The Chandrayaan programme ( ) (
Sanskrit
Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...
: 'Moon', 'Craft, Vehicle', )
also known as the Indian Lunar Exploration Programme is an ongoing series of outer space missions by the
Indian Space Research Organisation
The Indian Space Research Organisation (ISRO ) is India's national List of government space agencies, space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), ...
(ISRO) for the
exploration of the Moon
The physical exploration of the Moon began when ''Luna 2'', a space probe launched by the Soviet Union, made a deliberate impact on the surface of the Moon on 14 September, 1959. Prior to that the only available means of lunar exploration had ...
. The program incorporates a lunar orbiter, an impactor, a
soft lander and a
rover spacecraft.
There have been three missions so far with a total of two orbiters, landers and rovers each. While the two orbiters were successful, the first lander and rover which were part of the
Chandrayaan-2 mission, crashed on the surface. The second lander and rover mission
Chandrayaan-3
Chandrayaan-3 ( ) is the third mission in the Chandrayaan programme, a series of Exploration of the Moon, lunar-exploration missions developed by the ISRO, Indian Space Research Organisation (ISRO). The mission consists of a Chandrayaan-2#Vikra ...
successfully landed on the Moon on 23 August 2023, making India the first nation to successfully land a spacecraft in the
lunar south pole
The lunar south pole is the southernmost point on the Moon. It is of interest to scientists because of the lunar water, occurrence of water ice in Crater of eternal darkness, permanently shadowed areas around it. The lunar south pole region fea ...
region, and the
fourth country to soft land on the Moon after the
Soviet Union
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
, the United States and China.
Background
The Indian space programme had begun with no intentions of undertaking sophisticated initiatives like human spaceflight and extraterrestrial missions during the initial days. It was only after ISRO developed the capabilities of creating satellites and orbital launch vehicles like
PSLV
The Polar Satellite Launch Vehicle (PSLV) is an expendable medium-lift launch vehicle designed and operated by the Indian Space Research Organisation (ISRO). It was developed to allow India to launch its Indian Remote Sensing (IRS) satellite ...
, that the possibilities of India's first extraterrestrial exploration mission to the Moon were being explored in the early 2000s. The idea of a lunar scientific mission was first raised in 1999 during a meeting of the
Indian Academy of Sciences
The Indian Academy of Sciences, Bangalore was founded by Indian Physicist and List of Nobel laureates, Nobel Laureate Chandrasekhara Venkata Raman, C. V. Raman, and was registered as a society on 27 April 1934. Inaugurated on 31 July 1934, it ...
(IAS) which was then carried forward by the Astronautical Society of India (ASI) in 2000.
The robotic exploration programme is intended as a precursor until
Indian astronauts land on the Moon to carry forward further explorations, with the robotic programme planned to continue beyond crewed landings as a support to the crewed missions.
History
First Mission
Soon after the proposals by the Indian Academy of Sciences in 1999 and by the Astronautical Society of India in 2000, a National Lunar Mission Task Force (NLMTF) was set up which constituted ISRO and leading
Indian scientists and technologists across the nation to conduct the feasibility study. The study report was then reviewed by a peer group of 100 scientists from various fields.
The recommendations put forward were as follows:
*The Indian Moon Mission assumes significance in the context of the international scientific community considering several exciting missions in planetary exploration, in the new millennium.
*ISRO has the necessary expertise to develop and launch the Moon Mission with imaginative features and it would be different from the past missions. Hence ISRO should go ahead with the project approval and implementation.
*Apart from technological and scientific gains, it would provide the needed thrust to basic science and engineering research in the country. The project would help return young talents to the arena of fundamental research.
*The Academia, in particular, the university scientists would find participation in such a project intellectually rewarding. In this context, the scientific objectives would need further refinement to include other innovative ideas from a broader scientific community through Announcement of Opportunity, etc.
On 15 August 2003, then prime minister
Atal Bihari Vajpayee
Atal Bihari Vajpayee (25 December 1924 – 16 August 2018) was an Indian poet, writer and statesman who served as the prime minister of India, first for a term of 13 days in 1996, then for a period of 13 months from 1998 ...
announced the project which was estimated to cost . In November of the same year, the government approved the Chandrayaan project which would consist of an orbiter that would conduct mineralogical and chemical mapping of the surface. During the assembly of the orbiter only mission, then president
A.P.J. Abdul Kalam visited the ISRO office and advised that orbiter alone would not suffice and proposed of another instrument that could be dropped on the surface. Following the advice, the scientists made design changes to the project and included an impact probe named
Moon Impact Probe (MIP). The MIP was planned to be dropped from altitude and would acquire close-range images of the surface, collect telemetry data for future soft landing missions and measure the constituents of the lunar atmosphere.

The project required India set up
its deep space network and the entire project cost . On 22 October 2008, Chandrayaan-1 was successfully launched aboard the PSLV rocket. After earth bound maneuvers and trans lunar injection, Chandrayaan-1 entered the lunar orbit on 10 November, making India the fifth nation to orbit Moon.
Four days later, on 14 November, the Moon Impact Probe (MIP) impacted near the
Shackleton crater, in the
lunar south pole
The lunar south pole is the southernmost point on the Moon. It is of interest to scientists because of the lunar water, occurrence of water ice in Crater of eternal darkness, permanently shadowed areas around it. The lunar south pole region fea ...
, this made India the fifth country to reach the lunar surface.
The MIP made the most significant discovery by confirming the existence of water on Moon. This discovery was not made public until NASA's
Moon Mineralogy Mapper payload onboard Chandrayaan-1 orbiter confirmed the same on 24 September 2009.
The mission was intended to last two years, but the contact with the orbiter was lost on 28 August 2009, which officially ended the mission.
Second Mission
After the success of the Chandrayaan-1 mission, a follow-up mission worth was already being planned and was targeted for a launch in 2012. Abdul Kalam suggested for collaboration between India and the United States for the Chandrayaan-2 mission, which would soft land near the lunar south pole and perform robotic penetrations into the surface to study more about the lunar water. However, an agreement had already been signed in the year 2007 by ISRO and
Roscosmos
The State Corporation for Space Activities "Roscosmos", commonly known simply as Roscosmos (), is a State corporation (Russia), state corporation of the Russian Federation responsible for space science, space flights, List of space agencies, c ...
, the Russian federal space agency, for the second lunar mission under the Chandrayaan-2 project.
Russian collaboration and back out
According to the agreement, ISRO had the responsibility of launching, orbiting, and deployment of the
Pragyan rover while Russia's Roscosmos would provide the lander.
The design of the spacecraft by ISRO was completed in 2009, the payloads were also finalized and the launch was targeted for 2013. The project then hit a roadblock when Russia delayed its development of the lander due to failure of its
Fobos-Grunt
Fobos-Grunt or Phobos-Grunt () was an attempted Russian sample return mission to Phobos (moon), Phobos, one of the moons of Mars. Fobos-Grunt also carried the Chinese Mars orbiter Yinghuo-1 and the tiny Living Interplanetary Flight Experiment f ...
mission which revealed technical issues in the similar parts that would be used in the lunar lander.
Russia then proposed a few changes which required ISRO to decrease mass of its rover due to increase in the mass of the lander. A delayed timeline and the Russian request to accept the risk meant that India had to undertake the entire project independently.
With Mars transfer window arriving in the 2013, ISRO repurposed the unused Chandrayaan-2 orbiter hardware for the
Mars Orbiter Mission
Mars Orbiter Mission (MOM), unofficially known as ''Mangalyaan'' (Sanskrit: 'Mars', 'Craft, Vehicle'), is a space probe orbiting Mars since 24 September 2014. It was launched on 5 November 2013 by the Indian Space Research Organisation (ISRO ...
.
Indigenous development of the lander
With the Russian agreement falling apart, India was left alone and now had complete responsibility for the project including the development of lander technology. For which, ISRO created a mimic of Chandrayaan-2's lunar landing site in
Challakere Challakere is a city and a taluk headquarter located in Chitradurga district in the Indian state of Karnataka Challakere called Science city and Oil city of Karnataka
Wikipedia:WikiProject Indian cities for details -->
Challakere is a city, mu ...
with craters that measured in diameter and were deep. This site was used for testing the electronics of the lander and rover. The project was now estimated to cost and was expected to launch in the first quarter of 2018 on
GSLV MK-II. Later in 2017, India signed a deal with Japan's JAXA to conduct a feasibility study for another joint lunar roving mission named
Lunar Polar Exploration Mission (LUPEX). For which a technical demonstration of soft landing was required to be conducted with Chandrayaan-2 mission.
In 2018, the mission faced its second delay after ISRO made design changes for the spacecraft as well as changes in its maneuver where the lander would orbit the Moon to assess the performance of various systems before performing landing. This was contrary to the previous plan where the lander would directly descend after arriving in the designated orbit. A fifth engine was added to the lander, the diameter of the landing legs was increased, two additional propellant tanks were added and additional support systems for power, structure, and thermal control were also provided. This significantly increased the mass of the composite and required ISRO to upgrade the GSLV Mk-II vehicle, but the scientists felt it would be risky to fly the test flight of the uprated Mk-II with Chandrayaan-2 payload, hence a more capable and already flown
LVM3
The Launch Vehicle Mark-3 or LVM3 (previously referred as the Geosynchronous Satellite Launch Vehicle Mark III or GSLV Mk III) is a Multistage rocket, three-stage medium-lift launch vehicle developed by the ISRO, Indian Space Research Organisati ...
vehicle was chosen.
During a landing test in February 2019, the lander suffered minor injuries in two of its legs due to a faulty orientation for the test, and the launch was then targeted for the second quarter of the year. Final cost for the Chandrayaan-2 project was around .
Flight
On 22 July 2019, Chandrayaan-2 was finally launched on
LVM3
The Launch Vehicle Mark-3 or LVM3 (previously referred as the Geosynchronous Satellite Launch Vehicle Mark III or GSLV Mk III) is a Multistage rocket, three-stage medium-lift launch vehicle developed by the ISRO, Indian Space Research Organisati ...
putting an end to several roadblocks that hit the mission during the decade.
After orbit-raising maneuvers and finally the trans lunar injection, Chandrayaan-2 attained the lunar Orbit on 20 August. On 6 September 2019, during the descent to the surface, the contact with the lander was lost after it crash-landed. According to the chairman
K. Sivan, the lander was operating as expected until it was just above the surface when it started deviating from the intended trajectory. Four years later, ISRO chairman
S. Somanath revealed three major reasons for the failure, the presence of five engines that generated a higher thrust which made the errors accumulate over time, the lander being unable to turn very fast because it was not expected to perform at such a high pace turning and the final reason was the small 500x500 m landing site chosen that left the lander with less room for error.
Third Mission
Development
Two months after the failure of Chandrayaan-2, the third mission was proposed with the lander and rover being the primary components of the mission, unlike previously where the orbiter carried a greater scientific payload. The Chandrayaan-3 would be a re-attempt to demonstrate the landing capabilities needed for the LUPEX mission, a proposed partnership with
Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
that was planned for 2025-26 time frame.
ISRO sought from the government as initial funding for the Chandrayaan-3 project that included a propulsion module, a lander, and a rover. It was expected to launch a year later in November 2020. On 19 December 2019,
P Veeramuthuvel was appointed as the director of the mission. The work on the project was underway come January 2020 and K. Sivan revealed that the launch may happen in early 2021 with the total cost of the project being . Later in March, the government confirmed that the launch could take place in the first half of 2021. The earlier addition of the fifth engine in the Chandrayaan-2's lander that caused the additional thrust was now removed from the design of Chandrayaan-3. Like Chandrayaan-2, the testing for the lander was to be conducted in Challakere where ISRO's previously built Moon like site with craters had deteriorated. A total of was spent on recreating the site with craters of similar dimensions ( wide and deep).
The launch which was planned for early 2021, was then delayed to 2022 due to
COVID-19 pandemic in India
The COVID-19 pandemic in India is a part of the COVID-19 pandemic, worldwide pandemic of COVID-19, coronavirus disease 2019 () caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of , according to Indian government ...
. The propulsion module which was ready before the pandemic had begun its testing, following which the lander and rover tests were to be conducted but the pandemic delayed the project and pushed its tentative launch date to the third quarter of 2022. Few more changes with strengthening the landing legs, improvisation in instruments, a failure-proof configuration and additional testing meant that the new schedule for the launch was moved to second quarter of 2023.
In May 2023, the spacecraft was in its final stage of the assembly of payloads at the
U R Rao Satellite Centre with the launch targeted for the first or second week of July.
Successful soft landing
On 14 July 2023, Chandrayaan-3 was successfully launched on
LVM3
The Launch Vehicle Mark-3 or LVM3 (previously referred as the Geosynchronous Satellite Launch Vehicle Mark III or GSLV Mk III) is a Multistage rocket, three-stage medium-lift launch vehicle developed by the ISRO, Indian Space Research Organisati ...
and was inserted in the
lunar sphere of gravitational influence on 5 August 2023.
On 23 August 2023, the lander ''Vikram'' successfully soft landed in the lunar south pole region, achieving humanity's first soft landing in the region and making India the fourth country to soft land on the Moon after Soviet Union, United States and China. Soon after the touchdown, the rover
''Pragyan'' got down of the ramp and drove making India only the third country to operate a robotic rover on the Moon after Soviet Union and China.
Spacecrafts
The Chandrayaan programme consists of robotic explorers such as the
Moon Impact Probe (MIP) an impactor, Chandrayaan-1 and 2 the orbiters, Vikram lander and
Pragyaan rover.
Impactor: Moon Impact Probe
The Moon Impact Probe (MIP) weighed with 25 minutes of expected operating duration. It carried a
Radar altimeter
A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it t ...
to record the altitude data which would be used in qualifying technologies for future soft landing missions, a Video imaging system to acquire close-range pictures of the lunar surface, and a
Mass spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...
to study the tenuous atmosphere of the Moon. On 12 November 2008, the MIP separated from the orbiter and impacted near the lunar south pole's
Shackleton crater.
While descending, the probe's Chandra's Altitudinal Composition Explorer (CHACE) instrument detected the presence of water.
Orbiters
Chandrayaan-1

Chandrayaan-1 launched on 22 October 2008 aboard
PSLV-XL was a solar-powered cuboid orbiter that weighed along with the Moon Impact Probe. It was powered by a single-sided solar array during the day and supported by
lithium-ion batteries
A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. Li-ion batteries are characterized by higher specific energy, energy ...
at night. The
attitude
Attitude or Attitude may refer to:
Philosophy and psychology
* Attitude (psychology), a disposition or state of mind
** Attitude change
* Propositional attitude, a mental state held towards a proposition
Science and technology
* Orientation ...
of the spacecraft was controlled by
three-axis stabilization method using two
star sensors,
gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining Orientation (geometry), orientation and angular velocity. It is a spinning wheel or disc in ...
s and four
reaction wheel
A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through conservation of angular momentum. A reaction wheel can rotate only around its center ...
s. The scientific data transmission was conducted in
X band
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is set at approximately 7.0–11.2&nbs ...
frequencies while telemetry tracking was done in
S band
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventiona ...
frequencies. To store these data, two
solid-state recorders (SSR) were used with SSR-1 carrying 32 GB dedicated capacity for scientific data while SSR-2 carrying 8 GB capacity for the rest of the scientific data and attitude information.
Moon Mineralogy Mapper, an American scientific payload onboard carried its own SSR with 10 GB capacity.
The orbiter-impactor composite entered the lunar sphere of gravitational influence on 8 November 2008. After orbital reduction manoeuvres, it attained an elliptical polar orbit of , upon which, two of the eleven scientific payloads, the Terrain Mapping Camera (TMC) which had a
spatial resolution
In physics and geosciences, the term spatial resolution refers to distance between independent measurements, or the physical dimension that represents a pixel of the image. While in some instruments, like cameras and telescopes, spatial resoluti ...
of and Radiation Dose Monitor (RADOM) were switched on for operations.
Post deployment of MIP, rest of the nine scientific instruments began operations.
On 25 November 2008, just a couple of weeks after entering lunar orbit, the orbiter's temperature rose to after receiving equal amounts of heat from the sun as well as the moon (due to its
Albedo
Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
). Efforts such as rotating the craft by 20 degrees, shutting down the mission computers, and increasing its orbit to were made to bring its temperature down and to avoid damaging the onboard instruments. A year later, the overheating problem was responsible for ending the mission as it damaged the star sensors which maintained the orientation of craft. The orientation was then barely maintained with the help of gyroscopes as a temporary measure before losing contact on 28 August 2009, which ended the mission a year before its intended duration. However, the mission was analyzed to be 95% successful with its intended operations.
Chandrayaan-2
Chandrayaan-2 was the second mission under the programme and it included an orbiter, lander, and rover. After the failure of the Chandrayaan-1 orbiter, the Chandrayaan-2 orbiter enabled ISRO to conduct science with modern cameras and instruments. The primary objectives of this mission were to soft land on the surface and operate a rover, to study the lunar surface,
its exosphere,
minerals
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): M ...
and
water ice Water ice may refer to:
*Ice formed by water (as opposed to other substances)
*In ice climbing, ice made from flowing water (as opposed to ice from precipitation)
*The alternate term for various similar frozen fruit-flavoured desserts:
** Italian ic ...
. While the Chandrayaan-2 composite (orbiter, lander and rover) weighed in total, the orbiter alone weighed . It carried eight scientific instruments with two of the instruments; the Terrain Mapping Camera 2 (TMC-2) and Chandrayaan-2 Atmospheric Compositional Explorer 2 (ChACE-2) being upgraded versions of Terrain Mapping camera (TMC) and Chandra's Atmospheric Compositional Explorer (CHACE) onboard Chandrayaan-1 orbiter and Moon Impact Probe respectively.
The Chandrayaan-2 was launched on 14 July 2019
and attained the lunar orbit on 20 August 2019. After five orbital reduction manoeuvres, the composite attained a near circular orbit of ,
which was followed by the separation of ''Vikram'' on 2 September 2019.
The crash landing of Vikram left the orbiter as a sole successful component of the mission with its new mission duration being extended from one year to seven and a half years. The Orbiter High-Resolution Camera (OHRC) during the time remained the most advanced camera in the lunar orbit with a spatial resolution of , four times higher than Chandrayaan-1 orbiter's resolution. The orbiter is currently studying the lava tubes and caves which were previously spotted by the Chandrayaan-1 orbiter.
Chandrayaan-3

With the Chandrayaan-2 orbiter already operational and the need of demonstrating landing capabilities, Chandraayn-3's orbiter carried only a single payload and for its main purpose served as a propulsion module for carrying ''Vikram'' to the Moon. The Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload was developed to study Earth's atmosphere from distance and it would aid in the study of
Exoplanets' atmospheres, which employs a similar technique. Chandrayaan-3 was launched on 14 July 2023 aboard
LVM3
The Launch Vehicle Mark-3 or LVM3 (previously referred as the Geosynchronous Satellite Launch Vehicle Mark III or GSLV Mk III) is a Multistage rocket, three-stage medium-lift launch vehicle developed by the ISRO, Indian Space Research Organisati ...
and on 16 August 2023, the composite attained a final lunar orbit of . A day later, the orbiter separated from the lander and began its independent operations with SHAPE. The orbiter also known as Propulsion Module (PM) of Chandrayaan-3, was moved from its orbit around Moon to an orbit around Earth.
While the initial plan was to operate SHAPE for about three months during the mission life of orbiter, the precise lower earth orbit injection by LVM3 and optimal earth / lunar burn maneuvers, resulted in the availability of over of fuel in the orbiter after over one month of operations in the lunar orbit. It was decided to use the available fuel in it to derive additional information for future lunar missions and demonstrate the mission operation strategies for a sample return mission. In order to continue SHAPE payload for Earth observation, it was decided to re-orbit the orbiter to a suitable Earth orbit. This mission plan was worked out considering the collision avoidance such as preventing the orbiter from crashing on to the Moon's surface or entering into the Earth's GEO belt at 36000 km and orbits below that. Considering the estimated fuel availability and the safety to GEO spacecraft, the optimal Earth return trajectory was designed for October 2023.
It operated until 22 August 2024.
Landers
Vikram (Chandrayaan-2)
The lander was named ''Vikram'' and it weighed including the rover named ''Pragyan'' that it housed inside. ''Vikram'' had eight
thrusters for attitude control and five liquid main engines that were derived from ISRO's
liquid apogee motors and it was designed to safely land on slopes up to 12°. It carried four payloads to study lunar seismic activity, measure the lunar sub-surface temperatures and to measure density and variation of lunar surface plasma (using a
langmuir probe).
After two de-orbiting manoeuvers, ''Vikram'' attained a final orbit of after which the powered descent phase began on 7 September 2019. During the descent and landing, the onboard computers had complete control over the lander. The initial descent and critical braking procedures went as intended but upon reaching altitude, the lander began deviating and lost its contact with the mission control after subsequent crash landing. Upon analysis, it was found that the main engines had higher thrust than normal which led to errors being accumulated over time and this meant the lander could not change its attitude at such a fast pace due to safety constraints in the onboard computer that had a limit on the maximum rate with which it can change its attitude. Coarse throttling of main engines, error in computing the remaining time in the mission and a small landing site of 500 x 500 m were the other reasons attributed to the failure.
Vikram (Chandrayaan-3)

Chandrayaan-3's ''Vikram'' lander had undergone major changes after its predecessor crash landed.
There were now four instead of five main engines that provided of thrust and had
slew rate
In electronics and electromagnetics, slew rate is defined as the change of voltage or current, or any other electrical or electromagnetic quantity, per unit of time. Expressed in SI units, the unit of measurement is given as the change per seco ...
changing capabilities, unlike previously when the centrally mounted fifth engine lacked the capability. This enabled the lander to control the attitude and thrust during all phases of descent. The attitude correction rate was also increased from Chandrayaan-2's 10°/s to 25°/s with Chandrayaan-3. An additional
laser Doppler velocimeter (LDV) was equipped that allowed attitude measurements in all three directions.
The impact legs were made larger and stronger relative to Chandrayaan-2. The OHRC onboard Chandrayaan-2 enabled the mission to have an expanded landing site with landing area. The lander underwent several tests including a helicopter drop test that helped in improving the structural rigidity. In the event of a failure during descent and landing, multiple contingency systems were added to improve the survivability chances of the lander. The landing region was unchanged from the previous mission, with the area of new site being expanded to from previous . Other major changes in the new 'failure-based' approach included the removal of the fifth engine, an increase in fuel capacity, an increase in vertical velocity component, and other software changes.
On 23 August 2023, the lander that had previously reduced its orbit to via de-orbit burns, began descending using all of its four engines after it reached near its Periselene at . Roughly after eleven minutes of powered descent, the lander maintained the altitude of for 10 seconds before changing its attitude to vertical position for the final vertical descent phase. It then used two of its four engines to slow its descent to and then hovered twice for about thirty seconds before touching down on the chosen optimal spot.
On 3 September 2023, before putting ''Vikram'' to sleep mode, ISRO conducted a hop on the lunar surface by firing its engines that moved it vertically as well as laterally before touching down again. The hop experiment proved to be the most significant test conducted by ISRO as the data would aid in future sample return missions under the programme. ISRO also attained a unique record of conducting its first
vertical take-off and landing
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-wing ...
on an extraterrestrial surface before Earth; that was planned to be conducted under its
Reusable technology demonstration programme.
Rovers
Pragyan (Chandrayaan-2)
The Rover named ''Pragyan'' carried two scientific payloads that were to be used in determining the elemental composition and its abundance near the landing site.
It was designed to travel at a speed of and could drive up to in its lifetime. Both the lander and rover were expected to operate for one lunar day as they lacked any
Radioisotope heater unit
A radioisotope heater unit (RHU) is a small device that provides heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of ...
(RHU) and were entirely dependent on solar power for operations. The Chandrayaan-2's Pragyaan was precluded from its operations after the crash landing of its carrier ''Vikram''.
Pragyan (Chandrayaan-3)
Unlike the lander, there were no changes made in the ''Pragyan'' rover except for switching ISRO's logo with Emblem of India on the left and right wheels respectively that would imprint them on the regolith. The scientific objectives too remained unchanged since the previous mission. On 23 August 2023, a few hours after the soft landing, the ramp was deployed for the ''Pragyan'' to touch down and begin its operations on the surface. A few days later, the instruments were turned on and the rover moved on the surface, thus achieving the primary goal of the mission. On 3 September 2023, with the lunar night approaching, the rover was shut down and put into 'sleep mode'.
Science
The Chandrayaan programme has been vastly regarded as successful, especially with the discovery of
lunar water.
It continues to provide scientific data and high-resolution imagery thanks to Orbiter High Resolution Camera (OHRC) which is the most advanced lunar camera so far with spatial resolution and it is currently operational onboard Chandrayaan-2's orbiter.
Chandrayaan-1 lost its contact a year before its intended duration, however, the Chandrayaan-2's orbiter is carrying forward the research from the orbit and is expected to operate until 2026.
The first soft landing and on-site science mission of Chandrayaan-3 conducted the first experiments in the lunar south pole region thus contributing to the understanding of the region which holds the potential for a future
crewed lunar base.
Discovery of water on the Moon

The presence of water on the Moon has always been a matter of intense debate since the last century. The first study for the lunar water was conducted in 1961 and it revealed that the polar regions, which have a high density of
cold traps, have more probability of lunar water ice than the equatorial regions. The samples returned from the equatorial region during
Apollo program
The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...
me failed to provide definitive evidence, reinforcing the need for research on the lunar poles. Since there hadn't been any missions to the lunar poles and since the poles had been speculated to harbour the water ice, Moon Impact Probe's impact site was chosen in the lunar south pole to search for firm evidence of the same in the lunar atmosphere.
The Chandra's Altitudinal Composition (ChACE) was one of the three scientific instruments on board the Chandrayaan-1's Moon Impact Probe (MIP). It was a
mass spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...
that was developed to study the composition of the tenuous lunar exosphere through mass spectroscopy. On 12 November 2008, the MIP separated from the Chandrayaan-1 orbiter and began its descent to the surface, during which it detected the clear presence of molecules with
atomic mass unit
The dalton or unified atomic mass unit (symbols: Da or u, respectively) is a unit of mass defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. It is a non-SI unit accepted ...
18 i.e., water. The ionized water molecules () and their fragments (such as and ions) were detected by ChACE. Three months later, the
Moon Mineralogy Mapper (M
3) an
imaging spectrometer on board the Chandrayaan-1 orbiter also detected the presence of water. While observing the
reflectance spectra of the Moon, it observed the absorption features of the water ice which are in the 1.0-2.5 μm wavelength region. The shadowed regions that received the reflected light were chosen for the study with water ice being found near the polar region.
The ChACE profile indicates a steady rise in the concentration of water molecules starting from 20 degrees south to the poles, however, it peaks at 60-70 degrees south and then declines. Overlaying the M
3 profile which begins at 43.1 degrees south depicts a complementary nature of the recordings, confirming the double evidence of lunar water near the south pole. However, the detection of water in every spectrum of ChACE coupled with the fact that it does not indicate either a steady rise or decline or a constant level in its profile, could possibly be due to contamination of water from Earth. Adding to the concerns was the M
3's profile which showed a steady increase towards the south pole, unlike ChACE which saw a decline beyond 70 degrees south. But according to Indian mathematician
Ramaiyengar Sridharan, if the water ice acts as a source due to
sublimation, which would be a strong function of temperature in the prevailing ultra high vacuum condition, then, in the absence of fresh sources during the measurement phase, the increase/decrease in the concentration measured by ChACE should be at the cost of what M
3 has detected in the form of ice; which means, the peak measurement recorded may be due to the presence of many water ice sources and the decline may be due to fewer such sources and while M
3 mapped the water ice sources on the surface the MIP detected the vapour generated from these sources, thus complementing each other.
Despite the Chandrayaan-1 mission ending a year earlier than the intended duration of two years, the data recorded from the instruments onboard over 310 days were very useful even a decade later. In 2018, the data obtained from the M
3 was used by the scientist at
University of Hawaii
A university () is an educational institution, institution of tertiary education and research which awards academic degrees in several Discipline (academia), academic disciplines. ''University'' is derived from the Latin phrase , which roughly ...
, Dr. Shuai Li and his team to research lunar water in the dark craters of the poles. Since the data was patchy and hard for them to work with the dark craters, they used the traces of sunlight that had bounced off crater walls and analyzed the spectral data to find places where the three specific wavelengths (in the range of 1.0-2.5 μm) of near-infrared light were absorbed that indicated the presence of water ice. They conducted thorough statistical analysis to ensure that their findings were not influenced by random anomalies or errors in the instruments. ''"I consider this to be the most convincing evidence that you actually do have true water ice at the uppermost surface — what we call the optical surface — of the Moon"'', Li said on the results.
Surface features
Mapping and Studying the lunar surface features were the primary scientific objectives of Chandrayaan-1. The first images of the surface were acquired by the Terrain Mapping Camera (TMC) onboard the mission's orbiter. The
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss
", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...
camera with resolution and swath in the
Panchromatic
A panchromatic emulsion is a type of photographic emulsion that is sensitive to all wavelengths of visible light, and produces a monochrome photograph—typically black and white. Most modern commercially available film is panchromatic, and the t ...
band, was activated on 29 October 2008 (within the earth's orbit) and it had captured over 70,000 images during its 3,000 orbits around the Moon. While the other scientific missions at the time usually had a resolution, many of TMC's images had a sharp resolution of thus enabling the production of a detailed map of the Moon.
During mapping
Rille
Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers w ...
s and
Lava tubes
A lava tube, more rarely called a pyroduct, is a 'roofed conduit through which molten lava travels away from its vent'. If lava in the tube drains out, it will leave an empty cave. Lava tubes are common in low-viscosity volcanic systems. La ...
on the lunar surface, the TMC discovered a large lava tube near the equator (specifically in the
Oceanus Procellarum
Oceanus Procellarum ( ; from ) is a vast lunar mare on the western edge of the near side of the Moon. It is the only one of the lunar maria to be called an "Oceanus" (ocean), due to its size: Oceanus Procellarum is the largest of the maria ("s ...
, to the north of the rille named
Rima Galilaei above the lunar equator). The tube measured about in length and in width. The lunar lava tubes are considered as
potential habitation sites for future crewed outposts since they act as natural protectors from
cosmic radiation
Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Sol ...
, solar radiation,
meteorite
A meteorite is a rock (geology), rock that originated in outer space and has fallen to the surface of a planet or Natural satellite, moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical ...
s,
micrometeorites, and ejecta from impacts. They are also insulated from the extreme temperature variations on the lunar surface.
Summary
List of missions
;Landing
Named sites
Future
On-site sampling and Sample return
With successful demonstration in soft landing and roving, the programme then moved into its next phase where a rover with greater scientific payload is to be sent to conduct on-site sample analysis. The mission named
Lunar Polar Exploration Mission (LUPEX) is suggested to be launched in the time frame of 2028–29.
India is collaborating with Japan in this mission. It will be a lander-rover mission near lunar pole to perform on-site sampling and analysis of collected lunar material
and demonstrate lunar night survival technologies.
The Indian Government gave approval for the mission, referred as Chandrayaan-5 on 14th March 2025.
Chandrayaan-4 is a planned
lunar sample-return mission of ISRO and will be the fourth mission in its Chandrayaan programme. It consists of four modules namely ''Transfer module (TM), Lander module (LM), Ascender module (AM) and Reentry Module (RM).'' The planned mission life is 1
lunar day
A lunar day is the time it takes for Earth's Moon to complete on its axis one synodic rotation, meaning with respect to the Sun. Informally, a lunar day and a lunar night is each approximately 14 Earth days. The formal lunar day is therefore t ...
, and the landing site is near to
Statio Shiv Shakti, the landing site of Chandrayaan-3's Lander.
Long duration exploration
Building upon this foundation subsequent missions, such as Chandrayaan-5 and Chandrayaan-6, will explore long-term presence on the Moon, including the potential development of habitats. Each flight is designed to progressively expand India's capabilities in lunar exploration, potentially with the co-operation of all
Artemis accords
The Artemis Accords are a series of non-binding multilateral arrangements between the United States government and other world governments that elaborates on the norms expected to be followed in outer space. The Accords are related to the Artem ...
signatories.
In an Interview ISRO chairman S Somanath has informed that India will continue sending robotic lunar explorers until an indigenous crewed mission, with the robotic program also continuing after that.
Gallery
File:380742main erlanger miniSAR large.jpg, Mini SAR radar image of Erlanger crater by Chandrayaan-1.
File:On the Way Down (3036669129).jpg, Images taken by Moon Impact Probe before performing a hard landing near the outer rim of Shackleton crater in the Lunar south pole
The lunar south pole is the southernmost point on the Moon. It is of interest to scientists because of the lunar water, occurrence of water ice in Crater of eternal darkness, permanently shadowed areas around it. The lunar south pole region fea ...
region.
File:Moon as viewed by Chandrayaan-2 LI4 Camera on 21 August 2019, 1903 UTC.png, Far side of the Moon
The far side of the Moon is the hemisphere of the Moon that is facing away from Earth, the opposite hemisphere is the near side. It always has the same surface oriented away from Earth because of synchronous rotation in the Moon's orbit. C ...
as viewed by Chandrayaan-2's LI4 (Lander Imager 4) Camera, 21 August 2019.
File:The Moon, as viewed by Chandrayaan-3 during Lunar Orbit Insertion on 5 August 2023.webm, The Moon, as viewed by Chandrayaan-3 during Lunar Orbit Insertion.
See also
*
List of missions to the Moon
Missions to the Moon have been numerous and include some of the earliest space missions, conducting exploration of the Moon since 1959.
The first partially successful lunar mission was Luna 1 (January 1959), the first probe to leave Earth ...
*
Indian Mars exploration missions
*
Indian Human Spaceflight Programme
*
*
*
Chinese Lunar Exploration Program
References
{{Use Indian English, date=October 2014
Missions to the Moon
ISRO programs
2003 establishments in India