SpaDeX update: The Indian Space Research Organisation (Isro) is currently working towards docking the two satellites as part of the Space Docking Experiment (SaDeX). However, the anticipated space handshake may be postponed until March 2025. If the docking process is not completed soon, Isro may experience delays due to the intricacies of operating satellites in Low Earth Orbit (LEO).
After facing several setbacks, the agency is currently analysing sensor data from January 11. During this time, the two satellites were positioned just three meters apart and aligned for docking when they were unexpectedly triggered into safe mode.
January 12 marked a major achievement for ISRO's Space Docking Experiment (SpaDeX) mission. The Chaser (SDX01) and Target (SDX02) satellites successfully approached within a distance of 3 metres during the trials.
Why the delay till March
In low Earth orbits, where the SpaDeX satellites SDX01 and SDX02 are positioned, certain unique challenges are presented. According to former Isro scientist Manish Purohit, the Earth’s rotation causes the spacecraft's footprint to shift after each orbit, which complicates tracking efforts.
Traveling at a speed of approximately 7 km/s, the satellites complete an orbit in about 90 minutes, allowing ground stations only a limited time window of 15-20 minutes for maintaining contact.
For the SpaDeX mission to be successful, optimal conditions are required, such as a good sunlit cycle for the solar panels and an extended visibility duration for ground operations. Purohit, an expert in solar energy and spacecraft solar panels, emphasized the importance of these factors.
"The SpaDeX mission requires optimal conditions, including a good sunlit cycle for the solar panels and extended visibility duration for operations from the ground," Purohit told India Today.
ISRO was previously excited about the close proximity of the satellites, noting that at a distance of 15 meters they could see each other more clearly, likening it to being just 50 feet away for an anticipated handshake. Following the successful launch on December 30, 2024, via a PSLV C60 rocket from the Satish Dhawan Space Centre in Sriharikota, the SpaDeX mission involves two small satellites, each weighing approximately 220 kg.
These satellites were placed into a circular orbit at an altitude of 475 kilometers. The agency is now in the process of analyzing the data gathered, in preparation for the next attempt. Originally scheduled for January 7, the launch was postponed to January 9 due to technical difficulties. The SpaDeX mission aims to demonstrate cost-effective technology for in-space docking—an ability currently held by only three countries: the United States, Russia, and China.