Space Science------------Chandrayaan-1:India's first scientific mission to moon

Chandrayaan-1:India's first scientific mission to moon

Chandrayaan-1 (Hindi: चन्द्रयान-१) was India's first lunar probe. 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, serial number C11,on 22 October 2008 from Satish Dhawan Space Centre, Sriharikota, Nellore District, Andhra Pradesh, about 80 km north of Chennai, at 06:22 IST (00:52 UTC).Former prime minister Atal Bihari Vajpayee announced the project on course in his Independence Day speech on 15 August 2003. 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 successfully inserted into lunar orbit on 8 November 2008.

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 the crater Shackleton at 20:31 ejecting underground soil that could be analysed for the presence of lunar water ice.

The estimated cost for the project was INR3.86 billion (US$64 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 carried 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 01:30 IST on 29 August 2009 shortly after which, the ISRO officially declared the mission over. 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.

Data collected analysis result

Chandrayaan's Moon Mineralogy Mapper has confirmed the magma ocean hypothesis, meaning that the Moon was once completely molten.

The terrain mapping camera on board Chandrayaan-1, besides producing more than 70,000 three dimensional images, has recorded images of the landing site of U.S. spacecraft Apollo 15, rubbishing conspiracy theories that the U.S. mission to land on the Moon four decades back was a hoax.

TMC and HySI payloads of ISRO have covered about 70% of the lunar surface, while M3 covered more than 95% of the same and SIR-2 has provided high-resolution spectral data on the mineralogy of the Moon.

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 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.

The Chandrayaan-1 payload has enabled scientists to study the interaction between the solar wind and a planetary body like the Moon without a magnetic field.

In its 10-month orbit around the Moon, Chandrayaan-1’s X-ray Spectrometer (C1XS) detected titanium, confirmed the presence of calcium, and gathered the most accurate measurements yet of magnesium, aluminium and iron on the lunar surface.

Lunar water discovery

These images show a very young lunar crater on the side of the Moon that faces away from Earth, as viewed by Chandrayaan-1's NASA Moon Mineralogy Mapper equipment

On 24 September 2009 Science magazine reported that the Moon Mineralogy Mapper (M3) on Chandrayaan-1 had detected water on the Moon.[93] But, on 25 September 2009, ISRO announced that the MIP, another instrument on board Chandrayaan-1 had discovered water on the moon just before impact and had discovered it 3 months before NASA's M3.The announcement of this discovery was not made until NASA confirmed it.

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 had discussed the possibility of water repositories for decades. 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."

Lunar water production

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 hydroxyl (HO-) and water (H2O).

SARA (Sub keV Atom Reflecting Analyser) instrument developed by ESA and the Indian Space Research Organisation, was designed and used to study the Moon’s surface composition and solar wind-surface interactions. SARA’s results highlight a mystery: not every hydrogen nucleus is absorbed. One out of every five rebounds into space, combining to form an atom of hydrogen.[clarification needed][citation needed] Hydrogen shoots off at speeds of around 200 km per second and escapes without being deflected by the Moon’s weak gravity. This knowledge provides timely advice for scientists who are readying ESA’s BepiColombo mission to Mercury, as that spacecraft will carry two instruments similar to SARA.

Lunar caves

Chandrayaan-1 discovered a large cave below the lunar surface.The tunnel, which was discovered near the lunar equator, is an empty volcanic tube, measuring about 2 kilometres (1.2 mi) in length and 360 metres (1,180 ft) 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 the Moon. Earlier, Japanese Lunar orbiter Kaguya (SELENE) had also discovered a cave on Moon.


Data from the microwave sensor (MiniSAR) of the Chandrayan- 1 satellite processed using the image analysis software ENVI, has revealed a good amount of past tectonic activity on the lunar surface.The researchers think that the faults and fractures discovered could be features of past interior tectonic activity coupled with meteorite impacts.

End of the mission

The mission was launched on 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 was expected to 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 supplied by MDI failed due to overheating.

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