Even though it is around the same size as our own Moon and a whole lot farther from the Sun, Jupiter's moon Europa is considered one of our solar system's most likely candidates for harboring extraterrestrial life. A deep and mysterious ocean is thought to exist below its icy crust and has beckoned scientists for more than a decade. NASA is in the process of conceptualizing a future mission to explore Europa, and has now confirmed which scientific instruments it will send along to do the job.
Back in February, NASA announced that it had asked Congress for US$30 million to fund the mission, which is slated for lift-off sometime in the 2020s. If approved, the mission would see a solar-powered spacecraft orbit Jupiter and conduct 45 close flybys of Europa at distances ranging from 16 to 1,700 mi (25 to 2,700 km).
Last year, researchers were invited to put forward proposals for scientific tools to study Europa. A total of 33 submissions has now been whittled down to nine (which unfortunately don't include roving robotic squids). Cameras and spectrometers will be used to capture high-res images of Europa's surface and to offer new insights into its composition. A magnetometer will be used to gauge the strength and direction of the magnetic field, while also measuring the depth and salinity of the ocean.
Scientists will attempt to work out the thickness of the icy crust and hunt for lakes underneath using an ice penetrating radar, while a thermal emission imaging system will comb the frozen surface for eruptions of warmer water. An ultraviolet spectrograph and mass spectrometer will sweep Europa's atmosphere for surface materials and water plumes being ejected into space.
In particular, scientists will be on the lookout for small water plumes erupting near the south pole. In 2012, the Hubble Space Telescope found evidence of water vapor over this region. If these are shown to exist and to be erupting from a subsurface ocean it could make things a lot simpler for researchers, as it would make it possible to study the chemical makeup of the environment while lessening the need to drill through huge bulks of ice.
"Europa has tantalized us with its enigmatic icy surface and evidence of a vast ocean, following the amazing data from 11 flybys of the Galileo spacecraft over a decade ago and recent Hubble observations suggesting plumes of water shooting out from the moon," says John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. "We’re excited about the potential of this new mission and these instruments to unravel the mysteries of Europa in our quest to find evidence of life beyond Earth."