The Sun up close: Aditya-L1 mission and its objectives

The Sun up close: Aditya-L1 mission and its objectives

Context- The Aditya-L1 mission, launched on Saturday, will take India into an elite group of nations that have sent probes to study the Sun. While India has carried out experiments to study the Sun using satellites earlier, Aditya-L1, which aims to park a spacecraft in the ‘L1’ spot in space (see box and illustration), is the country’s first dedicated solar mission.

Aditya-L1 is also ISRO’s ISRO’s second astronomy observatory-class mission after AstroSat (2015).

Special mission

  • Indian scientists have so far observed the Sun through telescopes on the ground, and relied on data from solar missions launched by the United States, Europe, the United Kingdom, and Japan.

(Credits- ISRO)

  • All these years, India has been observing the Sun using only ground-based telescopes, which have grown old now. As India lacked a large-scale modern observational facility, we were dependent on other sources for solar data.
  • Aditya-L1 presents a unique opportunity to not only address the existing gaps but also complement with newer data to address the unsolved problems in solar physics

Eyes in space

  • Disturbances in the form of solar flares, Coronal Mass Ejection, or solar winds directed towards Earth, can adversely impact space weather; studying the Sun is, therefore, of paramount importance.
  • While AstroSat, India’s first dedicated astronomy mission aimed at studying celestial sources in X-ray, optical, and UV spectral bands simultaneously, remains operational almost eight years after its launch, Aditya-L1 can potentially pave the way for future Indian astronomy missions.
  • AstroSat, weighing 1,515 kg, lifted off with five in situ instruments; Aditya-L1, weighing 1,475 kg, will carry seven payloads, four of which will directly look at the Sun. The other three will perform in situ (on site) studies of particles and magnetic fields at and around the L1 point.

Space weather alerts

  • The mission hopes to generate user-friendly information that can help safeguard a range of satellite-dependent operations such as telecommunications, mobile-based Internet services, navigation, power grids, etc. Once tested, tailormade information obtained from the data can be used to issue space weather alerts.
  • We can also get information about the environment around the L1 point, which is key for understanding space weather.

L1 and afterward

  • Aditya-L1 will travel for nearly 100 days to cover the 1.5 million km distance to L1. This is a shorter voyage than Mangalyaan, which took 298 days to reach the Martian orbit in 2014.
  • Like the Chandrayaan-3 mission, Aditya-L1 too, will undergo multiple apogee-raising orbital manoeuvres, and is expected to exit the Earth’s orbit on the fifth day after launch.
  • Six of the mission’s payloads — VELC, SUIT, SoLEXS, HEL1OS, PAPA, and MAG — will remain in the ‘off’ mode until around January 6, 2024, when the spacecraft is expected to be inserted into a ‘halo’ orbit near L1. The Aditya Solar wind Particle Experiment (ASPEX), built by the Physical Research Laboratory, will turn on while in transit.
  • Designed to image the Sun in the 200-400 nanometre (nm) of the ultraviolet band, SUIT’s imager will continuously record the entire disk of the Sun through 11 filters. SUIT’s images of these layers could help improve our understanding of the Sun’s immediate atmosphere.
  • By early 2024, scientists are hopeful of being able to commence a series of experiments lasting 2-3 months towards calibrating the instruments before high quality scientific data begin to roll out.


The place between the Sun and Earth, where the spacecraft will park itself, is called L1, or Lagrange Point 1 — one of the five Lagrange Points that exist between any moving two-body system in space. The destination is the reason the mission is called ‘Aditya-L1’.

Conclusion- Being positioned at a Lagrange point makes sense because the spacecraft requires very little energy to just stay put and make continuous observations. At any other place, the spacecraft would feel additional force, and would need to expend energy to remain stationary relative to both the Earth and Sun.

Syllabus- GS-3; Science and Tech

Source- Indian Express