Edward Stone Retires After 50 Years on Voyager Mission

Edward Stone retired as the project scientist for the Voyager mission after 50 years in the role. He had joined the project in 1972 – years before they even launched.

Edward Stone also served as head of the Jet Propulsion Laboratory from 1991 to 2001. While in that capacity, he continued to serve as Voyager’s project scientist – making him the only one until now.

Voyager Project Manager Suzanne Dodd praised Stone’s leadership:

“From the flybys of the outer plants in the 1970s and ’80s, to the heliopause crossing and current travels through interstellar space, Voyager never ceases to surprise and amaze us. All those milestones and successes are due to Ed’s exceptional scientific leadership and his keen ability to share his excitement about these discoveries to the world.”

Edward Stone joined National Academy of Sciences in 1984. He received the National Medal of Science in 1991. Stephen Colbert presented him with the NASA Distinguished Public Service Medal during an interview in 2013.

Linda Spilker will take over as Voyager’s new project scientists. She previously served as Voyager’s deputy project scientist. Her experience also includes serving as Cassini’s project scientist until Cassini spectacularly ended its mission by diving into Jupiter’s atmosphere in 2017.

Jamie Rankin, a member of Voyager’s science steering group, will fill the role of deputy project scientist.

About Voyager 1 and Voyager 2

Voyager 1 and Voyager 2 launched in 1977 and are most famous for having made the “Grand Tour” through the outer solar system. Both planets visited Jupiter and Saturn. Voyager 2 went on to visit Uranus and Neptune, while Voyager 1 changed course to become the first human-made spacecraft to leave the heliosphere in 2012. Voyager 2 left the heliosphere in 2018.

The twin spacecraft made exciting discoveries like active volcanoes on Jupiter’s moon, Io. They also sent back a more detailed look at Saturn’s intricate rings.

Voyager 1 discovered the Jovian moons Thebe and Metis, five new moons orbiting Saturn, and Saturn’s G ring. Voyager 2 discovered 10 of Uranus’ moons and one of its rings. Voyager 2 also discovered the Great Dark Spot on Neptune, as well as five of Neptune’s moon’s and four rings.

Voyager 2 is still the only spacecraft to have visited either Uranus or Neptune. After Voyager 2 flew past Neptune, NASA renamed the project to the Voyager Interstellar Mission (VIM). The two spacecraft still operate at a reduced capacity and will eventually run out of electricity.

When they do run out of power, they will silently drift through the cosmos. They famously carry messages on gold-plated copper discs with a “map” giving the location of Earth in relation to several pulsars in case they are ever found by extraterrestrials — or, perhaps, our distant descendants should they ever develop the capacity for crewed interstellar travel.

Does NASA have any future missions to the ice giants planned?

New Horizons was called part of Voyager’s legacy even though it didn’t directly take the same route that the Voyager probes did. However, it did cover quite a distance to a flyby of Pluto and Charon and will also eventually leave the solar system.

NASA proposed several mission concepts to our solar system’s “ice giants” in 2017. One more recently proposed mission, the Uranus Orbiter and Probe (UOP), could reach Uranus by 2040 if it is approved by NASA’s bureaucracy. Amy Simon, Francis Nimmo, and Richard C. Anderson created a detailed planetary mission concept study on the UOP for the 2023-2032 decadal survey.

(Note to NASA: Asking the public to name a mission to Uranus is a very poor idea.)

The 2023-2032 decadal study also includes a Neptune orbiter and Triton explorer called the Triton Ocean World Explorer. Triton is the largest of Neptune’s 13 known moons and the only one that orbits its host planet in retrograde, or in the direction opposite Neptune’s rotation. It is similar enough to Pluto that scientists think it was a Kuiper Belt object captured by Neptune’s gravity millions of years ago.

Triton is cold enough to have a crust of mostly frozen nitrogen. Voyager 1 actually measured its temperature at -391 degrees Fahrenheit (-235 degrees Celsius), along with spotting icy geysers indicating that Triton is geologically active.

For now, the proposed missions for the decadal study are still theoretical. The Voyager team, with Edward Stone as part of the leadership as project scientist for 50 years, helped to lay the groundwork for any future scientific missions to the ice giants.