In January 2025, India became the fourth nation in the world to successfully dock two satellites in space. What was the name of this mission?

The correct option is SpaDeX.

Detailed Explanation:
SpaDeX, which stands for Space Docking Experiment, is a landmark mission developed by the Indian Space Research Organisation (ISRO). In January 2025, ISRO successfully docked two satellites in orbit, demonstrating the capability of autonomous docking in space. With the success of this mission, India joined an elite group, becoming the fourth nation in the world to master this complex technology, after the United States, Russia, and China.

Key Objectives and Significance of SpaDeX:
- Autonomous Docking: The mission involved two spacecraft—a "Chaser" and a "Target"—that automatically approached, aligned, and physically joined together in space without human intervention.
- Foundation for Future Missions: Space docking technology is essential for transfer of crew, refueling satellites, and assembling structures in space. This experiment is a crucial stepping stone for India's upcoming space station (Bharatiya Antariksha Station) and future sample-return missions.

Why the Other Options Are Incorrect:
- Mars Orbiter Mission (MOM): Also known as Mangalyaan, this was India's maiden interplanetary mission launched in 2013 to study the Martian surface and atmosphere.
- Chandrayaan-3: This was India's third lunar exploration mission, famous for executing a successful soft landing near the Moon's south pole in August 2023.
- Gaganyaan: This is India's crewed orbital spacecraft project designed to send Indian astronauts (Gaganauts) into a low Earth orbit, but it is not the name of the satellite docking demonstration mission.