India has successfully launched its first mission to the Moon.
The unmanned Chandrayaan 1 spacecraft blasted off smoothly from a launch pad in southern Andhra Pradesh to embark on a two-year mission of exploration.
The robotic probe will orbit the Moon, compiling a 3-D atlas of the lunar surface and mapping the distribution of elements and minerals.
The launch is regarded as a major step for India as it seeks to keep pace with other space-faring nations in Asia.
Indian PM Manmohan Singh hailed the launch as the “first step” in a historic milestone in the country’s space programme.
“Our scientific community has once again done the country proud and the entire nation salutes them,” Mr Singh said in a message.
The launch was greeted with applause by scientists gathered at the site.
The chief of the Indian Space Research Organisation (ISRO), Madhavan Nair, said it was a “historic moment” for the country.
“Today what we have charted is a remarkable journey for an Indian spacecraft to go to the moon and try to unravel the mysteries of the Earth’s closest celestial body and its only natural satellite,” Nair said.
The BBC’s Sanjoy Majumder in Delhi says there has been a lot of excitement about the event, which was broadcast live on national TV.
An Indian-built launcher carrying the one-and-a-half-tonne satellite blasted off from Satish Dhawan Space Centre in Sriharikota, an island off the coast of Andhra Pradesh, at about 0620 local time (0050 GMT).
Indian views on the country’s first space mission
One key objective will be to search for surface or sub-surface water-ice on the Moon, especially at the poles.
Another will be to detect Helium 3, an isotope which is rare on Earth, but is sought to power nuclear fusion and could be a valuable source of energy in future.
Powered by a single solar panel generating about 700 Watts, the Indian Space Research Organisation (ISRO) probe carries five Indian-built instruments and six that are foreign-built.
The mission is expected to cost 3.8bn rupees (£45m; $78m).
The Indian experiments include a 30kg probe that will be released from the mothership to slam into the lunar surface.
1 – Chandrayaan Energetic Neutral Analyzer (CENA)
2 – Moon Impact Probe (MIP)
3 – Radiation Dose Monitor (RADOM)
4 – Terrain Mapping Camera (TMC)
5 – Moon Mineralogy Mapper (M3)
6 – Chandrayaan 1 X-ray Spectrometer (C1XS)
7 – Solar Panel
India sets its sights on the Moon
In Pictures: India Moon mission
The Moon Impact Probe (MIP) will record video footage on the way down and measure the composition of the Moon’s tenuous atmosphere.
“Chandrayaan has a very competitive set of instruments… it will certainly do good science,” said Barry Kellett, project scientist on the C1XS instrument, which was built at the Rutherford-Appleton Laboratory in the UK.
C1XS will map the abundance of different elements in the lunar crust to help answer key questions about the origin and evolution of Earth’s only natural satellite.
Researchers say the relative abundances of magnesium and iron in lunar rocks could help confirm whether the Moon was once covered by a molten, magma ocean.
“The iron should have sunk [in the magma ocean], whereas the magnesium should have floated,” Mr Kellett told BBC News.
“The ratio of magnesium to iron for the whole Moon tells you to what extent the Moon melted and what it did after it formed.”
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The instrument will look for more unusual elements on the Moon’s surface, such as titanium. This metallic element has been found in lunar meteorites, but scientists know little about its distribution in the lunar crust.
Chandrayaan (the Sanskrit word for ‘moon craft’) will also investigate the differences between the Moon’s near side and its far side. The far side is both more heavily cratered and different in composition to the one facing Earth.
The Polar Satellite Launch Vehicle (PSLV) rocket will loft Chandrayaan into an elliptical “transfer orbit” around Earth.
The probe will later carry out a series of engine burns to set it on a lunar trajectory.
The spacecraft coasts for about five-and-a-half days before firing the engine to slow its velocity such that it is captured by the Moon’s gravity.
Chandrayaan will slip into a near-circular orbit at an altitude of 1,000km. After a number of health checks, the probe will drop its altitude until it is orbiting just 100km above the lunar surface.
India, China, Japan and South Korea all have eyes on a share of the commercial satellite launch business and see their space programmes as an important symbol of international stature and economic development.
Last month, China became only the third country in the world to independently carry out a spacewalk.
But the Indian government’s space efforts have not been welcomed by all.
Some critics regard the space programme as a waste of resources in a country where millions still lack basic services.