HELSINKI — India successfully launched spacecraft Monday designed to test docking technologies crucial to the country’s major space ambitions.
A Polar Satellite Launch Vehicle (PSLV) lifted off at 11:30 a.m. Eastern (1630 UTC; 10 p.m. local time) Dec. 30 from the Satish Dhawan Space Centre in Sriharikota, with the rocket climbing into the night sky.
The PSLV-C60 rocket carried the primary payload in the form of the Space Docking Experiment (SpaDeX) as well as 24 different experiments aboard the POEM-4 secondary payload module. Of the latter, 14 are Indian Space Research Organisation (ISRO) and institutional payloads and 10 further payloads from non-government entities. These include a walking robotic arm, a debris capture robotic manipulator, a compact plant research module and a range of sensors.
SpaDeX is a mission by ISRO aimed at demonstrating on-orbit docking technology using two small spacecraft. This capability is crucial for India’s future space endeavors including lunar sample return missions and the development of the Bharatiya Antariksh Station (BAS).
ISRO chairman S. Somanath congratulated the rocket and spacecraft teams in comments following successful separation of the two SpaDeX spacecraft.
“I’m really happy to announce the successful accomplishment of the launch of PSLV-C60 for the SpaDeX mission,” S. Somanath said. Nominal time for docking of the two spacecraft is Jan. 7, he added. S. Somanath also confirmed successful deployment of solar arrays on the two spacecraft.
SpaDeX includes two 220-kilogram spacecraft: SDX01, the chaser spacecraft, and SDX02, the target. The pair were placed into their intended 475-kilometer circular orbits with a 55 degree inclination.
The mission includes an indigenous, low-impact docking system with an approach velocity of about 10 millimeters per second, as well as a Laser Range Finder (LRF), Corner Cube Retro Reflectors, and other advanced sensors to facilitate precise docking maneuvers. A GNSS-based Relative Orbit Determination and Propagation (RODP) processor will be used for accurate relative positioning.
“After successful docking and rigidization, electrical power transfer between the two satellites will be demonstrated before undocking and separation of the two satellites to start the operation of their respective payloads for the expected mission life of up to two years,” ISRO stated in a mission briefing.
The mission is part of India’s efforts to become the fourth country to develop independent human spaceflight capabilities with its Gaganyaan program, with a first crewed flight currently planned for 2026. Uncrewed test flights are scheduled for 2025.
The docking technology will also be needed for India’s Chandrayaan-4 lunar south pole sampling mission, expected to launch around 2027 or 2028. Docking will be required to get samples collected from the surface from an ascent vehicle and into a service module capable of returning to Earth.
The launch of SpaDeX and POEM-4 was India’s fifth orbital launch of 2024. Previous missions were the January launch of the XPoSat X-ray astronomy satellite on a PSLV, the INSAT-3DS meteorological satellite on a GSLV in February, the solid SSLV rocket launch of the EOS-08 Earth observation satellite in September, and the launch of the Proba-3 mission for the European Space Agency in early December.
