Indian Prime Minister Manmohan Singh on Sunday defended spending millions of dollars on space exploration despite many people in the country living in grinding poverty.

India plans to launch a probe to orbit Mars next year at an estimated cost of four to five billion rupees ($70-90 million), and hopes to send its first manned mission to space in 2016.

"Questions are sometimes asked about whether a poor country like India can afford a space programme and whether the funds spent on space exploration, albeit modest, could be better utilised elsewhere," Singh said in a speech.

"This misses the point that a nation's state of development is finally a product of its technological prowess."

India comes 134th among 187 countries in the United Nations' overall development rankings, while a survey earlier this year revealed that 42 percent of Indian children aged under five are underweight due to malnutrition.

Singh made his remarks in Andhra Pradesh state after witnessing the launch of India's 100th space mission when a rocket carrying two foreign commercial satellites was fired into orbit.

"India is justly proud of its space scientists, who have overcome immense odds to set up world-class facilities and develop advanced technologies," he said.

In September 2009, India's Chandrayaan-1 lunar probe discovered water on the moon, boosting the country's credibility among more experienced space-faring nations.

But the space programme suffered a setback in December 2010 when a satellite launch vehicle blew up and fell into the Bay of Bengal after veering from its intended flight path.