Pragyan has a mass of about 27 kg (60 lb) and dimensions of 0.9 m × 0.75 m × 0.85 m (3.0 ft × 2.5 ft × 2.8 ft), with a power output of 50watts.[10] It is designed to operate on solar power.[11][12] The rover moves on six wheels and is intended to traverse 500 m (1,600 ft) on the lunar surface at the rate of 1 cm (0.39 in) per second, performing on-site analysis and sending the data to its lander for relay back to the Earth.[13][14][15][16][17] For navigation, the rover is equipped with:
Stereoscopic camera-based 3D vision: two 1-megapixel,monochromatic NAVCAMs in front of the rover to provide the ground control team with a 3D view of the surrounding terrain, and help in path-planning by generating adigital elevation model of the terrain.[18]IIT Kanpur contributed to the development of the subsystems for light-based map generation and motion planning for the rover.[19]
Control and motor dynamics: the rover design has arocker-bogie suspension system and six wheels, each driven by independentbrushless DC electric motors. Steering is accomplished by differential speed of the wheels or skid steering.[20]
The expected operating time of the rover is one lunar day or around 14 Earth days, as its electronics are not designed to endure the frigid lunar night. Its power system has a solar-powered sleep and wake-up cycle, which could result in a longer operation time than planned.[21][22]
Both the planned site and the alternative site are located within the polar LQ30quadrangle. The surface likely consists of impact melt, possibly mantled by ejecta from the massiveSouth Pole–Aitken basin and mixing by subsequent nearby impacts.[25] The nature of the melt is mostlymafic,[25] meaning it is rich insilicate minerals,magnesium, andiron. The region could also offer scientifically valuable rocks from thelunar mantle if the basin impactor excavated all the way through the crust.[26]
The landerVikram, carryingPragyan, separated from theChandrayaan-2 orbiter on 7 September 2019 and was scheduled to land on the Moon at around 1:50 a.m.IST. The initial descent was considered within mission parameters, passing critical braking procedures as planned. The descent and soft-landing was to be done by the onboard computers onVikram, with mission control unable to make corrections.[27]
The lander's trajectory began to deviate at about 2.1 kilometers (1.3 mi; 6,900 ft) above the surface.[28] The finaltelemetry readings during ISRO's live-stream show thatVikram's final vertical velocity was 58 m/s (210 km/h; 130 mph) at 330 m (1,080 ft) above the surface, which according to the MITTechnology Review was "quite fast for a lunar landing".[29] Initial reports suggested a crash,[30][31] and were later confirmed by ISRO chairman K. Sivan, stating that the lander location had been found, and "it must had been a hard landing".[7][32][33] TheLunar Reconnaissance Orbiter took images of the crash site, showing that the lander had been destroyed by the impact, creating an impact site and debris field spanning kilometers.[34]
^"Chandrayaan-2 Spacecraft". Archived fromthe original on 18 July 2019. Retrieved24 August 2019.Chandrayaan 2's Rover is a 6-wheeled robotic vehicle named Pragyan, which translates to 'wisdom' in Sanskrit.
^Annadurai, Mylswami; Nagesh, G.; Vanitha, Muthayaa (28 June 2017).""Chandrayaan-2: Lunar Orbiter & Lander Mission", 10th IAA Symposium on The Future of Space Exploration: Towards the Moon Village and Beyond, Torin, Italy". Archived fromthe original on 28 June 2017. Retrieved14 June 2019.Mobility of the Rover in the unknown lunar terrain is accomplished by a Rocker bogie suspension system driven by six wheels. Brushless DC motors are used to drive the wheels to move along the desired path and steering is accomplished by differential speed of the wheels. The wheels are designed after extensive modelling of the wheel-soil interaction, considering the lunar soil properties, sinkage and slippage results from a single wheel test bed. The Rover's mobility has been tested in the Lunar test facility wherein the soil simulant, terrain and the gravity of the moon are simulated. The limitations w.r.t slope, obstacles, pits in view of slippage/sinkage have been experimentally verified with the analysis results.Alt URL
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
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