Instrument development technician Carlisa Drew stands next to the Europe Clipper’s propulsion module early in the module’s wiring process, in a clean room at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. A former commercial electrician, Drew led the APL team that installed the appliances. Credit: Johns Hopkins APL
She went from being a commercial electrician to connecting the electrical system for NASA’s Europa Clipper propulsion module – the “workhorse” that has the enormous task of getting the spacecraft into orbit around Jupiter.
Carlisa Drew, a professional electrician, was accustomed to connecting simple, single cables. But in her role as lead instrument development technician at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland, Drew worked on a specially assembled set of electrical wires and connectors called a “harness,” which powers the Europe Clipper’s propulsion unit and its payload. The belt box climbs the propulsion module’s spine like a central nervous system, sending branches of electrical wires around the cylindrical frame to power different parts of the spacecraft.
In 2030, after nearly six years of sailing through the solar system, Europa Clipper will hurtle toward Jupiter so fast that it could swing directly in front of the gas giant and continue out into deep space if it is not caught in Jupiter’s orbit. The propulsion module that Drew attached is designed to curb speed, so the spacecraft can safely orbit Jupiter and perform its aeronautics to determine whether the icy moon Europa could host conditions suitable for life.
Spacecraft deliveries were not Drew’s intended area of expertise.
In high school, she thought she would pursue a career in business. But as Drew learned more about the field, she realized it wasn’t for her. Her school offered informational videos and hands-on demonstrations for students to try various crafts, and Drew’s school counselor suggested she start there. Drew tried some careers where she could work with her hands, because that’s what she always preferred.
Carlisa Drew installs wires on the Europe Clipper’s propulsion unit in a clean room at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. Drew and her team have installed hundreds of meters of wire and cable that will distribute electricity to the spacecraft’s instruments, allowing the Europe Clipper’s various systems and subsystems to communicate with each other. Credit: Johns Hopkins APL
the bread? “I don’t want to do this.”
Laying bricks? “Too big and dusty.”
Electrical work? “I can read print! I can build things!”
Drew was hooked. Through an apprenticeship program offered by the Electrical Workers Union, she spent five years working during the day and studying at night. Upon completion of his apprenticeship, Drew began working as a commercial electrician.
After 15 years of doing electrical work mostly outdoors, Drew noticed that the winters were very cold and the summers were very hot. She was looking for a job that would allow her to stay mostly indoors. Little did Drew know at the time that she would end up working in some of the most stringent climate-controlled environments on Earth.
For a time, Drew worked at a Baltimore cable company, where she learned much of what she uses today. Her electrical mentors have also helped her, along with APL’s training programs, which Drew describes as “excellent.”
When he was hired at APL, Drew expected to work on cables for ground support or testing. “I never thought I would be building cables that would one day end up in space.”
When she was given the opportunity to be the lead drivetrain belt technician, she was thrilled. “At first, I felt very confident,” she says with a laugh. “So they handed me the plans and then released me.”
Wiring the drive unit was no simple task. The harness that Drew helped build weighs about 150 pounds (68 kilograms) and contains thousands of wires and electrical connectors. If placed side by side, these components would extend nearly 2,100 feet (640 metres), enough to wrap twice the circumference of a football field.
The Europa Clipper’s propulsion unit has 24 motors, 16 of which are directed aft. The unit is about 10 feet (3 meters) high and 5 feet (1.5 meters) in diameter, about the size of an SUV.
Although Drew was the lead instrument technician for this mission, she did not do it alone and is grateful to her fellow team members at APL. “For my first assignment, I could not have been placed with a better group of people.”
She and several colleagues spent about a year assembling the harness on a prototype drive unit, connecting the wires together, attaching pins to the ends of the wires, and inserting pins into the connectors. They had “packing parties”, covering conductors with up to 18 layers of copper or lead sheets in order to protect them from Jupiter’s harsh radiation environment.
“The amazing part of this effort is the people who designed the system,” Drew says. “Having wires running in every direction to different components is a remarkable achievement.”
Drew and her team finished installing the wiring harnesses in the propulsion unit. In early June, a cargo plane carried the propulsion module, along with the radio frequency (RF) module, to NASA’s Jet Propulsion Laboratory in Southern California, where it will be integrated with the rest of the spacecraft.
“It’s bittersweet,” says Drew, completing the wiring for the propulsion unit. “It’s the coolest thing I’ve ever worked on in my entire life.”
