On August 9, the Indian Space Research Organisation (ISRO) successfully executed yet another orbit reduction manoeuvre for India’s third lunar mission, Chandrayaan-3. This manoeuvre was carried out from the ISRO Telemetry, Tracking, and Command Network (ISTRAC) center located in Bengaluru. As a result of this operation, the spacecraft has now achieved a proximity of just 1,437 kilometers from the moon’s surface.
ISRO’s official statement remarked, “Chandrayaan-3’s orbit has been meticulously adjusted to dimensions of 174 km x 1437 km after the manoeuvre conducted today, bringing it even closer to the moon’s terrain.” The subsequent manoeuvre is scheduled for August 14, 2023, to be executed between 11:30 and 12:30 Hours Indian Standard Time (IST).
The concluding orbit reduction manoeuvre, the fifth in the series, is slated for August 16.
Chandrayaan-3, launched on July 14, comprises a lander module (LM), a propulsion module (PM), and a rover. Following the lunar orbit insertion on August 5, ISRO elaborated on their approach: “As the mission progresses, a sequential sequence of manoeuvres has been charted to gradually fine-tune Chandrayaan-3’s orbit, aligning it with the lunar poles. Subsequent to these maneuvers, the propulsion module will detach from the lander during its orbital trajectory. A sequence of intricate braking manoeuvres will then be executed to enable a gentle touchdown within the southern polar region of the moon on August 23, 2023.”
The separation between the PM and LM is planned for August 17. A series of de-boost manoeuvres will be enacted prior to the power descent phase, crucial for a soft landing on the lunar surface. The anticipated touchdown of the lander is scheduled for August 23 at 5:47 PM.
ISRO Chairman S. Somanath, during a presentation on August 8 regarding Chandrayaan-3 – Bharat’s Pride Space Mission, emphasized that the lander possesses the capability to successfully land even in the event of sensor failure during the soft landing attempt on August 23. He underscored, “Should all sensors encounter failure, our lander will still accomplish a landing, contingent upon the functionality of the propulsion system. Even in the unlikely event of both engines failing, a successful landing is assured, in accordance with the meticulously crafted design.” Mr. Somanath went on to highlight the heightened robustness of all systems, revised guidance design, and the integration of innovative algorithms in this mission.
