Pragyan (Chandrayaan-2)

Pragyan (from ) is a lunar rover that forms part of Chandrayaan-2, a lunar mission developed by the Indian Space Research Organisation (ISRO). The rover was launched as part of Chandrayaan-2 on 22 July 2019 and was destroyed with its lander, Vikram, when it crashed on the Moon on 6 September 2019.Vikram lander located on lunar surface, wasn't a soft landing: Isro. Times of India. 8 September 2019.

In July 2023, Chandrayaan-3 launched, carrying new versions of Vikram and Pragyan, which successfully landed near the lunar south pole on 23 August 2023.

Overview Pragyan has a mass of about and dimensions of , with a power output of 50 watts. It is designed to operate on solar power. The rover moves on six wheels and is intended to traverse on the lunar surface at the rate of per second, performing on-site analysis and sending the data to its lander for relay back to the Earth. 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 a digital elevation model of the terrain. IIT Kanpur contributed to the development of the subsystems for light-based map generation and motion planning for the rover. Control and motor dynamics: the rover design has a rocker-bogie suspension system and six wheels, each driven by independent brushless DC electric motors. Steering is accomplished by differential speed of the wheels or skid steering. Alt URL

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.

History

Planned landing site Two landing sites were selected in the lunar south polar region, each with a landing ellipse of . The prime landing site (PLS54) is at , approximately north of the rim of the South Pole–Aitken basin.Geological Insights into Chandrayaan-2 Landing Site in the Southern High Latitudes of the Moon. Rishitosh K. Sinha, Vijayan Sivaprahasam, Megha Bhatt, Harish Nandal, Nandita Kumari, Neeraj Srivastava, Indhu Varatharajan, Dwijesh Ray, Christian Wöhler, and Anil Bhardwaj. 50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132). The alternative landing site (ALS01) is at . The prime site is on a high plain between the craters Manzinus C and Simpelius N,Chandrayaan-2: How 'Lander Vikram' will touchdown on the moon? Srishti Choudhary, Live Mint 14 July 2019. on the near side of the Moon. The criteria used to select the landing zones were a location in the south polar region and on the near side, a slope less than 15 degrees, with boulders less than in diameter, a crater and boulder distribution, being sunlit for at least 14 days, and with nearby ridges not shadowing the site for long durations.

Both the planned site and the alternative site are located within the polar LQ30 quadrangle. The surface likely consists of impact melt, possibly mantled by ejecta from the massive South Pole–Aitken basin and mixing by subsequent nearby impacts.Update on the Geologic Mapping of the Lunar South Pole Quadrangle (LQ-30): Evaluating Mare, Cryptomare and Impact Melt Deposits. S. C. Mest, D. C. Berman, N.E. Petro, and R. A. Yingst. 46th Lunar and Planetary Science Conference (2015). The nature of the melt is mostly mafic, meaning it is rich in silicate minerals, magnesium, and iron. The region could also offer scientifically valuable rocks from the lunar mantle if the basin impactor excavated all the way through the crust.As India prepares for another Moon mission, here is what makes Chandrayaan-2 special. Sandhya Ramesh, The Print. 14 July 2019.

Crash landing The lander Vikram, carrying Pragyan, separated from the Chandrayaan-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 on Vikram, with mission control unable to make corrections.Chandrayaan 2: Here's everything about ISRO Moon-landing its Vikram lander. Financial Express. Ribhu Mishra, 7 September 2019.

The lander's trajectory began to deviate at about 2.1 kilometers (1.3 mi; 6,900 ft) above the surface.India Just Found Its Lost Vikram Lander on the Moon, Still No Signal. Tariq Malik ,Space. 8 September 2019. The final telemetry readings during ISRO's live-stream show that Vikram final vertical velocity was at above the surface, which according to the MIT Technology Review was "quite fast for a lunar landing". Initial reports suggested a crash,India's Moon Mission Continues Despite Apparent Lander Crash. Mike Wall, Space. 7 September 2019. Quote: "India's Moon Mission Continues Despite Apparent Lander Crash." 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". The Lunar 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.

Pragyan (Chandrayaan-2)

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