Chandrayaan-2 will attempt to soft land a lander and rover in a high plain between two craters, Manzinus C and Simpelius N, at a latitude of about 70° south. If successful, Chandrayaan-2 will be the first mission to land a rover near the lunar south pole
According to ISRO, this mission will use and test various new technologies and conduct new experiments. The wheeled rover will move on the lunar surface and will perform on-site chemical analysis. The data will be relayed to Earth through the Chandrayaan-2 orbiter, which will piggyback on the same launch.
Chandrayaan-2 will make India the 4th country in the world to soft-land on the moon, a feat achieved only by US, USSR and China till now.
On 12 November 2007, representatives of the Russian Federal Space Agency (Roscosmos) and ISRO signed an agreement for the two agencies to work together on the Chandrayaan-2 project. ISRO would have the prime responsibility for the orbiter and rover, while Roscosmos was to provide the lander.
Although ISRO finalised the payload for Chandrayaan-2 per schedule, the mission was postponed in January 2013 and rescheduled to 2016 because Russia was unable to develop the lander on time. Roscosmos later withdrew in wake of the failure of the Fobos-Grunt mission to Mars, since the technical aspects connected with the Fobos-Grunt mission were also used in the lunar projects, which needed to be reviewed. When Russia cited its inability to provide the lander even by 2015, India decided to develop the lunar mission independently.
The spacecraft's launch had been scheduled for March 2018, but was first delayed to April and then to October to conduct further tests on the vehicle. On 19 June 2018, after the program's fourth Comprehensive Technical Review meeting, a number of changes in configuration and landing sequence were planned for implementation, pushing the launch to the first half of 2019. Two of the lander's legs got minor damage during one of the tests in February 2019. Chandrayaan-2 launch is tentatively scheduled between 9 to 16 July 2019, with landing expected on 6 September 2019.
Orbiter and lander in stacked configuration with the rover inside the lander
The orbiter will orbit the Moon at an altitude of 100 km (62 mi). The mission will carry five instruments on the orbiter. Three of them are new, while two others are improved versions of those flown on Chandrayaan-1. The approximate launch mass will be 2,379 kg (5,245 lb). The Orbiter High Resolution Camera (OHRC) will conduct high-resolution observations of the landing site prior to separation of the lander from the orbiter. Interfaces between the orbiter and its GSLV Mk III launch vehicle have been finalised. The orbiter's structure was manufactured by Hindustan Aeronautics Limited and delivered to ISRO Satellite Centre on 22 June 2015.
The mission's lander is called Vikram (Sanskrit: विक्रम, lit. 'Valour') named after Vikram Sarabhai (1919-1971) who is widely regarded as the father of the Indian space programme.
The Vikram lander will detach from the orbiter and descend to a lunar orbit of 30 km × 100 km (19 mi × 62 mi) using its 800 N (180 lbf) liquid main engines. It will then perform a comprehensive check of all its on-board systems before attempting to land on the lunar surface. Unlike Chandrayaan-1's Moon Impact Probe, the Vikram lander will make a soft landing, deploy the rover, and perform some scientific activities for approximately 15 days. The approximate combined mass of the lander and rover is 1,471 kg (3,243 lb). The preliminary configuration study of the lander was completed in 2013 by the Space Applications Centre (SAC) in Ahmedabad.
The lander's propulsion system consists of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) Liquid Apogee Motor. Initially, the lander design employed four main liquid engines, but a centrally mounted engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine is expected to mitigate upward draft of lunar dust during the soft landing.
Some associated technologies include a high resolution camera, navigation camera, hazard avoidance camera, an 800 N throttleable liquid main engine and attitude thrusters, altimeter, velocity meter, accelerometer, and the software needed to run these components. The lander's main engine has successfully undergone a high altitude test for a duration of 513 seconds, and closed loop verification tests of the sensors, actuators and software were completed in 2016. Engineering models of the lander began undergoing ground and aerial tests in late October 2016, in Challakere in the Chitradurga district of Karnataka. ISRO created roughly 10 craters on the surface to help assess the ability of the lander's sensors to select a landing site.
The mission's rover is called Pragyan (Sanskrit: प्रज्ञान, lit. 'Wisdom'). The rover's mass will be about 27 kg (60 lb) and will operate on solar power. The rover will move on 6 wheels traversing 300 to 400 meter distance on the lunar surface, performing on-site chemical analysis and sending the data to the orbiter above, which will relay it to the Earth station.
The initial plan was for the rover to be designed in Russia and fabricated in India. However, after Russia proved unable to contribute to the mission, ISRO decided on designing and fabricating the rover itself. IIT Kanpur is developing three subsystems to provide mobility:
Stereoscopic camera-based 3D vision using two NAVCAMs in front of rover will provide the ground team controlling the rovers a 3D view of the surrounding terrain and help in path planning by generating a digital elevation model of the terrain.
Kinematic traction control - will enable the rover to negotiate the rough lunar terrain using independent steering provided on four of its wheels.
Control and motor dynamics - The rover will have six wheels, each driven by an independent electric motor. Four of the wheels will also be capable of independent steering. A total of 10 electric motors will be used for traction and steering.
ISRO selected five scientific instruments for the orbiter, four for the lander, and two for the rover. While it was initially reported that NASA and ESA would participate in the mission by providing some scientific instruments for the orbiter, ISRO in 2010 had clarified that due to weight restrictions it will not be carrying foreign payloads on this mission. However in a last moment update just a month before the launch of the mission, NASA's laser retroreflector was added to lander's payload to help scientists measure exact distances to the moon.
L and S bandSynthetic Aperture Radar (SAR) from Space Applications Centre (SAC), Ahmedabad for probing the first few tens of metres of the lunar surface for the presence of different constituents, including water ice. SAR is expected to provide further evidence confirming the presence of water ice below the shadowed regions of the Moon.
Imaging IR Spectrometer (IIRS) from SAC, Ahmedabad for mapping of lunar surface over a wide wavelength range for the study of minerals, water molecules and hydroxyl present.
^Elumalai, V.; Kharge, Mallikarjun (7 February 2019). "Chandrayaan - II"(PDF). PIB.nic.in. Archived from the original(PDF) on 7 February 2019. Retrieved 7 February 2019. Lander (Vikram) is undergoing final integration tests. Rover (Pragyan) has completed all tests and waiting for the Vikram readiness to undergo further tests.