This photograph of Earth and the Moon was taken by the JANUS camera onboard ESA’s Jupiter Icy Moons Explorer (Juice). It was taken on 9 September 2024 Juice sailed off towards Venus following its lunar-Earth flyby. At the time, it was 5.7 million km away from Earth, and 5.3 million km from the Moon.
After flying past Venus in August 2025, Juice will pass by Earth again in September 2026 and January 2029. These so-called flybys help direct and accelerate the spacecraft so that it reaches Jupiter in July 2031 using just a minimum amount of fuel.
JANUS is Juice’s scientific camera, designed to take detailed, high-resolution photos of Jupiter and its icy moons. It will study global, regional and local features and processes on the moons, as well as mapping Jupiter’s clouds. It will have a resolution up to 2.4 m per pixel on the jovian moon Ganymede and about 10 km per pixel at Jupiter.
The main aim of JANUS’s observations during and shortly following the lunar-Earth flyby was to evaluate how well the instrument is performing, not to make scientific measurements.
JANUS was developed by an industrial consortium led by Leonardo SpA, under the supervision of the Italian Space Agency (ASI) and in collaboration with the Italian National Institute for Astrophysics (INAF), which is responsible for instrument science, the German Aerospace Center (DLR), CSIC-IAA in Granada (Spain) and CEI-Open University in Milton Keynes (UK).