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 the first rover on Mars, died Tuesday. He is 88 years old.
A physicist who got in on the ground floor of space exploration, Stone played a leading role in NASA’s missions to Mars, Jupiter, Saturn, Uranus and Neptune. Discoveries made under his watch 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 wonderful person” who was “as close to perfect as a project scientist.”
“When two science teams are arguing about some spacecraft resources, and Ed has to decide between the two, even the loser thinks, ‘If this is what Ed decided, it must be the right answer.'” Porco said by email Tuesday. . “I’m glad I got to know Ed. And like most 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 asked to be the chief scientist for a daring plan to send a spacecraft to explore the four giant planets of the solar system for the first time.
It was the opportunity of a lifetime, but he wasn’t sure he wanted the gig.
“I hesitated because I was a young professor at the time. I still had a lot of research to do,” he recalled 40 years later.
He took it too, and from the mission’s first encounter with Jupiter in 1979 to its final flyby of Neptune in 1989, Stone was the scientific face of the Voyager mission. They are leading the science agenda and helping the public understand revolutionary images and data not only from Jupiter, Saturn, Uranus and Neptune, but from many of our amazing moons.
Stone and more than 200 science collaborators were the first to discover lightning on Jupiter and volcanoes on its moon Io. They discovered six never-before-seen moons around Saturn and found evidence of the largest ocean in the solar system on Jupiter’s moon Europa, as well as geysers on Neptune’s moon Triton.
“It seems like everywhere we look, when we come across these planets and moons, we’re surprised,” Stone told the Los Angeles Times in 2011. 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 in 2018.
The twin probes continue to send weekly communications to Earth from interstellar space. Stone is retiring in 2022 on the mission’s 50th anniversary.
“Ed’s part lived on two Voyager spacecraft. The fingerprints of his dedication and diligent 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 crowning achievement, but not the only one.
He was the principal investigator on nine NASA missions and co-investigator on five others, including several satellites designed to study cosmic rays, the solar wind and the Earth’s magnetic field.
He became director of the Jet Propulsion Laboratory at La Cañada Flintridge in 1991, a role 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 sent the Sojourner rover to the Red Planet. This marks the first time humans have put a robotic rover on the surface of another planet.
Throughout his tenure at JPL, Stone continued to work and teach at Caltech, even teaching freshman physics during some of Voyager’s interplanetary voyages.
He also chairs the board of the California Assn. for Research in Astronomy, which is responsible for building and operating the WM Keck Observatory and 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.
The eldest of two brothers, Stone was fascinated by science from an early age. Under his father’s watchful eye, he learned how to take apart and assemble all kinds of technology, from radios to cars.
“I’m always interested in learning about whether there is this way and no way,” Stone to the interviewee in 2018. “I want to understand and measure and observe.”
After studying physics at Burlington Junior College, he earned a master’s degree and a doctorate at the University of Chicago. Shortly after he began his graduate studies, news broke in 1957 that the former Soviet Union had launched Sputnik, the world’s first artificial satellite.
“It’s like that, because of the Cold War and we had to match Sputnik, new territory was opened up,” he said.
Stone built a device to measure the intensity of solar energy particles above the atmosphere that flew into space aboard an Air Force satellite in 1961. Unfortunately, the spacecraft’s transmitter was not working, so only a very limited amount of data was returned to Earth. . However, it is still sufficient to indicate that the particle intensity is lower than expected.
Despite the transmitter interference, Stone said the project was fun. “We are taking the first step in a new area of ​​research and exploration,” he said. “We were right in the beginning.”
He joined the faculty at Caltech in 1964 and created another space experiment, this time for NASA.
A special area of ​​interest for rocks is cosmic rays – high-speed atomic nuclei that can come from explosive events in the sun or from violent events outside the solar system.
One of the cosmic ray experiments was among the 11 major Voyager experiments.
Colleagues praised Stone for his leadership of the Voyager science team.
“He was a great hero, a giant among people,” Porco said, adding that Stone was known for treating everyone — from top scientists to graduate students — with respect.
Voyager team scientist Thomas Donahue had this to say: “Over the years, Ed Stone has proven remarkably good at keeping many prima donnas on track.”
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 in Astronomy in 2019, an award that comes with an award of $1.2 million. In 2012 his hometown of Burlington, Iowa, took on a new name secondary school after him.
“This is truly an honor because it comes from the community where my journey of exploration began,” Stone said toward local newspaper.
Decades after Voyager’s launch, he was asked to choose his favorite moment from the mission. He chose the discovery of a volcano on Jupiter’s moon Io.
“Finding a moon that is 100 times more volcanically active than the entire Earth is amazing,” he said. “And this is typical of what Voyager will do during its journey through the outer solar system.
“Over time, we discovered that nature is more inventive than our models,” he said.
His wife, Alice, whom he met on a blind date at the University of Chicago and married in 1962, died in December. The couple is survived by two daughters, Susan and Janet Stone, and two grandsons.