Chandrayaan-2 facts for kids
Chandrayaan-2 composite
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Mission type | Lunar orbiter, lander, rover |
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Operator | Indian Space Research Organisation (ISRO) |
Mission duration |
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Spacecraft properties | |
Manufacturer | Indian Space Research Organisation (ISRO) |
Launch mass | Combined (wet): 3,850 kg (8,490 lb) Combined (dry): 1,308 kg (2,884 lb) Orbiter (wet): 2,379 kg (5,245 lb) Orbiter (dry): 682 kg (1,504 lb) Vikram lander (wet): 1,471 kg (3,243 lb) Vikram lander (dry): 626 kg (1,380 lb) Pragyan rover: 27 kg (60 lb) |
Power | Orbiter: 1 kW (1.3 hp)
Vikram lander: 650 W Pragyan rover: 50 W |
Start of mission | |
Launch date | 22 July 2019, 14:43:12 IST (09:13:12 UTC) |
Rocket | GSLV Mark III M1 |
Launch site | Satish Dhawan Space Centre Second Launch Pad |
Contractor | Indian Space Research Organisation (ISRO) |
Moon orbiter | |
Orbital insertion | 20 August 2019, 09:02 IST (03:32 UTC) |
Orbit parameters | |
Pericynthion | 100 km (62 mi) |
Apocynthion | 100 km (62 mi) |
Moon lander | |
Spacecraft component | Rover |
Landing date | 7 September 2019, 01:53 IST (failure) (6 September 2019, 20:23 UTC) |
Landing site | Lunar south pole (intended) |
Chandrayaan-2 (candra-yāna, transl. "mooncraft"; ) is the second lunar exploration mission developed by the Indian Space Research Organisation (ISRO), after Chandrayaan-1. As of September 2019, it consists of a lunar orbiter, and also included the Vikram lander, and the Pragyan lunar rover, all of which were developed in India. The main scientific objective is to map and study the variations in lunar surface composition, as well as the location and abundance of lunar water.
The spacecraft was launched on its mission to the Moon from the second launch pad at the Satish Dhawan Space Centre in Andhra Pradesh on 22 July 2019 at 2.43 p.m. IST (09:13 UTC) by a GSLV Mark III M1. The craft reached the Moon's orbit on 20 August 2019 and began orbital positioning manoeuvres for the landing of the Vikram lander. The lander and the rover were scheduled to land on the near side of the Moon, in the south polar region at a latitude of about 70° south on 6 September 2019 and conduct scientific experiments for one lunar day, which approximates to two Earth weeks. A successful soft landing would have made India the fourth country after the Soviet Union, United States and China to do so.
However, the lander deviated from its intended trajectory while attempting to land on 6 September 2019 which caused a 'hard landing'. According to a failure analysis report submitted to ISRO, the crash was caused by a software glitch. ISRO may re-attempt a landing by the second quarter of 2021 with Chandrayaan-3.
Contents
History
On 12 November 2007, representatives of the Roscosmos and ISRO signed an agreement for the two agencies to work together on the Chandrayaan-1's follow-up project, Chandrayaan-2. ISRO would have the prime responsibility for the orbiter and rover, while Roscosmos was to provide the lander. The Indian government approved the mission in a meeting of the Union Cabinet, held on 18 September 2008 and chaired by Prime Minister Manmohan Singh. The design of the spacecraft was completed in August 2009, with scientists of both countries conducting a joint review.
Although ISRO finalised the payload for Chandrayaan-2 on schedule, the mission was postponed in January 2013 and rescheduled to 2016 because Russia was unable to develop the lander on time. In 2012, there was a delay in the construction of the Russian lander for Chandrayaan-2 due of the failure of the Fobos-Grunt mission to Mars, since the technical issues connected with the Fobos-Grunt mission which were also used in the lunar projects including the lander for Chandrayaan-2 needed to be reviewed. When Russia cited its inability to provide the lander even by 2015, India decided to develop the lunar mission independently.
The spacecraft's launch had been scheduled for March 2018 initially after the India's decision, but was first delayed to April and then to October to conduct further tests on the vehicle. On 19 June 2018, after the program's fourth Comprehensive Technical Review meeting, a number of changes in configuration and landing sequence were planned for implementation, pushing the launch to the first half of 2019. Two of the lander's legs received minor damage during one of the tests in February 2019.
Chandrayaan-2 launch was scheduled for 14 July 2019, 21:21 UTC (15 July 2019 at 02:51 IST local time), with the landing expected on 6 September 2019. However, the launch was aborted due to a technical glitch and was rescheduled. The launch occurred on 22 July 2019 at 09:13 UTC (14:43 IST) on the first operational flight of a GSLV MK III M1.
On 6 September 2019, the lander during its landing phase, deviated from its intended trajectory starting at 2.1 kilometres (1.3 mi) altitude, and had lost communication when touchdown confirmation was expected. Initial reports suggesting a crash were confirmed by ISRO chairman K. Sivan, stating that "it must have been a hard landing". The Failure Analysis Committee concluded that the crash was caused by a software glitch. Unlike ISRO's previous record, the report of the Failure Analysis Committee has not been made public.
Objectives
The primary objectives of the Chandrayaan-2 lander were to demonstrate the ability to soft-land and operate a robotic rover on the lunar surface.
The scientific goals of the orbiter are:
- to study lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water ice
- to study the water ice in the south polar region and thickness of the lunar regolith on the surface
- to map the lunar surface and help to prepare 3D maps of it
Design
The name Chandrayaan means "mooncraft" in Sanskrit and Hindi. The mission was launched on a Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III) M1 with an approximate lift-off mass of 3,850 kg (8,490 lb) from Satish Dhawan Space Centre on Sriharikota Island of Andhra Pradesh. As of June 2019[update], the mission has an allocated cost of ₹ 9.78 billion (approximately US$141 million) which includes ₹ 6 billion for the space segment and ₹ 3.75 billion as launch costs on GSLV Mk III M1. Chandrayaan-2 stack was initially put in an Earth parking orbit of 170 kilometres (110 mi) perigee and 40,400 kilometres (25,100 mi) apogee by the launch vehicle.
Orbiter
The Chandrayaan-2 orbiter is orbiting the Moon on a polar orbit at an altitude of 100 km (62 mi). It carries eight scientific instruments; two of which are improved versions of those flown on Chandrayaan-1. The approximate launch mass was 2,379 kg (5,245 lb). The Orbiter High Resolution Camera (OHRC) conducted high-resolution observations of the landing site prior to separation of the lander from the orbiter. The orbiter's structure was manufactured by Hindustan Aeronautics Limited and delivered to the ISRO Satellite Centre on 22 June 2015.
- Dimensions: 3.2 × 5.8 × 2.2 m
- Gross lift-off mass: 2,379 kg (5,245 lb)
- Propellant mass: 1,697 kg (3,741 lb)
- Dry mass: 682 kg (1,504 lb)
- Power generation capacity: 1000 W
- Mission duration: approximately 7.5 years, extended from the planned 1 year owing to the precise launch and mission management, in lunar orbit
Vikram lander
The mission's lander is called Vikram (Sanskrit: विक्रम, lit. 'Valour') named after cosmic ray scientist Vikram Sarabhai (1919–1971), who is widely regarded as the founder of the Indian space programme. The Vikram lander detached from the orbiter and descended to a low lunar orbit of 30 km × 100 km (19 mi × 62 mi) using its 800 N (180 lbf) liquid main engines. After checking all of its on-board systems it attempted a soft landing that would have deployed the rover, and performed scientific activities for approximately 14 Earth days. Vikram crash-landed during this attempt. The combined mass of the lander and rover was approximately 1,471 kg (3,243 lb).
The preliminary configuration study of the lander was completed in 2013 by the Space Applications Centre (SAC) in Ahmedabad. The lander's propulsion system consisted of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) liquid apogee motor. Initially, the lander design employed four main throttle-able liquid engines, but a centrally mounted fixed-thrust engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine was expected to mitigate upward draft of lunar dust during the soft landing. Vikram was designed to safely land on slopes up to 12°.
Some associated technologies include a high resolution camera, Laser Altimeter (LASA), Lander Hazard Detection Avoidance Camera (LHDAC), Lander Position Detection Camera (LPDC), Lander Horizontal Velocity Camera (LHVC), an 800 N throttleable liquid main engine, attitude thrusters, Ka band radio altimeters, Laser Inertial Reference & Accelerometer Package (LIRAP), and the software needed to run these components. Engineering models of the lander began undergoing ground and aerial tests in late October 2016, in Challakere in the Chitradurga district of Karnataka. ISRO created roughly 10 craters on the surface to help assess the ability of the lander's sensors to select a landing site.
- Dimensions: 2.54 by 2 by 1.2 metres (8 ft 4 in × 6 ft 7 in × 3 ft 11 in)
- Gross lift-off mass: 1,471 kg (3,243 lb)
- Propellant mass: 845 kg (1,863 lb)
- Dry mass: 626 kg (1,380 lb)
- Power generation capability: 650 W
- Mission duration: ≤14 days (one lunar day)
Pragyan rover
The mission's rover was called Pragyan (Sanskrit: प्रज्ञान, lit. 'Wisdom') ) with a mass of 27 kg (60 lb), and would have operated on solar power. The rover was to move on six wheels, traversing 500 metres (1,600 ft) on the lunar surface at the rate of 1 centimetre (0.39 in) per second, perform on-site analyses and send the data to the lander, which would have relayed it to the Mission Control on the Earth. For navigation, the rover would have used:
- 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 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. However, its power system has a solar-powered sleep/wake-up cycle implemented, which could have resulted in longer service time than planned. Two aft wheels of the rover had the ISRO logo and the State Emblem of India embossed on them to leave behind patterned tracks on the lunar surface.
- Dimensions: 0.9 × 0.75 × 0.85 m
- Power: 50 W
- Travel speed: 1 cm/sec
- Mission duration: ≤14 days (one lunar day)
Science payload
ISRO selected eight scientific instruments for the orbiter, four for the lander, and two for the rover. While it was initially reported that NASA and ESA would participate in the mission by providing some scientific instruments for the orbiter, ISRO in 2010 had clarified that due to weight restrictions it will not be carrying foreign payloads on the mission. However, in an update a month before launch, an agreement between NASA and ISRO was signed to include a small laser retroreflector from NASA to the lander's payload to measure the distance between the satellites above and the microreflector on the lunar surface.
Orbiter
Payloads on the orbiter are:
- Chandrayaan-2 Large Area Soft X-ray Spectrometer (CLASS) from the ISRO Satellite Centre (ISAC), which makes use of X-ray fluorescence spectra to determine the elemental composition of the lunar surface
- Solar X-ray monitor (XSM) from Physical Research Laboratory (PRL), Ahmedabad, for mapping the lunar surface
- Dual Frequency L and S band Synthetic Aperture Radar (DFSAR) from the Space Applications Centre (SAC) for probing the first few metres of the lunar surface for the presence of different constituents. DFSAR was expected to provide further evidence confirming the presence of water ice, and its distribution below the shadowed regions of the Moon. It has lunar surface penetration depth of 5 metres (16 ft) (L-band).
- Imaging IR Spectrometer (IIRS) from the SAC for mapping of lunar surface over a wide wavelength range for the study of minerals, water molecules and hydroxyl present. It featured an extended spectral range (0.8 μm to 5 μm), an improvement over previous lunar missions whose payloads worked up to 3 μm.
- Chandrayaan-2 Atmospheric Compositional Explorer 2 (ChACE-2) Quadrupole Mass Analyzer from Space Physics Laboratory (SPL) to carry out a detailed study of the lunar exosphere
- Terrain Mapping Camera-2 (TMC-2) from SAC for preparing a three-dimensional map essential for studying the lunar mineralogy and geology
- Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere – Dual Frequency Radio Science experiment (RAMBHA-DFRS) by SPL for the studying electron density in the lunar ionosphere
- Orbiter High Resolution Camera (OHRC) by SAC for scouting a hazard-free spot prior to landing. Used to help prepare high-resolution topographic maps and digital elevation models of the lunar surface. OHRC had a spatial resolution of 0.32 metres (1 ft 1 in) from 100 kilometres (62 mi) polar orbit, which was the best resolution among any lunar orbiter mission to date.
Vikram lander
The payloads on the Vikram lander were:
- Instrument for Lunar Seismic Activity (ILSA) MEMS based seismometer by LEOS for studying Moon-quakes near the landing site
- Chandra's Surface Thermo-physical Experiment (ChaSTE) thermal probe by SPL, Vikram Sarabhai Space Centre (VSSC) for estimating the thermal properties of the lunar surface
- RAMBHA-LP Langmuir probe by SPL, VSSC for measuring the density and variation of lunar surface plasma
- A laser retroreflector array (LRA) by the Goddard Space Flight Center for taking precise measurements of distance between the reflector on the lunar surface and satellites in lunar orbit. The microreflector weighed about 22 grams and cannot be used for taking observations from Earth-based lunar laser stations.
Pragyan rover
Pragyan rover carried two instruments to determine the abundance of elements near the landing site:
- Laser induced Breakdown Spectroscope (LIBS) from the laboratory for Electro Optic Systems (LEOS), Bangalore
- Alpha Particle Induced X-ray Spectroscope (APXS) from PRL, Ahmedabad
Mission profile
Launch
The launch of Chandrayaan-2 was initially scheduled for 14 July 2019, 21:21 UTC (15 July 2019 at 02:51 IST local time). However, the launch was aborted 56 minutes and 24 seconds before launch due to a technical glitch, so it was rescheduled to 22 July 2019. Unconfirmed reports later cited a leak in the nipple joint of a helium gas bottle as the cause of cancellation.
Finally Chandrayaan-2 was launched on board the GSLV MK III M1 launch vehicle on 22 July 2019 at 09:13 UTC (14:43 IST) with a better-than-expected apogee as a result of the cryogenic upper stage being burned to depletion, which later eliminated the need for one of the apogee-raising burns during the geocentric phase of mission. This also resulted in the saving of around 40 kg fuel on board the spacecraft.
Immediately after launch, multiple observations of a slow-moving bright object over Australia were made, which could be related to upper stage venting of residual LOX/LH2 propellant after the main burn.
Geocentric phase
After being placed into a 45,475 × 169 km parking orbit by the launch vehicle, the Chandrayaan-2 spacecraft stack gradually raised its orbit using on-board propulsion over 22 days. In this phase, one perigee-raising and five apogee-raising burns were performed to reach a highly eccentric orbit of 142,975 × 276 km followed by trans-lunar injection on 13 August 2019. Such a long Earth-bound phase with multiple orbit-raising manoeuvres exploiting the Oberth effect was required because of the limited lifting capacity of the launch vehicle and thrust of the spacecraft's on-board propulsion system. A similar strategy was used for Chandrayaan-1 and the Mars Orbiter Mission during their Earth-bound phase trajectory. On 3 August 2019, the first set of Earth images were captured by the LI4 camera on the Vikram lander, showing the North American landmass.
Selenocentric phase
After 29 days from its launch, the Chandrayaan-2 spacecraft stack entered lunar orbit on 20 August 2019 after performing a lunar orbit insertion burn for 28 minutes 57 seconds. The three-spacecraft stack was placed into an elliptical orbit that passed over the polar regions of the Moon, with 18,072 km (11,229 mi) aposelene and 114 km (71 mi) periselene. By 1 September 2019 this elliptical orbit was made nearly circular with 127 km (79 mi) aposelene and 119 km (74 mi) periselene after four orbit-lowering manoeuvres followed by separation of Vikram lander from the orbiter on 7:45 UTC, 2 September 2019.
Planned landing site
Landing site | Coordinates |
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Prime landing site | 70°54′10″S 22°46′52″E / 70.90267°S 22.78110°E |
Alternate landing site | 67°52′27″S 18°28′10″W / 67.87406°S 18.46947°W |
Two landing sites were selected, each with an ellipse of 32 by 11 kilometres (19.9 mi × 6.8 mi). The prime landing site (PLS54) was at 70.90267°S 22.78110°E (600 km (370 mi) from the south pole), and the alternate landing site (ALS01) was at 67.87406°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.
Loss of Vikram
Vikram began its descent at 20:08:03 UTC, 6 September 2019 and was scheduled to land on the Moon at around 20:23 UTC. The descent and soft-landing were to be performed by the on-board computers on Vikram, with mission control unable to make corrections. The initial descent was considered within mission parameters, passing critical braking procedures as expected, but 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) at 330 metres (1,080 ft) above the surface, which a number of experts noted, would have been too fast for the lunar lander to make a successful landing. Initial reports suggesting a crash were confirmed by ISRO chairman K. Sivan, stating that "it must have been a hard landing".
Radio transmissions from the lander were tracked during descent by analysts using a 25-metre (82 ft) radio telescope owned by the Netherlands Institute for Radio Astronomy. Analysis of the doppler data suggests that the loss of signal coincided with the lander impacting the lunar surface at a velocity of nearly 50 m/s (180 km/h) (as opposed to an ideal 2 m/s (7.2 km/h) touchdown velocity). The powered descent was also observed by NASA's Lunar Reconnaissance Orbiter (LRO) using its Lyman-Alpha Mapping Project instrument to study changes in the lunar exosphere due to exhaust gases from the lander's engines. K. Sivan, tasked senior scientist P. S. Goel to head the Failure Analysis Committee to look into the causes of the failure.
Both ISRO and NASA attempted to communicate with the lander for about two weeks before the lunar night set in, while NASA's LRO flew over on 17 September 2019 and acquired some images of the intended landing zone. However, the region was near dusk, causing poor lighting for optical imaging. NASA's LRO images, showing no sight of the lander, were released on 26 September. The LRO flew over again on 14 October under more favorable lighting conditions, but was unable to locate it. The LRO performed a third flyover on 10 November.
On 16 November 2019, the Failure Analysis Committee released its report to the Space Commission, concluding that the crash was caused by a software glitch. Phase One of descent from an altitude of 30 km to 7.4 km above the Moon's surface went as intended with velocity being reduced from 1,683 m/s to 146 m/s. But velocity reduction during the second phase of descent was more than expected. This deviation from nominal was beyond the designed parameters of on-board software, causing Vikram to land hard, though it managed to impact relatively near the intended landing site. The complete findings have not been made public.
Vikram's impact site was located at 70°52′52″S 22°47′02″E / 70.8810°S 22.7840°E by the LROC team after receiving helpful input from Shanmuga Subramanian, a volunteer from Chennai, Tamil Nadu, who located debris from the spacecraft in pictures released by NASA. While initially estimated to be within 500 metres (1,600 ft) of the intended landing site, best-guess estimates from satellite imagery indicate initial impact about 600 m away. The spacecraft shattered upon impact, with debris scattered over almost two dozen locations in an area 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.
Phase | Date | Event | Detail | Result | References | |
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Apogee / Aposelene |
Perigee / Periselene |
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Geocentric phase | 22 July 2019 09:13:12 UTC | Launch | Burn time: 16 min 14 sec | 45,475 km (28,257 mi) | 169.7 km (105.4 mi) | |
24 July 2019 09:22 UTC | 1st orbit-raising maneuver | Burn time: 48 sec | 45,163 km (28,063 mi) | 230 km (140 mi) | ||
25 July 2019 19:38 UTC | 2nd orbit-raising maneuver | Burn time: 883 sec | 54,829 km (34,069 mi) | 251 km (156 mi) | ||
29 July 2019 09:42 UTC | 3rd orbit-raising maneuver | Burn time: 989 sec | 71,792 km (44,609 mi) | 276 km (171.5 mi) | ||
2 August 2019 09:57 UTC | 4th orbit-raising maneuver | Burn time: 646 sec | 89,472 km (55,595 mi) | 277 km (172 mi) | ||
6 August 2019 09:34 UTC | 5th orbit-raising maneuver | Burn time: 1041 sec | 142,975 km (88,841 mi) | 276 km (171 mi) | ||
13 August 2019 20:51 UTC | Trans-lunar injection | Burn time: 1203 sec |
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Selenocentric phase | 20 August 2019 03:32 UTC | Lunar orbit insertion 1st lunar bound maneuver |
Burn time: 1738 sec | 18,072 km (11,229 mi) | 114 km (71 mi) | |
21 August 2019 07:20 UTC | 2nd lunar bound maneuver | Burn time: 1228 sec | 4,412 km (2,741 mi) | 118 km (73 mi) | ||
28 August 2019 03:34 UTC | 3rd lunar bound maneuver | Burn time: 1190 sec | 1,412 km (877 mi) | 179 km (111 mi) | ||
30 August 2019 12:48 UTC | 4th lunar bound maneuver | Burn time: 1155 sec | 164 km (102 mi) | 124 km (77 mi) | ||
1 September 2019 12:51 UTC | 5th lunar bound maneuver | Burn time: 52 sec | 127 km (79 mi) | 119 km (74 mi) | ||
Vikram lunar landing | 2 September 2019 7:45 UTC | Vikram separation |
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127 km (79 mi) | 119 km (74 mi) | |
3 September 2019 3:20 UTC | 1st deorbit burn | Burn time: 4 sec | 128 km (80 mi) | 104 km (65 mi) | ||
3 September 2019 22:12 UTC | 2nd deorbit burn | Burn time: 9 sec | 101 km (63 mi) | 35 km (22 mi) | ||
6 September 2019 20:08 UTC | Powered descent | Burn time: 15 min | Landing (planned) | Landing (planned) | ||
6 September 2019 20:23 UTC | Vikram landing | Trajectory deviation started at 2.1 km altitude, telemetry was lost seconds before touchdown. | Lost upon crash landing. | |||
7 September 2019 00:00 UTC−01:00 UTC (planned) | Pragyan rover deployment | Lander failure, rover was not deployed. |
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Aftermath
There was an outpouring of support for ISRO from various quarters in the aftermath of the crash landing of its lunar lander. However, prominent Indian news media also criticized ISRO's lack of transparency regarding the crash of the lander and its analysis of the crash. Indian media also noted that unlike ISRO's previous record, the report of the Failure Analysis Committee was not made public. ISRO's lack of consistency regarding the explanation around the rover's crashing was criticized, with the organization providing no proof of its own positions until the efforts of NASA and a Chennai based volunteer located the crash site on the lunar surface. In the wake of the events surrounding Chandrayaan-2, former ISRO employees criticized unverified statements from the ISRO chairman and what they claimed is the top-down leadership and working culture of the organization.
Scientists involved in the mission
Key scientists and engineers involved in the development of Chandrayaan-2 include:
- Ritu Karidhal – Mission Director
- Muthayya Vanitha – Project Director
- K. Kalpana – Associate Project Director
- G. Narayanan – Associate Project Director
- G. Nagesh – Project Director (former)
- Chandrakanta Kumar – Deputy Project Director (Radio-frequency systems)
- Amitabh Singh – Deputy Project Director (Optical Payload Data Processing, SAC)
Chandrayaan-3
In November 2019, ISRO officials stated that a new lunar lander mission is being studied for launch in Q2 2021; this new proposal is called Chandrayaan-3 and it would be a re-attempt to demonstrate the landing capabilities needed for the Lunar Polar Exploration Mission proposed in partnership with Japan for 2024. If funded, this re-attempt would not include launching an orbiter. The proposed configuration would have a detachable propulsion module, a lander and a rover. According to VSSC director, S. Somanath, there will be more follow-up missions in the Chandrayaan programme.
Images for kids
See also
In Spanish: Chandrayaan-2 para niños