Chandrayaan 2 is the second lunar mission being conducted by Indian Space Research Organization. The first mission was Chandrayaan 1 (22 Oct 2008-28 Aug 2009) which was a successful mission. Chandrayaan 1 orbiter was the first manmade lunar orbiter to find water on the moon. It was because of Chandrayaan 1 mission, India built its deep space network.

Chandrayaan 2 is a successor of Chandrayaan 1, but it has three modules unlike chandrayaan 1 which had two modules, one is orbiter and another is Lunar Impact Probe which put the first Indian flag on the surface of the moon. The three modules are Orbiter, a soft lander and rover.

Launching of Chandrayaan 2

Courtesy: ISRO

Chandrayaan 1 was launched on a XL variant of Polar Satellite Launch Vehicle ( PSLV-XL ); but PSLV series rockets are not heavy lift vehicles although it can be noted that PSLV-XL was used to launch Mars Orbiter Mission ( MOM ) which was a successful mission. But the need of a heavy lift vehicle always felt by ISRO.

That’s why ISRO started to develop a new launch vehicle. That is when GSLV series came into the picture. Chandrayaan 2 was launched on 22nd July 2019 on a GSLV Mark-III Rocket. GSLV MARK-III uses two solid fuel boosters at first stage attached with the second stage or main rocket engine; for the second stage it uses liquid propellant. For the third stage it is Cryogenic Engine. It should be noted that GSLV series is the first kind of rockets where India first uses Cryogenic Engines.

Orbit and Trajectory

On 22nd July 2019 at 2:43 PM Chandrayaan 2 was launched. The GSLV MK-III put Chandrayaan 2 in a highly elliptical orbit of apogee of around 170 km and perigee of 45475 km above earth surface at an inclination of 21.35 degree about the equatorial plane.

There are some successful earth-bound maneuver performed to raise the orbit and the translunar insertion will be performed on 14th August, 2019 between 0300 – 0400 hrs (IST) [ Translunar lunar insertion means it will leave the earth orbit and move towards the moon ].

It is scheduled to enter the moon trajectory that is lunar orbit insertion on 20th August. Then orbiter will orbit the moon at a 100 x 100 km altitude above moon that is nearly circular orbit.

Now the primary modules of Chandrayaan 2 is explained below.

Orbiter

Courtesy: ISRO

The Chandrayaan-2 orbiter will circle the moon and provide information about its surface. "The payloads will collect scientific information on lunar topography, mineralogy, elemental abundance, lunar exosphere and signatures of hydroxyl and water-ice", ISRO commented on its website. The mission will also send a small, 20-kilogram (44 lbs.), six-wheeled rover to the surface.

• Terrain Mapping Camera 2 ( TMC-2 ), which will map the lunar surface in three dimensions using two on-board cameras. A predecessor instrument called TMC flew on Chandrayaan-1.

• Collimated Large Array Soft X-ray Spectrometer ( CLASS ), which will map the abundance of minerals on the surface. A predecessor instrument called CIXS ( sometimes written as C1XS ) flew on Chandrayaan-1.

• Solar X-ray Monitor ( XSM ), which looks at emissions of solar X-rays.

• Chandra's Atmospheric Composition Explorer ( ChACE-2 ), which is a neutral mass spectrometer. A predecessor instrument called CHACE flew on Chandrayaan-1's Moon Impact Probe.

• Synthetic Aperture Radar (SAR), which will map the surface in radio waves. Some of its design is based on Chandrayaan-1's MiniSAR.

• Imaging Infra-Red Spectrometer ( IIRS ), which will measure the abundance of water/hydroxl on the surface.

• Orbiter High Resolution Camera ( OHRC ) to examine the surface, particularly the landing site of the lander and rover.

The orbiter will orbit the Moon at an altitude of 100 km. The mission life of the Orbiter is one year and it will be placed in a 100X100 km lunar polar orbit.

Vikram Lander

The Lander of Chandrayaan 2 is named Vikram after Dr Vikram A Sarabhai, the Father of the Indian Space Programme. It is designed to function for one lunar day, which is equivalent to about 14 Earth days. Vikram has the capability to communicate with IDSN at Byalalu near Bangalore, as well as with the Orbiter and Rover. The Lander is designed to execute a soft landing on the lunar surface. It weighs 1471 kg.

The lander's instruments include :

• Instrument for Lunar Seismic Activity ( ILSA ), to look for moonquakes

• Chandra's Surface Thermophysical Experiment ( ChaSTE ), to examine the surface's thermal properties

• Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere ( RAMBHA-Langmuir Probe ), to look at plasma density on the surface

The lander will make a soft landing on the surface and send out the rover. Chandrayaan-2's lander and rover are targeted for a location about 600 kilometers ( 375 miles ) from the south pole, which would be the first time any lander will touched down the moon's serface so far from the moon's equator.

Pragyan Rover

Pragyan Rover

Chandrayaan 2's Rover is a 6-wheeled robotic vehicle named Pragyan, which translates to 'wisdom' in Sanskrit. It can travel up to 500 m and leverages solar energy for its functioning. It can only communicate with the Lander.

It weighs only 27kg and will operate on solar power. The rover will move on 6 wheels traversing 500 meters on the lunar surface at the rate of 1 cm per second, performing on-site chemical analysis and sending the data to the lander, which will relay it to the Earth station.

The expected operating time of Pragyan rover is one lunar day or around 14 Earth days but its power system has a solar-powered sleep/wake-up cycle implemented, which could result in longer service time than planned.

The rover will carry two science instruments to look at the composition of the surface: the Laser-Induced Breakdown Spectroscope ( LIBS ) and the Alpha Particle X-Ray Spectrometer ( APXS ). The rover will move semi autonomously, examining the lunar regolith's composition.

Data Sources: http://isro.gov.in

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