Making Voyager Continue: Difficult Decisions for NASA's Project Scientist Loom as the Legendary Mission Nears Conclusion
Revamped Space Odyssey:
In the distant reaches of the cosmos, two groundbreaking spacecraft, Voyager 1 and Voyager 2, were shooting for the stars way back in 1977. These bad boys were on a mission to explore realms never before ventured, venturing beyond the protective bubble of our solar system known as the heliosphere - a region still influenced by the comforting warmth of our sun.
Fast forward to 2012, and Voyager 1 was the first to reach the beginning of interstellar space, with its older brother Voyager 2 following suit in 2018. They've been wandering this alien landscape for nearly 48 years now, but the end is drawing near as they run low on juice, much like our lives after spending too much time worrying about technology.
Powered by heat from decaying plutonium, these ancient space explorers have been slowly losing power, shedding around 4 watts every year. To keep 'em ticking, the mission team has dumped any systems deemed redundant, including several science instruments. Once brimming with 10 instruments, these spacecraft now barely manage to hum along with just three each. Switching off two more instruments is on the horizon, according to the team's tough but necessary decisions.
These pesky power issues aren't the only challenges the team faces. The cold, harsh space surroundings can be downright menacing, with glitches popping up here and there, forcing the engineers to constantly come up with creative solutions to keep these relics running.
Despite the hurdles, Linda Spilker, the Voyager mission's project scientist, remains excited. She joined the team as a young whippersnapper in 1977 and has seen it all. Spilker shared her experiences and insights with Gizmodo during an exhilarating discussion.
Passant Rabie (Gizmodo): So, Linda, how long have you been with the Voyager mission, and how has it evolved over the years?
Linda Spilker: My first job out of college was with Voyager back in 1977. I remember two options: the Viking extended mission or the Voyager mission. I hadn't heard of Voyager, so I asked where it was going, and they said Jupiter, Saturn, and on to Uranus and Neptune if things went well. The thought of visiting those planetary giants from my tiny third-grade telescope was too enticing to resist.
Over the years, the mission has shrunk in size. Initially, we had big teams working on the remote sensing instruments, cameras, and spectrometers, but as we turned off more instruments, the mission became smaller. We had a whole lot less staff than during the planetary days.
Gizmodo: How's it going for you guys nowadays? Are you making emotional decisions to turn off instruments?
Spilker: It's definitely tough to see instruments turned off, especially for the team members who helped build them in the 1970s. It's like losing an old friend after being together for 50 years. There's a lot of pride in what we've achieved, but it's a mix of emotions as the spacecraft age and we have to make difficult power management decisions.
Gizmodo: What about the technical challenges that come with operating the mission for this long?
Spilker: We're dealing with technology from the 70s, and some components have been past their warranty for a long time. We have less power every year due to the radioisotope thermoelectric generators losing 4 watts annually. This forces us to find 4 watts of power to turn off on the spacecraft every year. The spacecraft had a lot of redundancy, but we've had to turn off even the backup units. Now, to really save some power, we're looking at turning off some of the science instruments.
We're also concerned about the spacecraft's temperature dropping with fewer watts. They have a bus filled with electronics, and these components are starting to get chilly. There's a risk the lines could freeze, which could wreak havoc with the thrusters that align the spacecraft and keep the antenna pointed at Earth for transmitting data.
Some of the tiny thrusters used to align the spacecraft and maintain contact are clogging up with silica residue, weakening the propellant streams. But we're keeping our fingers crossed, hoping that one or both spacecraft will make it to the 2027 Voyager golden anniversary and perhaps even into the 2030s with one or two science instruments still humming.
Gizmodo: What about the machine language that the spacecraft use?
Spilker: They use a unique machine language, with three different computers controlling the spacecraft: the attitude control computer, the command processor, and the data system. We're dealing with insanely small computer memories, and solving problems with these aging components can be like solving a detective mystery. Sometimes, we have to dig deep into our files to find useful memos, piece together old diagrams, and stick post-it notes all over the place to figure out the solutions.
It's a massive challenge, but we're determined to keep the missions alive, so we bring in experts to help us troubleshoot different issues and educate younger members of the team. Many of the senior members from the 70s are still involved, helping to pass on their knowledge to the next generation of scientists and engineers.
Gizmodo: Are the same people still working on the mission, or do you need to bring in new people and fill them in on the situation?
Spilker: Most of the team members are new, but there are a few veterans who were there in the 70s, and they've come back to work part-time. It's rewarding for them to return and help us keep the legacy alive. We're also training new people in the roles we need to maintain the missions, and mentoring the next generation of scientists interested in space exploration.
Gizmodo: What have been your most significant findings from the Voyager mission, and what do you hope to achieve in the future?
Spilker: One of the coolest discoveries was during Voyager's flyby of Saturn's moon Titan. The instruments couldn't penetrate through the thick haze surrounding the moon, suggesting the possibility of liquid oceans on the surface. This was a major factor in planning the Cassini mission, which ultimately revealed a complex and fascinating world beneath the smog.
We hope to learn even more about interstellar space as the Voyagers continue their journey through the cosmos, and we dream of launching another interstellar probe in the future. Who knows what secrets the universe holds, waiting to be unlocked by humanity's relentless curiosity.
- The aging Voyager spacecraft, launched in 1977, have been venturing into realms never before explored, now entering their 48th year in space, making the future discoveries they could unveil quite promising for science.
- Despite the challenges, such as constraints imposed by dwindling power supplies and harsh interstellar conditions, the Voyager team remains hopeful, looking forward to the next decade, where one or both spacecraft may continue their mission with a few science instruments still functioning.
- Linda Spilker, project scientist for the Voyager mission, has been with the program since 1977 and has witnessed its evolution, now facing tough decisions such as turning off instruments due to power management issues, much like the aging process in life.
- Working with technology from the 70s, the Voyager team must deal with regular glitches and diminishing power, as well as constraints imposed by the space environment, using creative problem-solving techniques to keep the spacecraft operational, much like engineers and scientists strive to adapt to new challenges in the field of space technology.
