On 14 November 2008, the Moon Impact Probe separated from the Chandrayaan orbiter at 20:06 and struck the south pole in a controlled manner, making India the fourth country to place its flag on the Moon. The probe impacted near Shackleton Crater at 20:31 ejecting underground soil that could be analysed for the presence of lunar water ice.
The estimated cost for the project was 386 crore (US$90 million).
The remote sensing lunar satellite had a mass of 1,380 kilograms (3,042 lb) at launch and 675 kilograms (1,488 lb) in lunar orbit. It carried high resolution remote sensing equipment for visible, near infrared, and soft and hard X-ray frequencies. Over a two-year period, it was intended to survey the lunar surface to produce a complete map of its chemical characteristics and three-dimensional topography. The polar regions are of special interest as they might contain ice. The lunar mission carries five ISRO payloads and six payloads from other space agencies including NASA, ESA, and the Bulgarian Aerospace Agency, which were carried free of cost.
After suffering from several technical issues including failure of the star sensors and poor thermal shielding, Chandrayaan stopped sending radio signals at 1:30 AM IST on 29 August 2009 shortly after which, the ISRO officially declared the mission over. The Main culprit is said to be the failure of onboard DC-DC Converter manufactured by mdipower USA. The converters failed to meet the radiation specifications for the intended mission time. Chandrayaan operated for 312 days as opposed to the intended two years but the mission achieved 95 percent of its planned objectives. Among its many achievements was the discovery of the widespread presence of water molecules in lunar soil.
ObjectivesThe mission had the following stated scientific objectives:
- to design, develop, launch and orbit a spacecraft around the Moon using an Indian-made launch-vehicle
- to conduct scientific experiments using instruments on the spacecraft which would yield data:
- for the preparation of a three-dimensional atlas (with high spatial and altitude resolution of 5–10 m) of both the near and far sides of the Moon
- for chemical and mineralogical mapping of the entire lunar surface at high spatial resolution, mapping particularly the chemical elements magnesium, aluminium, silicon, calcium, iron, titanium, radon, uranium, and thorium
- to increase scientific knowledge
- to test the impact of a sub-satellite (Moon Impact Probe — MIP) on the surface on the Moon as a fore-runner to future soft-landing missions
- 1,380 kg at launch, 675 kg at lunar orbit, and 523 kg after releasing the impactor.
- Cuboid in shape of approximately 1.5 m
- X band, 0.7 m diameter dual gimballed parabolic antenna for payload data transmission. The Telemetry, Tracking & Command (TTC) communication operates in S band frequency.
- The spacecraft is mainly powered by its solar array, which includes one solar panel covering a total area of 2.15 x 1.8 m generating 750 W of peak power, which is stored in a 36 A·h lithium-ion battery for use during eclipses.
- The spacecraft uses a bipropellant integrated propulsion system to reach lunar orbit as well as orbit and altitude maintenance while orbiting the Moon. The power plant consists of one 440 N engine and eight 22 N thrusters. Fuel and oxidizer are stored in two tanks of 390 litres each.
- Navigation and control
- The craft is 3-axis stabilized with two star sensors, gyros and four reaction wheels. The craft carries dual redundant bus management units for attitude control, sensor processing, antenna orientation, etc.
Specific areas of study
- High-resolution mineralogical and chemical imaging of the permanently shadowed north- and south-polar regions
- Searching for surface or sub-surface lunar water-ice, especially at the lunar poles
- Identification of chemicals in lunar highland rocks
- Chemical stratigraphy of the lunar crust by remote sensing of the central uplands of large lunar craters, and of the South Pole Aitken Region (SPAR), an expected site of interior material
- Mapping the height variation of features of the lunar surface
- Observation of X-ray spectrum greater than 10 keV and stereographic coverage of most of the Moon's surface with 5 m resolution
- Providing new insights in understanding the Moon's origin and evolution
PayloadsThe scientific payload had a total mass of 90 kg and contained five Indian instruments and six foreign instruments.
- TMC or the Terrain Mapping Camera is a CCD camera with 5 m resolution and a 40 km swath in the panchromatic band and was used to produce a high-resolution map of the Moon. The aim of this instrument was to completely map the topography of the Moon. The camera works in the visible region of the electromagnetic spectrum and captures black and white stereo images. When used in conjunction with data from Lunar Laser Ranging Instrument (LLRI), it can help in better understanding of the lunar gravitational field as well. TMC was built by the ISRO's Space Applications Centre (SAC) at Ahmedabad. The TMC was successfully tested on 29 October 2008 through a set of commands issued from ISTRAC.
- HySI or Hyper Spectral Imager performed mineralogical mapping in the 400-900 nm band with a spectral resolution of 15 nm and a spatial resolution of 80 m.
- LLRI or Lunar Laser Ranging Instrument determines the height of the surface topography by sending pulses of infrared laser light towards the lunar surface and detecting the reflected portion of that light. It operated continuously and collected 10 measurements per second on both the day and night sides of the Moon. It was successfully tested on 16 November 2008.
- HEX is a High Energy aj/gamma x-ray spectrometer for 30 – 200 keV measurements with ground resolution of 40 km, the HEX measured U, Th, 210Pb, 222Rn degassing, and other radioactive elements.
- MIP or the Moon Impact Probe developed by the ISRO, is an impact probe which consisted of a C-band Radar altimeter for measurement of altitude of the probe, a video imaging system for acquiring images of the lunar surface and a mass spectrometer for measuring the constituents of the lunar atmosphere. It was ejected at 20:00 hours IST on 14 November 2008. The Moon Impact Probe successfully crash landed at the lunar south pole at 20:31 hours IST on 14 November 2008. It carried with it a picture of the Indian flag. India is now the fourth nation to place a flag on the Moon after the Soviet Union, United States and Japan.
Payload from other countries
- C1XS or X-ray fluorescence spectrometer covering 1- 10 keV, mapped the abundance of Mg, Al, Si, Ca, Ti, and Fe at the surface with a ground resolution of 25 km, and monitored solar flux. This payload results from collaboration between Rutherford Appleton laboratory, U.K, ESA and ISRO. It was activated on 23 November 2008.
- SARA, The Sub-keV Atom Reflecting Analyser from the ESA mapped mineral composition using low energy neutral atoms emitted from the surface.
- M3, the Moon Mineralogy Mapper from Brown University and JPL (funded by NASA) is an imaging spectrometer designed to map the surface mineral composition. It was activated on 17 December 2008.
- SIR-2, A near infrared spectrometer from ESA, built at the Max Planck Institute for Solar System Research, Polish Academy of Science and University of Bergen, also maped the mineral composition using an infrared grating spectrometer. The instrument is similar to that of the Smart-1 SIR. It was activated on 19 November 2008 and scientific observations were successfully started on 20 November 2008.
- miniSAR, designed, built and tested for NASA by a large team that includes the Naval Air Warfare Center, Johns Hopkins University Applied Physics Laboratory, Sandia National Laboratories, Raytheon and Northrop Grumman; it is the active Synthetic Aperture Radar system to search for lunar polar ice. The instrument transmitted right polarised radiation with a frequency of 2.5 GHz and monitored scattered left and right polarised radiation. The Fresnel reflectivity and the circular polarisation ratio (CPR) are the key parameters deduced from these measurements. Ice shows the Coherent Backscatter Opposition Effect which results in an enhancement of reflections and CPR, so that water content of the Moon's polar regions can be estimated.
- RADOM-7, Radiation Dose Monitor Experiment from the Bulgarian Academy of Sciences maps the radiation environment around the Moon. It was successfully tested on 16 November 2008.
Space flightChandrayaan-1 was launched on 22 October 2008 at 6.22 am IST from Satish Dhawan Space Centre using the ISRO's 44.4 metre tall four-stage PSLV launch rocket. Chandrayaan-1 was sent to the Moon in a series of orbit-increasing manoeuvres around the Earth over a period of 21 days as opposed to launching the craft on a direct trajectory to the Moon. At launch the spacecraft was inserted into geostationary transfer orbit (GTO) with an apogee of 22,860 km and a perigee of 255 km. The apogee was increased with a series of five orbit burns conducted over a period of 13 days after launch.
For the duration of the mission, ISRO's telemetry, tracking and command network (ISTRAC) at Peenya in Bangalore, tracked and controlled Chandrayaan-1. Scientists from India, Europe, and the U.S. conducted a high-level review of Chandrayaan-1 on 29 January 2009 after the spacecraft completed its first 100 days in space.
Earth orbit burns
- First orbit burn
- Second orbit burn
- Third orbit burn
- Fourth orbit burn
- Final orbit burn
Lunar orbit insertionChandrayaan-1 successfully completed the lunar orbit insertion operation on 8 Nov 2008 at 16:51 IST. This manoeuvre involved firing of the liquid engine for 817 seconds (about thirteen and half minutes) when the spacecraft passed within 500 km from the Moon. The satellite was placed in an elliptical orbit that passed over the polar regions of the Moon, with 7502 km aposelene (point farthest away from the Moon) and 504 km periselene (nearest to the Moon). The orbital period was estimated to be around 11 hours. With the successful completion of this operation, India became the fifth nation to put a vehicle in lunar orbit.
- First orbit reduction
- Second orbit reduction
- Third orbit reduction
- Final orbit
Impact of the MIP on the lunar surfaceThe Moon Impact Probe (MIP) crash-landed on the lunar surface on 14 November 2008, 15:01 UTC (20:31 Indian Standard Time (IST)) near the crater Shackleton at the south pole. The MIP was one of eleven scientific instruments (payloads) on board Chandrayaan-1.
The MIP separated from Chandrayaan at 100 km from lunar surface and began its nosedive at 14:36 UTC (20:06 IST). going into free fall for thirty minutes. As it fell, it kept sending information back to the mother satellite which, in turn, beamed the information back to Earth. The altimeter then also began recording measurements to prepare for a rover to land on the lunar surface during a second Moon mission - planned for 2012.
Following the successful deployment of the MIP, the other scientific instruments were turned on, starting the next phase of the mission.
After scientific analyses of the received data from the MIP, the Indian Space Research Organisation confirmed the presence of water in the lunar soil and published the finding in a press conference addressed by its then Chairman Sri. G. Madhavan Nair.
Rise of spacecraft's temperatureISRO had reported on 25 November 2008 that Chandrayaan-1's temperature had risen above normal to 50 °C, scientists said that it was caused by higher than normal temperatures in lunar orbit. The temperature was brought down by about 10 °C by rotating the spacecraft about 20 degrees and switching off some of the instruments. Subsequently ISRO reported on 27 November 2008 that the spacecraft was operating under normal temperature conditions. In subsequent reports ISRO says, since the spacecraft was still recording higher than normal temperatures, it would be running only one instrument at a time until January 2009 when lunar orbital temperature conditions are said to stabilise. The spacecraft was experiencing high temperature because of radiation from the Sun and infrared radiation reflected by the Moon.
Mapping of mineralsThe mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper (M3), a NASA instrument on board the orbiter. The presence of iron was reiterated and changes in rock and mineral composition have been identified. The Oriental Basin region of the Moon was mapped, and it indicates abundance of iron-bearing minerals such as pyroxene.
Mapping of Apollo landing sitesISRO claims that the landing sites of the Apollo Moon missions have been mapped by the orbiter using multiple payloads. Six of the sites have been mapped including that of Apollo 11, the first mission that brought humans on the Moon.
Images acquisitionThe craft completed 3000 orbits acquiring 70000 images of the lunar surface, which many in ISRO believe is quite a record compared to the lunar flights of other nations. ISRO officials estimated that if more than 40,000 images have been transmitted by Chandrayaan's cameras in 75 days, it worked out to nearly 535 images being sent daily. They were first transmitted to Indian Deep Space Network at Byalalu near Bangalore, from where they were flashed to ISRO's Telemetry Tracking And Command Network (ISTRAC) at Bangalore.
Some of these images have a resolution of up to 5 metres, providing a sharp and clear picture of the Moon's surface, while many images sent by some of the other missions had a 100-metre resolution.
On 26 November, the indigenous Terrain Mapping Camera, which was first activated on 29 October 2008, acquired images of peaks and craters. This came as a surprise to ISRO officials because the Moon consists mostly of craters.
Detection of X-Ray signalsThe X-ray signatures of aluminium, magnesium and silicon were picked up by the C1XS X-ray camera. The signals were picked up during a solar flare that caused an X-ray fluorescence phenomenon. The flare that caused the fluorescence was within the lowest C1XS sensitivity range.
Full Earth imageOn 25 March 2009 Chandrayaan beamed back its first images of the Earth in its entirety. These images were taken with the TMC. Previous imaging was done on only one part of the Earth. The new images show Asia, parts of Africa and Australia with India being in the center.
Orbit raised to 200 km due to malfunctionsAfter the completion of all the major mission objectives, the orbit of Chandrayaan-1 spacecraft, which was at a height of 100 km from the lunar surface since November 2008, had to be raised to 200 km due to malfunctions. The orbit raising manoeuvres were carried out between 09:00 and 10:00 IST on 19 May 2009. The spacecraft in this higher altitude enabled further studies on orbit perturbations, gravitational field variation of the Moon and also enabled imaging lunar surface with a wider swath. However, it was later revealed that the true reason for the orbit change was that it was an attempt to keep the temperature of the probe down. It was "...assumed that the temperature [of the spacecraft subsystems] at 100km above the Moon's surface would be around 75 degrees Celsius. However, it was more than 75 degrees and problems started to surface. We had to raise the orbit to 200km."
Altitude sensing due to Star Sensor failureThe star sensor, a device used for pointing attitude determination of which the mission carried two, failed in orbit after nine months of operation. Afterward, the direction of Chandrayaan was determined using a back-up procedure using a two axis Sun sensor and taking a bearing from a ground station. This was used to update three axis gyroscopes which enabled spacecraft operations, although some failures may have reduced the craft's lifetime. The second failure, detected on 16 May, was attributed to excessive radiation from the Sun.
Bistatic RADAR experiment with LROOn 21 August 2009 Chandrayaan-1 along with the Lunar Reconnaissance Orbiter was used to perform a bistatic radar experiment to detect the presence of water ice on the lunar surface. In this experiment, Chandrayaan emanated RADAR pulses which, after reflection from the surface, were picked up by the receivers of both the Chandrayaan and the LRO. Both receivers, Mini-SAR in Chandrayaan and Mini-RF in LRO, were pointed at the Erlanger crater for four minutes during which the observations were made. In March 2010, it was reported that the Mini-Sar experiment onboard the Chandrayaan-1 had discovered cold dark spots which are hypothesized to contain an estimated "at least 600 million metric tonnes" of water-ice held within northern polar craters.
End of the missionThe mission was launched in 22 October 2008 and expected to operate for 2 years. However, at 09.02 (UTC) on 29 August 2009 communication with the spacecraft was suddenly lost. The probe had operated for 312 days. The craft will remain in orbit for approximately another 1000 days, eventually crashing into the lunar surface.
A member of the science advisory board of Chandrayaan-1 said that it is difficult to ascertain reasons for the loss of contact. ISRO Chairman -Madhavan Nair- said that due to very high radiation, power-supply units controlling both the computer systems on board failed, snapping the communication connectivity. However, information released later showed that the power supply failed due to overheating.
Completion of primary objectivesAlthough the mission was less than 10 months in duration, and less than half the intended 2 years in length, a review by scientists termed the mission successful, as it had completed 95% of its primary objectives, consisting of:
- To construct the complex spacecraft with 11 scientific instruments.
- To place the spacecraft in a circular orbit around the Moon by orbit raising manoeuvres from a near Earth orbit.
- To place the Flag of India on the Moon.
- To carry out imaging operations and to collect data on the mineral content of the lunar soil.
- To set up a deep space tracking network and implement the operational procedures for travel into deep space. 
Data collected analysis resultChandrayaan's Moon Mineralogy Mapper has confirmed the magma ocean hypothesis, meaning that the moon was once completely molten. "It proves beyond doubt the magma ocean hypothesis. There is no other way this massive rock type could be formed," said Carle Pieters, science manager at the NASA-supported spectroscopy facility at Brown University in the US.
The Terrain mapping camera Camera on board Chandrayaan-1 , besides producing more than 70,000 three dimensional images, has recorded images of the landing site of US spacecraft Apollo 15, rubbishing conspiracy theories that the US mission to land on the moon four decades back was a hoax.
"TMC and HySI payloads of ISRO have covered about 70 per cent of the lunar surface, while M3 covered more than 95 per cent of the same and SIR-2 has provided high-resolution spectral data on the mineralogy of the moon", ISRO said.
Indian Space Research Organisation said interesting data on lunar polar areas was provided by Lunar Laser Ranging Instrument (LLRI) and High Energy X-ray Spectrometer (HEX) of ISRO as well as Miniature Synthetic Aperture Radar (Mini-SAR) of the USA.
LLRI covered both the lunar poles and additional lunar regions of interest, HEX made about 200 orbits over the lunar poles and Mini-SAR provided complete coverage of both North and South Polar Regions of the moon.
Another ESA payload - Chandrayaan-1 imaging X-ray Spectrometer (C1XS) - detected more than two dozen weak solar flares during the mission duration. The Bulgarian payload called Radiation Dose Monitor (RADOM) was activated on the day of the launch itself and worked until the mission's end.
ISRO said scientists from India and participating agencies expressed satisfaction on the excellent performance of Chandrayaan-1 mission as well as the high quality of data sent by the spacecraft.
They have started formulating science plans based on the data sets obtained from the mission. It is expected that in the next few months, interesting results about lunar topography, mineral and chemical contents of the moon and related aspects are expected to be published,ISRO said.
A Chandrayaan-1 moon mission payload has enabled scientists to study the interaction between the solar wind and a planetary body like moon without a magnetic field, a meeting convened by ISRO was told.
In its 10-month orbit around the moon, Chandrayaan-1’s X-ray Spectrometer (C1XS) has detected titanium, confirmed the presence of calcium, and gathered the most accurate measurements yet of magnesium, aluminium and iron on the lunar surface.
Water discovered on the moonMoon Mineralogy Mapper (M3) on Chandrayaan-1 has detected water on the moon. M3 detected absorption features near 2.8-3.0 µm on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer H abundance data suggests that the formation and retention of OH and H2O is an ongoing surficial process. OH/H2O production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.
The Moon Mineralogy Mapper (M3), an imaging spectrometer, was one of the 11 instruments on board Chandrayaan-I that came to a premature end on 29 August 2009. M3 was aimed at providing the first mineral map of the entire lunar surface.
Lunar scientists have for decades contended with the possibility of water repositories. They are now increasingly “confident that the decades-long debate is over,” a report says. “The moon, in fact, has water in all sorts of places; not just locked up in minerals, but scattered throughout the broken-up surface, and, potentially, in blocks or sheets of ice at depth.” The results from the Chandrayaan mission are also “offering a wide array of watery signals.” 
How the moon produces its own waterA scientific instrument on Chandrayaan-1 — the Sub keV Atom Reflecting Analyser or SARA — made this discovery that was published in the latest edition of the Planetary and Space Science journal.
According to European Space Agency (ESA) scientists, hydrogen nuclei from solar winds are absorbed by the lunar regolith (a loose collection of irregular dust grains making up the moon’s surface). An interaction between the hydrogen nuclei and oxygen present in the dust grains are expected to produce hydroxyls and water.
SARA, developed by the ESA and the Indian Space Research Organisation, was designed to study the moon’s surface composition and solar wind-surface interactions. Recently, another instrument on the Indian spacecraft, the Moon Mineralogy Mapper — an imaging spectrometer developed by the U.S. National Aeronautics and Space Administration — first found water molecules on the lunar surface.
SARA’s results also highlight a mystery: not every hydrogen nucleus is absorbed. One out of every five rebounds into space, combining to form an atom of hydrogen. “We didn’t expect to see this at all,” said Stas Barabash of the Swedish Institute of Space Physics, who is the European Principal Investigator for SARA.
Hydrogen shoots off at speeds of around 200 km per second and escapes without being deflected by the moon’s weak gravity, the team found.
This knowledge provides timely advice for scientists who are readying ESA’s BepiColombo mission to mercury. The spacecraft will carry two instruments similar to SARA and may find that the innermost planet is reflecting more hydrogen than the moon because the solar wind is more concentrated closer to the sun.
Discovery of caves on the moonChandrayaan-1 discovered large caves below the lunar surface - caves that could act as shelters for humans. The tunnel, which has been discovered near the lunar equator, is an empty volcanic tube, measuring about two km in length and 360 metres in width. According to AS Arya, scientist SF of Ahmedabad-based Space Application Centre (SAC), this could be a potential site for human settlement on moon. Earlier, Japanese Lunar orbiter Kaguya (SELENE) had also discovered a cave on moon.
Award for Chandrayaan-1The American Institute of Aeronautics and Astronautics (AIAA) has selected ISRO's Chandrayaan-1 mission as one of the recipients of its annual AIAA SPACE 2009 awards, which recognizes key contributions to space science and technology.
The International Lunar Exploration Working Group (ILEWG) chose the Chandrayaan-1 team for giving the International Cooperation award, M, Annadurai, project director, Chandrayaan-1.The Chandrayaan team of the Indian Space Research Organisation (ISRO) was chosen for the award for accommodation and tests of the most international lunar payload ever (from 20 countries consisting of India, the European Space Agency representing 17 European countries, NASA and Bulgaria) and the successful launch of the probe on PSLV rocket on 22 October and the lunar insertion of the spacecraft carried out subsequently.
TeamThe scientists considered instrumental to the success of the Chandrayaan-1 project are:
- G. Madhavan Nair – Chairman, Indian Space Research Organization
- Dr. T. K. Alex – Director, ISAC (ISRO Satellite Centre)
- Dr.Mylswamy Annadurai – Project Director, Chandrayan-1
- S. K. Shivkumar – Director - Telemetry, Tracking and Command Network
- Mr. M.Pitchaimani – Operations Director, Chandrayan-1
- Mr. Leo Jackson John – Spacecraft Operations Manager, Chandrayan-1
- Dr. K. Radhakrishnan (scientist) – Director, VSSC
- George Koshy – Mission Director, PSLV-C11
- Srinivasa Hegde – Mission Director, Chandrayaan-1
- Prof. J N Goswami – Director of Physical Research Laboratory and Principal Scientific Investigator of Chandrayaan-1
- Rajendra Masanta - Server Operation Lead Specialist - Pool - 19 Space Satellite
- Anil Prasad - Server Operation Specialist - Pool - 19 Space Satellite