India's second lunar mission, aiming to land on the Moon's south pole after being slingshotted with no manual control out of Earth's orbit, has launched successfully.
Chandrayaan-2 (Moon chariot 2) was launched at 2.43pm local time on Monday from the Sriharikota space station.
The spacecraft has entered the Earth's orbit, where it will stay for 23 days before it begins a series of manoeuvres that will take it into lunar orbit.
India hopes the $US145m mission will be the first to land on the Moon's south pole, on 6 or 7 September as planned despite the week-long delay of the launch.
India's space chief said his agency had "bounced back with flying colours" after that aborted first attempt. The countdown on 15 July was stopped 56 minutes before launch after a "technical snag was observed in [the] launch vehicle system", according to the Indian Space Research Organisation (Isro).
Indian media reported that a leak from a helium gas bottle in the cryogenic engine of the rocket was to blame. The fuel from the rocket was drained and the scientists resolved the glitch.
If successful, India will become the fourth country to make a soft landing on the Moon's surface. Only the former Soviet Union, the US and China have been able to do so.
Monday's lift-off was broadcast live on TV and the space agency's official social media accounts.
There was applause in the Isro control room minutes after the launch of the most complex mission ever attempted by India's space agency, as the rocket took off towards the outer atmosphere.
For the first time in India's space history, an interplanetary expedition is being led by two women - Muthaya Vanitha, the project director, and Ritu Karidhal, the mission director.
"It is the beginning of a historical journey of India towards the moon," said Isro chief K Sivan in a speech after the launch.
He thanked and congratulated the nearly 1000 scientists, engineers and other staff who had worked on the mission: "It is my duty to salute all the people who have done the work."
Prime Minister Narendra Modi praised the mission for being "fully indigenous".
Indian at heart, Indian in spirit!— Narendra Modi (@narendramodi) July 22, 2019
What would make every Indian overjoyed is the fact that #Chandrayaan2 is a fully indigenous mission.
It will have an Orbiter for remote sensing the Moon and also a Lander-Rover module for analysis of lunar surface.
The mission will focus on the lunar surface, searching for water and minerals and measuring moonquakes, among other things.
India is using its most powerful rocket, the Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk-III), in this mission. It weighs 640 tonnes (almost 1.5 times the weight of a fully-loaded 747 jumbo jet) and, at 44 metres (144ft), is as high as a 14-storey building.
The spacecraft used in the mission has three distinct parts: an orbiter, a lander and a rover. The orbiter, which weighs 2379kg and has a mission life of a year, will take images of the lunar surface.
The lander (named Vikram, after the founder of Isro) weighs about half as much, and carries within it a 27kg Moon rover with instruments to analyse the lunar soil. In its 14-day life, the rover (called Pragyan - wisdom in Sanskrit) can travel up to a half a kilometre from the lander and will send data and images back to Earth for analysis.
The journey of 384,000km, taking more than six weeks, is a lot longer than the four days the Apollo 11 mission 50 years ago which first landed humans on the lunar surface.
To save fuel, India's space agency has chosen a circuitous route to take advantage of the Earth's gravity, which will help slingshot the lander towards the Moon.
India does not have a rocket powerful enough to hurl Chandrayaan-2 on a direct path. The Saturn V rocket used by the Apollo programme remains the largest and most powerful rocket ever built.
"There will be 15 terrifying minutes for scientists once the lander is released and is hurled towards the south pole of the Moon," Dr Sivan said prior to the first launch attempt.
He explained that those who had been controlling the spacecraft until then would have no role to play in those crucial moments. So, the actual landing would happen only if all the systems performed as they should. Otherwise, the lander could crash into the lunar surface.
Earlier this year, Israel's first Moon mission crash-landed while attempting to touch down.