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A NASA spacecraft will fly past one of the most interesting ocean worlds in our solar system on Thursday.
The Juno spacecraft, which has been orbiting Jupiter since 2016, was due to make its closest approach to the moon Europa at 5:36 a.m. ET, flying within 222 miles (358 kilometers) of its icy surface.
Juno will capture some of the highest-resolution images ever taken of Europa’s icy shell. The spacecraft is also expected to collect data on the moon’s interior, where a salty ocean is believed to exist.
The ice shell that makes up the surface of the Moon is 10 to 15 miles (16 to 24 kilometers) thick, and the overlying ocean is estimated to be 40 to 100 miles (64 to 161 kilometers) deep.
Juno’s Microwave Radiometry instrument will study the ice sheet to determine more about its temperature and composition. This is the first time that this kind of information about Europa’s icy shell will be collected.
The data and images collected by Juno could inform NASA’s Europa Clipper mission, which will launch in 2024 to make a series of 50 flybys around the moon after arriving in 2030. Europa Clipper can help scientists determine whether an internal ocean exists. and if the moon—one of many orbiting Jupiter—has the potential to be habitable for life.
Clipper will eventually go from an altitude of 1,700 miles (2,735 kilometers) to 16 miles (26 kilometers) above the moon’s surface. While Juno is largely focused on studying Jupiter, Clipper will be dedicated to observing Europa.
“Europa is a very interesting Jovian moon that is the focus of a future NASA mission,” Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio, said in a statement.
“We are pleased to provide the Europa Clipper team with data that can help them plan their missions, as well as provide new scientific information about this icy world.”
All of Juno’s instruments will collect data during the flyby, including ones that can measure Europa’s upper atmosphere and how Europa interacts with Jupiter’s magnetic field. The team expects to see a plume of water emerging from cracks in the ice shell. Previous missions have observed plumes of water vapor blasting through the ice shell into space.
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“We have the right equipment to do the job, but it’s going to take a lot of luck to catch a feather,” Bolton said. “We have to be in the right place at the right time, but if we’re very lucky, it’s surely home.”
Images taken of Europa during the flyby can be compared with those taken by previous missions to study how the moon’s surface may have changed over the past 20 years.
Europa is about 90% the size of Earth’s moon, and Juno’s flyby will be the closest a NASA spacecraft has come to it since the Galileo mission flew by in 2000.
Juno is in the extended part of the mission, which was due to end in 2021. The spacecraft is now focused on flybys of some of Jupiter’s moons. The spacecraft visited Ganymede in 2021 and will zoom past Io in 2023 and 2024. Its mission will now end in 2025.
The Europa maneuver will also shorten Juno’s orbit around Jupiter from 43 days to 38 days.
“The relative velocity between the spacecraft and the moon will be 14.7 miles per second (23.6 kilometers per second), so we’re screeching along pretty fast,” said John Bordi of the Juno mission at NASA’s Jet Propulsion Laboratory in Pasadena, California. deputy directors statement
“All steps must go like clockwork to successfully acquire the planned data, because soon after the flyby, the spacecraft must be reorientated for the closest approach to Jupiter, which is only 7½ ½. hours later.”