Third time’s the charm? SpaDeX satellites 230 metres apart, ISRO may attempt docking today

Officials told The Indian Express that the final docking manoeuvre may be carried out on Sunday.

ISRO had to postpone the docking plans on two occasions earlier, on January 7 and January 9, because the satellites had not been able to achieve the required alignment.

“After the last manoeuvre, the satellites had drifted away, but they were safe. Now, we are re-attempting the entire process. There are certain fixed hold points, the satellites would be brought to these hold points again, before we attempt docking again,” an ISRO official had said at that time.

As per the docking plan, the Chaser satellite is supposed to be progressively brought closer to the Target satellite, holding positions at a distance of 5 km, 1.5 km, 500 metres, 225 metres, 15 metres and 3 metres, before joining together.

SpaDeX is a technology demonstrator mission in which ISRO is attempting a docking manoeuvre for the first time. In-space docking is a critical capability for the more ambitious missions that ISRO has planned in the future, including the sample return mission, manned moon mission, and the building and operation of the Bharat Antariksh Station.

Only three other countries — US, Russia and China — currently have this capability.

The first actual mission requiring the docking capability is likely to be Chandrayaan-4, which is supposed to bring back lunar samples to Earth. The re-entry module of this mission, which will be designed to withstand the heat of re-entry to the Earth’s atmosphere, is planned to be launched separately. The transfer module carrying samples from the Moon will dock with the re-entry module in the Earth’s atmosphere.

The first module of Bharatiya Antariksh Station is expected to be launched in 2028. It is supposed to have five modules, which are expected to be launched separately and brought together in space.

The human mission to the Moon is not expected to happen before 2040.