Axiom-4 Mission

Context

On June 25, 2025, Axiom-4 mission was launched by SpaceX using the Falcon 9 rocket, carrying four astronauts, including Group Capt. Shubhanshu Shukla from India, aboard the Dragon crew capsule to the International Space Station (ISS). This mission is notable for India's growing human spaceflight participation and highlights advancements in commercial space collaboration.

Mission Overview:

Mission Name: Axiom-4 (AX-4)
Operator: Axiom Space (Private company based in the U.S.)
Launch Vehicle: SpaceX Falcon 9
Spacecraft: Crew Dragon (SpaceX)
Indian Representative: Group Capt. Shubhanshu Shukla (Mission Pilot)
Launch Site: NASA’s Kennedy Space Center, Florida
Destination: International Space Station (ISS), ~400 km above Earth
Docking Time: ~28 hours post-launch

Orbital Mechanics – Why 28 Hours to Dock:

The capsule does not travel straight up to 400 km; instead, it enters an elliptical parking orbit (~200 km).
Initial orbit period of Dragon: ~88 minutes
ISS orbit period: ~92 minutes
Dragon performs phasing burns (thruster firings) to gradually raise its orbit and synchronize with ISS trajectory.
Docking choreography adheres to orbital mechanics, safety protocols, and velocity matching.

Approach and Docking Procedure:

Pre-docking Profile: 18 orbits (~28 hours)
Corridor alignment and velocity control: Capsule slows down from kilometres/sec to centimetres/sec near the ISS.
Holding Points: 400 m, 220 m, 20 m, and 1 m with go/no-go polls and LIDAR scans.
Safety Rule: Even one sensor error triggers automated retreat protocol.
Conservative docking profile selected to prioritize fuel availability, crew rest, and system checkouts.

Relevance for India and Space Exploration:

Demonstrates India’s growing human spaceflight capability and training.
Showcases private-public collaboration (NASA, Axiom Space, SpaceX).
Offers learnings for ISRO’s Gaganyaan mission, especially in orbital rendezvous and docking operations.