Jupiter, the king of the solar system, will get new visitors. The largest planet orbiting the sun is interesting in itself, but its massive moons are the ultimate prize — some of which are hunks of icy rock that could harbor life-harvesting oceans beneath their surfaces. .
The robotic mission that will leave for Jupiter on Thursday is Juice, or the Jupiter Icy Moons Explorer, from the European Space Agency, or ESA, which aims to closely study three of Jupiter’s moons: Callisto, Europa and Ganymede.
“This is one of the most exciting missions we’ve flown in the solar system,” said Josef Aschbacher, the head of ESA, and “by far the most complex.”
Here’s what you need to know about Juice’s mission.
When will the launch happen, and how can I watch it?
The juice is set to launch on April 13 at 8:15 am Eastern time. ESA will do stream the launch live on its website and in its YouTube channel.
The spacecraft will head into space aboard an Ariane 5 rocket from the Guiana Space Center in Kourou, French Guiana, on the northeast coast of South America. The same type of rocket launched the James Webb Space Telescope from a European-run launch site in December 2021.
What is Juice’s mission, and what will it study?
Weighing six tons, the European spacecraft carries 10 advanced scientific instruments to study the moon and take pictures. Jupiter is not the primary target of the mission. Instead, it aims to examine Ganymede, the largest moon in the solar system, and two other moons, Europa and Callisto.
But reaching Jupiter will take Juice more than eight years, with a series of swings or gravitational assists past Venus, Mars and Earth to give the spacecraft the push it needs to enter orbit. of Jupiter in July 2031.
When Juice finally reaches Jupiter, it will repeatedly fly over three moons in a spinning orbit, staying outside the giant planet’s dangerous radiation belt while it collects data. In total, 35 flybys are planned as the spacecraft looks for magnetic signals and other evidence to confirm the presence and size of oceans bubbling beneath the moon’s surfaces. It will also track how the outer parts of the moons move in response to Jupiter’s gravitational pull, possibly influenced by subsurface oceans.
The moon that may hold the most promise for finding life is Europa. Astronomers think its ocean is in direct contact with a rocky floor, which could provide food and energy for life as hydrothermal vents erupt upward. Juice will make two European flybys.
The spacecraft will also conduct 21 flybys of Callisto. That moon was not thought to be able to support life in its oceans. Its surface is very old and covered in craters, and there appears to be no solid core that could provide the ocean with the nutrients necessary for life.
“We don’t know why that’s the case,” said Michele Dougherty from Imperial College London, who leads the magnetometer instrument on Juice.
But the main objective of Juice’s mission is the study of Ganymede, a moon that is so large that it is larger than the planet Mercury. The spacecraft’s path around the Jovian system should allow the spacecraft to be captured in orbit around Ganymede in December 2034 — the first spacecraft to orbit a moon in the outer solar system. Starting at about 3,100 miles above the surface, the spacecraft’s altitude will gradually drop to just over 300 miles by 2035 — and perhaps lower, fuel permitting.
“If we had enough propellant, which means we had a good trip to Jupiter without too many problems, we would reduce the orbit to” an altitude of about 150 miles, said Giuseppe Sarri, the project manager for Juice at ESA .
Orbiting Ganymede will allow scientists to fully understand the moon’s properties. It is the only moon in the solar system known to have its own magnetic field, possibly from a liquid iron core like our own planet. “If you were standing on top of Ganymede and you had a compass needle, it would point to the north pole just like on Earth,” said Dr. Dougherty. “We want to understand why.”
Juice should be able to determine Ganymede’s internal structure, including the size and extent of its ocean. It should also be able to measure the salt content of the ocean resulting from the minerals circulating inside, which could support life. “We’re trying to understand where the salts come from,” said Dr. Dougherty.
Ganymede’s ocean is very different from Europa’s, but it’s still habitable.
“For habitation you need liquid water, a heat source and organic materials,” said Dr. Dougherty. “Whether we confirm or deny those three things, we’ve done what we said we were going to do.”
The mission will end in late 2035 with a crash landing on the surface of Ganymede, unless something is discovered during the mission that suggests it could contaminate the moon’s ocean.
What other missions will be studied at Jupiter?
Juice is not the only mission investigating Jupiter and its moons.
Juno, a NASA mission, has been orbiting Jupiter since 2016. Its focus is on the planet itself rather than its moons, although it has recently completed several close flybys of Europa and Ganymede, and will soon pass the volcano Io.
But Juice is also expected to be beaten to Jupiter by another new NASA mission, the Europa Clipper, which will launch in October 2024. It is scheduled to arrive in the Jovian system in April 2030, thanks to its more powerful launch vehicle. , a SpaceX Falcon Strong rocket. But there is no competition; the two missions are intended to work together.
“There will be two spacecraft at the same time looking at Jupiter and its moons,” said Dr. Aschbacher. “There’s a lot of science to be gained from that.”
The two missions were born in 2008 in response to exciting results from NASA’s Galileo spacecraftwhich orbited Jupiter from 1995 to 2003.
“Galileo saw this very intriguing magnetic signal that suggested there was a conductive ice layer beneath Europa’s shell,” said Louise Prockter of the Johns Hopkins Applied Physics Laboratory, who is part of the Europa Clipper team.
Scientists now think that’s a sign of a global ocean that covered Europa’s interior.
Hubble Space Telescope observations in 2018 suggest that Europa may occasionally spurt its ocean into the blue through cracks in its icy shell, which is at least 10 miles thick. This could provide a new way to directly study the ocean and look for signs of life as Clipper darts across the moon’s surface, sometimes at an altitude as low as 15 miles.
“We can fly on a feather,” said Dr. Prockter.
The results of both Juice and Clipper will reveal whether a landing on a Jupiter moon should be attempted in a future mission, likely to Europa, to directly search for ocean life, something NASA has proposed. Such a mission may be two decades away, but its scientific value is enormous. said Dr. Aschbacher that Europe is interested in something similar.
“We talked about a sample return mission from one of the icy moons,” he said, which would bring materials back to Earth for closer study. “What we learn from Juice will be an invaluable input for that.”
Right now, the spotlight is on Juice, the first of a new era of spacecraft designed specifically to hunt the oceans of alien worlds. “I can’t wait,” said Dr. Dougherty. “This is the next step.”
