ISRO to dock SpaDeX satellites on January 9, epic space chase in final phase

By R Anil Kumar

• Launched on December 30, 2024, the SpaDeX satellites are currently engaged in a carefully orchestrated sequence to close the distance between them

• ISRO’s SpaDeX Satellites are Being Tracked by S2A Systems

• ISRO’s pair of SpaDex satellites are being tracked by a global network of Space Situational Awareness (SSA) hardware deployed by Swiss-based s2a systems, that provides optical surveillance for space infrastructure

• A Swiss company called s2a systems is providing optical tracking for the pair of SpaDex satellites. Their Space Situational Awareness hardware is deployed around the world

Bengaluru, January 6. India’s ambitious Space Docking Experiment (SpaDeX) mission is poised for a historic milestone as its two satellites, the Chaser and Target, prepare to dock in orbit on January 9, 2025.

This mission marks a significant advancement in India’s space capabilities, positioning the country among an elite group of nations capable of executing on-orbit docking operations.

Launched on December 30, 2024, the SpaDeX satellites are currently engaged in a carefully orchestrated sequence to close the distance between them.

Initially separated by approximately 20 kilometres, the satellites are gradually reducing this gap through precise manoeuvres.

According to M. Sankaran, Director at the UR Rao Satellite Centre, the onboard propulsion systems will be activated to maintain and then decrease this distance to facilitate successful docking.

The docking process involves intricate coordination, with the satellites set to communicate via an inter-satellite radio frequency link once they are within 5 kilometres of each other.

This communication will allow them to exchange vital data regarding their positions and orientations, crucial for the final approach. The docking mechanism itself is designed to execute a “hugging” action, ensuring a secure connection between the two spacecraft.

This mission is not just a technical demonstration; it represents years of research and development. The concept dates back to 1989, but it gained momentum after project approval in 2016.

Extensive testing has been conducted to validate the docking mechanisms and sensors required for this operation.

Successful completion of the SpaDeX mission would not only demonstrate India’s growing prowess in space technology but also lay the groundwork for future endeavours such as satellite servicing and the establishment of India’s planned space station, Bharatiya Antariksha Station.

India is set to become the fourth country globally to achieve such advanced docking capabilities.

With the countdown underway, all eyes are on ISRO as it prepares for this landmark event that could redefine India’s role in global space exploration.

Meanwhile, ISRO’s SpaDeX satellites, launched on December 30, 2024, are currently being tracked by S2A Systems. This tracking is crucial for monitoring the satellites’ positions and operations as they conduct their mission to demonstrate in-space docking technology.

The SpaDeX mission aims to develop and demonstrate the technology necessary for spacecraft rendezvous, docking, and undocking in low Earth orbit. This mission is a significant step towards India’s future space endeavours, including lunar missions and the establishment of a space station.

The mission consists of two small satellites, designated SDX01 (Chaser) and SDX02 (Target), each weighing approximately 220 kg. They will perform various tests, including autonomous docking and power transfer between the two spacecraft.

Tracking Details

What Is S2A Systems?

S2A systems is a Swiss company founded by space enthusiasts in 2022. The firm develops and operate customised systems for optical space surveillance worldwide.

S2A Systems performs optical observations of individual objects and entire constellations in all orbits, from LEO over MEO to GEO. We provide astrometric image analysis and are capable of monitoring the behaviour, attitude control, and neighbourhood of the observed objects. We also perform precise brightness measurements and generate light curves of objects in all orbits.

S2A Systems and SpaDeX

S2A Systems has been actively tracking the SpaDeX satellites since their launch. As of January 5, 2025, reports indicate that the two satellites are approximately 8 km apart. The tracking data is essential for ensuring the successful execution of their docking manoeuvres and other mission objectives.

This mission not only enhances India’s capabilities in space technology but also positions ISRO as a key player in the global space exploration arena by developing advanced docking systems necessary for future missions.

The Space Docking Experiment

The pair of satellites are known as the Chaser and the Target, with both the satellites being equipped to operate as either. Both the satellites have a sophisticated suite of instruments on board that allows them to precisely determine their own position and orientation, as well as the position and orientation of the other.

ISRO intends to livestream and broadcast the docking operation on 9 January. The Chaser satellite will carefully approach the Target, and then dock using an androgynous mechanism. One satellite will then attempt to transfer power and operate the other during the docking. ISRO may opt for multiple dockings during the course of the mission