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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Chandrayaan-3 | 2/5 | https://en.wikipedia.org/wiki/Chandrayaan-3 | reference | science, encyclopedia | 2026-05-05T12:59:53.549254+00:00 | kb-cron |
==== Vikram lander ==== The Vikram lander was responsible for the soft landing on the Moon. It is also box-shaped, with four landing legs and four landing thrusters capable of producing 800 newtons of thrust each. It carried the rover and had various scientific instruments to perform on-site analysis. The lander has four variable-thrust engines with slew rate changing capabilities, unlike Chandrayaan-2's lander, which had five, with the fifth one being centrally mounted and capable only of fixed thrust. One of the main reasons for Chandrayaan-2's landing failure was altitude increase during the camera coasting phase. This was removed by allowing the lander to control altitude and thrust during all phases of descent. Altitude correction rate was increased from Chandrayaan-2's 10°/s to 25°/s with Chandrayaan-3. Additionally, the Chandrayaan-3 lander is equipped with a laser Doppler velocimeter (LDV) to allow measuring altitude in three directions. The impact legs were made stronger compared to Chandrayaan-2 and instrumentation redundancy was improved. It targeted a more precise 16 km2 (6.2 sq mi) landing region based on images provided by the Orbiter High-Resolution Camera (OHRC) onboard Chandrayaan-2's orbiter. ISRO improved the structural rigidity, increased polling in instruments, increased data frequency and transmission, and added additional multiple contingency systems to improve lander survivability in the event of failure during descent and landing.
==== Rover pragyan ==== The Pragyan rover is a six-wheeled vehicle with a mass of 26 kilograms (57 pounds). It is 917 by 750 by 397 millimetres (36.1 in × 29.5 in × 15.6 in) in size. The rover is expected to take multiple measurements to support research into the composition of the lunar surface, the presence of water ice in the lunar soil, the history of lunar impacts, and the evolution of the Moon's atmosphere.
=== Payloads ===
==== On lander ==== Chandra's Surface Thermophysical Experiment (ChaSTE) will measure the thermal conductivity and temperature of the lunar surface. Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site. Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere—Langmuir Probe (RAMBHA-LP) will estimate the near-surface plasma density over time. Laser Retroreflector Array (LRA) supplied by NASA's Goddard Space Flight Center serving as a fiducial marker on the moon.
==== On rover ==== An alpha particle X-ray spectrometer (APXS) will derive the chemical composition and infer the mineralogical composition of the lunar surface. Laser-induced breakdown spectroscopy (LIBS) will determine the elemental composition (Mg, Al, Si, K, Ca, Ti, Fe) of lunar soil and rocks around the lunar landing site.
==== On the propulsion module ==== Spectro-polarimetry of Habitable Planet Earth (SHAPE) will study spectral and polarimetric measurements of Earth from the lunar orbit in the near-infrared radiation (NIR) wavelength range (1–1.7 μm). Findings of SHAPE might aid in future exoplanet research and search for extraterrestrial life.
== Mission profile ==
=== Launch ===
Chandrayaan-3 was launched aboard an LVM3-M4 rocket on 14 July 2023, at 09:05 UTC from Satish Dhawan Space Centre Second Launch Pad in Sriharikota, Andhra Pradesh, India, entering an Earth parking orbit with a perigee of 170 km (106 mi) and an apogee of 36,500 km (22,680 mi). On 15 November 2023, the Cryogenic Upper Stage (C25) of the rocket (NORAD ID: 57321) made an uncontrolled re-entry into the Earth's atmosphere around 9:12 UTC. The impact point is predicted over the North Pacific Ocean and the final ground track did not pass over India.
=== Orbit === After a series of Earth bound manoeuvres that placed Chandrayaan-3 in a trans-lunar injection orbit, ISRO performed a lunar-orbit insertion (LOI) on 5 August, successfully placing the Chandrayaan-3 spacecraft into an orbit around the Moon. The LOI operation was carried out from the ISRO Telemetry, Tracking, and Command Network (ISTRAC) in Bengaluru. On 17 August, the Vikram lander separated from the propulsion module to begin landing operations.
=== Landing ===
On 23 August 2023, as the lander approached the low point of its orbit, its four engines fired as a braking manoeuvre at 30 kilometres (19 mi) above the Moon's surface. After 11.5 minutes, the lander was 7.2 km (4.5 miles) above the surface; it maintained this altitude for about 10 seconds, then stabilized itself using eight smaller thrusters and rotated from a horizontal to a vertical position while continuing its descent. It then used two of its four engines to slow its descent to roughly 150 metres (490 ft); it hovered there for about 30 seconds and located an optimal landing spot before continuing downward and touching down at 12:33 UTC.
=== Surface operations ===
On 3 September, the rover was put into sleep mode after it had completed all of its assignments. Its batteries were charged and receiver left on, according to ISRO, in preparation for the impending lunar night. "The rover's payloads are turned off and the data it collected has been transmitted to Earth via the lander", the statement said. Chandrayaan-3's lander and rover were expected to operate only for one lunar daylight period, or 14 Earth days, and the on-board electronics were not designed to withstand the −120 °C (−184 °F) nighttime temperatures on the Moon. On 22 September, the lander and rover missed their wake-up calls, and by 28 September neither had responded, diminishing hopes for further surface operations. Hop experiment Vikram fired its engines for a brief 'hop' on the lunar surface on 3 September, ascending 40 cm (16 in) off the lunar surface and translating a 50 cm laterally across the surface. The lander came to a rest on a nearby slope of roughly 2.6, and turned about −0.97°,1.15°,2° (X,Y,Z-cordinates) with respect to its initial orientation.The test demonstrated capabilities to be used in potential future sample return missions. The instruments and rover deployment ramp were retracted for the hop and redeployed afterwards.