When the Indian space agency, ISRO, made a ‘chaser’ spacecraft get after and hook itself with the ‘target’ spacecraft on January 16, effectively achieving ‘docking’ – for the first time in its history – its mission was still less than complete.
The completion was achieved today, when the chaser de-docked from the target.
The de-docking was announced by the Union Science Minister, Jitendra Singh, via his X post.
Complex process
One intuitively thinks of de-docking as a simple affair, compared with the extremely complex docking, where the speeds and orientation of two spacecrafts have to be matched to perfection. But experts note that de-docking too is not as easy as unhooking.
PV Venkitakrishnan, a former ISRO scientist who today teaches at IIT Madras, told businessline that de-docking is “controlled separation”. De-docking, too, is a highly complex process, he said.
The process calls for a high level of precision in execution, as in the microgravity conditions of space, where there is no atmospheric drag, even minor forces can result in collision. This involves precise, low-force separation, using springs or thrusters, so as to avoid unintended drift. Latches and hooks must be carefully and sequentially disengaged – remotely.
Also, typically, there is a pressurised tunnel between the spacecraft, the decompression must be carefully managed, though it is not clear if ISRO’s spacecrafts, SDX01 and SDX02 had this feature. ISRO has not released details of the de-docking. Finally, the two separated spacecrafts must be maneuvered into their separate, designated orbits.
ISRO has said that it intends to do more docking-undocking exercises, to gain mastery over the difficult task. Learning docking is crucial for ISRO’s upcoming missions such as Chandrayaan-4, which is expected to bring back soil and rock samples, and Gaganyaan, the human space flight mission.
More importantly, learning docking paves the way for refueling in space, enhancing the life of a satellite, which in turn obviates the need for costly fresh launches. Venkitakrishnan observed that docking would serve many strategic and Defence applications too.
