Overview
India’s maiden crewed mission, Gaganyaan, will use the HLVM‑3 to inject the OM into the desired orbit.
Key Developments
- The OM consists of a Crew Module and a Service Module, joined by a detachable joint.
- After orbital operations, the Service Module fires its thrusters to de‑orbit, then separates from the Crew Module.
- The Crew Module follows a sphere‑cone configuration, enabling aero‑braking and a safe splash‑down.
- Both modules descend, but the Service Module burns up while the Crew Module lands in the sea.
- The module is designed to be mono‑stable in both aerodynamic and hydrodynamic phases, though two stable positions exist and are managed by thrusters and an up‑righting gas system.
Important Facts
1. A pure sphere offers maximum volume with minimum structural mass, but provides no lift, leading to high g‑forces during vertical fall.
2. The sphere‑cone shape creates a detached shockwave that diverts heat away from the vehicle and supplies lift for a controlled descent.
3. Dynamic instability can arise near Mach 1, causing rapid oscillations; it is mitigated by small control thrusters and timely parachute deployment.
4. Similar three‑module designs (e.g., Russia’s Soyuz and China’s Shenzhou) include an extra habitation/docking module that is jettisoned before re‑entry.
Exam Relevance
The Gaganyaan p