Dr. Naderi, who was trained as an electrical engineer, left his native Iran in the wake of the Islamic revolution of 1979 and was hired later that year by NASA’s Jet Propulsion Laboratory (JPL) in California.

Over nearly four decades, he emerged as a linchpin of the laboratory’s missions, particularly the landing of the Spirit and Opportunity rovers on Mars in 2004, one of NASA’s most momentous achievements in recent decades.

“Firouz Naderi was a giant,” Bill Nelson, the NASA administrator and former Democratic senator from Florida, wrote on Twitter after Dr. Naderi’s death. “He helped to redefine humanity’s knowledge about Mars and reinvigorate our sense of curiosity.”

Dr. Naderi had a wide-ranging career at NASA and served as director for solar system exploration before his retirement in 2016. But he was perhaps best known for his work as head of the Mars exploration program at JPL, a role he held from 2000 to 2005.

The Mars program had previously suffered setbacks, including the loss in 1999 of the $125 million Mars Climate Orbiter because of an elementary error involving the conversion of non-metric and metric units. Another craft, the Mars Polar Lander, failed later that year, at a cost of $165 million.

“If there is such a thing as institutional depression,” Dr. Naderi later told the Houston Chronicle, “we felt it here at JPL after the 1999 back-to-back failures.”

The successes of the Mars program under Dr. Naderi included the Mars Odyssey launched in 2001, a spacecraft that is still in use and holds the record, according to NASA, for “longest continually active spacecraft in orbit around a planet other than Earth.”

The launch of Spirit and Opportunity proved even more thrilling. Designed for 90-day missions, the twin rovers outperformed expectations in spectacular fashion. Spirit lasted more than six years, and Opportunity explored the surface of Mars for nearly 15 years.

Together they helped scientists gather evidence that Mars was once a warmer, wetter planet and could have been an abode of life.

Recalling the emotions of the moment when the first rover landed, Dr. Naderi remarked that “it was the first time I heard my heart beat.”

Like many of his colleagues, he spoke of the rovers as if they were living things. He commented that Spirit, during its ascent to Mars, was like “a baby in a mother’s womb with all the limbs tightly folded.” When the rover landed, he noted, the limbs would unfold, like those of an infant in the moments after birth. He spoke of the rover in rest mode as having a “good night of sleep.”

The missions had personal importance for Dr. Naderi, who saw himself as a representative of Iranians and Iranian Americans at a time when many felt misunderstood, if not vilified, by American society. In his 2002 State of the Union address, President George W. Bush had labeled Iran, along with North Korea and Iraq, part of the “axis of evil.”

“I had this additional self-imposed stress,” Dr. Naderi told an interviewer at the Caltech Heritage Project. “I was thinking if we fail the headlines would say ‘NASA fails again at Mars and this time under a native Iranian program manager!’ The pressures that we manufacture and put on ourselves over and above the real pressures.”

He sought “to show what is positive” about Iranian culture, he said, and became a champion of Iranian and Iranian American students and scientists.

At the Academy Awards in 2017, he joined Anousheh Ansari, an Iranian American who became the first female private space traveler, in collecting the best foreign-language film Oscar on behalf of Asghar Farhadi, director of the Iranian drama “The Salesman.”

Farhadi had boycotted the evening in protest of the newly elected Trump administration’s restrictions on travel by citizens of Iran and other Muslim-majority countries. The travel ban, Dr. Naderi said, was particularly harmful to students seeking to further their education in the United States.

Until the end of his life, Dr. Naderi remained an advocate for human rights in his native country. His honors included NASA’s Distinguished Service Medal, the space agency’s highest recognition. When he retired, an asteroid was named in his honor.

“It will be going around the Sun for billions of years after I am gone,” Dr. Naderi remarked.

Firouz Michael Naderi was born in Shiraz, Iran, on March 25, 1946. He described his father as a recipient of inherited wealth who “never had to work unless it amused him.”

Dr. Naderi’s parents were divorced when he was 4. After attending elementary school in Shiraz, he was sent to a boarding school in Tehran run by Catholic priests.

He decided to pursue university studies in the United States, where he was to be met in New York by a stepsister who had funds from his father.

“As immigrants typically do, I had this overstuffed large suitcase, schlepping it around the airport,” he recalled. Because of a miscommunication, his stepsister was not there to immediately receive him, and for a week, until her arrival, he subsisted on hot dogs purchased with the $2 he had.

Dr. Naderi received a bachelor’s degree in electrical engineering from Iowa State University in 1969. He continued his studies at the University of Southern California, where he received a master’s degree in 1972 and a PhD in 1976, also in electrical engineering.

He returned to Iran, where he worked with earth-science satellites for the state Remote Sensing Agency. When the shah was deposed and the Ayatollah Ruhollah Khomeini took power, Dr. Naderi left Iran and never went back.

At JPL, he served in positions including project manager for mobile satellite experiments. Before his appointment to the Mars program, he was manager of the Origins program, which, among other missions, explored the formation of early life on Earth and looked for earthlike planets in other galaxies.

A complete list of survivors was not immediately available.

Dr. Naderi was active with the Public Affairs Alliance of Iranian Americans and other organizations promoting Iranian and Iranian American causes.

“Once you go away from the Earth into space, and you look back at the Earth, you see it as a single blue marble,” he said. “You see no borders, no lines, separating people.”