Beyond the stratosphere
A space pioneer, 79, is ready to track Juno for Nasa
Susan G. Finley began working on rockets before Nasa existed. And now at the age of 79, instead of watching fireworks on the Fourth of July, she was at her post in Nasa’s Jet Propulsion Laboratory in Pasadena, California, waiting for confirmation that the latest of its space adventures would succeed.
Finley, an engineering specialist for the Deep Space Network of radio telescopes, monitored radio signals, waiting for one critical beep — a signal sent from Juno, the solar-powered planetary explorer — announcing it had finally reached Jupiter, the largest planet in the solar system, after a five-year journey.
“It’s a hard signal to track,” Finley said. “We do think it’s going to work.”
Her computer plucked tones out of the data sent by Juno and receive by an array of four radio telescopes in Canberra, Australia. Those tones were translated and displayed as 36 reassuring messages over four hours.
“It has real words in it about what’s happening,” Finley said.
While agency officials will want to know what the tones mean in real time, Finley said the signals are often most important when something goes awry.
Tones are useful when a spacecraft’s main antenna is not pointed at Earth, as is the case with Juno during the phase in which it fires its engine to get captured by Jupiter’s gravity. The smaller, weaker antenna can transmit only simple tones as communication.
This is a far different job from one Finley had in January 1958 when she first walked into the Jet Propulsion Laboratory. One of the female space pioneers featured in the book Rise Of The Rocket Girls by Nathalia Holt, Finley started just before the launch of Explorer I, the first satellite that the United States successfully sent into space.
Six months later, Congress passed the law creating Nasa, and at the end of the year, the laboratory, which had been performing rocketry work for the Army, was transferred to the space agency to focus on sending robotic probes to explore the planets.
Finley was not an engineer. In college, she aspired to become an architect, but dropped out after three years. “I couldn’t learn art,” she said.
She had taken some mathematics classes and, with an affinity for numbers, she literally became a human computer.
Electronic computers were still rare and expensive, so engineers — invariably men back then — handed off the equations they needed to have solved to a computer, almost always a female employee. Finley computed, first at Convair, an aeronautics company in Pomona, California, then at the Jet Propulsion Laboratory.
“You just wrote across the top a step-by-step breakdown of how to use the numbers and then down the other side were the numbers you were going to have to try,” Finley recalled. “You just went across, plugging in and clanking away. And then at the end, you gave them the piece of paper with all the answers on it.”
Even if the work appeared to be tedious, “if you liked puzzles and things like that, it was fun,” she said.
“And you always got an answer,” she said, “unlike a lot of problems in the world that there are no answers to.”
She left for six years to raise two sons until the younger one entered nursery school, and then returned in 1969, picking up computer programming and becoming an engineer. “Being a programmer is more fun than being a computer,” she said.
Over the years, she also worked as a test engineer and then an engineer on the Deep Space Network. Nasa used the simple tones technique in landing Mars Pathfinder in 1997. But it left them out for two later Mars spacecraft, Climate Orbiter and Polar Lander, which were both lost in 1999. Investigations into what went wrong were hampered without the data supplied by the tones.
Nasa resumed using the tones for its next Mars mission, two rovers, Spirit and Opportunity, which landed in 2004.
For the Spirit landing, Finley went to the Goldstone observatory in California, part of the Deep Space Network, to process the tones as Spirit bounded to the surface of Mars inside a cocoon of air bags. (Back then, the engineers did not trust the internet to reliably convey the signals to mission control.)
During the last moments of the landing, the tones dropped out. “A lot people were worried for 15 minutes,” Finley recalled, although she was not one of the worriers. “I knew I had seen it bouncing. I knew it had landed OK.”
The engineers had taken into account the shift in frequencies because of changing velocities of the spacecraft as it descended. They had assumed that once on the ground, Spirit’s transmitter would send a steady signal back. But the frequency drifted as the transmitter warmed up. “We found it,” Finley said. “It was there.” To this point, the tones appear to be good luck. All of the missions that have used them have succeeded, Finley said.
Throughout much of her career, which spans more than five decades, Finley was classified as an engineer, a point of pride. But a laboratory-wide review of jobs and pay in 2008 altered her employment status.
“We redesigned our entire compensation structure, and all disciplines were reviewed and updated to accurately describe employee duties and responsibilities,” said Veronica McGregor, a laboratory spokeswoman, in an email.
An explanatory memo the laboratory distributed when the changes were revealed said that “a four-year college degree in engineering, science or similar technical field is required to be classified as an engineer, consistent with industry and Nasa.”
Instead, Finley, who never finished her degree, fell into a newly created classification: engineering specialist, an hourly position.
Her overall pay did not change, and she is now eligible for overtime.
“She retained her same salary and standing,” McGregor said. But the change still irks Finley; she must mark down her arrival each day, her half-hour of lunch and the time she leaves to go home.
“It’s a demotion,” she said. “No one wants a demotion. We want to be treated like we deserve. But it’s true: I don’t have a degree.”
She added: “I think I’m kind of smart, maybe.” Finishing a degree was not an option. “I just hate school,” she said. “I love work.”
Once Juno is in orbit around Jupiter, with its big antenna pointing at Earth, it will no longer be sending tones but complex data about the planet’s interior during its 20-month stint.
Finley will return to her usual duties, with no plans to retire.
When the next rover lands on Mars in 2021 — sending out its tones — she hopes to be back at her post.
It’s a hard signal to track. We do think it’s going to work