Chandrayaan-2’s landing module ‘Vikram‘ will begin its final descent to pull off a historic soft landing on the lunar surface in the early hours of Saturday, as the Indian Space Research Organisation awaits with bated breath for the ‘terrifying moment.’

A successful landing will make India the fourth country after Russia, the US and China to achieve a soft landing on the moon. But it will be the first to launch a mission to the unexplored lunar south pole.Joined by about 60-70 high school students from across the country, PrimeMinister Narendra Modi will be present at the ISRO centre in Bengaluru to witness live the space feat, according to officials.

‘Vikram‘ with rover ‘Pragyaan‘ housed inside is scheduled for a powered-descent between 1 am and 2 am on 7 September, followed by its touchdown between 1.30 am and 2.30 am. The lander is now in an orbit that would be about 35 km from the lunar surface at its nearest point from where it will begin its final descent.

ISRO has said Chandrayaan-2 will attempt to soft land thelander and rover in a high plain between two craters, Manzinus C and SimpeliusN, at a latitude of about 70 south. ISRO Chairman K Sivan said the proposedsoft landing on the Moon was going to be a “terrifying” moment as the ISRO hasnot done it before, whereas Lunar Orbit Insertion (LOI) manoeuvre was successfully carried out during the Chandrayaan-1 mission.Explaining the landing man oeuvres,Sivan had said once the man oeuvre starts from about 30 km to land on the surface of the moon, it will take 15 minutes. “This 15 minutes travel of landeris new to ISRO. It is for the first time we are going to another body where there is no atmosphere and using the propulsion system we will have to break the velocity and bring the vehicle safely to soft land. To achieve this, we will have to balance between the gravity and thrust. So we have to modulate the thrust of the engine,” he had said.Following the landing, the rover ‘Pragyaan‘will roll out from ‘Vikram‘ between 5.30 am and 6.30 am. While, the ‘Pragyaan‘will carry out experiments on the lunar surface for a period of one lunar day,which is equal to 14 earth days, the main orbiter will continue its mission fora year.

The lander and rover carry country’s symbols on them, which will remain on the moon for long. “The rover has six wheels (three each on both sides), the back two wheels- one has Ashoka Chakra on it and the other has ISROemblem. Also, the ramp of the lander on which rover will come out and land onmoon has Indian flag on it,” Sivan had earlier said.

The Rs 978 crore unmanned moon mission (satellite cost Rs603 crore, GSLV MK III cost Rs 375 crore) is expected to shed light on acompletely unexplored section of the Moon – its South Polar region. Pointingout that Chandrayaan 2 was going to South Pole, a place where nobody else hasgone, ISRO Chairman K Sivan had said, the entire scientific community of thenation and the globe were eagerly waiting for the mission.According to ISRO,the lunar South Pole is especially interesting because of the lunar surfacearea here that remains in shadow is much larger than that at the North Pole andthere was a possibility of the presence of water in permanently shadowed areasaround it. In addition, South Pole region had craters that are “cold traps” andcontain a fossil record of the early Solar System.

India’s Geosynchronous Satellite Launch Vehicle, GSLVMkIII-M1 had successfully launched the 3,840-kg Chandrayaan-2 spacecraft intothe earth’s orbit on 22 July. Chandrayaan-2 satellite began its journey towardthe moon leaving the earth’s orbit in the dark hours on 14 August, after acrucial manoeuvre called Trans Lunar Insertion (TLI) that was carried out byISRO to place the spacecraft on ‘Lunar Transfer Trajectory.’The spacecraftsuccessfully entered the lunar orbit on 20 August by performing Lunar OrbitInsertion (LOI) manoeuvre. On 2 September, the lander ‘Vikram‘ successfullyseparated from the orbiter, following which two de-orbiting manoeuvres wereperformed to bring the lander closer to the Moon.

The health of the spacecraft is being continuously monitoredfrom the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking andCommand Network (ISTRAC) in Bengaluru with support from Indian Deep SpaceNetwork (IDSN) antennas at Bylalu, near Bengaluru.The orbiter carries eightscientific payloads for mapping the lunar surface and study the exosphere(outer atmosphere) of the Moon while the lander carries three scientificpayloads to conduct surface and subsurface science experiments.

The rover carries two payloads to enhance the understandingof the lunar surface. The rover will be rowing on the moon on its ownpropulsion at the speed of one cm per second and will cover 500 metres in itslifetime. According to ISRO, the mission objective of Chandrayaan-2 is todevelop and demonstrate the key technologies for end-to-end lunar missioncapability, including soft-landing and roving on the lunar surface.

On the science front, the mission aims to further expand theknowledge about the moon through a detailed study of its topography,mineralogy, surface chemical composition, thermo-physical characteristics andatmosphere, leading to a better understanding of the origin and evolution ofthe moon.