Nearly 47 years ago, two NASA spacecraft were bound for one of the grandest journeys across our solar system to fly by and learn about our outer gas giants.
They launched within a special planetary window, which occurs only once every 176 years. It allows these spacecraft to use the gravitational pull of each planet it flies by to alter its trajectory, allowing them to arrive at the next planet on its path with minimal use of fuel.
The Voyager spacecrafts paved the way for our understanding of our solar system, but it's now over 15 billion miles away from Earth. It takes light and radio signals about 23 hours to reach it one way, and it is still changing our understanding of the cosmos.
The instruments still onboard and operational were built, and are still operated by, the University of Iowa's Department of Physics and Astronomy.
One of them is the Plasma Wave Subsystem, which measures subtle waves within plasma fields around planets and in space.
The instrument has been pivotal in some of our most incredible discoveries in space, including the data set confirming when Voyager entered the interstellar medium beyond our solar system in 2012.
It was also instrumental indetecting lightning on another planet for the first time back in the early 80s. Lightning sends off a wide array of electromagnetic waves. Due to the different speeds at which each of these waves travels, it creates an odd, descending whistling tone.
That noise was caught through the University of Iowa's instrument on the voyager as it flew by, using the technique that first discovered the tell-tale sound of lightning when spies were trying to listen in on on their enemies in the early days of World War II.
The methodology shows just how research over the course of decades can continue to pile on to each other, growing into greater discoveries over the years.
Dr. Bill Kurth, a research scientist at the University of Iowa and a co-investigator of the Voyager Plasma Wave, was part of the initial development of the instrument nearly half a century ago, and continues to monitor data sent back from the aging spacecraft to this day.
While I was a graduate student, I worked on hardware that was going to fly with the Voyager spacecraft. I defended my PhD thesis literally a month before Voyager 1 got to Jupiter, and afterward I asked if I could stick around longer to see what kind of data we'd get back. I didn't realize I'd still be doing that 45 years later,"Dr. Kurth said.
It's really a thrill I think, every time I look at a new data file, I realize that I'm seeing something that nobody has ever seen before.
As the spacecrafts continue to age, instruments are being shut down to conserve power and extend the spacecraft's lifespan. Of the nearly 10 instruments on board, only four remain. The University of Iowa's instrument that still furthers our understanding of our place in the stars is one of them still in operation.
It's still uncertain how much longer the voyager probes have left, but predictions show they may make it into the early 2030s. However, they will still be drifting through the vastness of space, likely outliving our own star, the sun, well after they shut down.
You can find more information about the University of Iowa's involvement in the Voyager missions here or their involvement in a multitude of flagship NASA missions here.
by Garrett Heyd, Iowa's News Now