Ed Stone, the scientist who guided NASA's groundbreaking Voyager mission to the outer planets for 50 years and led the Jet Propulsion Laboratory when it landed its first rover on Mars, died Tuesday. He was 88 years old.
Stone, a physicist who entered the early phase of space exploration, played a leading role in NASA missions to Mars, Jupiter, Saturn, Uranus and Neptune. The discoveries made under his direction revolutionized scientists' understanding of the solar system and fueled humanity's ambition to explore distant worlds.
Carolyn Porco, who worked on imaging on JPL's Voyager and Cassini missions, called Stone “a completely charming man” who was “as close to perfection as a project scientist could ever be.”
“When two scientific teams were in dispute over some spacecraft resource, and Ed had to decide between the two, even the one who lost came away thinking, 'Well, if this is what Ed has decided, then it must be the answer.' correct'. '” Porco said via email Tuesday. “I feel blessed to have known Ed. And like many people today, I am very sad to know that he is gone.”
Stone was a 36-year-old Caltech physics professor in 1972 when he was asked to serve as chief scientist for an audacious plan to send a pair of spacecraft to explore the solar system's four giant planets for the first time.
It was the opportunity of a lifetime, but he wasn't sure he wanted the job.
“I hesitated because at that time I was a fairly young teacher. I still had a lot of research I wanted to do,” he recalled 40 years later.
He accepted it anyway, and from the mission's first encounter with Jupiter in 1979 until its final flyby of Neptune in 1989, Stone became the scientific face of the Voyager mission. He guided the scientific agenda and helped the public make sense of revolutionary images and data not only of Jupiter, Saturn, Uranus and Neptune, but of their many fascinating moons.
Stone and his more than 200 scientific collaborators were the first to discover lightning bolts on Jupiter and volcanoes on its moon Io. They discovered six never-before-seen moons around Saturn and found evidence of the solar system's largest ocean on Jupiter's moon Europa, as well as geysers on Neptune's moon Triton.
“It seemed like everywhere we looked, when we found those planets and their moons, we were surprised,” Stone told the Los Angeles Times in 2011. “We were finding things we never imagined, gaining a clearer understanding of the environment that Earth was a part of. “. of. “I can close my eyes and still remember every part.”
The Voyager 1 spacecraft became the first man-made object to reach interstellar space in 2012, and Voyager 2 followed suit in 2018.
Stone, photographed with a model of the Voyager spacecraft, said the discovery of volcanoes on Io was a highlight of the mission.
(POT)
The twin probes continue to send weekly communications to Earth from interstellar space. Stone retired in 2022 on the mission's 50th anniversary.
“A part of Ed is still alive on both Voyager spacecraft. Traces of his dedication and enthusiastic leadership are woven into the Voyager mission,” said Linda Spilker, who joined the mission in 1977 and succeeded him as project scientist.
The Voyager mission was Stone's greatest achievement, but not his only one.
He was principal investigator on nine NASA missions and co-investigator on five others, including several satellites designed to study cosmic rays, the solar wind, and Earth's magnetic field.
He became director of the Jet Propulsion Laboratory at La Cañada Flintridge in 1991, a position he held for a decade.
It was an era of cost-cutting at NASA, but Stone still managed to launch the five-year Galileo mission to Jupiter and send the Cassini spacecraft to Saturn. He also led the agency when Mars Pathfinder delivered the Sojourner rover to the Red Planet. It was the first time humans put a robot on the surface of another planet.
Throughout his tenure at JPL, Stone continued to work and teach at Caltech, including teaching physics to freshmen during some of Voyager's long cruises between planets.
He also served as president of the board of directors of the California Association. of Astronomy Research, responsible for the construction and operation of the WM Keck Observatory and its two 10-meter telescopes on Mauna Kea, Hawaii.
Edward Carroll Stone Jr. was born in Iowa on January 23, 1936, and grew up in Burlington, where his father ran a small construction business and his mother kept the company's books.
Stone, the eldest of two brothers, was drawn to science from a young age. Under the watchful eye of his father, he learned to disassemble and reassemble all types of technology, from radios to automobiles.
“I was always interested in why something is this way and not another way,” Stone he told an interviewer in 2018. “I wanted to understand, measure and observe.”
After studying physics at Burlington Junior College, he earned his master's and doctorate at the University of Chicago. Shortly after beginning his graduate studies, news broke in 1957 that the former Soviet Union had launched Sputnik, the world's first artificial satellite.
“Just like that, because of the Cold War and our need to match Sputnik, a whole new realm absolutely opened up,” he said.
Stone built a device to measure the intensity of solar energetic particles above the atmosphere that traveled to space aboard an Air Force satellite in 1961. Unfortunately, the spacecraft's transmitter did not work, so only a very Limited data returned to Earth. . However, it was still enough to indicate that the intensity of the particles was lower than expected.
Despite the transmitter problem, Stone said the project was exciting. “We were taking the first steps in a completely new area of research and exploration,” she said. “We were right at the beginning.”
He joined the Caltech faculty in 1964 and created more space experiments, this time for NASA.
Stone's particular area of interest was cosmic rays: high-speed atomic nuclei that can originate from explosive events in the sun or from violent events beyond the solar system.
One of his cosmic ray experiments was included among Voyager's 11 major experiments.
Ed Stone in 2011, about a year before Voyager 1 entered interstellar space.
(Al Seib / Los Angeles Times)
Colleagues praised Stone for his leadership of Voyager's science team.
“He was a great hero, a giant among men,” Porco said, adding that Stone was known to treat everyone, from top scientists to graduate students, with respect.
Voyager team scientist Thomas Donahue put it this way: “Over the years, Ed Stone has proven remarkably adept at keeping a group of prima donnas on the right path.”
Stone was elected to the National Academy of Sciences in 1984 and received the National Medal of Science from President George HW Bush in 1991 in recognition of his leadership of the Voyager mission. He won the Shaw Prize for Astronomy in 2019, an honor that comes with a $1.2 million prize. In 2012, his hometown of Burlington, Iowa, named his new middle School after him.
“This is truly an honor because it comes from the community where my journey of exploration began,” Stone said. said a local newspaper.
Decades after Voyager's launch he was asked to select his favorite moment from the mission. She chose the discovery of volcanoes on Io, Jupiter's moon.
“To find a moon that is 100 times more volcanically active than the entire Earth is really surprising,” he said. “And this was typical of what Voyager was going to do on the rest of its journey through the outer solar system.
“Time and time again we discovered that nature was much more inventive than our models,” he said.
His wife, Alice, whom he met on a blind date at the University of Chicago and whom he married in 1962, deceased in December. The couple is survived by their two daughters, Susan and Janet Stone, and two grandchildren.
