India’s First Solar Mission Aditya-L1 to be Launched by 2020

The Indian Space Research Organisation (ISRO) is planning to launch the first solar mission, Aditya-L1. The project is approved and the satellite will be launched during 2019 – 2020 timeframe by PSLV-XL from Sriharikota, ISRO mentioned on its website. Aditya-L1 mission is aimed at studying the Sun from an orbit around the Sun-Earth Lagrangian point 1 (L1) which is about 1.5 million kilometres from the Earth. It would carry seven payloads to observe the photosphere, chromosphere and the outermost layers of the Sun, the corona in different wavebands.

ISRO’s Aditya-L1 is a fully indigenous effort with the participation of national institutions. Indian Institute of Astrophysics (IIA), Bengaluru is the lead institute for the development of Visible Emission Line Coronagraph (VELC) and Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune is developing the Solar Ultraviolet Imager (SUIT) payload for the Aditya-L1 mission. The main aim of the solar mission is to do coronal and near UV studies of the sun and help resolve some unanswered questions in solar physics.

In a written reply to a question in Lok Sabha today, Union Minister Dr Jitendra Singh informed that ISRO’s Aditya-L1 can provide observations on the corona and in addition can provide observations on the solar Chromosphere using the UV payload and on the flares using the X-ray payloads. Singh further added saying that the particle detectors and the magnetometer payload can provide information on charged particles and the magnetic field reaching the halo orbit around L1.

The Aditya-1 mission was conceived as a 400kg class satellite carrying one payload, the Visible Emission Line Coronagraph (VELC) and was planned to launch in a 800 km low earth orbit. A Satellite placed in the halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/ eclipses. Therefore, the Aditya-1 mission has now been revised to “Aditya-L1 mission” and will be inserted in a halo orbit around the L1, which is 1.5 million km from the Earth. The satellite carries additional six payloads with enhanced science scope and objectives.

To recall, NASA-ESA mission SOHO was launched in 1995 that made many discoveries. But its coronagraph which was meant to image the sun broke down shortly after the mission commenced. As of now, there is no satellite imaging the sun from space. With the launch of Aditya-L1, the gap will be filled and detailed information about the sun can be traced. Aditya-1 was meant to observe only the solar corona. The outer layers of the Sun, extending to thousands of km above the disc (photosphere) is termed as the corona. It has a temperature of more than a million degree Kelvin which is much higher than the solar disc temperature of around 6000K. How the corona gets heated to such high temperatures is still an unanswered question in solar physics.