The Vikram lander is a crucial component of India's Chandrayaan lunar exploration missions, specifically designed to achieve a soft landing on the Moon's surface. It is a robotic spacecraft module, named after Dr. Vikram Sarabhai, the father of the Indian space program. The lander's origin is tied to the second and third Indian lunar missions, Chandrayaan-2 and Chandrayaan-3, both developed by the Indian Space Research Organisation (ISRO). The primary problem it was designed to solve was demonstrating India's capability to execute a controlled, soft landing on an extraterrestrial body, a feat previously achieved by only a few nations.
The lander's mechanism involves a complex sequence of maneuvers, including de-boosting, rough braking, and fine braking, culminating in a vertical descent. It is equipped with four main throttleable liquid propulsion engines and eight smaller attitude control thrusters to manage its speed and orientation. The lander also carries a suite of scientific instruments, such as the Chandra's Surface Thermophysical Experiment (ChaSTE) and the Instrument for Lunar Seismic Activity (ILSA), to conduct experiments on the lunar surface.
The Vikram lander is intrinsically connected to the Chandrayaan-3 mission, which successfully landed near the Moon's south pole on August 23, 2023. This success followed the partial failure of the Chandrayaan-2 mission in September 2019, where the original Vikram lander hard-landed due to a software glitch. The recent change involved significant redesigns for the Chandrayaan-3 lander, including a stronger structure, enhanced software, and the addition of a Laser Doppler Velocimeter (LDV) for precise altitude and velocity measurements, ensuring a successful landing where the previous attempt failed. The core function of carrying the Pragyan rover and deploying it for lunar surface exploration remained the same across both missions.