A.P.J. Abdul Kalam, shown here in 2007, died July 27. (Christophe Karaba/EPA)

Former Indian President A.P.J. Abdul Kalam, a scientist who was known as the father of the country’s military missile program, died July 27 after collapsing while delivering a lecture. He was 83.

Mr. Kalam fell sick while addressing students at the Indian Institute of Management in the Meghalaya state capital, Shillong, said P.B. Warjri, chief secretary of the state. He was rushed to a hospital but was declared dead after doctors could not revive him, Warjri said. India Today reported that the cause was a heart attack.

Mr. Kalam served from 2002 until 2007 as president, a largely ceremonial role but one that reflected the prominence he had attained. He was a scientist and science administrator for four decades, mainly at the state-run Defense Research and Development Organization and the Indian Space Research Organization.

He was credited with helping develop his country’s first space satellites. In the 1980s, he was helped design the nuclear-capable Prithvi and Agni ballistic missiles.

He played a crucial role when India tested its nuclear weapons in 1998. The test resulted in sanctions against the country but helped elevate Mr. Kalam to the status of folk hero in his country.

“We must think and act like a nation of a billion people, and not like that of a million people,” he said at that time. “Dream, dream, dream! Conduct these dreams into thought, and then transform them into action.”

After his presidential term, Mr. Kalam traveled to remote schools and colleges, speaking to students. Even after he left office, he received hundreds of e-mails each day from young people. He would reply to most of the children who wrote to him.

India’s President Pranab Mukherjee said that Mr. Kalam “would be long remembered for his passion for science and innovation and his contribution as an eminent scientist, administrator, educationist and writer.”

Prime Minister Narendra Modi said “his death is a great loss to the scientific community. He took India to great heights.”

Avul Pakir Jainulabdeen Abdul Kalam, a member of India’s Muslim minority, was born in Dhanushkodi, in the southern state of Tamil Nadu, on Oct. 15, 1931. He had a humble beginning: His father owned boats which he rented out to local fishermen.

A.P.J. Abdul Kalam studied aeronautical engineering at Madras Institute of Technology. He wrote several books, notably the autobiography “Wings of Fire” and “I gnited Minds: Unleashing the Power Within India.

Mr. Kalam received several prestigious awards, including Bharat Ratna, India’s top civil honor conferred by the government. He wrote poetry in Tamil, his native language, and played the veena, a traditional instrument.

Mr. Kalam was not married. A complete list of survivors was not immediately available.

—From staff and wire reports