CHENNAI: The stage is set for India’s second lunar mission, when Chandrayaan-2, carrying an Orbiter, Lander (Vikram) and Rover (Pragyan), take to skies tomorrow from the SHAR Range at Sriharikota, commencing its 3.844 lakh km, month long journey for a soft landing on the Moon’s South Pole. Weighing 3,850 kg, the launch of Chandrayaan-2, would take place from the Second Launch Pad at 1443 on Monday afternoon when the 43.43m tall heaviest home grown rocket, Geosynchronous Satellite Launch Vehicle Mark-III (GSLV MkIII-M1), capable of launching 4-ton class of satellites to the Geosynchronous Transfer Orbit (GTO), lifts off from the spaceport.
ISRO sources said the Launch rehearsal has been completed and much to their delight the performance was normal. After a meeting of the Launch Authorisation Board and Mission Readiness Review Committee, the countdown for the launch would begin.
The launch was earlier scheduled on July 15, but was deferred an hour before the take off due to a technical snag in the launch vehicle. On July 18, ISRO announced that the expert committee identified the root cause of the technical snag and all corrective actions implemented. “Thereafter, the system performance is normal and Chandrayaan-2 launch is now rescheduled for July 22 at 1443 hrs”, it said. About 16 minutes after lift off and after ignition and separation of all the three stages, Chandrayaan-2 will be injected into an earth parking 170.06 x 40,400 km orbit.
Carrying 13 Indian Payloads (eight on Orbiter, 3 on Lander and two on Rover) and one passive experiment from NASA, Chandrayaan-2 is on a mission unlike any before. Leveraging nearly a decade of scientific research and engineering development, the second lunar expedition will shed light on a completely unexplored section of the Moon—its South Polar region, a site not explored by any country yet. Only Russia, the United States and China have soft-landed on the moon.
India’s first Lunar Mission Chandrayaan-1 was launched using a PSLV on October 22, 2018 and it detected presence of water on the Lunar surface.
While the technical difficulties of landing on the Moon’s South Polar region have deterred many previous attempts, Chandrayaan-2 will be the first to reach this part of the lunar surface—taking the Indian tricolour where no human has been before.
The landing has been planned for September 6 or the next day, almost a month after the spacecraft nears the Moon and starts orbiting it.
The spacecraft has been designed to go around Earth for 17 days in increasingly bigger loops. In the process it makes use of Earth’s gravity to build up power and saves some fuel. With the delay in the launch, ISRO might shrink the original 17-day period that the spacecraft was set to go around the Earth in increasingly higher orbits before being put on course to the Moon. Sources said going by the experience of Chandrayaan-1 and the Mars Orbiter Mission of 2013, there was enough cushion in the mission to reduce the number of Earth orbits—and later even around moon (28 days). A reduced number of earth orbits could make up for the lost days.
However, the day it must leave earth and the day it must enter moon’s
orbit could not be touched, so as to keep the landing position and schedule
intact, the sources added.
A series of maneuvers will be carried out to raise its orbit and put Chandrayaan-2 on Lunar Transfer Trajectory. On entering Moon’s sphere of influence, on-board thrusters will slow down the spacecraft for Lunar Capture. The Orbit of Chandrayaan-2 around the moon will be circularized to 100×100 km orbit through a series of orbital maneuvers. On the day of landing, the lander will separate from the Orbiter and then perform a series of complex maneuvers comprising of rough braking and fine braking.
Imaging of the landing site region prior to landing will be done for finding safe and hazard-free zones.
After a month long journey and traversing 3.844 lakh km, the lander-Vikram will finally land near South Pole of the moon on September six and subsequently, Rover will roll out and carry out experiments on Lunar surface for a period of one Lunar day which is equal to 14 Earth days.
The Orbiter will continue its mission for a duration of one year. This mission will help ISRO gain a better understanding of the origin and evolution of the Moon by conducting detailed topographical studies, comprehensive mineralogical analyses, and a host of other experiments on the lunar surface. It would also explore discoveries made by Chandrayaan-1, such as the presence of water molecules on the Moon and new rock types with unique chemical composition.
Through this mission, ISRO aims to expand India’s footprint in space, inspire a future generation of scientists, engineers and explorers and surpass international aspirations. ISRO said “We aim to improve our understanding of the Moon, which could lead to discoveries that will benefit India and humanity as a whole.”
These insights and experiences would cause a paradigm shift in how lunar expeditions were approached for years to come, propelling further voyages into the farthest frontiers. Chandrayaan-2 has several science payloads to expand the lunar scientific knowledge through detailed study of topography, seismography, mineral identification and distribution, surface chemical composition, thermo-physical characteristics of top soil and composition of the tenuous lunar atmosphere, leading to a new understanding of the origin and evolution of the Moon. The Orbiter payloads will conduct remote-sensing observations from a 100 km, orbit while the Lander and Rover payloads will perform in-situ measurements near the landing site. For understanding of the Lunar composition, it was planned to identify the elements and mapping its distribution on the lunar surface both at global and In-situ level.
In addition detailed 3-dimensional mapping of the lunar regolith will be done. Measurements on the near surface plasma environment and electron density in the Lunar ionosphere will be studied. Thermo-physical property of the lunar surface and seismic activities will also be measured along with study of water molecule distribution using infra red spectroscopy, synthetic aperture radiometry and polarimetry as well as mass spectroscopy techniques. Other key payloads included Chandrayaan 2 Large Area Soft X-ray Spectrometer for Elemental composition of the Moon, Imaging IR Spectrometer for Mineralogy mapping and water-ice confirmation, Synthetic Aperture Radar L and S Band for Polar-region mapping and sub-surface water-ice confirmation, Orbiter High Resolution Camera for High-resolution topography mapping, Chandra’s Surface Thermo-physical Experiment for Thermal conductivity and temperature gradient, Alpha Particle X-ray Spectrometer and Laser Induced Breakdown Spectroscope for In-situ elemental analysis and abundance in the vicinity of landing site.
(AGENCIES)
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