The Indian Space Research Organisation (ISRO) would attempt to land a rover on the lunar surface on the 7th of September.
The mission dubbed as Chandrayaan-2, carry forwards the achievements of its predecessor Chandrayaan-1 which was launched in 2008 and discovered the presence of water molecules on the lunar surface.
The mission comprises of an orbiter, a lander and rover. The Chandrayaan-2 started it’s journey from Earth on the 22nd of July. It entered the moon’s orbit a month later after completing a series of trickey, complex manoeuvres before its lander was cut loose on the 2nd of September.
On the 7th of September, the lander which contains the rover will be sent towards the ground where it is expected to make a landing near the South Pole of the Moon. The last 15 minutes of the mission, when the Vikram lander will attempt to autonomously guide itself to the lunar surface with no support from ground control is dubbed as “15 minutes of terror” by the ISRO chief K Sivan.
The Chandrayaan-2 orbiter is expected to circle the Moon for a year. During that time, it will map lunar minerals, take high resolution photos and search for water on the lunar surface, using infrared imager and radars. The high resolution camera will help make a digital terrain map of the moon. It will also analyse the thin lunar atmosphere.
The lander would use a technology called a “powered descent” which means that the velocity of the lander is steadily reduced with its own rocket engines. The lander will be moving horizontally across the surface of the Moon as it descends. The rocket engines must bring that horizontal movement to a stop whilst at the same time controlling the rate of descent to near zero just before the moment of touchdown. A parachute could not be used because the moon does not have an atmosphere.
The lander is named Vikram, while the six-wheeled rover is named Pragyaan.
The lander will would measure Moon quakes in it’s vicinity, do a thermal profile of the lunar “soil” among many other things. Meanwhile, the rover will further analyse the lunar soil.
The rear wheels of the rover are imprinted with the national emblem – the Ashoka Chakra – and the Isro logo, which means a permanent mark of India’s visit will be left on the surface of the Moon.
But the extreme temperatures on the Moon’s surface are a real challenge to the mission. When the Sun shines, the lunar temperature can cross 100C and when it sets the temperature can drop to -170C. As their batteries must be recharged with sunlight, the nominal life of both the rover and lander is expected to be one lunar day — that is about 14 earth days.
Both will send back photos of each other so the first Indian “selfies” from the lunar surface are expected soon after they land.
The Moon’s south pole has been picked up as the landing site. The South Pole of the Moon is still a largely unexplored area, and India is targeting a spot that no other landing craft has reached so far. ISRO says the lunar South Pole is especially interesting because the surface area that remains in shadow here is much larger than that of the Moon’s North Pole. This means that there is a possibility of water in areas that are permanently shadowed.
If India does succeed in touching down with the Vikram lander intact, it will become the fourth country to do so after the US, Russia and China.
Source : Various