Observe from a halo orbit

Aditya-L1 is India’s dedicated space-based solar observatory. It launched on PSLV-C57 on September 2, 2023 and entered its targeted halo orbit on January 6, 2024. Its observing region is near the Sun–Earth L1 point, about 1.5 million kilometres from Earth toward the Sun. It did not travel to the Sun’s surface.

The cleanroom photograph shows the physical Aditya-L1 spacecraft with its Solar Ultraviolet Imaging Telescope, SUIT, identified by the source’s arrow. Ground integration, launch, transfer and arrival are separate phases. A view of the assembled observatory establishes neither its later orbit nor the results of its instruments.

L1 is understood in a reference frame that turns with the Earth–Sun system. The gravitational influences and the motion of the frame allow a small object to maintain a particular relative configuration in an idealized model. This is not a place where all gravity disappears, and the L1 point is not a massive object around which a spacecraft circles like a moon around a planet.

Aditya-L1 follows a three-dimensional halo trajectory around the L1 region. A diagram projected onto one plane can look like a flat loop while omitting motion out of that plane. Read the coordinate frame and projection before interpreting the drawing as the full physical path.

The L1 region is dynamically unstable: small departures do not simply correct themselves indefinitely. Orbit determination and occasional thruster maneuvers keep the spacecraft near its intended path. This maintenance is called station keeping, even though the observatory is moving rather than sitting still.

ISRO’s July 2, 2024 report marked completion of the first halo circuit, described as 178 days. It recorded station-keeping maneuvers on February 22, June 7 and July 2. That is a dated record of the first circuit, not a guarantee that every later maneuver schedule or exact period remains unchanged.