2) What “simulation” means here (and what ISRO is doing now)

A simulation is a realistic rehearsal that copies launch, spaceflight, and return—without taking the real-world risk. ISRO is running simulations to practise crew procedures, communications, life-support operations, and emergency responses.

These exercises run alongside real hardware tests like escape system trials, parachute air-drops, and propulsion hot-fires. The idea is simple: find problems on the ground, not in the sky.

Why this matters

• Simulations reduce risk by catching design and procedure errors early.
• They train astronauts and mission controllers to react within seconds.
• They prove safety systems—escape tower, parachutes, flotation, recovery—before anyone flies.

3) How the rehearsals actually look

• Crew “analogs”: Astronauts live and work in a spacecraft-like module to follow checklists, keep strict comms discipline, manage sleep–work cycles, and handle stress.
• Hardware-in-the-loop: Flight computers, sensors, and life-support are connected to a virtual mission so engineers see how software + hardware behave in both normal and fault conditions.
• Abort and recovery drills:
  • Launch escape tests to pull the capsule away if the rocket has trouble.
  • Parachute air-drop tests with a dummy capsule to check drogue-to-main chute sequence and safe splashdown.
  • Sea recovery rehearsals with the Indian Navy to locate, hook, and lift the capsule on board.

Recent milestones

• Service Module hot-fire tests to validate propulsion for orbit and de-orbit.
• Integrated Air-Drop Test of the parachute chain using a heavy dummy capsule.
• Pad/launch escape and rocket-sled trials to check escape dynamics.
• Multiple recovery drills at sea.

4) How Axiom Space links to Gaganyaan (learning by doing)

• In June–July 2025, Axiom Mission-4 (Ax-4) flew to the International Space Station with Group Captain Shubhanshu Shukla serving as pilot.
• This mission is separate from Gaganyaan but gives India real, hands-on experience with crew operations, microgravity living, emergency drills, international coordination, and post-splashdown procedures.
• These lessons feed straight into Gaganyaan training, control-room checklists, and recovery discipline—think of it as driving on a real highway before we take out our own car.

5) Quick timeline you can remember

• 2024–early 2025: Multiple escape trials, continued qualification of life-critical systems.
• July 2025: Service Module propulsion hot-fires and longer-duration qualification run cleared.
• June–July 2025: Ax-4 completes; Indian pilot gains ISS experience (helps operating culture and procedures).
• Late 2025 (planned): G1 uncrewed flight with the Vyommitra humanoid to test ascent, orbit, re-entry, and recovery end-to-end.
• Crewed mission (working target): 2027, after all uncrewed tests and safety gates are closed. (Dates can shift if tests demand more work; safety stays first.)

6) Prelims pointers

• Launcher: Human-rated LVM3.
• Stack: Crew Module (re-entry capsule) + Service Module (power, propulsion).
• Crew Escape System: Pulls the capsule away from the rocket during any serious launch emergency.
• Parachutes: Step-by-step sequence—apex cover, drogue, pilot, then main chutes—for a controlled sea landing.
• G1 goal: Full dress-rehearsal without crew to certify systems and recovery chain.

One-line wrap

Practise on the ground, prove safety in parts, then fly—Gaganyaan is moving step-by-step to a safe first human spaceflight, boosted by real lessons from the Axiom-4 mission.