SpaDeX Mission (Space Docking Experiment)

Launch Vehicle: PSLV-C60

Launch Date: Dec 21, 2024

Orbit: 470 km circular, 55° inclination

Satellites: 2 spacecraft (~220 kg each)

Update (Jan 9, 2025):

Primary Objective – Demonstrate rendezvous, docking, and undocking of two spacecraft in LEO.
Secondary Objectives:
- Demonstration of electric power transfer between docked spacecraft.
- Composite spacecraft control.
- Payload operations post-undocking.

Chaser & Target separated by PSLV with small relative velocity.
Separation builds up to 10–20 km → controlled maneuvers reduce distance to 5 km → 1.5 km → 500 m → 225 m → 15 m → 3 m.
Final low-impact docking at ~10 mm/s.
Post docking: Power transfer, then undocking → both satellites operate payloads for ~2 years.

Docking Mechanism: Low-impact, androgynous, compact design (450 mm).
Sensors:
- Laser Range Finder, Corner Cube Retro-Reflectors (6000–200 m).
- Rendezvous Sensors (2000–10 m).
- Proximity & Docking Sensors (30–0.4 m).
- Video monitoring + Mechanism Entry Sensors.
Autonomous Systems:
- Inter-satellite communication link (ISL).
- GNSS-based Relative Orbit Determination & Propagation (RODP) processor.
- Novel autonomous rendezvous & docking strategy.
Algorithms: V-bar, n-Pulse, Glideslope, PV guidance for precision approach.

SDX-01 (Chaser): High-Resolution Camera (HRC).
SDX-02 (Target):
- Miniature Multi-Spectral Payload (MMX) – vegetation & resource monitoring.
- Radiation Monitor (RadMon) – space radiation studies (useful for human spaceflight).

Makes India the 4th nation to develop in-space docking technology (after USA, Russia, China).
Paves way for:
- Bharatiya Antariksh Station (BAS)
- Chandrayaan-4 sample return mission
- Human spaceflight & lunar exploration
Strengthens India’s strategic autonomy in advanced space technology.

Updated - December 21, 2024 ; 10: 23 PM | ISRO Official Website