Soldiers stand guard near the Polar Satellite Launch Vehicle (PSLV-C25) at the Satish Dhawan Space Center in southern India, Oct. 30 ,2013. India’s Mars orbiter mission is scheduled to be launched by PSLV-C25 on Nov. 5. (Arun Sankar K/AP)

India’s space agency has begun its formal countdown to the launch of its unmanned orbiter to Mars, a voyage that India hopes will help contribute to the growing body of scientific data on the far-off planet.

On Tuesday afternoon, if all goes as planned, India will launch the spacecraft — called Mangal­yaan, or the Mars Orbiter Mission probe — from a small island near Chennai on the country’s southern coast. The craft will take 11 months to reach the atmosphere of the cold, forbidding planet, traveling 140 million miles from Earth.

Indian Prime Minister Manmohan Singh announced plans for the mission during a major address in August 2012, a few months after rival China’s attempt to send an orbiter on a Russian mission failed. The plans raised talk of a new space race in Asia.

But Deviprasad Karnik, a spokesman for India’s space agency, said the primary objective of the trip is to “showcase technological capability to reach Mars” and collect data for future space missions.

India’s space program, which is a half-century old, has long been a source of national pride, especially in recent years as the rapidly modernizing country raised its ambitions beyond satellite technology to lunar and planetary travel. An unmanned probe that India sent to the moon in 2008 contained an instrument — financed by the United States — that detected water trapped in lunar rocks.

But the space program has not been without its critics, who wonder why the country is spending $74 million on interplanetary travel while millions of its people remain poor and malnourished.

“It’s a national milestone for the country to conquer territories beyond planet Earth,” said Bharath Gopalaswamy, a Chennai native who is the deputy director of the South Asia Center at the Atlantic Council. “India has its own ambitions. Just because we’re poor doesn’t mean we shouldn’t have any ambitions. That’s not the way we think about ourselves, right?”

The program’s defenders have said that it helped develop satellite technology for India that was used for the benefit of the underserved, bringing classrooms and health care to remote areas and mapping water resources for wells.

India is entering the Mars arena as the international space race has grown far more competitive and globalized. A growing number of countries and commercial entities have set their sights on sending a manned mission to Mars sometime in the next two decades. NASA head Charles Bolden has said that a human mission to Mars, which the U.S. space agency hopes to launch by 2030, is a priority for the agency and that the “entire exploration program is aligned to support this goal.”

Close on the heels of the India launch, NASA will launch its newest Mars probe, called Maven, from Cape Canaveral on Nov. 18. Scientists hope it will lend insights into climate changes that can help them understand climate shifts on Earth.

Meanwhile, the United States has been losing its historical dominance in the arena as funding has slumped and other nations have jumped into the fray. Scientists say the India mission will help continue to map the surface of Mars, which in many ways remains a mystery.

“Despite the existing data, we really do not understand the planet’s history and its potential for life,” Jeff Plescia, a scientist with the Applied Physics Laboratory at Johns Hopkins University, wrote in an e-mail.

Plescia said previous spacecraft have seen small channels forming, dusty material moving around the planet’s surface, craters from asteroids forming, and ice being exposed and evaporating. “Having more sensors in orbit provides a better understanding of those events and how they occur,” he said.

If all goes as scheduled, the Mangalyaan spacecraft is expected to reach Mars’s orbit in September, making India the fourth nation or group to reach Mars, after the United States, Russia (and the former Soviet Union) and the European Space Agency.

But NASA’s director of planetary science, Jim Green, said the Indian mission faces long odds. Of 40 missions to Mars by various countries, he said, only 16 have been successful.

“The track record tells us Mars is very, very hard,” Green said. He noted that some missions have missed the planet entirely and that some have crashed into it.

India’s orbiter — should it make it all the way to Mars — will carry a sensor that could help detect the presence of methane, a gas produced by living microbes. If found, the presence of methane could answer the question that has dogged scientists for years: Is there life on Mars?

Although NASA scientists think that they found methane in earlier experiments, the Mars rover Curiosity, which landed on the cratered surface last year, has not found any. But the scientists have not given up hope.

“We are seeking signs of life, and methane can be one of those signatures,” Green said. “We’d like to know if Mars is currently harboring life that’s generating methane now, so the India mission is a great step.”

Suhasini Raj contributed to this report.