Moons · Space Codex
Europa
A bright ice shell, cracked and stained, hides a salty ocean that may hold twice the water of all Earth's oceans.
An ocean world under ice
At a glance
Key points
It is one of the best places in the Solar System to look for life beyond Earth.
- Its ocean may hold about twice the water of Earth's oceans
- Surface only 40–90 million years old
- Europa Clipper arrives in April 2030 for 49 flybys
Interior
Under 15–25 km of ice lies a global saltwater ocean 60–150 km deep, sitting on a rocky mantle and iron core. Because the ocean touches rock, chemical reactions at the seafloor could supply the energy and nutrients that life on Earth relies on in the deep sea.
Surface
Europa has very few craters, so its surface must be young, perhaps only 40–90 million years old. Dark reddish lines run for thousands of kilometres; many are double ridges with a bright central groove. Patches of 'chaos terrain', where the crust has broken into rafted blocks, may form over lens-shaped lakes trapped inside the ice.
Exploration
Galileo's magnetometer gave the first strong evidence for the ocean in the late 1990s. NASA's Europa Clipper launched in October 2024, makes an Earth gravity assist on 3 December 2026 and arrives at Jupiter in April 2030 for 49 close Europa flybys. ESA's JUICE will make two Europa flybys before settling around Ganymede.
What we still don't know
Whether the ocean is habitable, how thick the ice is at any given spot, and whether water really escapes in plumes that a spacecraft could sample.
Missions
- 1989–2003
Galileo
NASACompletedFirst Jupiter orbiter (1995–2003) and first probe into a giant planet's atmosphere.
- 2011–
In Jupiter orbit since Jul 2016 on an extended mission. NASA's status page is inconsistent; perijoves are planned into 2027.
- 2024–
Launched 14 Oct 2024; Earth gravity assist 3 Dec 2026; arrives at Jupiter Apr 2030 for 49 Europa flybys.
- 2023–
Earth flyby Sep 2026, another in Jan 2029; Jupiter arrival Jul 2031, then orbit Ganymede.
First-hand · our 3D model
How we render it
Europa is a sphere wrapped in a global map built from USGS and NASA spacecraft mosaics.
It is drawn at about 7.4% of Jupiter's radius, enlarged from its true 2.2% so it stays visible. It orbits in Jupiter's equatorial frame, inclined 0.5°, with a 3.53-day period kept in true ratio to its neighbours, and keeps one face towards Jupiter.
Moon sizes and orbits are compressed so a whole system fits on screen, but never reordered: each moon is drawn at 0.72 × (true size ratio)^0.6 of its planet, capped so no large moon is drawn bigger than it really is, and orbit distances are log-compressed into a band that clears the planet's rings. Orbital periods keep their true ratios, every moon is tidally locked, and on lighter devices only the two largest moons of each planet are drawn.
Related entries
- JupiterLargest planet · gas giant
- Europa ClipperNASA's ocean-world explorer
- JUICEESA's Jupiter Icy Moons Explorer
Sources
- JPL Solar System Dynamics: satellite physical parameters (opens in a new tab)
- JPL Solar System Dynamics: satellite mean orbital elements (opens in a new tab)
- NASA NSSDC Jovian Satellite Fact Sheet (opens in a new tab)
- NASA Science: Europa facts (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.