Did India just master a critical Space skill in secret? SpaDeX holds the answer

India’s SpaDeX mission, launched on December 30, marks a major step forward in space exploration, as it focuses on mastering the complex process of docking two spacecraft in orbit. This technology demonstration, involving two small spacecraft launched aboard the PSLV rocket, is critical for India’s future goals, including human space missions and assembling structures in space.

The docking maneuver, originally scheduled for January 7 and later postponed to January 9, faced delays due to an unexpected drift between the two spacecraft. This coincided with a change in leadership at ISRO, as V. Narayanan stepped in as the new chairman. Despite these challenges, ISRO actively kept the public informed through updates on its X (formerly Twitter) account. On January 9, the agency announced that the drift had been controlled and that the spacecraft were in a slow approach path towards each other.

By January 10, the two spacecraft were reported to be 1.5 kilometers apart and in hold mode. The next step involved reducing the distance to 500 meters. Since then, ISRO has shifted its communication approach, opting to announce the mission’s completion rather than providing real-time updates. This strategy seems aimed at minimizing public focus on delays and instead highlighting the mission’s achievements.

The SpaDeX mission is a significant milestone for India’s space program, showcasing its commitment to mastering advanced space technologies. If the docking is successful, India will join an elite group of nations—the US, Russia, and China—that have demonstrated this capability. Such expertise is critical for ISRO’s future plans, including bringing samples back from the Moon, establishing a space station by 2035, and sending astronauts to the Moon by 2040.

The mission involves two spacecraft, SDX01 (Chaser) and SDX02 (Target), placed 20 kilometers apart in low-Earth orbit. The Chaser satellite is programmed to approach the Target in carefully planned stages, stopping and holding at specific distances: 5 kilometers, 1.5 kilometers, 500 meters, 225 meters, 15 meters, and finally 3 meters. Once the Chaser reaches the closest point, the two satellites will dock.

Despite initial setbacks, the SpaDeX mission underlines India’s growing capabilities in space exploration. It represents a critical step towards achieving ambitious goals and reinforces India’s position as a key player in the global space industry.

Chandrayaan-4: India’s Docking Dance Around the Moon

The docking experiment is essential for several reasons. A former ISRO official explained that the immediate goal is to support the Chandrayaan-4 mission, while the long-term focus is on India’s planned space station.

The Chandrayaan-4 mission will require multiple docking and undocking operations, both in Earth’s orbit and around the Moon.

The docking experiment is important for many reasons. According to a former ISRO official, the immediate purpose is to assist the Chandrayaan-4 mission, while the long-term goal is to prepare for India’s future space station.

The Chandrayaan-4 mission will involve several docking and undocking operations, both in Earth’s orbit and around the Moon, as reported by the Indian Express.

Two separate modules will be launched using two rockets. These modules will meet and connect in the Geostationary Transfer Orbit (GTO). From there, they will travel together to the Moon. Once they reach the Moon, one module will remain in orbit, while the other will land on the lunar surface to collect samples.

According to P. Veeramuthuvel, an ISRO scientist and project director of the successful Chandrayaan-3 mission in 2023, one of the modules that lands on the Moon will later take off and return to the lunar orbit. There, it will dock with the module that remains parked in lunar orbit. He shared this information in October 2024 at the International Astronautical Conference in Milan.

The collected samples will be moved from the ascent module to the transfer module. After this, the ascent module will detach, and the transfer module will leave the Moon’s gravitational pull. It will then head toward Earth’s orbit using a trans-Earth injection. Once near Earth, the transfer module will release the re-entry module, which will re-enter Earth’s atmosphere and land at a designated location.

Docking: The Cosmic Handshake that Will Build India’s Space Station

Docking is like the crucial handshake in space, allowing different spacecraft to connect securely. For India’s planned Bharatiya Antariksh Station (BAS), this is vital for several reasons:

Building the Station: Think of BAS like a giant Lego set in space. Docking allows individual modules to be launched separately and joined together in orbit, constructing the complete station.
Crew Transfers: Astronauts will need to travel to and from the station. Docking enables crew capsules to safely attach and detach, ensuring their safe passage.

Supplies and Experiments: Just like we need groceries and deliveries, BAS will need regular supplies and new experiments. Docking allows cargo spacecraft to deliver these essentials.1
International Collaboration: India may partner with other countries on BAS. Docking allows spacecraft from different nations to connect, fostering collaboration.

Future Missions: BAS could serve as a launchpad for missions further into space. Docking would be essential for spacecraft to link up with BAS before embarking on these journeys.

Mastering docking technology, as demonstrated by SpaDeX, is a crucial step towards realizing India’s ambitious space station plans.

(The author of this article Girish Linganna is an award-winning Science Writer and a Defence, Aerospace & Political Analyst based in Bengaluru. He is also Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. You can reach him at: girishlinganna@gmail.com)