Juice used Earth’s shadow to rehearse Jupiter operations
Earth’s shadow let Juice rehearse work at Jupiter, but did its autonomous pointing test deliver the needed accuracy?
On September 28, 2026, ESA’s Juice spacecraft flew past Earth, using its penultimate gravity assist to rehearse operations for Jupiter.
Juice combined its Earth gravity assist with tests of operations during darkness, spending three hours in full shadow and six in partial shadow. ESA also exercised its EAGLE autonomous pointing software in flight for the first time, using Earth-Moon geometry to stand in for Jupiter and Io; those re…
Juice combined its Earth gravity assist with tests of operations during darkness, spending three hours in full shadow and six in partial shadow. ESA also exercised its EAGLE autonomous pointing software in flight for the first time, using Earth-Moon geometry to stand in for Jupiter and Io; those results will be analyzed in the coming months. [3]
Why it matters: Juice will need to conduct science through long periods of darkness at Jupiter and keep instruments accurately pointed during close moon flybys. This encounter provided a rehearsal years before arrival rather than leaving those operational strategies untested until then. [3]
Key insights: EAGLE uses two navigation cameras to track a moon’s illuminated edge, refining the spacecraft’s position estimate and keeping observations on target. [3] | Darkness also created an observing opportunity: blocking the Sun temporarily eased the pointing restrictions imposed by Juice’s hot cruise environment. [3]
Cheatsheet facts: What happened: The September 28 Earth flyby served as both a gravity assist and a rehearsal for Jupiter operations. [3] | Why: Three hours in full shadow and six in partial shadow offered conditions resembling the darkness Juice will encounter at Jupiter. [3] | The catch: The first in-flight EAGLE exercise has taken place, but its results will be analyzed over the coming months. [3]