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 2.43p.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.
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 MinisterManmohan 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 (1.3mi) 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.
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 Chandrayaan-2 orbiter is orbiting the Moon on a polar orbit at an altitude of 100km (62mi). It carries eight scientific instruments; two of which are improved versions of those flown on Chandrayaan-1. The approximate launch mass was 2,379kg (5,245lb). 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.
Mission duration: approximately 7.5 years, extended from the planned 1 year owing to the precise launch and mission management, in lunar orbit
The mission's lander is called Vikram (Sanskrit: विक्रम, lit.'Valour') Pronunciation(help·info) named after 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 30km ×100km (19mi ×62mi) using its 800N (180lbf) 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. Vikramcrash-landed during this attempt. The combined mass of the lander and rover was approximately 1,471kg (3,243lb).
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 50N (11lbf) thrusters for attitude control and five 800N (180lbf) liquid main engines derived from ISRO's 440N (99lbf)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 800N 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 (8ft 4in ×6ft 7in ×3ft 11in)
The mission's rover was called Pragyan (Sanskrit: प्रज्ञान, lit.'Wisdom') Pronunciation(help·info)) with a mass of 27kg (60lb), and would have operated on solar power. The rover was to move on six wheels, traversing 500 metres (1,600ft) on the lunar surface at the rate of 1 centimetre (0.39in) 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, monochromaticnavcams 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.
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.
Dual Frequency L and S bandSynthetic 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 (16ft) (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.
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 (1ft 1in) from 100 kilometres (62mi) polar orbit, which was the best resolution among any lunar orbiter mission to date.
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 40kg 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.
After being placed into a 45,475 × 169km 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 × 276km 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.
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 18,072km (11,229mi) aposelene and 114km (71mi) periselene. By 1 September 2019 this elliptical orbit was made nearly circular with 127km (79mi) aposelene and 119km (74mi) periselene after four orbit-lowering manoeuvres followed by separation of Vikram lander from the orbiter on 7:45 UTC, 2 September 2019.
Two landing sites were selected, each with an ellipse of 32 by 11 kilometres (19.9mi ×6.8mi). The prime landing site (PLS54) was at 70.90267°S 22.78110°E (600km (370mi) 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 cratersManzinus C and Simpelius N, on the near side of the Moon.
Loss of Vikram
Location of the Vikram lander impact site
Ejecta field around Vikram lander impact site
Before and after image of the impact site
Before and after images of the impact site
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 (1.3mi; 6,900ft) above the surface. The final telemetry readings during ISRO's live-stream show that Vikram's final vertical velocity was 58m/s (210km/h) at 330 metres (1,080ft) 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 (82ft) 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 50m/s (180km/h) (as opposed to an ideal 2m/s (7.2km/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 30km to 7.4km above the Moon's surface went as intended with velocity being reduced from 1,683m/s to 146m/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″S22°47′02″E / 70.8810°S 22.7840°E / -70.8810; 22.7840 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 (1,600ft) 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.
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:
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.
According to The Times of India, work on Chandrayaan-3 commenced on 14 November 2019. In December 2019, it was reported that ISRO requested the initial funding of the project, amounting to ₹75 crore (US$11million), of which ₹60 crore (US$8.4million) is intended for machinery, equipment and other capital expenditure, while the remaining ₹15 crore (US$2.1million) is sought under revenue expenditure head. Confirming the existence of the project, K. Sivan stated that its cost would be around ₹615 crore (US$86million).
A lander is a spacecraft which descends toward and comes to rest on the surface of an astronomical body. By contrast with an impact probe, which makes a hard landing and is damaged or destroyed so ceases to function after reaching the surface, a lander makes a soft landing after which the probe remains functional.
The Indian Space Research Organisation is the space agency of the Government of India and has its headquarters in the city of Bengaluru. Its vision is to "harness space technology for national development while pursuing space science research & planetary exploration". The Indian National Committee for Space Research (INCOSPAR) was established by Jawaharlal Nehru under the Department of Atomic Energy (DAE) in 1962, with the urging of scientist Vikram Sarabhai recognising the need in space research. INCOSPAR grew and became ISRO in 1969, also under the DAE. In 1972, the Government of India had set up a Space Commission and the Department of Space (DOS), bringing ISRO under the DOS. The establishment of ISRO thus institutionalised space research activities in India. It is managed by the DOS, which reports to the Prime Minister of India.
Chandrayaan-1 was the first Indian lunar probe under Chandrayaan program. It was launched by the Indian Space Research Organisation in October 2008, and operated until August 2009. The mission included a lunar orbiter and an impactor. India launched the spacecraft using a PSLV-XL rocket on 22 October 2008 at 00:52 UTC from Satish Dhawan Space Centre, at Sriharikota, Andhra Pradesh. The mission was a major boost to India's space program, as India researched and developed its own technology in order to explore the Moon. The vehicle was inserted into lunar orbit on 8 November 2008.
A Moon landing is the arrival of a spacecraft on the surface of the Moon. This includes both crewed and robotic missions. The first human-made object to touch the Moon was the Soviet Union's Luna 2, on 13 September 1959.
The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes; having made his own telescope in 1609, the mountains and craters on the lunar surface were among his first observations using it.
The Geosynchronous Satellite Launch Vehicle Mark III, also referred to as the Launch Vehicle Mark 3 (LVM3), is a three-stage medium-lift launch vehicle developed by the Indian Space Research Organisation (ISRO). Primarily designed to launch communication satellites into geostationary orbit, it is also identified as launch vehicle for crewed missions under the Indian Human Spaceflight Programme and dedicated science missions like Chandrayaan-2. The GSLV Mk III has a higher payload capacity than the similarly named GSLV Mk II.
The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the Moon, characterizing the radiation environment, and demonstrating new technologies.
Several Asian countries have space programs and are actively competing to achieve scientific and technological advancements in space, a situation sometimes referred to as the Asian space race in the popular media as a reference to the earlier Space Race between the United States and the Soviet Union. Like the previous space race, issues involved in the current push to space include national security, which has spurred many countries to send artificial satellites as well as humans into Earth orbit and beyond. A number of Asian countries are seen as contenders in the ongoing race to be the pre-eminent power in space.
The Moon Impact Probe (MIP) developed by the Indian Space Research Organisation (ISRO), India's national space agency, was a lunar probe that was released by ISRO's Chandrayaan-1 lunar remote sensing orbiter which in turn was launched, on 22 October 2008, aboard a modified version of ISRO's Polar Satellite Launch Vehicle. It discovered the presence of water on the Moon.
Koppillil Radhakrishnan is an Indian space scientist who headed the Indian Space Research Organisation (ISRO) between November 2009 and December 2014 as Chairman of Space Commission, Secretary of the Department of Space and Chairman of ISRO. Prior to this, he was the Director of Vikram Sarabhai Space Centre (2007-2009) and Director of National Remote Sensing Agency (2005-2008) of the Department of Space. He had a brief stint of five years (2000-2005) in the Ministry of Earth Sciences as Director of Indian National Centre for Ocean Information Services (INCOIS).
A lunar rover or Moon rover is a space exploration vehicle designed to move across the surface of the Moon. The Apollo Program's Lunar Roving Vehicle was driven on the Moon by members of three American crews, Apollo 15, 16, and 17. Other rovers have been partially or fully autonomous robots, such as the Soviet Union's Lunokhods and the Chinese Yutus. Three countries have had operating rovers on the Moon: the Soviet Union, the United States and China. An Indian mission failed while Japan and Greece currently have planned missions.
TeamIndus is a private for-profit aerospace company headquartered in Bangalore, India. It consists of a team of professionals from various backgrounds in science, technology, finance, and media, that came together in 2010 with the aim of winning the Google Lunar X Prize competition announced in 2007. Although the competition ended in 2018 without a winner, TeamIndus is still working towards developing and launching their lunar rover mission sometime in 2020 after partnering with OrbitBeyond.
The Chandrayaan programme, also known as the Indian Lunar Exploration Programme is an ongoing series of outer space missions by the Indian Space Research Organisation (ISRO). The programme incorporates lunar orbiter, impactor, soft lander and rover spacecrafts. The name of the programme is from Sanskrit candrayāna.
Pragyan was the rover of Chandrayaan-2, a lunar mission developed by the Indian Space Research Organisation (ISRO).
The Lunar Polar Exploration Mission is a robotic lunar mission concept by Indian Space Research Organisation (ISRO) and Japan Aerospace Exploration Agency (JAXA) that would send a lunar rover and lander to explore the south pole region of the Moon in 2024. JAXA is likely to provide the under-development H3 launch vehicle and the rover, while ISRO would be responsible for the lander.
Chandrayaan-3 is a planned third lunar exploration mission by Indian Space Research Organisation.
1 2 "Chandrayaan-2: Three months on, ISRO yet to make public Vikram lander failure report details". The Indian Express. 19 December 2019. Retrieved 17 January 2020. This is unlike the ISRO’s previous record. For instance, after the failure of an operational fourth flight of the heavy lift GSLV rocket — the GSLV-F02 mission — on July 10, 2006, a 15-member FAC was tasked with providing a report in a month. After the report was submitted to the government, ISRO made the details public on September 6, 2006, on its website. In 2010, when GSLV D3, a developmental flight and the fifth heavy lift GSLV rocket, failed after launch on April 15, an FAC report was submitted with the government on May 24, 2010. Details of the report were made public on July 9. The same year, when GSLV F06, an operational sixth flight for GSLV rocket, failed on December 25, ISRO went public on December 31, with findings of an analysis of failure done by a preliminary FAC comprising space experts.
↑ Monier Monier-Williams, A Sanskrit-English Dictionary (1899): candra: "[...] m. the moon (also personified as a deity Mn. &c)" yāna: "[...] n. a vehicle of any kind , carriage , waggon , vessel , ship , [...]"
↑ "Chandrayaan-2 FAQ". Retrieved 24 August 2019. The name Chandrayaan means "Chandra- Moon, Yaan-vehicle", –in Indian languages (Sanskrit and Hindi), – the lunar spacecraft.
↑ "ISRO developing vehicle to launch small satellites". Frontline. Retrieved 29 August 2018. Making a throttleable engine of 3 kilonewtons or 4 kilonewtons is a totally new development for us. But we wanted to make use of available technologies. We have a LAM [liquid apogee motor] with a 400 newton thruster, and we have been using it on our satellites. We enhanced it to 800 newtons. It was not a major, new design change.
↑ "Chandrayaan-2: First step towards Indians setting foot on moon in near future". The New Indian Express. Retrieved 8 July 2019. As solar energy powers the system, a place with good visibility and area of communication was needed. Also, the place where the landing takes place should not have many boulders and craters. The slope for landing should be less than 12 degrees. The South pole has a near-flat surface, with good visibility and sunlight available from the convenience point of view,
↑ Elumalai, V.; Kharge, Mallikarjun (7 February 2019). "Chandrayaan – II"(PDF). PIB.nic.in. Archived from the original(PDF) on 7 February 2019. Retrieved 7 February 2019. Lander (Vikram) is undergoing final integration tests. Rover (Pragyan) has completed all tests and waiting for the Vikram readiness to undergo further tests.
↑ Subhalakshmi, K.; Basavaraj, B.; Selvaraj, P.; Laha, J. (22 December 2010). "Design of Miniature Space Grade Navigation Camera for Lunar Mission". 2010 International Symposium on Electronic System Design: 169–174. doi:10.1109/ISED.2010.40. ISBN978-1-4244-8979-4.
↑ Annadurai, Mylswami; Nagesh, G.; Vanitha, Muthayaa (28 June 2017). ""Chandrayaan-2: Lunar Orbiter & Lander Mission", 10th IAA Symposium on The Future of Space Exploration: Towards the Moon Village and Beyond, Torin, Italy". International Academy of Astronautics. Archived from the original on 30 August 2017. Retrieved 14 June 2019. Mobility of the Rover in the unknown lunar terrain is accomplished by a Rocker bogie suspension system driven by six wheels. Brushless DC motors are used to drive the wheels to move along the desired path and steering is accomplished by differential speed of the wheels. The wheels are designed after extensive modelling of the wheel-soil interaction, considering the lunar soil properties, sinkage and slippage results from a single wheel test bed. The Rover mobility has been tested in the Lunar test facility wherein the soil simulant, terrain and the gravity of moon are simulated. The limitations w.r.t slope, obstacles, pits in view of slippage/sinkage have been experimentally verified with the analysis results.
↑ India Heads to the Moon With Chandrayaan 2. David Dickinson, Sky & Telescope. 22 July 2019. Quote: "Vikram carries a seismometer, thermal probe, and an instrument to measure variation and density of lunar surface plasma, along with a laser retro-reflector supplied by NASA's Goddard Spaceflight Center."
↑ "Unstarred Question number: 588". 220.127.116.11. Archived from the original on 20 November 2019. Retrieved 20 November 2019. The first phase of descent was performed nominally from an altitude of 30 km to 7.4 km above the moon surface. The velocity was reduced from 1683 m/s to 146 m/s. During the second phase of descent, the reduction in velocity was more than the designed value. Due to this deviation, the initial conditions at the start of the fine braking phase were beyond the designed parameters. As a result, Vikram hard-landed within 500 m of the designated landing site.
↑ "ISRO: Time for Change of leadership". Newsroom24x7. 18 December 2019. Retrieved 28 May 2020. Question that remains to be answered by ISRO is where ‘s the proof for what they have been claiming. Why no photographs or a video of the Lander’s undocking from the Lunar Orbiter have been made public till now. Only an objective probe will find answers to the questions regarding Chandrayaan-2 and what led to the Lander’s failure. There are also many lapses that should make the citizens of India, who fund ISRO’s working, sit up straight
↑ "Chandrayaan-2: Was India's Moon mission actually a success?". BBC News. 30 September 2019. Retrieved 28 May 2020. Mr Sivan's remarks have been met with criticism from scientists who said it was too early for Isro to term the mission a success, especially since its most important goal - to land a rover on the Moon's surface that can gather crucial data - remains unrealised.
Launches are separated by dots (•), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Cubesats are smaller. Crewed flights are bolded. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in brackets).