In a PSLV rocket, the Aditya-L1 spacecraft starts its ascent towards the Sun
In a PSLV rocket, the Aditya-L1 spacecraft starts its ascent towards the Sun

It’s interesting that this will be one of the rocket’s and Indian Space Research Organization’s (ISRO) longest missions.

2 September, Sriharikota (Andhra Pradesh) On Saturday morning, India’s Polar Satellite Launch Vehicle-C57 (PSLV-C57) launched the Aditya-L1 satellite, which was intended to investigate the Sun.


The 1,480.7 kilogramme Aditya-L1 satellite, which will research solar activity, is the only passenger on the PSLV-XL variant rocket.

At 11.50 a.m., the Aditya-L1 rocket, which is named after the Hindu Sun God and has a liftoff mass of 321 tonnes, was launched from the Satish Dhawan Space Centre’s (SDSC) second launch pad.

People gathered in the viewing gallery clapped their hands in celebration as the rocket slowly rose up into the sky with a big orange flame at its tail. The rocket accelerated with a sound imitating rolling thunder and climbed up and higher, leaving a thick plume.

It’s interesting that this will be one of the rocket’s and Indian Space Research Organization’s (ISRO) longest missions.

The rocket will expend Aditya-L1 around 63 minutes after liftoff, and the fourth stage’s passivation will bring the mission to a stop at roughly 73 minutes.

“We need to respond to the satellite’s perigee argument. For the fourth step, we are using two burn tactics. The extended flight time is due to a lengthy coasting phase after the first burn in order to reach the natural argument of perigee, according to Dr. S. Unnikrishnan, Director of the Vikram Sarabhai Space Centre (VSSC).

The fourth stage of the rocket will be turned off twice throughout the course of the mission, giving it a total of 30 minutes to coast: 26 minutes after the first cutoff and around 3 minutes after the second.

Aditya-L1 will launch into low earth orbit (LEO) first. The orbit would thus be elliptical. The spacecraft will leave the gravitational Sphere of Influence (SOI) of the earth as it moves closer to the Sun-Earth Lagrange Point (L1).

After leaving SOI, the spacecraft will enter its cruise phase before being launched into a large halo orbit around L1. At this altitude, the gravitational pull of the Sun and Earth will be equal, preventing the spacecraft from gravitating towards either planet.

Aditya-L1 would take about four months to journey from launch to L1, which would be 1.5 million kilometres away from Earth.

There are around 3,84,000 kilometres between the Earth and the Moon.

The main benefit of having a satellite in the halo orbit around the L1 point is that it can continually see the Sun without being obscured by clouds or eclipses. The ability to monitor solar activity and how it affects space weather in real time would be improved as a result, according to the ISRO.

The investigation of coronal heating, solar wind acceleration, coronal mass ejections (CME), solar atmosphere dynamics, and temperature anisotropy are some of the scientific goals of the Aditya-L1 mission.

In its standard design, the PSLV is a four-stage, expendable rocket with six booster motors attached to the first stage to provide more thrust during the first few seconds of flight. Solid and liquid fuels are used to power the solid and liquid engines, respectively.

The XL version of the rocket, which has longer strap-on engines, was the one that took off on Saturday.

It’s interesting to note that India’s first interplanetary mission, the Chandrayaan-1 or Moon Mission-1, was the first time the XL version rocket was deployed. Later, Chandrayaan-2 and the Mars Mission/Mars Orbiter Mission also utilised the rocket.

And on Saturday, a new interplanetary mission will use the PSLV-XL version, which will be flying for the 25th flight.

The Saturday rocketing takes place not long after India landed on the Moon on August 23, with its lander making a textbook-perfect safe touchdown on lunar surface. The rover began conducting investigations after rolling down later.

Nevertheless, the Aditya-L1 mission, according to the Indian space agency, is equipped with seven payloads that will use electromagnetic, particle, and magnetic field detectors to study the photosphere, chromosphere, and the Sun’s outermost layers (the corona).

Four payloads use the unique vantage point L1 to observe the Sun directly, while the other three payloads conduct in-depth particle and field studies at the Lagrange point L1. This data is crucial for understanding how solar dynamics affect the interplanetary medium, according to ISRO.

According to the Indian space agency, Aditya-L1’s seven payloads are anticipated to deliver the most important data for understanding coronal heating, coronal mass ejection, pre-flare and flare activities and their characteristics, dynamics of space weather, propagation of particle and fields, and other issues.

The ISRO said the major science objectives of Aditya-L1 mission are: Study of solar upper atmospheric (chromosphere and corona) dynamics, study of chromospheric and coronal heating, physics of the partially ionised plasma, and initiation of the coronal mass ejections, and flares.

Additionally, it will keep track of the in-situ particle and plasma environment, collecting information for the investigation of solar particle dynamics.

Other objectives are physics of solar corona and its heating mechanism, the diagnostics of the coronal and coronal loops plasma: Temperature, velocity and density, development, dynamics and origin of Coronal Mass Ejections (CME), to 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, and the drivers for space weather (origin, composition and dynamics of solar wind).

ISRO said that the Sun estimated to be 4.5 billion years old is a hot glowing ball of hydrogen and helium gases and is the source of energy for the solar system.

“The solar system’s objects are all held together by the gravity of the Sun. At the central region of the sun, known as ‘core’, the temperature can reach as high as 15 million degree Celsius,” it said.

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 degree Celsius, the ISRO said.

The Sun is the nearest star and therefore can be studied in much more detail as compared to other stars. By studying the Sun, we can learn much more about stars in our Milky Way as well as about stars in various other galaxies, the ISRO said.

The Sun is a very dynamic star that extends much beyond what we see. It shows several eruptive phenomena and releases immense amounts of energy in the solar system. If such explosive solar phenomena is directed towards the earth, it could cause various types of disturbances in the near earth space environment.

Various spacecraft and communication systems are prone to such disturbances and therefore an early warning of such events is important for taking corrective measures beforehand.

In addition to these, if an astronaut is directly exposed to such explosive phenomena, he/she would be in danger. The various thermal and magnetic phenomena on the sun are of extreme nature.

Thus, the Sun also provides a good natural laboratory to understand those phenomena which cannot be directly studied in the lab.

The Indians space agency said all the seven payloads carried by Aditya-L1 are indigenously developed by different laboratories in the country in close coordination with it.

The Visible Emission Line Coronagraph (VELC) instrument is developed at the Indian Institute of Astrophysics, Bengaluru; Solar Ultraviolet Imaging Telescope (SUIT) instrument at Inter University Centre for Astronomy & Astrophysics, Pune; Aditya Solar wind Particle Experiment (ASPEX) at Physical Research Laboratory, Ahmedabad; Plasma Analyser Package for Aditya (PAPA) at Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram; Solar Low Energy X-ray Spectrometer (SoLEXS) and High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) payloads at U R Rao Satellite Centre, Bengaluru and the Magnetometer at the Laboratory for Electro Optics Systems, Bengaluru.



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