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 bought in on the bottom flooring of area 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 totally pretty man” who was “as near excellent as a challenge scientist might ever be.”
“When two science groups had been in rivalry over some spacecraft useful resource, and Ed needed to resolve between the 2, even the man who misplaced went away considering, ‘Nicely, if that is what Ed has determined, then it have to be the best reply,’” Porco mentioned by e mail Tuesday. “I really feel blessed to have recognized Ed. And like many individuals at present, I’m very unhappy 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 wished the gig.
“I hesitated as a result of I used to be a reasonably younger professor at that time. I nonetheless had quite a lot of analysis I wished 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 last 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 photos and knowledge not simply from Jupiter, Saturn, Uranus and Neptune, however from lots 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 biggest ocean within the photo voltaic system on Jupiter’s moon Europa, in addition to geysers on Neptune’s moon Triton.
“It appeared like in all places we appeared, as we encountered these planets and their moons, we had been shocked,” Stone advised the Los Angeles Instances in 2011. “We had been discovering issues we by no means imagined, gaining a clearer understanding of the setting Earth was a part of. I can shut my eyes and nonetheless bear in mind each a part of it.”
The Voyager 1 spacecraft turned the first artifical object to achieve interstellar area in 2012, and Voyager 2 adopted swimsuit 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 area. Stone retired in 2022 on the mission’s fiftieth anniversary.
“Part of Ed lives on within the two Voyager spacecraft. The fingerprints of his dedication and eager management are woven into the Voyager mission,” mentioned Linda Spilker, who joined the mission in 1977 and succeeded him as challenge 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 review cosmic rays, the photo voltaic wind and the Earth’s magnetic discipline.
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 Pink 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 educate 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 development enterprise and his mom stored the corporate books.
The eldest of two brothers, Stone was drawn to science from a younger age. Below his father’s watchful eye, he discovered methods to take aside and reassemble all kinds of expertise, from radios to automobiles.
“I used to be at all times fascinated with studying about why one thing is this manner and never that method,” Stone advised an interviewer in 2018. “I wished to know and measure and observe.”
After learning physics at Burlington Junior Faculty, he acquired 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.
“Similar to that, due to the Chilly Struggle and our have to match Sputnik, a complete new realm completely opened up,” he mentioned.
Stone constructed a tool for measuring the depth of photo voltaic energetic particles above the ambiance that hitched a experience to area 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 challenge was thrilling. “We had been taking the primary steps in a complete new space of analysis and exploration,” he mentioned. “We had been proper at the start.”
He joined the college at Caltech in 1964 and created extra space experiments, this time for NASA.
Stone’s explicit 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 in all his cosmic-ray experiments was included among the many 11 main Voyager experiments.
Ed Stone in 2011, a couple of 12 months earlier than Voyager 1 entered interstellar area.
(Al Seib / Los Angeles Instances)
Colleagues praised Stone for his management of the Voyager science workforce.
“He was an awesome hero, a large amongst males,” 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 time, Ed Stone has proved to be remarkably adept at retaining a bunch of prima donnas on monitor.”
Stone was elected to the Nationwide Academy of Sciences in 1984 and acquired the Nationwide Medal of Science from President George H.W. Bush in 1991 in recognition of his management of the Voyager mission. He gained 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 college after him.
“That is really an honor as a result of it comes from the neighborhood the place my exploration journey started,” Stone advised an area newspaper.
Many years after Voyager’s launch he was requested to pick out his favourite second from the mission. He selected the invention of volcanoes on Jupiter’s moon Io.
“Discovering a moon that’s 100 occasions extra energetic volcanically than your entire Earth, it’s actually fairly hanging,” he mentioned. “And this was typical of what Voyager was going to do on the remainder of its journey via the outer photo voltaic system.
“Time after time, we discovered that nature was far more creative than our fashions,” 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.
