On December 30, Indian Space Research Organisation embarked on a mission whose concept envisions its indispensable application in future exploratory missions. The space docking experiment or SpaDeX mission is linked to the plan for setting up India’s own space station, named the Bharatiya Antariksh Station, by 2035 to carry out spacewalks and research in microgravity conditions.
Another important objective is to use this capability in the ambitious Chandrayaan-4 lunar mission, planned as a mission to bring back samples from the Moon, that is expected to be launched around 2027. This mission looks at returning with up to 3 kg of lunar regolith or surface deposits from near India’s Shiv Shakti lunar station, Chandrayaan-3’s landing site. As a forerunner to these goals, the Rs 375-crore SpaDeX mission aims to autonomously dock two 220-kg, unmanned craft in space—SDX01, the chaser, and SDX02, the target.
Docking is a crucial procedure to facilitate transfer of astronauts and equipment to and from space stations. As part of the December 30 mission, Isro’s PSLV-C60 launcher released the two spacecraft into a 470-km circular orbit at a 55-degree incline to the equator with a marginal relative velocity between the two. This is to enable the chaser SDX01 to close in on the target SDX02, and attach itself to the latter to achieve a successful docking on January 7. Post docking, electrical power transfer between the two spacecraft will be demonstrated before they are separated to begin working with their respective payloads for an expected mission life of up to two years.
The docking capability will be even more crucial in India’s future manned lunar and other planetary missions, wherein it will allow astronauts in capsules to undock from the orbiting spacecraft and return to it after missions to dock again and head back home. The SpaDeX mission also carried the PS4-orbital experiment module-4 or POEM-4 using the spent fourth stage of PSLV-C60—which otherwise ends as space debris—carrying 24 payloads. Isro Chairman S Somanath is looking ahead at a series of SpaDeX missions involving heavier spacecraft with more complex docking systems. This needs to be diligently aligned with India’s Space Vision 2047, which aims at being a leading space power, with its astronauts landing on the Moon using indigenous technologies.