From Europe to Europa – in search of life

From the earliest astronomers to the space race of the late 21st century, space exploration has always had one question in mind: is there life elsewhere in the universe? Although numerous exoplanets (planets located outside of our solar systems) offer habitable zones, scientists at ESA and NASA are looking a bit closer to home.


Europa photographed by the Galileo spacecraft Credit: NSSDC Photo Gallery

Europa, Jupiter’s sixth moon, is an icy world that has caught scientists’ eyes. First discovered in the 1600s by Galilei, it contains a small metal core and a liquid ocean covered by a thick layer of ice. It is this watery world that is thought to be habitable for microbial life. Between 1995 and 2003, NASA’s Galileo spacecraft was the first spacecraft to study both Jupiter and its moons from orbit [1], and provided some of the first evidence for Europa’s liquid water oceans.

Europa’s liquid water may offer a habitable region within the moons structure. Despite being so far from the sun, it is thought that strong gravitational pulls from Jupiter may create tidal motions and internal heat required for maintaining liquid water. [2] This internal heat may also be produced by deep-sea vents, as seen on Earth, which may be warmed by a molten core. Our own oceans are home to a vast array of life-forms, and scientists think that Europa may be able to sustain microbial life.


ESA’s JUICE mission will reach the Jovian system in 2030 [3]

In 2012, the European Space Agency (ESA) selected JUICE (JUpiter ICy moons Explorer) to explore Europa, alongside its neighbours Ganymede and Callisto. This mission aims to launch in 2022 and reach the Jovian system in 2030, from which it will become the first spacecraft to orbit one of Jupiter’s icy moons. This mission, however, will focus on Ganymede, orbiting it and using its array of onboard instruments to study this moon in further detail. [3]

Earlier this year, NASA invited the European Space Agency (ESA) to join its mission to explore Europa that aims to image the moon’s surface in high resolution, and to investigate its inner layers. This mission will take place as a multiple-flyby, passing Europa 45 times whilst orbiting Jupiter. [4] The craft will use an ice penetration radar to calculate the thickness of the ice and to investigate the presence of subsurface lakes, whilst thermal instruments will allow scientists to examine the moon’s surface to investigate whether the moon has been subject to recent eruptions of warmer water. [1] This suggestion follows observations made by the Hubble Space Telescope, in which water vapour above the south pole of Europa was noted, indicating the existence of water plumes. These may be important in order for scientists to be able to test the chemical makeup of Europa’s water whilst reducing the need for drilling through the icy shell.

ESA scientists, who met recently in Paris, have five main proposals for current and future Europa exploration missions, alone and in tandem with NASA. A remote-sensing instrument is favoured for the NASA flyby mission, with an ice penetrator gathering interest for future missions. In 2013, the ESA tested an ice penetrator prototype here on Earth, propelling the steel missile into a block of ice at 300 m/s (around 700 mph). The missile survived the impact, and will hopefully be able to gather data from Europa’s liquid ocean that can then be transmitted back to earth. [5] If chosen for future missions, this lander probe may also contain a seismometer to study Europa’s structure, or laboratory probes to investigate the presence of certain chemicals.

Certainly, these plans from both NASA and ESA are exciting steps towards learning more about our solar system. Michel Blanc, from the Research Institute in Astrophysics and Planetology in Toulouse states: “One thing is true: we are very enthusiastic about proposing something, and proposing for that mission which will land on Europa for the first time in the space age. It’s going to be a big event, and I am sure it is going to be a big priority for the world community.”[5]

[1] NASA Solar System Exploration: Jupiter Missions

[2] PBS: Life Beyond Earth – Europa


[4] Europa M5 Initiative Meeting #3 (2016)

[5] BBC News (2016): European scientists set eyes on ice moon Europa

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