Pragyan (rover) facts for kids

Quick facts for kids
Pragyan

Pragyan rover mounted on ramp of Vikram lander
Mission type	Lunar rover
Operator	ISRO
Mission duration	CH2: 0 days (landing failure) CH3: 14 days (planned)
Spacecraft properties
Manufacturer	ISRO
Landing mass	CH2: 27 kg CH3: 26 kg
Dimensions	0.9 m (3.0 ft) × 0.75 m (2.5 ft) × 0.85 m (2.8 ft)
Power	50 W from solar panels
Start of mission
Launch date	CH2: 22 July 2019 (2019-07-22) 14:43:12 IST, (09:13:12 UTC) CH3: 14 July 2023 (2023-07-14) 14:35 IST, (9:05 UTC)
Rocket	LVM3 M1, LVM3 M4
Launch site	SDSC Second launch pad
Contractor	ISRO
Deployed from	Vikram lander
Deployment date	CH2: Intended: 7 September 2019 Result: Never deployed from destroyed lander. CH3: 23 August 2023
Lunar rover
Landing date	6 September 2019, 20:00-21:00 UTC
Landing site	Attempted: 70.90267°S 22.78110°E (Intended) Crash landing at least 500m away from planned site. (Actual)
Distance covered	500 m (1,600 ft) (intended)
Chandrayaan Programme

Pragyan (Sanskrit: प्रज्ञान, romanized: prajñāna, lit. 'wisdom' ) was the rover of Chandrayaan-2 and is the rover for the Chandrayaan-3 mission, two lunar missions developed by the Indian Space Research Organisation (ISRO), Chandrayaan-2 launched on 22 July 2019. Pragyan was destroyed along with its lander, Vikram, when it crash-landed on the Moon on 6 September 2019 and never got the chance to deploy. The launch of Chandrayaan-3 occurred on 14 July 2023, at 2:35 pm IST, and landed on the Moon on 23 August 2023.

Overview

The rover's mass was about 27 kg (60 lb) and was designed to operate on solar power. The rover was to move on 6 wheels traversing 500 meters on the lunar surface at the rate of 1 cm per second, performing on-site analysis and sending the data to the Vikram lander, which would have relayed it to the Earth station. For navigation, the rover was equipped with:

• Stereoscopic camera-based 3D vision: two 1 megapixel, monochromatic NAVCAMs in front of the rover to provide the ground control team 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.

The expected operating time of Pragyan rover was one lunar day or around 14 Earth days, as its electronics were not designed to endure the frigid lunar night. Its power system had a solar-powered sleep/wake-up cycle implemented, which could have resulted in longer service time than planned.

• Dimensions: 0.9 × 0.75 × 0.85 m
• Power: 50 W
• Travel speed: 1 cm/sec.
• Planned mission duration: ≤14 days (one lunar day)

Planned landing site

Two landing sites were selected, each with a landing ellipse of 32 km x 11 km. The prime landing site (PLS54) was at 70.90267 S 22.78110 E (~350 km north of the South Pole-Aitken Basin rim), and the alternate landing site (ALS01) was at 67.874064 S 18.46947 W. The prime site was on a high plain between the craters Manzinus C and Simpelius N, on the near side of the Moon. The criteria used to select the landing zones were: south polar region, on the near side, slope less than 15 degrees, boulders less than 50 cm (20 in), crater and boulder distribution, sunlit for at least 14 days, nearby ridges do not shadow the site for long durations.

The planned landing site and its alternate 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. The nature of the melt is mostly mafic, meaning it is rich in silicate mineral, 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.

2019 crash landing

The Vikram lander, carrying the Pragyan rover, 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 on-board computers on Vikram, with mission control unable to make corrections and thus it impacted the lunar surface.

The lander's trajectory began to deviate at about 2.1 kilometres (1.3 mi; 6,900 ft) above the surface. The final telemetry readings during ISRO's live-stream show that Vikram's final vertical velocity was 58 m/s (210 km/h) from 330 meters above the surface which, according to the MIT Technology Review, is "quite fast for a lunar landing." Initial reports suggesting a crash, have been 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 and the Pragyan rover inside the lander had been destroyed by the impact, creating an impact site and debris field spanning kilometres.

The orbiter part of the mission, with eight scientific instruments, remains operational and will continue its seven-year mission to study the Moon.

See also