ISRO Postpones Space Docking Experiment for the Second Time

The Indian Space Research Organisation (ISRO) has postponed its much-anticipated Space Docking Experiment (SpaDeX) for the second time. Originally planned for Tuesday, the experiment was rescheduled to Thursday but has now been delayed indefinitely due to unexpected drift between the mission satellites.

In a statement posted on social media platform X, ISRO explained that while maneuvering the satellites to a 225-meter separation, an excessive drift was detected. The agency stated: "Satellites are safe. Stay tuned for updates." Earlier, ISRO had cited the need for further ground simulations after identifying an abort scenario during Tuesday's preparations.

SpaDeX aims to develop and demonstrate advanced technologies for spacecraft rendezvous, docking, and undocking, using two 220-kg satellites launched by ISRO’s PSLV on December 30, 2024. The satellites were placed in a 470-km circular orbit. This mission marks a significant step for India in mastering docking technology, a field currently dominated by the US, Russia, and China. The technology is critical for future missions like satellite servicing, space station operations, and interplanetary endeavors.

The mission involves two satellites: a chaser and a target, traveling at a speed of 28,800 km/h. Although their speed is immense, they appear stationary relative to each other due to zero relative velocity. The docking process includes progressive approach stages, where the chaser reduces the gap from 20 km to precise distances before finally docking at 3 meters. The chaser approaches the target at a speed of 10 nanometers per second and locks onto the target. Electrical power transfer between the satellites will confirm successful docking, and the two will operate as a single spacecraft. Once undocking occurs, they will function independently.

ISRO Chairman S Somanth emphasized that the docking exercise will proceed only after sensors are fully calibrated and all scenarios validated on the ground. He added, "Commands will be sent only when the spacecraft is ready for autonomous docking."

Docking is a challenging operation that only a few countries have mastered. This mission not only enhances India’s capabilities but also lays the groundwork for more ambitious projects in the future. The mission remains pivotal, and space enthusiasts await updates on the next docking attempt.