Aditya or Aditya-L1 is a spacecraft whose mission is to study the Sun. It was conceptualised by the Advisory Committee for Space Research in January 2008. It has been designed and will be built in collaboration between Indian Space Research Organisation (ISRO) and various Indian research organizations and will be launched by ISRO around 2019 or 2020. This will be the first Indian space mission to study the Sun, and also the first Indian mission to be placed at Lagrangian point L1-- far away from the Earth from where continuous solar observations are possible. Only NASA and ESA have successfully placed satellites at the L1 (Lagrange point) point as of date.
A Lagrange point is a location in space where the combined gravitational forces of two large bodies, such as Earth and the sun or Earth and the moon, equal the centrifugal force felt by a much smaller third body. The interaction of the forces creates a point of equilibrium where a spacecraft may be "parked" to make observations.