NEW DELHI: To take the first giant step towards launching India’s own space station and interplanetary missions, Isro is scheduled to launch the SpaDeX mission, which is aimed at developing and demonstrating a cost-effective technology required to dock and undock spacecraft in space, from Sriharikota at 9.58 pm on Dec 30 using its PSLV-C60 rocket.
Through this mission, India is marching towards becoming the fourth country in the world to have space docking technology, Isro said. In a post on X, the space agency said, “PSLV-C60, fully integrated up to PS4 at the PIF facility for the first time, was moved to the MST at the First Launch Pad—over three hours captured in just a few seconds.”
SpaDeX technology is essential for India’s space ambitions such as landing an Indian on the Moon, sample return from the Moon, and building and operation of Bharatiya Antariksh Station, Isro said in an explainer.
In-space docking technology is essential when multiple rocket launches are required to achieve common mission objectives. The SpaDeX mission was floated to develop and demonstrate the technology needed for rendezvous, docking and undocking of two small spacecraft in a low-Earth circular orbit, it said.
The SpaDeX mission consists of two small spacecraft Target and Chaser (about 220 kg each) to be launched by PSLV-C60, independently and simultaneously, into a 470 km circular orbit at 55° inclination. The demonstrated precision of PSLV will be used to give a small relative velocity between Target and Chaser spacecraft at the time of separation from the launch vehicle. This incremental velocity will allow the Target spacecraft to build a 10-20 km inter-satellite separation with respect to Chaser within a day.
At the end of this drift arrest manoeuvre, Target and Chaser will be in the same orbit with identical velocity, but separated by 20 km, known as Far Rendezvous. Chaser will then approach Target with progressively reduced inter-satellite distances of 5 km, 1.5 km, 500 m, 225 m, 15 m, and 3 m, ultimately leading to the docking of the two spacecraft.
After successful docking and rigidisation, electrical power transfer between the two satellites will be demonstrated before undocking and separation of the satellites to start the operation of their respective payloads for the expected mission life of up to two years.
Besides the docking demonstration, PSLV-C60 rocket’s fourth stage (POEM) will carry a total of 24 payloads that will be activated once two spacecraft are released in space. Of the 24, 14 payloads are from Isro centres and 10 payloads are from various non-government entities (NGEs) comprising academia and start-ups.
