ISRO will complete the year 2024 with the Space Docking Experiment Mission on December 30

ISRO’s SpaDeX mission, launching on PSLV-C60, will demonstrate space docking using two small spacecraft. | Photo credit: ANI

The Indian Space Research Organization (ISRO) will launch its final mission for 2024 with the PSLV C60/SPADEX mission on December 30. The launch is scheduled for 9:58 pm from Satish Dhawan Space Center in Sriharikota.

The space agency will conduct the Space Docking Experiment (SPADEX) mission for the first time, demonstrating docking in space using two small spacecraft.

According to ISRO, SPADEX will develop and demonstrate the technology required for rendezvous, docking and undocking of spacecraft using two small satellites. “SPADEX will serve as a milestone in advancing India’s capabilities in space docking, a critical technology for future space missions, including satellite servicing, space station operations and interplanetary missions,” the space agency said.

Demonstrating this technology is crucial for future missions such as sending an Indian astronaut to the moon, returning samples from the moon or building and operating the Indian space station.

The PSLV-C60 will separately launch the two small spacecraft Chaser and Target, also called SDX01 and SDX02, each weighing about 220 kg, into a 470 km circular orbit at an inclination of 55 degrees.

The SDX02 spacecraft will be the first to separate 15 minutes after launch, followed by the SDX01 spacecraft a few seconds later.

Incremental speed

“The proven precision of the PSLV vehicle will be used to achieve a low relative velocity between the target and chaser spacecraft at the time of separation from the launch vehicle. This incremental speed will allow the Target spacecraft to establish an inter-satellite distance of 10 to 20 km from the chaser within a day. At this point, the relative speed between the target is balanced by the propulsion system of the target spacecraft,” ISRO said.

ISRO added that at the end of this drift-arrest maneuver, the target and chaser will be in the same orbit at identical speed but about 20 km apart, which is known as far rendezvous.

“Using a similar strategy of introducing and then balancing a low relative velocity between the two spacecraft, the Chaser approaches the target with progressively smaller distances between the satellites of 5 km, 1.5 km, 500 m, 225 m, 15 m etc 3 m, which ultimately led to the docking of the two spacecraft,” it said.

Docking is expected to occur in the first week of January 2025.

Twenty-four PS4 Orbital Experiment Module (POEM-4) payloads will be flown aboard the PSLV-C60 SPADEX mission.