Ed Stone, the scientist who guided NASA’s breakthrough 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.
A physicist who obtained in on the bottom flooring of house exploration, Stone performed a number one position in NASA missions to Mars, Jupiter, Saturn, Uranus and Neptune. The discoveries made underneath his watch revolutionized scientists’ understanding of the photo voltaic system and fueled humanity’s ambition to discover distant worlds.
Carolyn Porco, who labored on imaging on JPL’s Voyager and Cassini missions, known as Stone “a thoroughly lovely man” who was “as close to perfect as a project scientist could ever be.”
“When two science teams were in contention over some spacecraft resource, and Ed had to decide between the two, even the guy who lost went away thinking, ‘Well, if this is what Ed has decided, then it must be the right answer,’” Porco mentioned by electronic mail Tuesday. “I feel blessed to have known Ed. And like many people today, I’m very sad to know he’s gone.”
Stone was a 36-year-old Caltech physics professor in 1972 when he was requested to function chief scientist for an audacious plan to ship a pair of spacecraft to discover the photo voltaic system’s 4 large planets for the primary time.
It was the chance of a lifetime, however he wasn’t certain he needed the gig.
“I hesitated because I was a fairly young professor at that point. I still had a lot of research I wanted to do,” he recalled 40 12 months later.
He took it anyway, and from the mission’s first encounter with Jupiter in 1979 to its ultimate flyby of Neptune in 1989, Stone turned the scientific face of the Voyager mission. He guided the science agenda and helped the general public make sense of revolutionary pictures and knowledge not simply from Jupiter, Saturn, Uranus and Neptune, however from a lot of their fascinating moons.
Stone and his greater than 200 science collaborators had been the primary to find lightning on Jupiter and volcanoes on its moon Io. They noticed six never-before-seen moons round Saturn and located proof of the most important ocean within the photo voltaic system on Jupiter’s moon Europa, in addition to geysers on Neptune’s moon Triton.
“It seemed like everywhere we looked, as we encountered those planets and their moons, we were surprised,” Stone advised the Los Angeles Instances in 2011. “We were finding things we never imagined, gaining a clearer understanding of the environment Earth was part of. I can close my eyes and still remember every part of it.”
The Voyager 1 spacecraft turned the primary artifical object to succeed in interstellar house in 2012, and Voyager 2 adopted go well with in 2018.
Stone, pictured with a mannequin of the Voyager spacecraft, mentioned the invention of volcanoes on Io was a spotlight of the mission.
(NASA)
The dual probes proceed to ship weekly communications to Earth from interstellar house. Stone retired in 2022 on the mission’s fiftieth anniversary.
“A part of Ed lives on in the two Voyager spacecraft. The fingerprints of his dedication and keen leadership are woven into the Voyager mission,” mentioned Linda Spilker, who joined the mission in 1977 and succeeded him as mission scientist.
The Voyager mission was Stone’s crowning achievement, however hardly his just one.
He was a principal investigator on 9 NASA missions and a co-investigator on 5 others, together with a number of satellites designed to check cosmic rays, the photo voltaic wind and the Earth’s magnetic area.
He turned director of the Jet Propulsion Laboratory in La Cañada Flintridge in 1991, a task he held for a decade.
It was an period of cost-cutting at NASA, however Stone nonetheless managed to launch Galileo’s five-year mission to Jupiter and ship the Cassini spacecraft to Saturn. He was additionally on the company’s helm when Mars Pathfinder delivered the Sojourner rover to the Purple Planet. It marked the primary time that people had put a robotic on the floor of one other planet.
All through his tenure at JPL, Stone continued to work and train at Caltech, even educating freshman physics throughout a few of Voyager’s lengthy cruise occasions between planets.
He additionally served as chairman of the board of the California Assn. for Analysis in Astronomy, which is accountable for constructing and working the W.M. Keck Observatory and its two 10-meter telescopes on Mauna Kea, Hawaii.
Edward Carroll Stone Jr. was born in Iowa on Jan. 23, 1936, and grew up in Burlington, the place his father ran a small building enterprise and his mom saved the corporate books.
The eldest of two brothers, Stone was drawn to science from a younger age. Beneath his father’s watchful eye, he discovered methods to take aside and reassemble all types of know-how, from radios to vehicles.
“I was always interested in learning about why something is this way and not that way,” Stone advised an interviewer in 2018. “I wanted to understand and measure and observe.”
After learning physics at Burlington Junior School, he obtained his grasp’s and doctorate on the College of Chicago. Shortly after he started his graduate research, information broke in 1957 that the previous Soviet Union had launched Sputnik, the world’s first synthetic satellite tv for pc.
“Just like that, because of the Cold War and our need to match Sputnik, a whole new realm absolutely opened up,” he mentioned.
Stone constructed a tool for measuring the depth of photo voltaic energetic particles above the environment that hitched a experience to house aboard an Air Drive satellite tv for pc in 1961. Sadly the spacecraft’s transmitter didn’t work, so solely a really restricted amount of information was returned to Earth. Nonetheless, it was nonetheless sufficient to point that the depth of the particles was decrease than anticipated.
Regardless of the transmitter glitch, Stone mentioned the mission was thrilling. “We were taking the first steps in a whole new area of research and exploration,” he mentioned. “We were right at the beginning.”
He joined the school at Caltech in 1964 and created extra space experiments, this time for NASA.
Stone’s specific space of curiosity was cosmic rays — high-speed atomic nuclei that may originate from explosive occasions on the solar or from violent occasions past the photo voltaic system.
One among his cosmic-ray experiments was included among the many 11 main Voyager experiments.
Ed Stone in 2011, a few 12 months earlier than Voyager 1 entered interstellar house.
(Al Seib / Los Angeles Instances)
Colleagues praised Stone for his management of the Voyager science workforce.
“He was a great hero, a giant among men,” mentioned Porco, including that Stone was recognized to deal with everybody — from prime scientists to graduate college students — with respect.
Voyager workforce scientist Thomas Donahue put it this manner: “Over the years, Ed Stone has proved to be remarkably adept at keeping a bunch of prima donnas on track.”
Stone was elected to the Nationwide Academy of Sciences in 1984 and obtained the Nationwide Medal of Science from President George H.W. Bush in 1991 in recognition of his management of the Voyager mission. He received the Shaw Prize in Astronomy in 2019, an honor that comes with a $1.2-million award. In 2012 his hometown of Burlington, Iowa, named its new center faculty after him.
“This is truly an honor because it comes from the community where my exploration journey began,” Stone advised an area newspaper.
A long time after Voyager’s launch he was requested to pick his favourite second from the mission. He selected the invention of volcanoes on Jupiter’s moon Io.
“Finding a moon that’s 100 times more active volcanically than the entire Earth, it’s really quite striking,” he mentioned. “And this was typical of what Voyager was going to do on the rest of its journey through the outer solar system.
“Time after time, we found that nature was much more inventive than our models,” he mentioned.
His spouse, Alice, whom he met on a blind date on the College of Chicago and married in 1962, died in December. The couple are survived by their two daughters, Susan and Janet Stone, and two grandsons.
