Jupiter’s moons hide giant subsurface oceans − Europa Clipper is one of 2 missions on their way to see if these moons could support life
NASA’s Europa Clipper and ESA’s JUICE missions aim to explore Jupiter’s icy moons, focusing on the potential habitability of their underground oceans, particularly Europa’s, by gathering vital scientific data.
On Oct. 14, 2024, NASA launched a robotic spacecraft named Europa Clipper to Jupiter’s moons. Clipper will reach the ice-covered Jovian moon Europa in 2030 and spend several years collecting and sending valuable data on the moon’s potential habitability back to Earth.
Clipper isn’t the only mission highlighting researchers’ interest in Jupiter and its moons.
On April 13, 2023, the European Space Agency launched a rocket carrying a spacecraft destined for Jupiter. The Jupiter Icy Moons Explorer – or JUICE – will spend at least three years on Jupiter’s moons after it arrives in 2031.
There are many reasons my colleagues and I are looking forward to getting the data that Europa Clipper and JUICE will hopefully be sending back to Earth in the 2030s. But perhaps the most exciting information will have to do with water. Three of Jupiter’s moons – Europa, Ganymede and Callisto – are home to large, underground oceans of liquid water that could support life.
This composite image shows, from top to bottom, Io, Europa, Ganymede and Callisto next to Jupiter. NASA, CC BY-ND
Meet Io, Europa, Ganymede and Callisto
Jupiter has dozens of moons. Four of them in particular are of interest to planetary scientists.
Io, Europa, Ganymede and Callisto are, like Earth’s Moon, relatively large, spherical complex worlds. Two previous NASA missions have sent spacecraft to orbit the Jupiter system and collected data on these moons. The Galileo mission orbited Jupiter from 1995 to 2003 and led to geological discoveries on all four large moons. The Juno mission is still orbiting Jupiter today and has provided scientists with an unprecedented view into Jupiter’s composition, structure and space environment.
These missions and other observations revealed that Io, the closest of the four to its host planet, is abuzz withgeological activity, including lava lakes, volcanic eruptions and tectonically formed mountains. But it is not home to large amounts of water.
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Europa, Ganymede and Callisto, in contrast, have icy landscapes. Europa’s surface is a frozen wonderland with a young but complex history, possibly including icy analogs of plate tectonics and volcanoes. Ganymede, the largest moon in the entire solar system, is bigger than Mercury and has its own magnetic field generated internally from a liquid metal core. Callisto appears somewhat inert compared to the others, but serves as a valuable time capsule of an ancient past that is no longer accessible on the youthful surfaces of Europa and Io.
Most exciting of all: Europa, Ganymede and Callisto all almost certainly possess underground oceans of liquid water.
Warmth from Europa’s interior and tidal energy from Jupiter likely maintain a massive liquid ocean beneath the moon’s icy surface. NASA/JPL-Caltech/Michael Carroll
Ocean worlds
Europa, Ganymede and Callisto have chilly surfaces that are hundreds of degrees below zero. At these temperatures, ice behaves like solid rock.
But just like Earth, the deeper underground you go on these moons, the hotter it gets. Go down far enough and you eventually reach the temperature where ice melts into water. Exactly how far down this transition occurs on each of the moons is a subject of debate that scientists hope to resolve with JUICE and Europa Clipper. While the exact depths are still uncertain, scientists are confident that these oceans exist.
The best evidence of these oceans comes from Jupiter’s magnetic field. Saltwater is electrically conductive. So as these moons travel through Jupiter’s magnetic field, they generate a secondary, smaller magnetic field that signals to researchers the presence of an underground ocean. Using this technique, planetary scientists have been able to show that the three moons contain underground oceans. And these oceans are not small – Europa’s ocean alone might have more than double the water of all of Earth’s oceans combined.
An obvious and tantalizing next question is whether these oceans can support extraterrestrial life. Liquid water is an important piece of what makes for a habitable world, but far from the only requirement for life. Life also needs energy and certain chemical compounds in addition to water to flourish. Because these oceans are hidden beneath miles of solid ice, sunlight and photosynthesis are out. But it’s possible other sources could provide the needed ingredients.
On Europa, for example, the liquid water ocean overlays a rocky interior. That rocky seafloor could provide energy and chemicals through underwater volcanoes that could make Europa’s ocean habitable. But it is also possible that Europa’s ocean is a sterile, inhospitable place – scientists need more data to answer these questions.
The Jupiter Icy Moons Explorer spacecraft will travel for eight years before reaching Jupiter. ESA/ATG medialab/NASA/JPL/University of Arizona/J. Nichols
Upcoming missions from ESA and NASA
Europa Clipper and JUICE are set up to give scientists game-changing information about the potential habitability of Jupiter’s moons. While both missions will gather data on multiple moons, JUICE will spend time orbiting and focusing on Ganymede, and Europa Clipper will make dozens of close flybys of Europa.
Both of the spacecraft will carry a suite of scientific instruments built specifically to investigate the oceans. Onboard radar will allow Europa Clipper and JUICE to probe into the moons’outer layers of solid ice. Radar could reveal any small pockets of liquid water in the ice, or, in the case of Europa, which has a thinner outer ice layer than Ganymede and Callisto, hopefully detect the larger ocean.
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Magnetometers will also beon both missions. These tools will give scientists the opportunity to study the secondary magnetic fields produced by the interaction of conductive oceans with Jupiter’s field in great detail and will hopefully give researchers clues to salinity and volumes of the oceans.
Scientists will also observe small variations in the moons’ gravitational pulls by tracking subtle movements in both spacecrafts’ orbits, which could help determine if Europa’s seafloor has volcanoes that provide the needed energy and chemistry for the ocean to support life.
Finally, both craft will carry a host of cameras and light sensors that will provide unprecedented images of the geology and composition of the moons’ icy surfaces.
Maybe one day, a spacecraft will be able to drill through the miles of solid ice on Europa, Ganymede or Callisto and explore oceans directly. Until then, observations from spacecraft like Europa Clipper and JUICE are scientists’ best bet for learning about these ocean worlds.
When Galileo discovered these moons in 1609, they were the first objects known to directly orbit another planet. Their discovery was the final nail in the coffin of the theory that Earth – and humanity – resides at the center of the universe. Maybe these worlds have another humbling surprise in store.
This article, originally published April 10, 2023, has been updated with details about the Europa Clipper launch.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
In a dramatic turn of events that captured international attention, the Soviet-era spacecraft Kosmos 482 has completed its final descent after spending over five decades in Earth’s orbit. The spacecraft, which had been closely monitored due to its deteriorating orbit pattern, crashed into the Indian Ocean west of Jakarta at approximately 11:24 p.m. Phoenix time on May 9, 2025, ending weeks of speculation about its potential impact in Arizona.
The Historic Background Originally launched in 1972 as part of an ambitious mission to Venus, Kosmos 482 became a remnant of the Cold War space race after its mission failed. The approximately 3-foot-diameter spacecraft had been trapped in Earth’s orbit for 53 years, joining the growing collection of space debris that concerns modern astronomers and space agencies.
Arizona’s Emergency Response The potential threat to Arizona prompted a swift and coordinated response from local authorities. The Phoenix metropolitan area, initially identified as one of the possible impact zones, activated its emergency response protocols. This included:
Establishment of a temporary command center by the Arizona Department of Emergency Management
Enhanced monitoring systems at Phoenix Sky Harbor International Airport
Coordination between local, state, and federal agencies
Implementation of emergency communication channels for public updates
Local Infrastructure Impact Coincidentally, this event intersected with Phoenix Sky Harbor’s ongoing modernization project, which aims to improve passenger experiences and facility capabilities. The airport’s emergency response teams incorporated spacecraft monitoring into their existing protocols, demonstrating the facility’s adaptive capacity during potential aerospace emergencies.
“This situation, while ultimately resolving without incident in our region, showcased our emergency response capabilities and the importance of our ongoing infrastructure improvements,” stated a Phoenix Sky Harbor spokesperson. The modernization project, which was already underway, proved particularly relevant during this potential aerospace emergency.
Community Response Local residents and businesses in the Phoenix metropolitan area remained vigilant throughout the monitoring period. Emergency management officials maintained regular communications with the public, providing updates through various channels to ensure community awareness and preparedness.
Technical Analysis Space tracking organizations employed advanced monitoring systems to track Kosmos 482’s descent. The spacecraft, powered by systems similar to other Cold War-era satellites, provided valuable data for modern space debris tracking programs. Unlike modern spacecraft such as Voyager 1, which continues to operate using a radioisotope power system, Kosmos 482 had long since lost its operational capabilities.
Final Outcome The spacecraft’s ultimate crash site in the Indian Ocean brought relief to Arizona residents and officials. The incident concluded at approximately 2:24 a.m. EDT (11:24 p.m. Phoenix time), with no reported casualties or damage.
Looking Forward This event serves as a crucial reminder of the challenges posed by orbital debris and the importance of maintaining robust emergency response systems. It also highlights Phoenix’s growing role in aerospace monitoring and emergency management, particularly as the city continues to expand its aviation infrastructure.
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The incident has prompted discussions about improving space debris monitoring systems and international cooperation in managing potential aerospace threats, ensuring better preparation for similar events in the future.
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The European Space Agency’s astronaut cohort includes a parastronaut, as part of a feasibility project.
AP Photo/Francois MoriJesse Rhoades, University of North Dakota and Rebecca Rhoades, University of North Dakota
Humans will likely set foot on the Moon again in the coming decade. While many stories in this new chapter of lunar exploration will be reminiscent of the Apollo missions 50 years ago, others may look quite different.
For instance, the European Space Agency is currently working to make space travel more accessible for people of a wide range of backgrounds and abilities. In this new era, the first footprint on the Moon could possibly be made by a prosthetic limb.
NASA plans to return humans to the lunar surface in the coming decade.NASA Goddard
Historically, and even still today, astronauts selected to fly to space have had to fit a long list of physical requirements. However, many professionals in the field are beginning to acknowledge that these requirements stem from outdated assumptions.
Some research, including studies by our multidisciplinary team of aerospace and biomechanics researchers, has begun to explore the possibilities for people with physical disabilities to venture into space, visit the Moon and eventually travel to Mars.
Current research
NASA has previously funded and is currently funding research on restraints and mobility aids to help everyone, regardless of their ability, move around in the crew cabin.
Additionally, NASA has research programs to develop functional aids for individuals with disabilities in current U.S. spacecraft. A functional aid is any device that improves someone’s independence, mobility or daily living tasks by compensating for their physical limitations.
The European Space Agency, or ESA, launched its Parastronaut Feasibility Project in 2022 to assess ways to include individuals with disabilities in human spaceflight. A parastronaut is an astronaut with a physical disability who has been selected and trained to participate in space missions.
At the University of North Dakota, we conducted one of the first studies focused on parastronauts. This research examined how individuals with disabilities get into and get out of two current U.S. spacecraft designed to carry crew. The first was NASA’s Orion capsule, designed by Lockheed Martin, and the second was Boeing’s CST 100 Starliner.
Alongside our colleagues Pablo De León, Keith Crisman, Komal Mangle and Kavya Manyapu, we uncovered valuable insights into the accessibility challenges future parastronauts may face.
Our research indicated that individuals with physical disabilities are nearly as nimble in modern U.S. spacecraft as nondisabled individuals. This work focused on testing individuals who have experienced leg amputations. Now we are looking ahead to solutions that could benefit astronauts of all abilities.
Safety and inclusion
John McFall is the ESA’s first parastronaut. At the age of 19, Mcfall lost his right leg just above the knee from a motorcycle accident. Although McFall has not been assigned to a mission yet, he is the first person with a physical disability to be medically certified for an ISS mission.
John McFall stands by a mock-up of the SpaceX Dragon crew capsule.SpaceX, CC BY-NC-SA
Astronaut selection criteria currently prioritize peak physical fitness, with the goal of having multiple crew members who can do the same physical tasks. Integrating parastronauts into the crew has required balancing mission security and accessibility.
However, with advancements in technology, spacecraft design and assistive tools, inclusion no longer needs to come at the expense of safety. These technologies are still in their infancy, but research and efforts like the ESA’s program will help improve them.
Design and development of spacecraft can cost billions of dollars. Simple adaptations, such as adding handholds onto the walls in a spacecraft, can provide vital assistance. However, adding handles to existing spacecraft will be costly.
Functional aids that don’t alter the spacecraft itself – such as accessories carried by each astronaut – could be another way forward. For example, adding Velcro to certain spots in the spacecraft or on prosthetic limbs could improve a parastronaut’s traction and help them anchor to the spacecraft’s surfaces.
Engineers could design new prosthetics made for particular space environments, such as zero or partial gravity, or even tailored to specific spacecraft. This approach is kind of like designing specialized prosthetics for rock climbing, running or other sports.
Accessibility can help everyone
Future space exploration, particularly missions to the Moon and Mars that will take weeks, months and even years, may prompt new standards for astronaut fitness. During these long missions, astronauts could get injured, causing what can be considered incidental disability.
An astronaut with an incidental disability begins a mission without a recognized disability but acquires one from a mission mishap. An astronaut suffering a broken arm or a traumatic brain injury during a mission would have a persistent impairment.
On longer missions, astronauts may need to troubleshoot issues on their own.NASA
During long-duration missions, an astronaut crew will be too far away to receive outside medical help – they’ll have to deal with these issues on their own.
Considering disability during mission planning goes beyond inclusion. It makes the mission safer for all astronauts by preparing them for anything that could go wrong. Any astronaut could suffer an incidental disability during their journey.
Safety and inclusion in spaceflight don’t need to be at odds. Instead, agencies can reengineer systems and training processes to ensure that more people can safely participate in space missions. By addressing safety concerns through technology, innovative design and mission planning, the space industry can have inclusive and successful missions.Jesse Rhoades, Professor of Education, Heath & Behavior, University of North Dakota and Rebecca Rhoades, Researcher in Education, Health & Behavior, University of North Dakota
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Voyager 1, shown in this illustration, has operated for decades thanks to a radioisotope power system.
NASA via APBenjamin Roulston, Clarkson University
Powering spacecraft with solar energy may not seem like a challenge, given how intense the Sun’s light can feel on Earth. Spacecraft near the Earth use large solar panels to harness the Sun for the electricity needed to run their communications systems and science instruments.
However, the farther into space you go, the weaker the Sun’s light becomes and the less useful it is for powering systems with solar panels. Even in the inner solar system, spacecraft such as lunar or Mars rovers need alternative power sources.
As an astrophysicist and professor of physics, I teach a senior-level aerospace engineering course on the space environment. One of the key lessons I emphasize to my students is just how unforgiving space can be. In this extreme environment where spacecraft must withstand intense solar flares, radiation and temperature swings from hundreds of degrees below zero to hundreds of degrees above zero, engineers have developed innovative solutions to power some of the most remote and isolated space missions.
So how do engineers power missions in the outer reaches of our solar system and beyond? The solution is technology developed in the 1960s based on scientific principles discovered two centuries ago: radioisotope thermoelectric generators, or RTGs.
RTGs are essentially nuclear-powered batteries. But unlike the AAA batteries in your TV remote, RTGs can provide power for decades while hundreds of millions to billions of miles from Earth.
Nuclear power
Radioisotope thermoelectric generators do not rely on chemical reactions like the batteries in your phone. Instead, they rely on the radioactive decay of elements to produce heat and eventually electricity. While this concept sounds similar to that of a nuclear power plant, RTGs work on a different principle.
Most RTGs are built using plutonium-238 as their source of energy, which is not usable for nuclear power plants since it does not sustain fission reactions. Instead, plutonium-238 is an unstable element that will undergo radioactive decay.
Radioactive decay, or nuclear decay, happens when an unstable atomic nucleus spontaneously and randomly emits particles and energy to reach a more stable configuration. This process often causes the element to change into another element, since the nucleus can lose protons.
Plutonium-238 decays into uranium-234 and emits an alpha particle, made of two protons and two neutrons.NASA
When plutonium-238 decays, it emits alpha particles, which consist of two protons and two neutrons. When the plutonium-238, which starts with 94 protons, releases an alpha particle, it loses two protons and turns into uranium-234, which has 92 protons.
These alpha particles interact with and transfer energy into the material surrounding the plutonium, which heats up that material. The radioactive decay of plutonium-238 releases enough energy that it can glow red from its own heat, and it is this powerful heat that is the energy source to power an RTG.
The nuclear heat source for the Mars Curiosity rover is encased in a graphite shell. The fuel glows red hot because of the radioactive decay of plutonium-238.Idaho National Laboratory, CC BY
Heat as power
Radioisotope thermoelectric generators can turn heat into electricity using a principle called the Seebeck effect, discovered by German scientist Thomas Seebeck in 1821. As an added benefit, the heat from some types of RTGs can help keep electronics and the other components of a deep-space mission warm and working well.
In its basic form, the Seebeck effect describes how two wires of different conducting materials joined in a loop produce a current in that loop when exposed to a temperature difference.
The Seeback effect is the principle behind RTGs.
Devices that use this principle are called thermoelectric couples, or thermocouples. These thermocouples allow RTGs to produce electricity from the difference in temperature created by the heat of plutonium-238 decay and the frigid cold of space.
Radioisotope thermoelectric generator design
In a basic radioisotope thermoelectric generator, you have a container of plutonium-238, stored in the form of plutonium-dioxide, often in a solid ceramic state that provides extra safety in the event of an accident. The plutonium material is surrounded by a protective layer of foil insulation to which a large array of thermocouples is attached. The whole assembly is inside a protective aluminum casing.
An RTG has decaying material in its core, which generates heat that it converts to electricity.U.S. Department of Energy
The interior of the RTG and one side of the thermocouples is kept hot – close to 1,000 degrees Fahrenheit (538 degrees Celsius) – while the outside of the RTG and the other side of the thermocouples are exposed to space. This outside, space-facing layer can be as cold as a few hundred degrees Fahrenheit below zero.
This strong temperature difference allows an RTG to turn the heat from radioactive decay into electricity. That electricity powers all kinds of spacecraft, from communications systems to science instruments to rovers on Mars, including five current NASA missions.
But don’t get too excited about buying an RTG for your house. With the current technology, they can produce only a few hundred watts of power. That may be enough to power a standard laptop, but not enough to play video games with a powerful GPU.
For deep-space missions, however, those couple hundred watts are more than enough.
The real benefit of RTGs is their ability to provide predictable, consistent power. The radioactive decay of plutonium is constant – every second of every day for decades. Over the course of about 90 years, only half the plutonium in an RTG will have decayed away. An RTG requires no moving parts to generate electricity, which makes them much less likely to break down or stop working.
Additionally, they have an excellent safety record, and they’re designed to survive their normal use and also be safe in the event of an accident.
RTGs in action
RTGs have been key to the success of many of NASA’s solar system and deep-space missions. The Mars Curiosity and Perseverance rovers and the New Horizons spacecraft that visited Pluto in 2015 have all used RTGs. New Horizons is traveling out of the solar system, where its RTGs will provide power where solar panels could not.
However, no missions capture the power of RTGs quite like the Voyager missions. NASA launched the twin spacecraft Voyager 1 and Voyager 2 in 1977 to take a tour of the outer solar system and then journey beyond it.
The RTGs on the Voyager probes have allowed the spacecraft to stay powered up while they collect data.NASA/JPL-Caltech
Each craft was equipped with three RTGs, providing a total of 470 watts of power at launch. It has been almost 50 years since the launch of the Voyager probes, and both are still active science missions, collecting and sending data back to Earth.
Voyager 1 and Voyager 2 are about 15.5 billion miles and 13 billion miles (nearly 25 billion kilometers and 21 billion kilometers) from the Earth, respectively, making them the most distant human-made objects ever. Even at these extreme distances, their RTGs are still providing them consistent power.
These spacecraft are a testament to the ingenuity of the engineers who first designed RTGs in the early 1960s.
Benjamin Roulston, Assistant Professor of Physics, Clarkson University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Jesse Rhoades, Professor of Education, Heath & Behavior, University of North Dakota and Rebecca Rhoades, Researcher in Education, Health & Behavior, University of North Dakota
This article is republished from The Conversation under a Creative Commons license. Read the original article.
