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NASA Celebrates the 40th Anniversary of the Voyager Outer Planet Missions

Gary A. Flandro, the first professor to fill the million-dollar Edward J. and Carolyn P. Boling Chair of Excellence in Space Propulsion at the University of Tennessee Space Institute (UTSI) joined several other participants in Washington, DC on September 5, 2017 to celebrate 40 years of the Voyager 1 and 2 Spacecraft.

Activities included panel discussions about the Voyagers’ creation and mission history, their unprecedented science findings and imagery, impact on Earth’s culture and how the spacecraft inspired countless scientists, engineers and the next generation of explorers.

Flandro, while a Caltech graduate student working at the NASA Jet Propulsion Laboratory in 1965, discovered the multi-planet Voyager “Grand Tour” mission opportunity to explore the four major outer planets of the solar system. He is now a UTSI Professor Emeritus and the Chief Engineer at Gloyer-Taylor Laboratories (GTL) in Tullahoma, TN.

To commemorate this historic event, NASA and the Smithsonian National Air and Space Museum celebrated the 40th anniversary of this history-making mission. The event was broadcast live on NASA Television and streamed on the agency’s website. Matthew Shindell, Curator, National Air and Space Museum stated, “it was an epic mission to explore the outer planets, a mission that to this day stands out as one of the most ambitious that NASA ever sent out to the solar system”. Shindell was also a participant in the panel discussions on the impact Voyager 1 and 2 has had on Earth’s culture. Other panel members included Gary Flandro (Voyager Mission Grand Tour creator, University of Tennessee, UTSI); Thomas Zurbuchen (Associate Administrator for NASA’s Science Mission Directorate, NASA Headquarters, Washington); Ed Stone (Voyager Project Scientist, Caltech, Pasadena, California); Suzanne Dodd (Voyager Project Manager, NASA’s Jet Propulsion Laboratory, Pasadena); Alan Cummings (Voyager Researcher, Caltech); Ann Druyan (Writer/Producer, Golden Record Visionary and with Carl Sagan the famous COSMOS series).

At age six, Flandro had been given Wonders of the Heavens, a book that showed the planets lined up like stepping-stones. “I thought about how neat it would be to go all the way through the solar system and pass each one of those outer planets,” he recalled. This may have planted a subconscious memory that came awake in 1965 when he was tasked to look for promising new missions for the Caltech Jet Propulsion Laboratory.

Flandro stated he plotted the future positions of Jupiter, Saturn, Uranus, and Neptune in search for practical trajectories. This led to the Voyager “Grand Tour” multi-planet mission utilizing the gravity-assist technique to reduce the mission duration from forty years to less than ten years. His plots of the positions outer planets revealed that Jupiter, Saturn, Uranus, and Neptune would align in such a way that one spacecraft could visit all four in a single mission if it launched by 1977. The craft would slingshot around each planet in succession, completing a “Grand Tour” in only 10 to 12 years rather than the decades such a venture would otherwise require. “The mission launch window would open for a matter of months in the late 1970s, then close for another 175 years”.

On August 20th and September 5, 1977, Voyager 1 and 2 left earth on a quest to study the outer solar system. It was an incredibly audacious mission and “NASA’s twin Voyager spacecraft have opened up new worlds for exploration, including Saturn, Jupiter, Uranus, and Neptune”. Although the twin spacecraft are now far beyond the planets in the solar system, NASA continues to communicate with them daily as they explore the frontier where interstellar space begins. Each Voyager spacecraft carries a copy of the golden record (created by Ann Druyan and Carl Sagan), a phonograph record with images and sounds of life on Earth.

The Voyagers Rock On

       NASA and the Smithsonian National Air and Space Museum celebrated 40 years of the

      Voyager 1 and 2 spacecraft — humanity’s farthest and longest-lived mission.

  Credit:  NASA/JPL-Caltech

Flandro was recognized for this work first by the British Interplanetary Society (1970 M. N. Golovine Award), and later by NASA (1998 Exceptional Achievement Medal, with the citation: “for seminal contributions to the design and engineering of multi-outer-planet missions, including the Grand Tour opportunity for the epic Voyager explorations”).

Flandro’s work has supported decades of space flight and has led to successful missions to the outer planets. He has written or co-written 95 conference papers, 54 refereed papers and coauthored several textbooks.

  The Grand Tour – JPL Travel Poster NASA’s Voyager mission took advantage of a once-every-175 year alignment of the outer planets for a grand tour of the solar system.  The twin spacecraft revealed details about Jupiter, Saturn, Uranus and Neptune – using each planets gravity to send them on to the next destination.  Voyager set the stage for such ambitious orbiter missions as Galileo to Jupiter and Cassini to Saturn.  Today both Voyager spacecraft continue to return valuable science from the far reaches of our solar system.    Credit: NASA/JPL – Caltech 
The Voyagers:  Reaching for the Stars This poster captures the spirit of exploration, the vastness of space and the wonder that has fueled this ambitious journey to the outer planets and beyond.  Credit: NASA/JPL Caltech

40th Anniversary Celebration of Voyager is available for download from NASA’s image and Video Library:

Highlights from Voyager’s 40th Anniversary may be seen at the following websites:

*Excerpts of commentaries taken from articles written by:

  • Andrew Malcolm, (Sacramento Bee: Voyager: The Little Spacecraft That Could, Did and Still Does, September 2017)
  • Timothy Ferris (National Geographic: The Space Issue, Fantastic Voyage-Deep in Space, Two Intrepid Travelers Turn 40, August 2017)
  • Elizabeth Landau (NASA Jet Propulsion Laboratory)
  • Stacy Liberatore (

University of Tennessee College of Engineering – Gary Flandro’s Website