Aditya-L1 Launch: Why has no spacecraft successfully landed on the Sun?

As India's Aditya-L1 mission sets out on its voyage to explore the Sun, it prompts a pertinent question — why has no spacecraft successfully touched down on the Sun's surface? As the Aditya-L1 mission embarks on its jounrye to the Sun, it is essential to understand the challenges associated with landing on the star at the centre of our Solar system.

While numerous countries have launched missions to study the Sun, none has been able to reach its surface (unlike the Moon). The primary obstacle preventing such a landing is the extreme temperature on the Sun. 

Aditya-L1 mission: Temperatures on the Sun

The Sun's core registers a scorching 27 million degrees Fahrenheit (15 million degrees Celsius), with its surface temperature hovering around 10,000 degrees Fahrenheit. Moreover, the Sun's structure consists of layers, including the corona, chromosphere, photosphere, convection zone, radioactive zone, and core. 

As one approaches the Sun's photosphere, gravitational forces cause objects to become 26 times heavier than on Earth. Delving deeper into the Sun's interior leads to temperatures exceeding 2 million degrees Celsius, rendering any spacecraft vulnerable to melting and complete destruction.

Aditya-L1 mission: NASA's Solar Probe

Despite these challenges, NASA's 'Parker Solar Probe,' launched in 2018, has come the closest to the Sun, reaching an area with temperatures around 2 million degrees Fahrenheit on December 14, 2021. It was even claimed that the probe passed through the Sun's corona.

Aditya-L1 mission: India's effort to conquer the Sun

India's Aditya-L1 is the country's first mission to the Sun, although 22 missions have been previously launched, aiming to study the Sun. These missions were planned by countries such as the United States of America, Germany, and the European Space Agency. 

Notably, NASA alone has launched 14 of these missions. In 1994, the European Space Agency partnered with NASA for a Sun mission. In 2001, NASA initiated the Genesis Mission, designed to sample solar wind while orbiting the Sun.

Aditya-L1 is a groundbreaking observatory-class mission, marking India's first space-based observatory. Prior to this mission, all Sun-related studies relied on ground-based telescopes, such as those at ARIES in Kodaikanal or Nainital.

These telescopes, however, couldn't provide insights into the Sun's atmosphere, which differs significantly from Earth's. The mission aims to address critical questions that can only be answered from space. Aditya spacecraft will remain stationed at the L1 point, monitoring the Sun's movements continuously and transmitting photographs to ground stations.

Aditya-L1 mission: Objectives of Aditya 

• Studying the Sun's atmosphere.
• Investigating chromospheric and coronal heating, as well as flare research.
• Exploring the physics of the solar corona and measuring its temperature.
• Diagnosing coronal and coronal loop plasma, extracting information about temperature, velocity, and density.
• Researching the origin, composition, and dynamics of the solar wind.

In summary, while landing on the Sun remains a formidable challenge due to its extreme temperatures, missions like Aditya-L1 are poised to unlock valuable insights into our star, the Sun, from their vantage point in space.