India’s Chandrayaan-3 moon mission is poised to make history, attempting to soft land the Vikram Lander, carrying the Pragyaan rover, near the moon’s south pole.
This historic event heralds a thrilling yet anxiety-filled period termed as the “20 Minutes of Terror”.
Journey of Chandrayaan-3 to the Moon
The voyage of Chandrayaan-3 began with an astounding lift-off, courtesy of ISRO’s Bahubali rocket, the Mark-3 launch vehicle, which successfully placed Chandrayaan-3 into orbit. Circling earth in elliptical paths, the spacecraft gained necessary velocity.
On 1st August, Chandrayaan-3 embarked on its 3.84 lakh km journey towards the moon. Four days later, it smoothly glided into the moon’s orbit.
Once within the lunar orbit, Chandrayaan-3 was stabilized to prepare for the separation of its components. This crucial and tricky maneuver occurred on the 17th of August.
The propulsion module and the Vikram lander, cradling the Pragyaan rover, detached successfully while remaining within the 153 km by 163 km orbit.
Afterward, the Vikram lander positioned nearer to the moon’s surface within a 134 km by 25 km elliptical orbit, in readiness for the powered descent, something India had successfully achieved with its predecessor Chandrayaan-2.
The Dreaded ’20 Minutes of Terror’
From a height of about 25 km, the Vikram lander began its descent towards the moon. Then, the lander starts to decelerate, transitioning into the ‘rough braking phase’, lasting approximately 11 minutes.
Subsequent maneuvers maneuver the lander into a vertical orientation, earmarking the ‘fine braking phase’ commencement. It was during this phase that the Chandrayaan-2 unfortunately faltered, losing control and crashing.
Once at 800 meters above the lunar surface, both velocities achieve zero and the lander hovers over the lunar surface, scouting for an ideal landing site
It continues its descent until it hovers again at 150 meters, capturing images for hazard detection and locating the best landing site.
Finally, the lander touches the lunar surface, with only two engines firing to cushion the landing. The sensors within the lander’s legs will detect the lunar surface, triggering the engine shutdown, hence concluding the nerve-wracking “20 Minutes of Terror”.
Once touchdown is confirmed, the lunar dust (regolith) stirred up by the landing is allowed to settle. Subsequently, the Pragyaan rover gently rolls onto the lunar surface.
This marks the beginning of actual scientific pursuits for the Vikram lander and the Pragyaan rover. Both solar-powered, they’ll function for one lunar day – equivalent to 14 Earth days.
Among the first actions, the missions will capture and beam back images of each other.
India’s Giant Leap
Chandrayaan-3’s mission represents a significant step for ISRO and a giant leap for India. Success will place India as the fourth country to achieve a soft landing on a celestial body. India has made a truly celestial leap!