ISRO successfully launches SpaDex mission

Tirupati:The Indian Space Research Organisation (ISRO) successfully launched the PSLV-C60 rocket from the Satish Dhawan Space Centre in Sriharikota on Monday, marking a crucial step forward in India’s Space exploration journey.

The mission carried the Space Docking Experiment (SpaDex), a landmark initiative to demonstrate advanced space docking technologies essential for interplanetary missions, satellite servicing, and future space station operations.

The SpaDex mission consists of two small spacecraft, Spacecraft A and Spacecraft B, each weighing approximately 220kg and built on the extended Microsat Bus. The mission’s primary goal is to showcase the autonomous capabilities of rendezvous, docking and undocking. These technologies are critical for extending spacecraft life, transferring resources between satellites and enabling long-term human presence in Space.

ISRO chairman S Somanath described the successful launch as a transformative moment for India’s space programme. He emphasised the importance of docking technologies, highlighting their role in enhancing mission flexibility and paving the way for ambitious future endeavours.

The PSLV-C60 deployed the SpaDex satellites into a precise 475-km circular orbit. The next phase of the mission will involve lowering the orbit to 350km to prepare for docking operations, which is expected on January 7, 2025.

The ISRO chairman confirmed that both satellites have successfully deployed their solar panels and are now operational.

Providing insights into the next steps of the mission, M Sankar, director of the UR Rao Satellite Centre (URSC) said, “The activity for us begins now”.

“The vehicle delayed the second satellite separation by about three seconds, creating a 10 m/s relative velocity. By tomorrow (Tuesday) evening, the satellites will drift 20 km apart.”

“Onboard propulsion will then stabilise this distance, allowing the satellites to orbit like twins. Four days are needed for the sun’s position to align favourably for docking, during which we will progressively reduce the inter-satellite distance from 20km to 1.5km. At this range, an inter-satellite RF link will activate, facilitating data exchange to evaluate software and sensors developed by our Laboratory for Electro-Optic Systems,” he explained.

Sankar detailed the docking sequence, stating that innovative guidance algorithms would minimise propellant consumption. “At 3 meters, the satellites will move at a constant velocity of 10mm/s for docking. Sensors will trigger latches and clamps to secure the satellites, creating a single rigid unit capable of power transfer between them. This demonstration advances docking technology for future missions, such as Bharatiya Antariksha Station,” he added.

In addition to SpaDex, the PSLV-C60 also carried the PSLV Orbital Experimental Module (POEM-4), which hosts 24 experimental payloads developed by startups, industries, academic institutions, and ISRO centres. This platform is designed to conduct various scientific and technological experiments during its orbital phase.

Mission Director M Jaya Kumar praised the mission as a significant achievement, highlighting the inclusion of innovative payloads addressing critical areas like green propulsion systems, advanced inertial sensors, plasma studies and biological experiments in microgravity.

The SpaDex mission itself incorporates cutting-edge technologies, with the spacecraft equipped with Laser Range Finders, Rendezvous Sensors and Proximity Docking Sensors to facilitate precise docking.

The docking mechanism includes a motor-driven system for capturing, retracting, and securing the spacecraft. Once docked, the two spacecraft can exchange power and perform independent payload operations.

Spacecraft A is equipped with a high-resolution camera for imaging, while Spacecraft B carries a Miniature Multispectral Payload and a Radiation Monitor for vegetation studies and radiation measurements.

The POEM-4 platform features a diverse range of experiments designed to advance India’s scientific and technological capabilities in Space.

Several payloads focus on Earth observation, using high-resolution cameras and spectrometers to study vegetation, atmospheric conditions and surface features. Others are designed to test next-generation satellite technologies, including AI-based navigation systems and modular components.

Experiments in communication technologies aim to develop laser-based systems for high-speed data transfer, while studies in thermal management and energy storage are expected to contribute to the development of efficient propulsion systems.

Biological experiments onboard POEM-4 will investigate plant growth and microbial behaviour in microgravity, exploring the potential for sustaining life during long-term missions.

Advanced propulsion systems and high-efficiency solar cells are also being tested, along with experiments to monitor space debris and study solar wind interactions. Another notable experiment involves 3D printing in space, which could revolutionize spacecraft construction and repair.

Meanwhile, the PSLV-C60 mission experienced a slight delay, with the launch rescheduled by two minutes from its original time of 9:58pm. ISRO did not disclose the reason, but the mission proceeded seamlessly, with the rocket deploying its payloads with precision.