Aditya (Sanskrit for Sun), is a planned mission of ISRO to study the Sun. Earlier named as Aditya-1, Aditya-L1 shall be the first space-based Indian mission to study the Sun. The Polar Satellite Launch Vehicle (PSLV-XL) is scheduled to launch the Aditya-L1 in 2023 from Sriharikota, Andhra Pradesh.

Differences between Aditya-1 and Aditya-L1:

• Aditya-1:
• • Aditya-1 was planned to be launched in an 800km low earth orbit.
• It was envisioned to be a 400 kg class satellite carrying a single payload, the Visible Emission Line Coronagraph (VELC).
• It was initially limited to observing only the solar corona.
• Aditya-L1:
• 0 Since a satellite placed in the halo orbit around the first Lagrangian Point (L1) of the Sun-earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses, the Aditya-1 mission was renamed as Aditya-L1 mission, which will be inserted in a halo orbit around the L1-1.5 million km from the earth towards the Sun.
• Against only one payload in Aditya-1, Aditya-L1 carries seven payloads.
• It aims to observe the photosphere, chromosphere, and the outermost layers of the sun (the corona) using electromagnetic particle and magnetic field detectors.
• The enhanced Aditya-L1 project would provide a thorough knowledge of the Sun’s dynamic processes and answer some significant problems in solar physics.

Scientific objectives of Aditya-L1:

• Study of solar upper atmospheric (chromosphere and corona) dynamics.
• Study of chromospheric and coronal heating, physics of the partially ionized plasma, initiation of the coronal mass ejections, and flares.
• Observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the Sun.
• Real-time observation of solar activities and their impact on space weather.
• Understand how solar winds and coronal mass ejections affect the geomagnetic field of the Earth and its magnetosphere.
• Identify the sequence of processes that occur at multiple layers (chromosphere, base, and extended corona), which eventually leads to solar eruptive events.
• Diagnostics of the coronal and coronal loops plasma: temperature, velocity, and density.
• Magnetic field topology and magnetic field measurements in the solar corona.

Thus, the suits of Aditya L1 payloads are expected to provide the most crucial information to understand the problem of coronal heating, coronal mass ejection, pre-flare, and flare activities and their characteristics, dynamics of space weather, propagation of particles and fields, etc. The mission will capture near-simultaneous photos of the many layers of the Sun’s atmosphere, revealing how energy is routed and transported from one layer to the next.