Next month, all being well, India will become the fifth country to touch down on the moon. A heavy rocket will blast off from the Satish Dhawan Space Centre at Sriharikota in the state of Andhra Pradesh carrying a 3890-kilogram uncrewed spacecraft called Chandrayaan-2, which was designed and developed by the Indian Space Research Organisation (ISRO). Unlike its predecessor, Chandrayaan-1, which merely orbited the moon in March 2008, it will become the first Indian moon landing and set down a lander and rover at the lunar south pole, then gather data about the moon’s topography, minerals and very thin atmosphere.
While orbiting, the craft’s onboard Imaging Infrared Spectrometer will begin searching for the signatures and relative abundance of hydroxyl ions and water molecules.
A radar instrument will scan the permanently shadowed crater floors in polar regions to detect water ice. It will also map the thickness of the regolith – the layer of debris that covers solid rock – and measure electrical conductivity.
On the moon’s surface, the lander, named Vikram after Indian astrophysicist Vikram Sarabhai, will turn on its sophisticated devices. Its seismometer will record moonquakes near the landing site, offering clues about the lunar core.
An onboard thermal probe will make the first-ever measurements of the vertical temperature and thermal conductivity profile of the soil, pushing down to a depth of 10 centimetres near the polar region.
The rover, named Pragyan and weighing 25 kilograms, will travel 100 metres, analysing soil content and sending data to the lander using a small radio antenna atop a vertically mounted solar panel. The lander will then relay the information to Earth.
Two front-facing digital navigation cameras will help Pragyan avoid obstacles such as craters, boulders and pits. Tucked away below the rover’s deck, a laser instrument will identify and estimate trace and volatile elements on the lunar surface from a distance of 200 millimetres.
“The instruments on the lander and rover will provide crucial data that cannot be obtained by remote sensing, and could act as a ground truth,” says Sriram Bhiravarasu, from the Lunar and Planetary Institute of Universities Space Research Association (USRA) in the US.
“By studying the moon’s polar volatile deposits, minerals, topography, elemental abundance, and exosphere, Chandrayaan-2 will provide new insights into the moon’s origin and early history.”
Chandrayaan-2 will also carry NASA-owned retro-reflectors, mirrors that reflect laser light signals sent from the Earth. The signals will help pinpoint the lander’s exact location, allowing scientists to more precisely calculate the distance to the moon.
Since its inception in 1969, ISRO has played a pivotal role in advancing India’s space exploration programs. In safely landing Chandrayaan-2’s rover on the moon, India will join the global moon club, following the Soviet Union in 1959, the US in 1969, China in December 2013, and Israel in 2019.
Next, India aims to send astronauts to space by 2022. ISRO scientists are already developing and testing the efficacy of Gaganyaan, a fully autonomous 3.7-tonne spacecraft designed to carry a thee-member crew to orbit and safely return to the Earth after a mission of seven days.
Biplab Das is a science writer based in Bangalore, India.
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