And the end of Voyager 2's planetary tour on August 25, 1989, culminates in a dazzling display of Neptune and moon, Triton. The images and scientific data returned by Voyager 2 will change our understanding of the solar system.
Voyager 2 is the only spacecraft to visit the outer planets of Neptune and Uranus.
Voyager provisions were launched in 1977. Together, they visited Saturn and Jupiter and their moons. But then, Voyager 2 has a unique opportunity.
"We had the opportunity to get a close flyby with Voyager 2," said Suzanne Dodd, Voyager Project Manager. "Due to the alignment of the planet when the provisions were introduced in 1977, the four giant outer planets were aligned on either side of the sun, so we could go from one to the next. This is a really good opportunity."
This allows the spacecraft to use gravity assistance from one planet to visit the next, allowing the Voyager program to visit four planets in four years. This alignment only occurs every 176 years.
Trina Ray works at NASA's Jet Propulsion Laboratory for the Neptune flyby of the Voyager 2 mission. He joined the General Science Data team as his first job outside of college.
There were monitors everywhere in the laboratory for Voyager operations in Building 264 at JPL, with teams spread across multiple floors. Because Voyager 2 always points the antenna back to Earth, it keeps returning data.
Chris Jones helped develop flight software for the Voyager mission and helped the agency identify the best ways to manage the ever increasing distance for spacecraft communication. He also helped the mission overcome the issue of reducing light levels to restore Neptune's clear images.
Images can be viewed on monitors, step by step. In Neptune's slow approach, the planet started out as a few pixels, a faint blue dot that grew a little bit each day.
As the approach approached, everything changed.
Ray sat at his desk and said, "Wow," which caused everyone to look at the monitors.
"That's the best Neptune image we've ever seen," said one of the scientists. They will return to work until someone else does, and they have a different image to live by.
"The incredible flow of encounters is incredibly exciting, ”Ray said. "Over the months leading up to the closest approach, you were really caught up in what was going on. There was a sense of acceleration. I haven't seen another profile of the spacecraft mission with the intensity of several months of development, which resulting in an incredible amount of data set from the days around the nearest approach. ”
During flyby week, Ray did not want to sleep or even stay away from monitors for seconds. Everything else is the same way. While the spacecraft was temporarily out of communication, Ray used one of the showers on site and slept. No one knew he was coming home.
Media from around the world camped out at the JPL parking lot, appearing for daily press conferences to discuss new images and scientific findings.
"It's been five days of unbelievable science," says Ray. "And there was this intense feeling of knowing that this was the last flyby. It was the end of an era."
A New Look at Neptune
The Voyager team has been working together for between 20 and 30 years, a smooth working machine full of people who know each other and what has ability to each other.
Ray is a new addition. Voyager will set all his expectations for how the teams work together for Ray's remaining 30-year career at NASA, which continues. This sparked a spark in him and he will spend the next 20 years working on the Cassini orbiter on Saturn, inspired by Voyager.
The science gathered on the Neptune flyby revealed that their existing models for the gas giant were too simple to reveal what was really going on.
They discovered that the magnetic field of Neptune was tinted on its side. They found a giant place called the Great Dark Spot on the planet, similar to Jupiter's Great Red. But the event is passing, as the Hubble Space Telescope was not there four years later. Neptune has been found to possess some of the fastest and coldest air in the solar system.
Four rings were found around the planet.
And when Voyager 2 flew Triton, Neptune's moon, scientists discovered it was retreating backward. Unlike other Neptune moons formed from the remnants after Neptune became a planet, Triton is a captured object in a retrograde orbit.
During the flyby, six additional months were found.
Triton was the coldest thing Voyager 2 ever witnessed, reaching a negative 391 degree Fahrenheit. Surface that looks wild has been proven to be geologically active, with geysers exploding from frozen ice of nitrogen at Triton.
Understanding the diversity of our solar system came from Voyager flybys.
"Time after time, we found things that were doing things we didn't expect," said Ed Stone, Voyager's project scientist since 1975 and professor of physics at the California Institute of Technology. "It has changed our outlook on the solar system."
"It was a great experience because there was so much to learn," said Stone, reflecting on his time in the Voyager mission. "We've been able to share this journey for decades with the public. We can take people on trips as we discover things on each of the flybys."
Stone believes that three aspects of Voyager contributed to NASA's continuity. spacecraft heritage: modern engineering, science transformation and extraordinary inspiration of learning what's "out there."
Voyager 1 and 2 are the longest flying spacecraft in history; 42 years after their launch, the two are still growing and transmitting data as they explore the interstellar space. This is the farthest we have driven the galaxy. And the spacecraft was first designed in just five years.
Dodd began work on Voyager in 1984 and stayed on the project to see the Uranus and Neptune encounters. After that, Dodd will work on missions inspired by the information gathered by Voyager's data. And now, Dodd is back in the Voyager helmet again.
The Dodd team of 12 people takes care of the same spacecraft to ensure the probes are healthy, safe, functioning well and not too cold.
Jones, who returned to help with spacecraft preservation engineer, describes himself as a "doctor with a permanent housecall," for Voyager. "You never know when you might need it," he said.
Voyager flybys inspired by orbiter missions such as Cassini to Saturn and its moons, Galileo and Juno to Jupiter and its moons and also planned missions.
"I have described Voyager as a grandmother of flying missions ever since," Dodd said.
No missions followed Uranus or Neptune, however. If a mission is ready to launch today, it will take ten years to reach Neptune. But the works are out of date, though Voyager's intriguing discovery has given him a reason to come back and investigate further.
"We need to build an orbiter for each of those planets," Dodd said. "In Uranus, the five major moons are very different. They have unique geological history, so we need to understand how they were formed or captured. Uranus has a rotational pole that folds to its side more than Earth, so we need an understanding of why that happened. In Neptune, there is a huge amount of environmental features like Jupiter and Saturn. And Neptune's moon Triton is interested because of the mite geysers in it. . "
When the Voyager spacecraft flew planets into our solar system, they helped answer a few questions while creating more, Ray said.
But the missions on the outer planets last longer, so the teams working with them know that maybe they can only work one or two of their lives.