Indian Space Research Organisation (ISRO) scientists are gearing up for a second SpaDeX mission after successfully bringing together two satellites in space. This time, the mission aims to dock two satellites in an elliptical orbit. The ability to join satellites in space, known as docking, is crucial for India's upcoming Chandrayaan-4 mission and the proposed Bharatiya Antariksh Station, the country's planned space station.

In the initial SpaDeX mission, two 220-kg satellites were launched into a 470-km circular orbit. By introducing a small relative velocity between them, the satellites were allowed to drift apart before being brought closer. On January 16, they successfully docked, showcasing power sharing between the satellites and their ability to function as a single unit.

India became the fourth country, after the US, Russia, and China, to demonstrate in-space docking capabilities. However, docking in an elliptical orbit presents more challenges due to the changing trajectory and velocity of the satellites. The upcoming SpaDeX 2 experiment will focus on docking in an elliptical orbit.

This capability will be crucial for future missions like Chandrayaan-4, where multiple modules may need to be docked and undocked in both Earth and lunar orbits. For moon missions, ISRO typically launches spacecraft into an elliptical Earth orbit and gradually raises the apogee to set up a trajectory towards the Moon.

The first docking operation took time as ISRO approached it cautiously. Sensors were meticulously calibrated for space readings, and simulations were conducted on Earth before attempting the actual docking. The second docking was smoother and quicker, with fewer halts en route to redocking.