UVS is one of 10 science instruments and 11 investigations for the JUICE spacecraft. The mission has overarching goals of investigating potentially habitable worlds around the gas giant and studying the Jupiter system as an archetype for gas giants in our solar system and beyond.

As it begins a roundabout 4.1-billion-mile (6.6-billion-kilometer), eight-year journey to the Jupiter system, the spacecraft has been busy deploying and activating its antennas, booms, sensors and instruments to check out and commission all its important subsystems. SwRI's UVS instrument is the latest to succeed in this task.

"Our team of SwRI scientists traveled to Darmstadt, Germany, to put JUICE-UVS through its paces," said Dr. Randy Gladstone, JUICE-UVS principal investigator. "On June 20, we opened the UVS aperture door to collect UV light from space for the first time. Soon after, we observed a swath of the sky to verify the instrument was performing well." The team imaged a segment of this data, as the instrument scanned a swath of the Milky Way.

SwRI has provided ultraviolet spectrographs for other spacecraft, including ESA's Rosetta comet orbiter, as well as NASA's New Horizons mission to Pluto, Lunar Reconnaissance Orbiter mission in orbit around the Moon and Juno mission to Jupiter.

"JUICE-UVS is the fifth in this series, and it benefits greatly from the design experience gained by our team from the Juno-UVS instrument, launched in 2011, as it pertains to operating in Jupiter's harsh radiation environment," said Steven Persyn, program manager for UVS. "Each successive instrument we build is more capable than its predecessor."

Weighing just over 40 pounds and drawing only 7.5 watts of power, UVS is smaller than a microwave oven, yet this powerful instrument will determine the relative concentrations of various elements and molecules in the atmospheres of Jupiter's moons once in the Jovian system. A similar instrument, Europa-UVS, will launch in 2024 aboard NASA's Europa Clipper, which will take a more direct route to arrive at the Jupiter system 15 months before JUICE and focus on studying the potential habitability of Europa.

"Having two UVS instruments making measurements in the Jupiter system at roughly the same time will offer exciting complementary science possibilities," said Dr. Kurt Retherford, principal investigator of Europa-UVS and deputy PI for JUICE-UVS.

Aboard JUICE, UVS will get close-up views of the Galilean moons Europa, Ganymede and Callisto, all thought to host liquid water beneath their icy surfaces. UVS will record ultraviolet light emitted, transmitted and reflected by these bodies, revealing the composition of their surfaces and tenuous atmospheres and how they interact with Jupiter and its giant magnetosphere. Additional scientific goals include observations of Jupiter itself as well as the gases from its volcanic moon Io that spread throughout the Jovian magnetosphere.

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