“Europa has always been my top choice in the solar system,” admits Quick. However, she mentions that other aquatic worlds could also be potential sites to hunt for indications of life. Among these candidates is Enceladus, Saturn’s tiny moon, which like Europa, possesses an ice-capped crust that covers an underlying ocean. The 2005 Cassini mission unveiled geysers at the Enceladus’ south pole, discharging water and organic compounds into the cosmos and feeding the furthest ring of Saturn.
Nevertheless, Europa has a larger size than Enceladus, and it is expected to feature a landscape overlaid with moving icy plaques, akin to the Earth’s plate tectonics process. This type of movement can contribute to the formulation of ingredients necessary for life. Ganymede, another moon orbiting Jupiter and the biggest in the solar system, also likely conceals a liquid ocean, though it is sandwiched between dual ice layers which can make life less likely due to the absence of an interface between minerals and water. Other potential hunting ground includes Titan, Saturn’s largest moon, where it is presumed a water ocean also lies beneath an icy crust. (Quick is a researcher for the Dragonfly mission intending to study Titan, with a set launch year of 2028.)
Mission engineers are constantly tackling obstacles related to energy as Europa only gets one-fifth of the sunlight the Earth does. The Clipper spacecraft seeks to resolve this issue via massive solar panels, stretching up to 30 meters when totally opened up.
The Clipper will employ nine fundamental tools to identify habitability markers. These tools will capture the surface’s images, detect water emissions, utilize ground-penetrating radar to evaluate the icy shell and spot the hidden ocean, as well as take precise magnetic field measurements.
The spacecraft will come so close to the moon to examine its sparse atmosphere, employing mass spectrometry to identify the gas molecules present. Another device will allow scientists to examine surface dust propelled into the atmosphere by meteorite impacts. The findings will be exciting for planetary geologists, regardless of whether the dust originated from below–from the encased ocean or from subsurface lakes within the ice–or from above, as pieces that migrated from nearby moon Io’s violent volcanoes.
Similar to the Clipper, ESA’s Juice mission carries matching instruments, and the two teams’ scientists are in regular contact to jointly leverage the data they collect in approximately five or six years from now. “These engagements are hugely beneficial to the planetary research community,” says Lorenzo Bruzzone, a telecommunications engineer with the University of Trento, who also leads the Juice mission’s radar tool squad.
Since Juice will explore the other ocean-bearing Galilean moons, the data from that mission can complement Clipper’s to create a more in-depth understanding of the geologic processes and potential habitability of all the aquatic worlds. “It enables us to analyze the variations in subsurface geology to better appreciate how the Jupiter system has evolved,” Bruzzone declares.
Radiation from Jupiter has the potential to mess up every measurement conducted, rendering a valuable signal into a pile of digital fuzz, similar to static on a television screen.
Both missions’ engineers and developers have contended with numerous trials to ensure the instruments function upon reaching their destinations. Among these trials, many revolve around the issue of energy supply, as Europa only receives a fifth of Earth’s sunlight. The Clipper will address this deficiency with enormous solar panels that, when completely stretched out, will cover an area of 30 meters. (Prior proposals for a Europa mission suggested nuclear-powered batteries, but the costly proposal was eventually discarded.)
