Johns Hopkins APL Team Delivers Critical Parts for Europa Clipper’s Mapping Instrument

The scanning mirror and data processing unit,
The scanning mirror and data processing unit, pictured above, of Europa Clipper’s MISE instrument are critical to determining the habitability of the ocean very likely beneath Europa’s surface.

Credit: Johns Hopkins APL/Craig Weiman

Two critical components developed by the Johns Hopkins Applied Physics Laboratory (APL) for the Mapping Imaging Spectrometer for Europa (MISE) infrared spectrometer on NASA’s Europa Clipper mission arrived at NASA’s Jet Propulsion Laboratory (JPL) in early November for instrument integration. The delivery completes a multiyear effort to provide key components for an instrument that will be critical to determining the habitability of Europa, the one of Jupiter’s many moons that’s most likely to harbor life.

Europa almost certainly has a salty ocean beneath its icy shell, which means it has one of the critical ingredients (liquid water) for life. But scientists remain uncertain whether or not Europa has the other ingredients life requires: the proper chemical building blocks (like carbon and nitrogen) and a suitable energy source (like food). All three of these ingredients must be present for life to gain a foothold.

NASA’s Europa Clipper mission, led by JPL with significant contributions from scientists and engineers at APL in Laurel, Maryland, is set to launch in 2024 and tackle that issue. Making 40-50 close flybys of Europa, the spacecraft will inspect Europa, searching for chemical signals to determine the potential habitability of the moon’s subsurface ocean.

Essential to the mission’s goals is the MISE instrument, a near-infrared imaging spectrometer. Capturing the infrared light reflected off Europa’s surface, or emitted from warm spots, MISE (pronounced “mize”) will map the moon’s surface to determine the distribution of chemical compounds critical to life, such as sulfate and carbonate salts, water ice, and organics. It will also provide understanding of the effects of radiation and other external factors on the surface, and it will characterize hot spots that could indicate ongoing geologic activity inside Europa.

MISE team package the instrument’s scanning mirror and data processing unit into a shipping container
Members of the MISE team at APL carefully package the instrument’s scanning mirror and data processing unit into a specialized shipping container.

Credit: Johns Hopkins APL/Craig Weiman

Karl Hibbitts, the deputy principal investigator of MISE, is enthusiastic about the potential science the instrument enables. “MISE is going to open new understandings not only to uncover details about the habitability of the subsurface ocean, but we anticipate it will provide new insights on how the surface evolves over time — understanding the interplay between internal geologic processes and external modifications from Jupiter’s radiation belt, meteorites and cosmic rays,” he said.

Over the last five years, the MISE team at APL has spent more than 137,000 hours designing, building and testing the instrument’s data processing unit (DPU) and its scanning mirror. The team also has developed intricate software that enables MISE to make its measurements.

The DPU controls the entire instrument, including the communication interface with the spacecraft, power supply, onboard memory, scanner electronics and software storage for data processing.

“It’s essentially the brains of the instrument, controlling the scanning mirror and serving as the command and telemetry interface between it and the spacecraft,” said Nelofar Mosavi, an electrical and computer engineer and the MISE program manager at APL.

MISE team members place the container in a shipping truck
MISE team members at APL place the container in a shipping truck, which transported the instrument parts to the Jet Propulsion Laboratory in Pasadena, California, in November.

Credit: Johns Hopkins APL/Craig Weiman

MISE works by imaging a slit of infrared light from Europa’s surface and splitting it into 421 discrete wavelengths. By doing this continually as the spacecraft flies over the surface, MISE will capture hundreds of slits that, when later merged, form a complete “spectral image” of that portion of the surface.

“It’s a lot like the sliding scanner on a copy machine,” Mosavi said. But rather than a scanning beam of light like that on a copy machine, MISE’s scanning mirror reflects the light from Europa’s surface through the slit of the spectrometer where it is then split into its separate wavelengths and focused onto the sensor.

The APL team began building the final flight components shortly after the start of the COVID-19 pandemic, requiring team members to work around COVID restrictions, child care and virtual school, and voluntary night and weekend work on a normal basis. Even with these hurdles, through continued regular virtual communications, meetings and reviews, the team met the challenge of building this sophisticated hardware.

“We could not have achieved this milestone without the MISE team’s dedication, hard work and personal sacrifices over the years,” Mosavi said. “Now, we are looking forward to scanning and mapping the surface of Europa and determining its habitability!”