About Chandrayaan 2 

• Chandrayaan 2 is an Indian lunar mission that attempted to conduct a soft landing on the Moon’s south polar region.
• Indian Space Research Organization (ISRO) launched Chandrayaan 2, a mission comprising an orbiter and a soft lander carrying a rover, in July 2019.
• The primary objective of Chandrayaan 2 is to demonstrate the ability to soft- land on the lunar surface and operate a robotic rover on the surface.
• Scientific goals include studies of lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water ice.
• Chandrayaan-2 mission was the successor of its parent mission Chandrayaan and consisted of an Orbiter, Lander and Rover.
• It was launched on GSLV Mk-III, India’s most powerful launcher to date, on July 22, 2019, and reached the lunar orbit on August 20. The lander and rover were set to land on the far side of the Moon on September 6 after being separated from the orbiter. However, the missions did not go as planned when the combination crash-landed on the surface of the Moon.
• While the lander and rover were lost in the accident, the orbiter continues operating in the lunar orbit to date providing key observations of the surface. 

Why in the news?

• Recently, the Indian Space Research Organisation (ISRO) released the information gathered by the scientific payloads of Chandrayaan-2  till now, some of which were still to be analysed and assessed.

What is the information gathered?

• The Orbiter is carrying eight instruments. Through different methods, these instruments are meant to carry out a few broad tasks — study in more detail the elemental composition of the lunar surface and environment, assess the presence of different minerals, and do a more detailed mapping of the lunar terrain.
• ISRO has said each of these instruments has produced a large amount of data that sheds new light on the moon, and offers insights that could be used in further exploration.

Some of the most significant results so far:

WATER MOLECULE:

• The presence of water on the Moon had already been confirmed by Chandrayaan-1, India’s first mission to the Moon that flew in 2008. Before that, NASA missions Clementine and Lunar Prospector too had picked up signals of water presence. But the instrument used on Chandrayaan-1 was not sensitive enough to detect whether the signals came from the hydroxyl radical (OH) or the water molecule (H2O, which too has OH ).
• Using far more sensitive instruments, the Imaging Infra-Red Spectrometer (IIRS) on board Chandrayaan-2 has been able to distinguish between hydroxyl and water molecules, and found unique signatures of both. This is the most precise information about the presence of H2O molecules on the Moon till date.
• Previously, water was known to be present mainly in the polar regions of the Moon. 
• Chandrayaan-2 has now found signatures of water at all latitudes, although its abundance varies from place to place. 
• The Imaging Infra-Red Spectrometer (IIRS) characterised hydration features in the north polar region on the far side of the Moon and has also quantified the hydration within a crater.
• Besides, the Dual Frequency Synthetic Aperture Radar, a microwave imaging instrument, has reported unambiguous detection of potential water ice at the poles as it has been able to distinguish properties of surface roughness from that of water ice, which is a first.

MINOR ELEMENTS:

          The Large Area Soft X-Ray Spectrometer (CLASS) measures the Moon’s X-ray spectrum to examine the presence of major elements such as magnesium, aluminium, silicon, calcium, titanium, iron, etc. This instrument has detected the minor elements chromium and manganese for the first time through remote sensing, thanks to a better detector. The finding can lay the path for understanding magmatic evolution on the Moon and deeper insights into the nebular conditions as well as planetary differentiation.

• CLASS has mapped nearly 95% of the lunar surface in X-rays for the first time.
• Sodium, also a minor element on the Moon surface, was detected without any ambiguity for the first time.
• Scientists at ISRO believe that based on the CLASS findings with respect to sodium, “a direct link of exospheric sodium to the surface can be established (with global data)”, a correlation that remains elusive till date. The finding also opens up the avenue to explore processes causing the sodium to be present on the surface as well as the exosphere.

STUDYING THE SUN: 

• One of the payloads, called Solar X-ray Monitor (XSM), besides studying the Moon through the radiation coming in from the Sun, has collected information about solar flares.
• Solar X-ray Monitor (XSM) has observed a large number of microflares outside the active region for the first time, and according to ISRO, this “has great implications on the understanding of the mechanism behind heating of the solar corona”, which has been an open problem for many decades.

How does all this help?

• While the Orbiter payloads build upon existing knowledge of the Moon in terms of its surface, sub-surface and exosphere, it also paves the path for future Moon missions. 
• Four aspects – mineralogical and volatile mapping of the lunar surface, surface and subsurface properties and processes involved, quantifying water in its various forms across the Moon surface, and maps of elements present on the moon — will be key for future scope of work.
• A key outcome from Chandrayaan-2 has been the exploration of the permanently shadowed regions as well as craters and boulders underneath the regolith, the loose deposit comprising the top surface extending up to 3-4m in depth. 
• This is expected to help scientists to zero in on future landing and drilling sites, including for human missions.

Reference:

1. https://indianexpress.com/article/explained/isro-chandrayaan-2-mission-to-the-moon-water-molecule-7499795/