point 1 (L1) of the Sun-Earth system.” A halo orbit is one where the plane of the orbit around the L1 point will always face the sun while the spacecraft is taking a revolution. This allows onboard instruments to make direct and uninterrupted measurements of the Sun.
In gist, through the mission, ISRO will study the impact of solar activities on the space and weather on Earth in real-time.
The distance from the Earth to the identified location where Aditya L1 will park (Lagrande Point) is 1.5 million km. It will be the first space-based observatory from India to study the Sun. The objective is to get uninterrupted and best view of the Sun, study the star’s radiations in pure form and gather data.
We all know that the Sun is an inferno with temperature so high that it would be difficult for landing a spacecraft of even going close by. It is the primary source of energy that is responsible for nourishing life on Earth. For example, humans get their much needed Vitamin D from exposure to sunlight. Similarly, photosynthesis in plants is triggered by Sun light, which is life sustaining.
At the same time the energy and radiations have destructive potential too. Direct exposure to sun rays are known to cause cancers (through ultra violet radiation), solar flares and winds cause damage to satellites, communication systems etc. The Earth’s magnetic field and atmosphere act as a cosmic shield against not just the Sun but also all other celestial objects complete impact on life.
Sun is an object to study
Therefore, a space-based study has been preferred to remotely studying from the Earth. In contrast the average distance to the Moon is 384, 400 km. The Chandrayaan-3 Mission took 40 days to reach and land near the South Pole region. Moon being a satellite of the Earth, it’s easier to study it from the Earth as well as orbit around and now land on it.
The Sun has been an object to study for the last few decades. The US Space Agency, NASA, ESA, JAXA, the Japanese Space Agency and even China as recently as in 2022 have been exploring and studying various aspects of the Sun and its role in the Universe and specially its impact on Planet Earth.
The prominent solar expeditions have been the launch of the SOHO (Solar and Heliospheric Observatory) in 1995, jointly by the NASA, ESA & JAXA. The NASA’s ‘Parker Solar Probe’ flew through the Sun’s Corona (upper atmosphere) in 2018 in a daring flight and collected data on the magnetic field there. The Chinese launched an Advanced, space-based, Solar Observatory in 2022.
The Importance of Aditya
The primary objective of the ISRO’s Aditya L1 Mission is to unravel some of the mysteries of the Sun. With a set of equipment on board the spacecraft it aims to provide a detailed analysis of the Sun’s behavior, which indirectly impacts Earth’s climate and satellite communication as well as life on our planet.
The word Aditya is a Sanskrit term which means the Sun God. It also is interpreted as “son of Aditi.” Adityas (“sons of Aditi”) are 12 in number and represent the solar deities. The ISRO’s nomenclature is in line with Chandrayaan (Moon Mission) and Mangalyaan (Mars Orbitter Mission).
The ISRO has been working on the Mission Aditya L1 with full throttle since 2019. The government of India sanctioned a budget and the entire mission is expected to be around Rs 400 crore or approx $46 million. After its launch on September 2, the spacecraft will fly for four months and is expected to reach L1 around January first week of 2024. The life of the mission is projected to be 5.2 years.
Lagrange Point 1 is closest
Now, the question is why L1? First, the Lagrange Point 1 it is one of the closest points. Second, scientists have found that it provides the most stable gravitational spot between Earth and the Sun. Thus, the Aditya Observatory can remain stationery, minimise fuel consumption and get an uninterrupted view and study the Sun. There are five such points in space from L1 to L5 in Sun-Earth configuration and are named after Joseph-Louis Lagrange, an Italian mathematician.
India’s efforts are being supported by the ESA which is providing deep space communication services to the mission. The ESA has three deep space antennas separated by 120 degrees Longitude. They can be used to communicate with the spacecraft anytime, from anyplace. Communication is the key of all missions. By this the ISRO will be able to track, command and receive data from Aditya L1 from anywhere in the solar system or specifically from its parking site.
Other important objectives of the Aditya L1 are to understand “coronal heating, coronal mass ejection, pre-flare and flare activities and their characteristics, dynamics of space weather, propagation of particles and fields, the ISRO listed.
The sun is too hot with its core temperatures reaching 15 million degrees Celsius, even the temperature in its outer atmosphere called corona the temperature is around 1 million degrees Celsius, so nothing survives there. Hence, the mission needs to undertake a study from a relatively safe distance.
The outcomes of the study from Aditya L1 will be keenly watched as they could have an important bearing on the Sun’s impact on Earth, satellites in space and changes in climate and many unknown phenomena.
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