Fort Atkinson’s Knowles winding down 15 years’ work on Cassini-Huygens mission

October 11, 2017 GMT

While Cassini plunged toward the surface of Saturn on Sept. 15, burning up in the planet’s atmosphere while transmitting the final moments of its 20-year mission to Earth, Fort Atkinson’s Ben Knowles sat with his co-workers watching the live NASA broadcast.

Only Knowles wasn’t in Fort Atkinson. He was in the Jet Propulsion Laboratory (JPL) at the California Institute of Technology in Pasadena, Calif., with other team members of the Cassini-Huygens mission.

A joint endeavor of NASA (National Aeronautics and Space Administration), the European Space Agency (ESA) and the Agenzia Spaziale Italiana (ASI or the Italian Space Agency), the Cassini-Huygens mission was the first to orbit Saturn … or any outer solar system planet, for that matter.

Launched on Oct. 15, 1997, from Cape Canaveral Air Force Station in Florida, the spacecraft — which included the Cassini orbiter and the Huygens probe — arrived at Saturn on July 1, 2004.

In January 2005, the Huygens probe descended to Titan, Saturn’s largest moon. It marked the first time a spacecraft had been dropped on an object in the outer solar system.

“There were a lot of firsts involved,” Knowles, who joined the mission in February 2002, said. “It collected a ton of data over time and really revolutionized what we know about Saturn and its system — the rings, the moons, the planet itself. … (The mission) pretty much rewrote the textbooks about Saturn and its system for this generation.”

It was through a serendipitous encounter that Knowles, who then was living in Boulder, Colo., became involved in the Cassini-Huygens mission.

“I had just left grad school with my master’s and decided I wasn’t going to continue on to get my Ph.D and was thinking about leaving astronomy,” Knowles, who graduated from the University of Colorado at Boulder with a master’s in astrophysics in 2001, explained. “I nearly did, actually. But I ran into a friend who was, at the time, working for my current boss and they were looking for a calibration person.”

He happened to have significant experience with the particular programming language they use.

So Knowles became part of the Imaging Science Subsystem (ISS) Operations team, which is based at the Space Science Institute in Boulder, Colo., as the calibration and archiving engineer.

He has worked remotely since moving to Fort Atkinson in 2007, when his wife, Diana Shull, landed a job as the reference and instructions technology librarian at the University of Wisconsin-Whitewater.

The ISS itself is one of 12 science instruments “designed to carry out sophisticated scientific studies of Saturn,” according to NASA. Consisting of wide- and narrow-angle digital cameras sensitive to visible wavelengths of light and to some infrared and ultraviolet wavelengths, it served as Cassini’s “main set of eyes” for viewing the Saturn system.

Knowles is in charge of calibrating the ISS cameras, which are where most of the “pretty pictures” from the mission came from, he said.

“(That means) writing the software that cleans up the images and making the numbers in the images correspond to a real scientifically meaningful brightness,” he explained. “(The cameras) are only one megapixel in size, which sounds tiny — and it is — but it’s also, in some ways, a good thing because we don’t have a lot of bandwidth for sending data back to earth.”

In addition, Knowles is in charge of archiving all the team’s data on the Planetary Data System (PDS).

“I also helped out with observation planning,” he said. “I helped write software that helps predict exposure times and image compression and stuff like that and helps scientists to actually design their observations.

“There are assorted uplink and downlink tasks,” Knowles added. “I’ve been with the mission a long time and have a lot of roles that I would all call behind the scenes in support of the mission scientists, basically.”

Cassini performed incredibly well with no major malfunctions, he said.

“There were a few little hiccups here and there, but, for the most part, it did exactly what people wanted it to do for 20 years,” Knowles noted. “That’s pretty incredible. Not all missions go so smoothly.”

The day before the mission’s end, Knowles and the rest of the ISS Operations team met at Hunting Gardens in Pasadena for a final team meeting at which they got to hear all the most recent research results.

“That was really nice, just to be reminded of the point of everything,” Knowles said. “When you’re working behind the scenes, sometimes you lose sight of what it is you’re actually doing, which is to make good science possible. So it was nice to hear some of the cutting-edge results that we’ve got from Cassini.

“It was also good to see co-workers that I often don’t get to see because everything is done online,” he added. “I work with a lot of people that I’ve never actually met face to face. So that was nice to get everybody together one last time.”

Those co-workers were the ones he sat with on Friday, Sept. 15, as Cassini made its fatal — and scientifically observational — dive through Saturn’s atmosphere.

“Usually we do an observation, collect data on a hard drive on the spacecraft and then the spacecraft points to earth and sends it back. But at the end, they basically did a continuous stream,” Knowles explained. “They pointed the spacecraft to Earth and then the data it was collecting was sent back in real time so that we could get every last bit of data possible.”

In other words, Cassini was used as a probe of Saturn’s atmosphere — a last hurrah for the spacecraft.

“It was pretty bittersweet watching the signal from Cassini fade into noise,” Knowles said. “It was an interesting sort of capstone to a really big mission. It’s hard to put such a giant undertaking into perspective, especially since I’ve been working on it for so long.”

Knowles said he expects people to associate him with Cassini for the rest of his life.

“I never expected the mission to be as long as it was,” he said. “It turned out to be a really big chunk of my life.”

Originally scheduled to end in 2008, the Cassini mission was extended twice, first for the equinox (2008-10) and then for the solstice (2010-17).

“I was involved for 15 years, which I didn’t really expect going in,” Knowles said. “I’m proud of the fact that I was involved in a mission that was so scientifically valuable and successful.”

Scientists will continue to analyze the data that has been gathered for years to come, he noted.

“There’s a lot of research that has yet to be done,” Knowles said, adding that he personally has about a year’s work left and expects funding through next August.

As for what’s next, Knowles isn’t sure yet.

He said he’d be interested in taking part in another NASA mission, but it would be “tricky” for various reasons, including the fact that he would like to remain in Fort Atkinson. It would be difficult to get involved in another mission and work remotely from the start.

“I’m still figuring out what my next move is going to be, but I may use it as an opportunity to switch gears to another career,” Knowles said. “I don’t know (what) yet. There are a few things I’m thinking of. I think I’ll wait and see.”