Chandrayaan-3
Chandrayaan-3 is the third mission in the Chandrayaan programme, a series of lunar-exploration missions developed by ISRO. The mission consists of Vikram, a lunar lander, and Pragyan, a lunar rover, as replacements for the equivalents on Chandrayaan-2, which had crashed on landing in 2019.
Quick factsChandrayaan-3
Chandrayaan-3 (CHUN-drə-YAHN /ˌtʃʌndrəˈjɑːn/; pronunciation; from Sanskrit: Chandra, "Moon" and yāna, "craft, vehicle") is the third mission in the Chandrayaan programme, a series of lunar-exploration missions developed by ISRO. The mission consists of Vikram, a lunar lander, and Pragyan, a lunar rover, as replacements for the equivalents on Chandrayaan-2, which had crashed on landing in 2019.
Chandrayaan-3 was launched on 14 July 2023, at 14:35 IST from Satish Dhawan Space Centre (SDSC) in Sriharikota, Andhra Pradesh. It entered lunar orbit on 5 August, and touched down near the lunar south pole, at 69°S, on 23 August 2023 at 18:04 IST (12:34 UTC). With this landing, ISRO became the fourth national space agency to successfully land on the Moon, after the Soviet space program, NASA and CNSA, and the first in human history to achieve a soft landing near the lunar south pole.
The lander was not built to withstand the cold temperatures of the lunar night, so it was shut down at sunset over the landing site, twelve days after landing. The orbiting propulsion module remained operational and was repurposed for scientific observations of Earth; it was shifted from lunar orbit to a high Earth orbit on 22 November 2023, where it remains in service.
History
On 22 July 2019, ISRO launched Chandrayaan-2 on board a LVM3 launch vehicle consisting of an orbiter, a lander and a rover. The lander was scheduled to touch down on the lunar surface on 6 September 2019 to deploy the Pragyan rover. The lander lost contact with mission control, deviated from its intended trajectory while attempting to land near the lunar south pole, and crashed.
The lunar south pole region holds particular interest for scientific exploration. Studies show large amounts of ice there. The ice could contain solid-state compounds that would normally melt under warmer conditions elsewhere on the Moon—compounds which could provide insight into lunar, Earth, and Solar System history. Mountains and craters create unpredictable lighting that protect the ice from melting, but they also make landing there a challenging undertaking for scientific probes. For future crewed missions and outposts, the ice could also be a source of oxygen, of drinking water as well as of fuel due to its hydrogen content.
The European Space Tracking network (ESTRACK), operated by the European Space Agency (ESA), and Deep Space Network operated by Jet Propulsion Laboratory of NASA are supporting the mission. Under a new cross-support arrangement, ESA tracking support could be provided for upcoming ISRO missions such as those of India's first human spaceflight programme, Gaganyaan, and the Aditya-L1 solar research mission. In return, future ESA missions will receive similar support from ISRO's own tracking stations.
Spacecraft
Chandrayaan-3 comprises three main components: a propulsion module, lander module, and rover.
The propulsion module carried the lander and rover configuration to a 100-kilometre (62 mi) lunar orbit. It was a box-like structure with a large solar panel mounted on one side and a cylindrical mounting structure for the lander (the Intermodular Adapter Cone) on top.
A few months after the conclusion of the lander portion of the mission, ISRO officials said that the propulsion module was equipped with two radioisotope heating units (RHU), designed and developed by Bhabha Atomic Research Centre (BARC). RHUs keep spacecraft at their operational temperature using the decay of radioactive material, to generate electricity to power heaters. Chandrayaan-3 project director P Veeramuthuvel said ISRO may use nuclear resources to maintain instruments in future rovers. ISRO officials later said the RHUs could not be installed on Chandrayaan-3's Vikram lander and Pragyan rover because it would have increased their mass. This reduced their maximum lifespan to 14 Eart
Mission profile
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, 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.
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.
Funding
In December 2019, ISRO requested the initial funding of the project, amounting to ₹750 crore (US$78 million), out of which ₹600 crore (US$62 million) would be for meeting expenditure towards machinery, equipment, and other capital expenditure, while the remaining ₹150 crore (US$16 million) was sought for operating expenditure. Amit Sharma, CEO of an ISRO vendor, said, "With local sourcing of equipment and design elements, we are able to reduce the price considerably."
Confirming the existence of the project in early 2020, ISRO's former chairman K. Sivan stated that the estimated cost would be around ₹615 crore (equivalent to ₹790 crore or US$82 million in 2026).
Results
The Associated Press, while commenting on the success of the mission, said, "The successful mission showcases India's rising standing as a technology and space powerhouse and dovetails with Prime Minister Narendra Modi's desire to project an image of an ascendant country asserting its place among the global elite." About results on water existence, "There was no word on the outcome of the rover searches for signs of frozen water on the lunar surface (...)".
ISRO also released data from the observations made by ChaSTE (Chandra's Surface Thermophysical Experiment), one of the four instruments present on the lander module. ChaSTE was designed to study the heat conductivity of the Moon's surface and measure the differences in temperatures at different points on and below the surface, with the overall objective of creating a thermal profile of the Moon.The in-situ measurements of the temperature profile were the first to be made regarding the thermophysical properties within the top 10 centimetres (3.9 in) of the lunar surface at a high latitude south polar landing location.
ISRO scientist BH Darukesha said that the high range of 70 °C (158 °F) temperature near the surface was "not expected".