The Indian Space Research Organisation (ISRO) is set to launch its “Space Docking Experiment” (SpaDeX) mission on Monday, December 31, at 9:58 PM from the Satish Dhawan Space Centre (SDSC) SHAR in Sriharikota. The mission will be carried out using the PSLV-C60 rocket.
Objective of the SpaDeX Mission
The primary goal of the SpaDeX mission is to develop and demonstrate the technology required for the rendezvous, docking, and undocking of two small spacecraft. The spacecraft involved are:
- SDX01 (Chaser): The spacecraft that will approach the target.
- SDX02 (Target): The spacecraft that will be docked by the Chaser.
The mission aims to perform these maneuvers in a low-Earth circular orbit.
Challenges of the SpaDeX Mission
Due to the small size and mass of the spacecraft, the SpaDeX mission presents unique challenges. The rendezvous and docking maneuvers require high precision, making the mission more complex than docking two larger spacecraft.
The mission is also a precursor to autonomous docking technology needed for future lunar missions, such as Chandrayaan-4, which will operate without the support of Global Navigation Satellite System (GNSS) from Earth.
Satellite Positioning and Technology
Both SpaDeX spacecraft are equipped with a differential GNSS-based Satellite Positioning System (SPS), which provides Position, Navigation, and Timing (PNT) solutions. The key technologies include:
- RODP Processor: A novel processor included in the SPS receiver to determine the relative position and velocity of the Chaser and Target.
- Carrier Phase Measurements: By subtracting measurements from the same GNSS satellites in both spacecraft, the relative states of the two satellites are determined with high accuracy.
- VHF/UHF Transceivers: These transceivers in both spacecraft transfer GNSS satellite measurements from one spacecraft to the other.
Development and Testing of the SpaDeX Spacecraft
The SpaDeX spacecraft were designed and developed by the UR Rao Satellite Centre (URSC) with the support of various ISRO centers, including:
- VSSC (Vikram Sarabhai Space Centre)
- LPSC (Liquid Propulsion Systems Centre)
- SAC (Space Applications Centre)
- IISU (Indian Institute of Remote Sensing)
- LEOS (Liquid Propulsion Systems Centre)
The spacecraft underwent full integration and testing at M/s Ananth Technologies, Bangalore, under the supervision of URSC. After completing all necessary tests and clearances, the spacecraft were moved from URSC to SDSC for final preparations before launch.
Ground Control and Launch Preparations
The spacecraft will be controlled from ISTRAC (Indian Space Research Organisation Telemetry, Tracking and Command Network) using ISRO ground stations and other externally hired ground stations during the orbital phase.
Currently, after all tests and clearances, the spacecraft are undergoing final preparations at SDSC SHAR in Sriharikota for the upcoming launch.
Multiple-Choice Questions (MCQs):
- What is the primary objective of the SpaDeX mission?
- A) To explore Mars
- B) To demonstrate autonomous docking technology
- C) To test the navigation system of spacecraft
- D) To launch a satellite into orbit
Answer: B) To demonstrate autonomous docking technology
- Which ISRO center designed and developed the SpaDeX spacecraft?
- A) VSSC
- B) SAC
- C) URSC
- D) LEOS
Answer: C) URSC
- What technology is used in the SpaDeX mission to determine the relative position and velocity of the Chaser and Target spacecraft?
- A) GPS-based Navigation
- B) RODP Processor
- C) VHF/UHF Transceivers
- D) Inertial Navigation System
Answer: B) RODP Processor
- Where is the SpaDeX mission set to launch from?
- A) ISRO Telemetry, Tracking and Command Network (ISTRAC)
- B) Vikram Sarabhai Space Centre (VSSC)
- C) Satish Dhawan Space Centre (SDSC) SHAR
- D) Ananth Technologies, Bangalore
Answer: C) Satish Dhawan Space Centre (SDSC) SHAR
- Which future mission is the SpaDeX mission a precursor to?
- A) Chandrayaan-4
- B) Gaganyaan
- C) Mars Orbiter Mission
- D) Aditya-L1
Answer: A) Chandrayaan-4