Chandrayan II — Seeks Moon’s South Pole

March 5, 2018 By Lt. General P.C. Katoch (Retd)
By Lt. General P.C. Katoch (Retd)
Former Director General of Information Systems, Indian Army


In October-November 2018, ISRO is scheduled to attempt what no country has done before. Chandrayan-II will carry an orbiter, a lander and a rover to the moon, with the rover spending 14 days on the surface of the Moon’s ‘South Pole’. Earlier, launch of Chandrayan-II was planned in April but now ISRO has decided to first launch the GSLV Mk II carrying the Gsat-6A satellite by end March, followed by navigation satellite IRNSS-1I that will be lifted off by the PSLV C-41 in first week of April. The Chandrayan-II after reaching lunar orbit, the lander will get detached from the orbiter and make a soft landing just after lunar sunrise on an ancient, table-flat plain some 600 km from the South Pole between two craters, Manzinus C and Simpelius N, at a latitude of about 70° south. The six-wheeled rover fixed in lander will then get released into territory never before explored on the moon’s surface. All previous lunar craft were set down near the equator. The rover has been designed in a manner that it will have power to spend a lunar day or 14 Earth days on the moon's surface, walking some 150-200 km, while undertaking several experiments and on-site chemical analysis of the surface. The rover is capable of sending data and images of the lunar surface back to the Earth through the orbiter within 15 minutes. After spending 14 earth days, the rover will go in a sleep mode but it is hoped it will come alive again part of the moon where the rover lands gets sunlit and the rover’s solar cells get recharged.

In addition to the rover, the orbiter will also capture images of the moon while orbiting it. Instruments aboard the lander and rover will collect data on the moon's thin envelope of plasma, as well as isotopes such as helium-3, a potential fuel for future fusion energy reactors. The orbiter itself will follow up on the discovery of water on the moon’s surface by Chandrayan-I (another first in the world). Chandrayan-II was reportedly to take off three years earlier, but Russia could not provide the lander it had promised. India therefore, had to develop its own lander. The rover weighing 25 kg, will also carry two spectrometers for probing the lunar surface's elemental composition. The is thought to be made up of rocks more than four billion years old that solidified from the magma ocean that covered the newly formed moon. The data would be compared with those from Apollo-era missions that landed in other ancient highlands closer to the equator. According to Dr K Sivan, Chairman ISRO, "All three components of the lunar module are almost ready. Currently, their integration is going on. Once the module is ready, it will have to go through rigorous tests. The launch date will depend on various factors like the moon's relative position with respect to the Earth”.

ISRO’s Chandrayan-I was launched by PSLV rocket but GSLV Mk II will launch the heavier 3,290 kg Chandraan-II. Latter is a challenging mission carrying an orbiter, a rover and a lander to the moon for the first time. Once the GSLV rocket carrying the spacecraft is launched, the orbiter will reach the moon's orbit in one to two months, the moon's orbit being 3,82,000 km from the earth's surface. According to Wu Ji, Director of the National Space Science Center in Beijing, “It (Chandrayan-II) is a difficult and complicated mission”; a landing so far from the lunar equator is especially tricky. Less sunlight reaches the poles, which means the lander and rover must be parsimonious with power. According to James Greenwood, Cosmochemist at Wesleyan University in Middletown, Connecticut in the US, “One of NASA's main priorities is to go to the South Pole on a sample return mission”. So it is not India alone but the whole world is looking at the Chandrayan-II mission eagerly. Considering ISRO’s past achievements and the confidence it displays, success should not be difficult. Successful Chandrayaan-II mission will pave the way for more ambitious ISRO missions like landings on Mars and an asteroid, and probe to the Venus; confirming India’s capability to undertake soft landings on other celestial bodies. Significantly, the Centre has allocated 107.83 billion for the Department of Space for FY 2018-2019, against 91.55 billion in the revised estimates for FY 2017-2018. The allocation includes about 89.63 billion for various space-related projects of the department, and also the targets to be achieved in the next fiscal year. Of 89.63 billion, a major chunk of around 65.76 billion has been budgeted for research and development in manufacturing spacecraft and launch vehicles. This will include three earth observation spacecraft, four Polar Satellite Launch Vehicle flights, one Geosynchronous Satellite Launch Vehicle MK-III and one GSLV. Additionally, the Centre wants to ensure operational launch services for domestic and commercial satellites and make the country self-sufficient in launching 2.5-3 and 4-ton class of communication satellites in geo-synchronous transfer orbit. ISRO is destined to take India to greater heights.