The Indian Space Research Organisation (ISRO) is scheduled to carry out a key operation to switch on Aditya L1’s engine on Saturday, aiming to successfully position the solar probe into its intended orbit.

Unlike the Chandrayaan 3 mission, where the Vikram lander touched down on the lunar south pole, Aditya L1 will not land on the Sun. Instead, it will revolve at the first Lagrange Point in the Earth-Sun system. This point is located 15 lakh km away from Earth. Remarkably, the 15 lakh km distance represents only 1 per cent of the total 15 crore km separation between Earth and the Sun.

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Has any probe ‘touched’ the Sun?

In December 2021, the National Aeronautics and Space Administration or NASA’s Parker Solar Probe achieved the unprecedented feat of flying by around the Sun.

This marked the first time in history that a spacecraft using other celestial bodies navigated through the Sun’s upper atmosphere, the corona, collecting samples of particles and magnetic fields. The Parker Probe ventured to a distance of approximately 78 lakh km from the Sun’s surface during this groundbreaking mission.

Subsequently, the probe has been engaged in a series of loops within a highly elliptical orbit around the Sun. With each orbit, it steadily approaches closer to the Sun, transmitting a wealth of observational data that continues to contribute valuable insights.

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Why is a direct flyby of Sun challenging?

“It takes 55 times more energy to go to the Sun than it does to go to Mars,” said a NASA report.

Our planet moves swiftly, approximately 1,07,826 km, predominantly sideways compared to the Sun. To reach the Sun, cancelling this sideways motion is crucial, the report added.

The Parker Solar Probe, skimming through the Sun’s atmosphere, only needs to reduce its sideways motion by 85,295 km to reach its destination. This task is challenging, requiring the use of the powerful Delta IV Heavy rocket. Additionally, the Parker Solar Probe undergoes Venus’s gravity assists, utilising Venus’ orbital energy well to shed sideways speed. These gravity assists draw the Parker Solar Probe’s orbit closer to the Sun, achieving a record approach of just 61.6 lakh km from the Sun’s visible surface on the final orbits, the NASA report explained.

While shedding sideways speed to approach the Sun, the Parker Solar Probe gains overall speed, propelled by the Sun’s intense gravity. According to NASA, it is set to break the record as the fastest human-made object, reaching 6,92,023 km on its final orbits, expected in 2025.

To provide perspective, this speed is fast enough to travel from New Delhi to Lahore in just two seconds!