New Delhi: The Indian Space Research Organisation (ISRO) has postponed the docking experiment of two of its satellites, SDX01 (Chaser) and SDX02 (Target), which were launched under the SpaDex mission. The decision comes after an unexpected drift between the two satellites, detected during a manoeuvre to reduce their distance to 225 meters.
The drift, which exceeded expectations, was observed during a non-visibility period, prompting ISRO to reassess the situation. Originally scheduled for January 7 and later for today, the docking experiment has been delayed. A revised timeline for the operation will be shared soon, as confirmed by the space agency through a tweet.
Both satellites, which were placed into low Earth orbit at an altitude of 475 km by the PSLV-C60 rocket on December 30, are functioning normally and remain safe. Weighing 220 kg each, the satellites are in orbit, but further adjustments are needed before the docking process can proceed.
Docking satellites in orbit is a highly complex task requiring precise orbital manoeuvres. To achieve the docking, ISRO uses onboard propulsion systems on one satellite to reduce the gap between them gradually. An inter-satellite radio frequency link is then activated, allowing real-time position data exchange for controlled coupling of the two satellites.
Advanced sensors developed by ISRO will play a critical role in guiding the satellites during the docking phase. The Chaser satellite will secure the Target satellite with the help of clamps and latches, and a retractable ring will tighten the hold. Once successfully docked, power will be transferred between the satellites to enable operations, including powering a heater.
This docking experiment is pivotal for future missions, including Chandrayaan 4 and the Bhartiya Antriksh station. Mastery of this technology will pave the way for satellite servicing, repairs, and operations in space, making India the fourth country to possess such capabilities.
