What is ISRO Space Docking Experiment SpaDEX ?

About Space Docking

• Definition: Space docking refers to the precise connection of two spacecraft, allowing them to function as a single unit.
  • Used for tasks such as refueling, repair, and crew exchange.
  • Crucial for assembling large facilities like the International Space Station (ISS).
• Docking vs. Berthing:
  • Docking: Spacecraft autonomously maneuvers and attaches itself to another spacecraft or station.
  • Berthing: Astronauts use the station’s robotic arm to capture the spacecraft. Mission Control then directs the arm to maneuver and attach it.

ISRO achieves historic space docking, making India the 4th nation to accomplish this feat.

Mission Overview

• Launch Date: December 30, 2024.
• Launch Vehicle: PSLV-C60.
• Launch Site: Satish Dhawan Space Centre, Sriharikota.
• Satellites:
  • Chaser (SDX01): 220 kg.
  • Target (SDX02): 220 kg.
• Orbit Details: 470 km low-Earth circular orbit; 55° inclination.
• Objectives:
  • Demonstrate in-space docking capabilities.
  • Test critical technologies like autonomous rendezvous, docking, and undocking.
  • Enable power transfer between docked spacecraft.
  • Conduct microgravity experiments using the PSLV’s fourth stage (POEM-4).

Innovative Use of PSLV’s Fourth Stage

• POEM-4 (PSLV Orbital Experimental Module):
  • Acts as a platform for microgravity experiments after the main mission.
  • Payloads: 24 payloads contributed by academic institutions and startups.

Mission Concept and Execution

• Deployment:
  • Satellites will be deployed simultaneously into orbit with minimal relative velocity.
  • The Target satellite will increase inter-satellite separation to 10-20 km in the Far Rendezvous phase.
• Approach Stages:
  • The Chaser will approach the Target in steps, progressively reducing separation:
    • 5 km → 1.5 km → 500 m → 225 m → 15 m → 3 m.
  • Final docking will occur at 3 meters, demonstrating autonomous precision maneuvering.
• Docking Demonstrations:
  • Docking will validate power transfer between the two spacecraft.
  • Post-docking, they will undock to perform payload experiments.

Why SpaDEX Matters?

• Global Leadership: Advances India’s role in global space exploration.
• Technological Leap: Builds expertise in:
  • Autonomous in-space docking.
  • Orbital control and satellite servicing.
  • Microgravity experimentation.
• Future Missions:
  • Critical for sustained human presence in space and interplanetary missions.

SpaDEX exemplifies India’s growing space ambitions and its commitment to innovative, cost-effective solutions in advanced space technology. With this mission, ISRO is poised to redefine its standing on the global space stage.

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