NASA's Jupiter-gazing spacecraft just got a rare closeup of an icy world.
Skimming just 219 miles (352 kilometers) above Europe's surface, the two-hour flyby was among the three closest-ever glimpses of the icy world. The last similar view that we received was on Jan. 3, 2000 with Galileo, officials with NASA's Jet Propulsion Laboratory (JPL) in Southern California said in a statement.
"Rugged terrain features are easily seen, including tall shadow-casting blocks, while bright and dark ridges and troughs curve across the surface. The oblong pit near the terminator might be a degraded impact crater," JPL officials wrote of Juno's flyby imagery on Thursday (Sept. 29).
While geology data from the flyby is just starting to come in, officials termed Juno's rare look as key to establishing observations for NASA's coming Europa Clipper mission, which will launch in just two years to study the icy moon.
"Europa Clipper will study the moon's atmosphere, surface, and interior, with its main science goal being to determine whether there are places below Europa's surface that could support life," JPL stated of the mission, which is scheduled to reach the Jupiter system in 2030.
As the sixth-largest moon in the solar system, Europa is similar in size to Earth's moon but has a much different formation and evolutionary history. Europa has a massive icy crust overlying an ocean that researchers think may be capable of supporting Earth-like life.
During its flyby, Juno collected some of the highest-ever resolution pictures of the moon at 0.6 miles or 1 km per pixel, JPL stated, along with information about the moon's environment, atmosphere, surface and interior structure.
"The science team will be ... looking to see if Europa's surface features have changed over the past two decades," said Candy Hansen, a Juno co-investigator who leads planning for JunoCam (which obtained the images) at the Planetary Science Institute in Tucson, Arizona.
Data from Juno's microwave radiometer instrument could be especially important for future missions such as Clipper, as it may help identify some potentially habitable "pockets" of liquid water just underneath the massive ice cap.
Scientists used the flyby to change Juno's trajectory slightly, as it now is slated to make a single orbit of Jupiter in 38 Earth days (compared with the previous 43.) Flybys of the volcanic Jovian moon Io are expected in 2023 and 2024, if the mission can continue surviving the intense radiation radiation belts near Jupiter.