The Juno probe passed over Jupiter's moon Europa and captured it at close range

Juno became the third spacecraft in history to fly less than 500 km above Europe's surface. It fell just short of setting the record, but the data from its measurements and surveys will be useful for its planned landing on the satellite.

Interplanetary station Juno ("Juno") was launched in 2011 to study Jupiter, where she arrived five years later. In 2021, the device has completed its main mission and was refocused on new research, including overflights over some of the larger satellites of the gas giant. The planned approach to the Europa satellite took place on 29 September, as described in a press release from NASA.

Europa is the smallest of Jupiter's four Galilean satellites. Its surface consists of smooth ice mottled with cracks. An ocean of water is thought to lurk beneath it, heated by tidal forces generated as the satellite moves in the giant planet's gravitational field. Europe's subglacial ocean is thought to be one of the most suitable places for life in the entire solar system, apart from Earth. New missions are being planned to look for possible traces of indigenous micro-organisms.

So far, only two spacecraft have come within 500 kilometres of Europa. The record is held by the Galileo probe, which in 2000 descended to 351, but the new passage was only slightly higher - 352 kilometres. Juno swept over the satellite at a speed of 23.6 kilometres per second and during the two hours of rapprochement made observations that will help better understand the composition of the surface and internal structure of Europe, its interaction with Jupiter's magnetic field.

Work began when the probe was more than 83,000 kilometres away from the satellite. On-board instruments recorded plasma flux particles moving around Europa under the influence of the planet's magnetic field. Measurements were made of the ionosphere, the temperature and composition of the satellite's ice crust, and signs of water ejection near its south pole. At the same time, the apparatus was filming with the JunoCam. The raw images it sent were made publicly available.

These data will certainly be useful for the preparation of the Europa Clipper mission, which is due to start in 2024 and will go directly to the satellite of Jupiter. It is planned to include an orbiter and landing module that will search for traces of possible life right on the icy surface of Europa. In the meantime, Juno itself is continuing work on an extended mission. Between 2023 and 2024, the spacecraft will make close approaches to another Galilean satellite, volcanic Io.