Chennai: India’s Second moon Mission, Chandrayaan-2, successfully entered the lunar orbit on Tuesday morning in a significant milestone that brings India closer to joining select nations that have explored the moon. ISRO Chairman Kailasavadivoo Sivan had earlier described this event as a major challenge.
Lunar Orbit Insertion (LOI) manoeuvre was completed successfully on 20 August 2019 at 0902 hrs IST, as planned, using the onboard propulsion system. The duration of the manoeuvre was 1,738 seconds. With this, Chandrayaan-2 was successfully inserted into a Lunar orbit. The orbit achieved was 114 km x 18,072 km.
The Indian Space Research Organisation (ISRO) fired the spacecraft’s liquid engine for a short while and placed it on a lunar bound orbit. From here, the spacecraft is scheduled to go through four more orbit manoeuvres to reach its final orbit passing over the lunar poles at a distance of about 100 km from the moon’s surface.
Subsequently, the lander will separate from the Orbiter and enter into a 100 km X 30 km orbit around the moon. Then, Chandrayaan-2 will perform a series of complex braking manoeuvres to soft-land in the South polar region of the moon on 7 September 2019.
Chandrayaan-2 will attempt to soft-land the lander Vikram, and rover Pragyan, in a high plain between two craters, Manzinus C and Simpelius N, at a latitude of about 70° south. The mission has 13 Indian payloads, including eight on Orbiter, three on lander and two on a rover, and one passive experiment from US space agency NASA.
The health of the spacecraft is being continuously monitored from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bengaluru with support from Indian Deep Space Network (IDSN) antennas at Bylalu, near Bengaluru. All the systems of Chandrayaan-2 are healthy.
The next Lunar bound orbit manoeuvre is scheduled tomorrow (21 August 2019) between 1230 and 13:30 hrs IST. Chandrayaan-2’s 384,000 km journey started on 22 July after the GSLV MkIII-M1 vehicle lifted off from ISRO’s spaceport at Sriharikota, near Chennai. According to the tentative schedule that ISRO released recently, the final manoeuver is expected to take place between 6 and 7 p.m. on 1 September. From here, the lander named Vikram, carrying the rover called Pragyaan, will separate from the orbit on 2 September.
“Two orbit manoeuvres will be performed on the lander before the initiation of a powered descent to make a soft landing on the lunar surface on 7 September 2019,” an ISRO statement said. The soft landing of the lander and the rolling out of the rover, which is completely designed and developed in India, is critical considering it is being executed by ISRO without any external help. Successful completion of this would prove the Space Agency’s prowess in conducting such missions independently, improving its stature in the global space scenario. The safe landing of the lander on the moon’s surface at the desired location is going to be “15 minutes of terror”, Sivan had said earlier.
While the lander and rover would land on the moon’s unexplored south pole surface, the orbiter would continue to travel through the lunar Orbit for almost a year. The process of landing from an already scheduled 30 km orbit will take 15 minutes, after which the lander’s doors will open for the rover to roll out on to the surface of the moon. This would take nearly four hours, as the rover will move at a speed of 1 cm per minute. It will stay within 500 metres of the lander during its one lunar day, which is equivalent to 14 earth days.
The lander and the rover will carry out experiments to find water on the lunar surface and map for chemicals and topography. ISRO has said that extensive mapping of the lunar surface to study variations in surface composition is essential to trace back the origin and evolution of the moon. Evidence of water molecules discovered by Chandrayaan-1 requires further studies on the extent of water molecule distribution on the surface, below the surface and in the tenuous lunar exosphere to address the origin of water on moon. “The lunar South Pole is especially interesting because the lunar surface area here that remains in shadow is much larger than that at the North Pole. There is a possibility of the presence of water in permanently shadowed areas around it. In addition, the South Pole region has craters that are cold traps and contain a fossil record of the early Solar System,” it says.
The mission was earlier postponed from the announced launch date of 15 July, after a technical snag was identified. The Space agency was quick enough to address the issue and execute the launch on 22 July, as the first step of its 48-day journey to the moon’s unexplored south pole, about 384,000 km away. If the mission becomes successful India will be the fourth nation — the other three are Russia, the United States and China — to land a spacecraft on the moon.