The United States spent about $25 billion - the equivalent of more than $100 billion in current prices - on 15 Apollo missions, including the six that put Armstrong and other astronauts on the moon. China spent $8.4 billion on its Chang'e 4 lunar craft in January, and Russia spent over $20 billion at today's values on lunar missions in the 1960s and 70s.

Almost the entire Chandrayaan-2's orbiter, lander and rover have been designed and made in India, and it will use its most powerful rocket launcher, GSLV Mk III, to carry the 2.4 tonne orbiter, which has a mission life of about a year.

The spacecraft will carry the 1.4 tonne lander Vikram - which in turn will take the 27-kilogramme rover Pragyan - to a high plain between two craters on the lunar South Pole.

Indian Space Research Organisation (ISRO) chief K Sivan said Vikram's 15-minute final descent "will be the most terrifying moments as we have never undertaken such a complex mission".

The solar-powered rover can travel up to 500 metres and is expected to work for one lunar day, the equivalent of 14 Earth days. Mr Sivan said the probe will be looking for signs of water and "a fossil record of the early solar system".

Prime Minister Narendra Modi has vowed to send a manned mission into orbit by 2022. Most experts say the geo-strategic stakes are small - but that India's low-cost model could win commercial satellite and orbiting deals.

"The fundamental question that we should ask ourselves in this context is not whether India should undertake such ambitious space ventures, but whether India can afford to ignore it," said K Kasturirangan, a former ISRO chief. India has to aim to be a leader in space, he added.

Amitabha Ghosh, a scientist for NASA's Rover mission to Mars, said the benefits of Chandrayaan-2 are huge, compared to its cost. "A spacecraft mission of the complexity of Chandrayaan-2 conveys a message that India is capable of delivering on difficult technology development endeavours," said Mr Ghosh.

However, some experts say anyone looking for a cheap ticket to space should think of the comfort on low-cost plane rides closer to Earth. Scott Hubbard, a former top NASA researcher now with Stanford University, examined the cost-effectiveness of the Indian Mars orbiter against the American Maven mission.