Missions like NASA’s Europa Clipper are a complex balancing act of meeting scientific and technical requirements while managing schedules, costs, risks, and more.
To help achieve this balance, Europa Clipper leverages the skills of a diverse team of systems engineers who look at the big picture and work with specialist engineers, scientists, and others to understand how various systems will interact with each other and contribute to the mission as a whole.
For a spacecraft, a “system” is a combination of elements that function together to meet specific needs, often including scientific instruments, spacecraft hardware, and software. Systems engineers make sure the various areas of the mission understand the impact their decisions have on others working on other parts of the system. It’s the job of systems engineers to balance scientific goals against technical demands, navigate demanding schedules, facilitate communication among teams, and help teams make the best use of shared resources—while assuring that the mission’s overall scientific objectives can be achieved.
“No one person can know or do everything,” said Nari Hwangpo, who works on Europa Clipper as a systems engineer at NASA's Jet Propulsion Laboratory. Systems engineers draw on prior experiences to face new and interesting challenges that arise. “That’s why we're often called jacks-of-all-trades.”
The Europa Clipper spacecraft will visit Jupiter’s moon Europa to determine whether the icy moon could harbor conditions suitable for life. To accomplish this, the spacecraft will have nine science instruments, in addition to a gravity/radio science investigation, to study Europa’s interior, each with its own associated hardware and science team members. The mission also includes subsystems for power, avionics, telecommunications, temperature management, propulsion, guidance, and control, ground operation of all these components, and more.
Each of these mission components has dedicated engineers working on it. It is the responsibility of systems engineers to view those parts of the project in consideration of the whole, and to ensure they effectively integrate into the overall Europa Clipper mission. For example, different engineers might be calculating how thick the radiation shielding needs to be for a given science instrument, or designing the wiring plan for the instrument, or determining the instrument’s temperature or power requirements. Commonly, those engineers report their work to a systems engineer, who helps ensure the instrument will successfully meet its scientific requirements while meeting the mission's schedule, budget, and risk requirements.
Hwangpo's focus is the mission operations system, which includes mission planning, ground data systems, navigation, software, and instrument teams, among others. She leads the mission’s flight rules working group, which works out in advance how to respond to various scenarios the spacecraft might encounter on its mission. To do so, she works with the cognizant engineers – the go-to experts who lead the development of specific parts and systems on a spacecraft. “I gather the cognizant engineers and make sure they give me a list of constraints for the software – rules about what not to do – so we can avoid damaging the spacecraft’s hardware or inhibiting the mission’s science returns,” she said.
“Systems engineering goes further than being smart,” Hwangpo said. It also requires a broad technical background, strong leadership skills, and being a lifelong learner. “We need to be team players. It can be challenging, but it’s all worth it.”
Marianne Gonzalez first joined JPL as an intern six years ago. She now splits her time there between chemical engineering research and systems engineering for Europa Clipper’s magnetometer instrument. Gonzalez has worked for other missions but says the complexity of Europa Clipper is a different experience. “I’ve never worked on something of this scale. There are so many people working on this mission.”
One of Gonzalez’s many tasks is testing flight software to check whether the magnetometer’s thermal control system is working correctly for the instrument's magnetic field detectors, called fluxgate sensors. “The fluxgate sensors are highly sensitive to temperature,” Gonzalez said, “so the instrument has its own temperature control system. I’m working to make sure that when the magnetometer is active, the spacecraft hands off temperature control to the instrument.” Gonzalez is also testing how the magnetometer behaves if ground controllers were to inadvertently send it a bad command.
The engineering exists to support the mission’s science goals. That fact is not lost on Gonzalez. “I find it interesting going to a place like Europa, where we might discover evidence for environments suitable for life. I feel very passionate about what I’m working on, and I’m excited about what we'll discover.”
In addition to the challenges inherent to these roles, systems engineers such as Gonzalez and Hwangpo have continued to make progress while working remotely through the pandemic, tailoring their work/life balance to be safe as they continue to make progress toward exploring Europa.