Read more<\/strong><\/strong><\/h3>- Does Europa glow in the dark<\/strong><\/em><\/a><\/li>
- Webb detects carbon on Europa<\/a><\/strong><\/em><\/li>
- Earth’s lakes could help find life on Europa<\/strong><\/em><\/a><\/li><\/ul><\/div>
NASA\/JPL-Caltech\/SwRI\/MSSS. Image processing: Bj\u00f6rn J\u00f3nsson (CC BY 3.0)<\/figcaption><\/figure><\/div><\/div>![\"Image](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/05\/jun-europa-platypus.jpg\")
Image of the surface of Jupiter’s moon Europa captured by NASA’s Juno spacecraft, 29 September 2022. Top right are double ridges and dark stains that could indicate plume activity. Bottom right is a feature nicknamed the ‘Platypus’. Credit: NASA\/JPL-Caltech\/SwRI<\/figcaption><\/figure>Why Europa?<\/strong><\/h2>Circling giant Jupiter at a distance of 671,000km (417,000 miles), Europa is an enigmatic moon, smaller in diameter than Australia is wide.<\/p>
Its surface rhythmically flexes under its parent planet\u2019s colossal gravity<\/a> and is washed by the intense Jovian magnetic field<\/a>, 20,000 times fiercer than Earth\u2019s.<\/p>Nine tenths as big as the Moon yet five times further from the Sun, Europa\u2019s daytime highs never climb above \u2013160\u00b0C (\u2013260\u00b0F).<\/p>
Its Texas-sized nickel-iron core and rocky mantle are overlaid by an icy crust, maybe 15\u201325km (10\u201315 miles) thick and rendered rock-solid under such frigid extremes.<\/p>
But hard as it may seem in this radiation-blasted wasteland, life of sorts might once (and could still) have thrived at Europa<\/a>: truly an unlikely Eden.<\/p>Visually, Europa bears few hallmarks of the only known harbour of life: our iridescent blue-and-white planet, Earth.<\/p>
Past missions to Europa<\/strong><\/h2>In 1979, NASA\u2019s Voyager 1 and 2 probes revealed what Europa Clipper deputy project scientist Bonnie Buratti of NASA\u2019s Jet Propulsion Laboratory (JPL) likens to \u201ca cracked egg\u201d: its 0.64 albedo (how much light its surface reflects) brighter than Arctic sea-ice; and its curious reddish tincture likely caused
The Voyagers photographed linear ridges and furrows crossing the surface, with peculiar blotches dotted across the glassy landscape.<\/p>![\"Image](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/10\/europa-voyager.jpg\")
Image of Jupiter’s moon Europa, captured by Voyager 2, 9 July 1979. Credit: NASA\/JPL<\/figcaption><\/figure>“Scientists date surfaces by counting craters,” says Buratti. And Europa\u2019s lack of craters implies a young surface, perhaps 20 million years old and still undergoing active internal change.<\/p>
Tantalisingly, the Voyagers detected fractures in that terrain, facilitating movement of dark subsurface material into the resulting gaps \u2013 and inviting speculation that a layer of water or warm ice might lurk beneath the Europan crust.<\/p>
In 1996\u20132000, NASA\u2019s Galileo probe<\/a> found strong evidence for a salty ocean holding 3 billion cubic kilometres (720 million cubic miles) of water, twice as much as our oceans.<\/p>![\"Two](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2021\/10\/Jupiter-moon-europa-192c2d4.jpeg\")
Two views of moon Europa captured by NASA’s Galileo spacecraft in June 1997. Credit: NASA, NASA-JPL, University of Arizona<\/figcaption><\/figure>That ocean could be 80\u2013100km (50\u201360 miles) deep \u2013 that\u2019s nine times deeper than the Mariana Trench, the deepest point in any ocean on Earth.<\/p>
The Galileo probe also showed that an upwelling of warm, slushy ice was indeed at work.<\/p>
It detected an intrinsic magnetic field and measured directional changes consistent with the presence of a subsurface \u2018shell\u2019 of electrically conducting material, like a salty liquid ocean.<\/p>![\"A](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2019\/08\/Europa_water_vapour-4214f8d-e1566371545727.jpg\")
A Hubble Space Telescope image of Europa showing suspected plumes of water vapour erupting at the 7 o’clock mark. These plumes could be evidence of a subsurface ocean below Europa’s icy crust.Elsewhere, the Hubble Space Telescope discovered Europa\u2019s thin oxygen atmosphere and in 2013\u20132017 saw water vapour emissions rising 100km (60 miles) high.<\/p>
That furnished persuasive evidence of material ejected directly from the ocean.<\/p>
In 2019, Hubble found sodium chloride (table salt), suggesting the ocean could be saltier and more Earth-like than originally thought\u2026 and more amenable to microbial life.<\/p>![\"Heat](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/10\/hydrothermal-vents.jpg\")
Heat and minerals expelled by hydrothermal vents allow creatures to survive without sunlight. Credit: Ralph White \/ Getty Images<\/figcaption><\/figure>Life on Europa?<\/strong><\/h2>“Every scenario for life on Earth has liquid water,” Buratti explains.<\/p>
“The search for life is top of the list: are we alone? But our understanding of how life originated and how it thrived has really evolved over the time that I\u2019ve been in this field.”<\/p>
On Earth, life sprouted in the unlikeliest of places, notably hydrothermal vents in deep ocean trenches with no sunlight.<\/p>
“Life formed in these thermal vents because the bacteria there are very primitive,” Buratti continues.<\/p>
“They\u2019re at the base of the tree of life, so our understanding of where to look for life has changed.”<\/p>
But Buratti remains cautiously guarded about finding life.<\/p>
“It looks like the conditions for life are there,” she says. “We\u2019re empiricists and we don\u2019t have any evidence yet. Our mission\u2019s going to find evidence and work from there.”<\/p>![\"A](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/03\/jupiter-moon-europa.jpg\")
A view of Jupiter’s moon Europa captured by the Juno spacecraft during its flyby on 29 September 2022. Credit: Image data: NASA\/JPL-Caltech\/SwRI\/MSSS Image processing: Kevin M. Gill CC BY 3.0 Full Image Details<\/figcaption><\/figure>How the Europa Clipper mission came about<\/strong><\/h2>A dedicated Europa mission has long held high-priority status.<\/p>
Top-level goals include measuring the thickness of the crust, deciphering Europa\u2019s complex geology and ascertaining the nature, size, saltiness and composition of the ocean.\u00a0<\/p>
In 1997, NASA proposed a radar-and-altimeter-equipped Europa Orbiter, but costs, power needs and a lengthy mission duration precipitated its 2002 cancellation.<\/p>
A Jupiter Icy Moons Orbiter (JIMO) with ion or nuclear electric propulsion was scratched in 2005 as too ambitious.<\/p>
Next came the US\/European Europa Jupiter System Mission (EJSM), including NASA\u2019s Jupiter Europa Orbiter.<\/p>
It too was axed in 2011. But a kernel of EJSM survived.<\/p>![\"Image](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/08\/esa-juice-earth-flyby-august-2024-social.jpg\")
Image of Earth captured by the European Space Agency’s Juice spacecraft during a flyby on 20 August 2024.<\/figcaption><\/figure>Europe\u2019s share of that mission became the Jupiter Icy Moons Explorer (JUICE)<\/a>, launched in 2023.<\/p>And a US mission recommended by the National Research Council in 2013 led to the selection of nine science instruments in 2015 and approval of a voyage which in 2017 became known as Europa Clipper.<\/p>
Europa Clipper’s name comes from 19th-century \u2018clippers\u2019: three-masted sailing ships that plied the world\u2019s oceans, delivering tea and other commodities.<\/p>
But for NASA it has another meaning: Europa Clipper will not circle Europa.<\/p>
Instead, it will orbit Jupiter, tweaking its trajectory to accomplish 44 fly-bys of the moon at distances from 26km (16 miles) to 2,700km (1,678 miles).<\/p>![\"Europa](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/10\/clipper-ship.jpg\")
Europa Clipper gets its name from the clipper ships of the 19th century. Credit: Greg Pease \/ Getty Images<\/figcaption><\/figure>Europa Clipper orbit and science objectives<\/strong><\/h2>Europa\u2019s location deep inside Jupiter\u2019s radiation field would ordinarily fry Europa Clipper\u2019s electronics within months.<\/p>
So to facilitate and survive a multi-year mission, it will \u2018clip\u2019 past the moon every few weeks \u2013 “rinse and repeat, many times,” says project scientist Robert Pappalardo of JPL \u2013\u00a0to spend as little time as needed in the high-radiation flux before heading outbound to safer distances to transmit data to Earth.<\/p>
And that data will be collected with a comprehensive toolkit:<\/p>
- High-resolution thermal infrared imager<\/li>
- Infrared spectrometer<\/li>
- Imaging system with wide- and narrow-angle cameras<\/li>
- Ultraviolet spectrograph,<\/li>
- Magnetometer on an 8.5-metre (25ft) boom<\/li>
- Plasma detector<\/li>
- Mass spectrometer<\/li>
- Dust sampler<\/li><\/ul>
They will allow Clipper to image Europa\u2019s surface at resolutions of 50cm (20 inches) per pixel, directly sample water vapour plumes during low-altitude fly-bys, determine crust thickness and ocean![\"NASA\u2019s](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/08\/europa-clipper-solar-arrays.jpg\")
NASA\u2019s Europa Clipper’s solar arrays pictured on 21 August 2024 at Kennedy Space Center in Florida. Credit: NASA\/Frank Michaux<\/figcaption><\/figure>And a 16-metre (52ft) ice-penetrating radar will \u2018sound\u2019 Europa\u2019s crust while an altimeter measures tides and surface roughness.<\/p>
All told, it will map 95% of Europa at resolutions of 100 metres (330 feet): a sixfold increase in coverage at five times better quality than earlier missions.<\/p>
Those nine instruments sit within Europa Clipper, the biggest spacecraft NASA has ever sent to a planet.<\/p>
At 6.6 metres (20ft) tall and weighing 6,000kg (13,370lb), the SUV-sized Europa Clipper includes a 3-metre (10ft) high-gain antenna for communications and gravity measurements, and 24 thrusters for manoeuvres and the lengthy, six-hour-plus Jupiter orbit insertion engine burn.<\/p>
And as clipper ships of old had large-area sails, so Europa Clipper\u2019s pair of five-piece solar arrays<\/a> are the biggest ever used at Jupiter.<\/p>Each extends to 14.2 metres (46.5ft) and the spacecraft spans an entire basketball court when fully deployed.<\/p>
Though sunlight at the distance of Jupiter is only 4% as intense as it is near Earth, the arrays will generate 600 Watts of electrical power.<\/p>
Messages from Earth<\/strong><\/h2>
Why Europa?<\/strong><\/h2>Circling giant Jupiter at a distance of 671,000km (417,000 miles), Europa is an enigmatic moon, smaller in diameter than Australia is wide.<\/p>
Its surface rhythmically flexes under its parent planet\u2019s colossal gravity<\/a> and is washed by the intense Jovian magnetic field<\/a>, 20,000 times fiercer than Earth\u2019s.<\/p>Nine tenths as big as the Moon yet five times further from the Sun, Europa\u2019s daytime highs never climb above \u2013160\u00b0C (\u2013260\u00b0F).<\/p>
Its Texas-sized nickel-iron core and rocky mantle are overlaid by an icy crust, maybe 15\u201325km (10\u201315 miles) thick and rendered rock-solid under such frigid extremes.<\/p>
But hard as it may seem in this radiation-blasted wasteland, life of sorts might once (and could still) have thrived at Europa<\/a>: truly an unlikely Eden.<\/p>Visually, Europa bears few hallmarks of the only known harbour of life: our iridescent blue-and-white planet, Earth.<\/p>
Past missions to Europa<\/strong><\/h2>In 1979, NASA\u2019s Voyager 1 and 2 probes revealed what Europa Clipper deputy project scientist Bonnie Buratti of NASA\u2019s Jet Propulsion Laboratory (JPL) likens to \u201ca cracked egg\u201d: its 0.64 albedo (how much light its surface reflects) brighter than Arctic sea-ice; and its curious reddish tincture likely caused
The Voyagers photographed linear ridges and furrows crossing the surface, with peculiar blotches dotted across the glassy landscape.<\/p>Image of Jupiter’s moon Europa, captured by Voyager 2, 9 July 1979. Credit: NASA\/JPL<\/figcaption><\/figure>“Scientists date surfaces by counting craters,” says Buratti. And Europa\u2019s lack of craters implies a young surface, perhaps 20 million years old and still undergoing active internal change.<\/p>
Tantalisingly, the Voyagers detected fractures in that terrain, facilitating movement of dark subsurface material into the resulting gaps \u2013 and inviting speculation that a layer of water or warm ice might lurk beneath the Europan crust.<\/p>
In 1996\u20132000, NASA\u2019s Galileo probe<\/a> found strong evidence for a salty ocean holding 3 billion cubic kilometres (720 million cubic miles) of water, twice as much as our oceans.<\/p>Two views of moon Europa captured by NASA’s Galileo spacecraft in June 1997. Credit: NASA, NASA-JPL, University of Arizona<\/figcaption><\/figure>That ocean could be 80\u2013100km (50\u201360 miles) deep \u2013 that\u2019s nine times deeper than the Mariana Trench, the deepest point in any ocean on Earth.<\/p>
The Galileo probe also showed that an upwelling of warm, slushy ice was indeed at work.<\/p>
It detected an intrinsic magnetic field and measured directional changes consistent with the presence of a subsurface \u2018shell\u2019 of electrically conducting material, like a salty liquid ocean.<\/p>A Hubble Space Telescope image of Europa showing suspected plumes of water vapour erupting at the 7 o’clock mark. These plumes could be evidence of a subsurface ocean below Europa’s icy crust.Elsewhere, the Hubble Space Telescope discovered Europa\u2019s thin oxygen atmosphere and in 2013\u20132017 saw water vapour emissions rising 100km (60 miles) high.<\/p>
That furnished persuasive evidence of material ejected directly from the ocean.<\/p>
In 2019, Hubble found sodium chloride (table salt), suggesting the ocean could be saltier and more Earth-like than originally thought\u2026 and more amenable to microbial life.<\/p>Heat and minerals expelled by hydrothermal vents allow creatures to survive without sunlight. Credit: Ralph White \/ Getty Images<\/figcaption><\/figure>Life on Europa?<\/strong><\/h2>“Every scenario for life on Earth has liquid water,” Buratti explains.<\/p>
“The search for life is top of the list: are we alone? But our understanding of how life originated and how it thrived has really evolved over the time that I\u2019ve been in this field.”<\/p>
On Earth, life sprouted in the unlikeliest of places, notably hydrothermal vents in deep ocean trenches with no sunlight.<\/p>
“Life formed in these thermal vents because the bacteria there are very primitive,” Buratti continues.<\/p>
“They\u2019re at the base of the tree of life, so our understanding of where to look for life has changed.”<\/p>
But Buratti remains cautiously guarded about finding life.<\/p>
“It looks like the conditions for life are there,” she says. “We\u2019re empiricists and we don\u2019t have any evidence yet. Our mission\u2019s going to find evidence and work from there.”<\/p>A view of Jupiter’s moon Europa captured by the Juno spacecraft during its flyby on 29 September 2022. Credit: Image data: NASA\/JPL-Caltech\/SwRI\/MSSS Image processing: Kevin M. Gill CC BY 3.0 Full Image Details<\/figcaption><\/figure>How the Europa Clipper mission came about<\/strong><\/h2>A dedicated Europa mission has long held high-priority status.<\/p>
Top-level goals include measuring the thickness of the crust, deciphering Europa\u2019s complex geology and ascertaining the nature, size, saltiness and composition of the ocean.\u00a0<\/p>
In 1997, NASA proposed a radar-and-altimeter-equipped Europa Orbiter, but costs, power needs and a lengthy mission duration precipitated its 2002 cancellation.<\/p>
A Jupiter Icy Moons Orbiter (JIMO) with ion or nuclear electric propulsion was scratched in 2005 as too ambitious.<\/p>
Next came the US\/European Europa Jupiter System Mission (EJSM), including NASA\u2019s Jupiter Europa Orbiter.<\/p>
It too was axed in 2011. But a kernel of EJSM survived.<\/p>Image of Earth captured by the European Space Agency’s Juice spacecraft during a flyby on 20 August 2024.<\/figcaption><\/figure>Europe\u2019s share of that mission became the Jupiter Icy Moons Explorer (JUICE)<\/a>, launched in 2023.<\/p>And a US mission recommended by the National Research Council in 2013 led to the selection of nine science instruments in 2015 and approval of a voyage which in 2017 became known as Europa Clipper.<\/p>
Europa Clipper’s name comes from 19th-century \u2018clippers\u2019: three-masted sailing ships that plied the world\u2019s oceans, delivering tea and other commodities.<\/p>
But for NASA it has another meaning: Europa Clipper will not circle Europa.<\/p>
Instead, it will orbit Jupiter, tweaking its trajectory to accomplish 44 fly-bys of the moon at distances from 26km (16 miles) to 2,700km (1,678 miles).<\/p>Europa Clipper gets its name from the clipper ships of the 19th century. Credit: Greg Pease \/ Getty Images<\/figcaption><\/figure>Europa Clipper orbit and science objectives<\/strong><\/h2>Europa\u2019s location deep inside Jupiter\u2019s radiation field would ordinarily fry Europa Clipper\u2019s electronics within months.<\/p>
So to facilitate and survive a multi-year mission, it will \u2018clip\u2019 past the moon every few weeks \u2013 “rinse and repeat, many times,” says project scientist Robert Pappalardo of JPL \u2013\u00a0to spend as little time as needed in the high-radiation flux before heading outbound to safer distances to transmit data to Earth.<\/p>
And that data will be collected with a comprehensive toolkit:<\/p>
- High-resolution thermal infrared imager<\/li>
- Infrared spectrometer<\/li>
- Imaging system with wide- and narrow-angle cameras<\/li>
- Ultraviolet spectrograph,<\/li>
- Magnetometer on an 8.5-metre (25ft) boom<\/li>
- Plasma detector<\/li>
- Mass spectrometer<\/li>
- Dust sampler<\/li><\/ul>
They will allow Clipper to image Europa\u2019s surface at resolutions of 50cm (20 inches) per pixel, directly sample water vapour plumes during low-altitude fly-bys, determine crust thickness and oceanNASA\u2019s Europa Clipper’s solar arrays pictured on 21 August 2024 at Kennedy Space Center in Florida. Credit: NASA\/Frank Michaux<\/figcaption><\/figure>And a 16-metre (52ft) ice-penetrating radar will \u2018sound\u2019 Europa\u2019s crust while an altimeter measures tides and surface roughness.<\/p>
All told, it will map 95% of Europa at resolutions of 100 metres (330 feet): a sixfold increase in coverage at five times better quality than earlier missions.<\/p>
Those nine instruments sit within Europa Clipper, the biggest spacecraft NASA has ever sent to a planet.<\/p>
At 6.6 metres (20ft) tall and weighing 6,000kg (13,370lb), the SUV-sized Europa Clipper includes a 3-metre (10ft) high-gain antenna for communications and gravity measurements, and 24 thrusters for manoeuvres and the lengthy, six-hour-plus Jupiter orbit insertion engine burn.<\/p>
And as clipper ships of old had large-area sails, so Europa Clipper\u2019s pair of five-piece solar arrays<\/a> are the biggest ever used at Jupiter.<\/p>Each extends to 14.2 metres (46.5ft) and the spacecraft spans an entire basketball court when fully deployed.<\/p>
Though sunlight at the distance of Jupiter is only 4% as intense as it is near Earth, the arrays will generate 600 Watts of electrical power.<\/p>
Messages from Earth<\/strong><\/h2>
Nine tenths as big as the Moon yet five times further from the Sun, Europa\u2019s daytime highs never climb above \u2013160\u00b0C (\u2013260\u00b0F).<\/p>
Its Texas-sized nickel-iron core and rocky mantle are overlaid by an icy crust, maybe 15\u201325km (10\u201315 miles) thick and rendered rock-solid under such frigid extremes.<\/p>
But hard as it may seem in this radiation-blasted wasteland, life of sorts might once (and could still) have thrived at Europa<\/a>: truly an unlikely Eden.<\/p> Visually, Europa bears few hallmarks of the only known harbour of life: our iridescent blue-and-white planet, Earth.<\/p> In 1979, NASA\u2019s Voyager 1 and 2 probes revealed what Europa Clipper deputy project scientist Bonnie Buratti of NASA\u2019s Jet Propulsion Laboratory (JPL) likens to \u201ca cracked egg\u201d: its 0.64 albedo (how much light its surface reflects) brighter than Arctic sea-ice; and its curious reddish tincture likely caused The Voyagers photographed linear ridges and furrows crossing the surface, with peculiar blotches dotted across the glassy landscape.<\/p> “Scientists date surfaces by counting craters,” says Buratti. And Europa\u2019s lack of craters implies a young surface, perhaps 20 million years old and still undergoing active internal change.<\/p> Tantalisingly, the Voyagers detected fractures in that terrain, facilitating movement of dark subsurface material into the resulting gaps \u2013 and inviting speculation that a layer of water or warm ice might lurk beneath the Europan crust.<\/p> In 1996\u20132000, NASA\u2019s Galileo probe<\/a> found strong evidence for a salty ocean holding 3 billion cubic kilometres (720 million cubic miles) of water, twice as much as our oceans.<\/p> That ocean could be 80\u2013100km (50\u201360 miles) deep \u2013 that\u2019s nine times deeper than the Mariana Trench, the deepest point in any ocean on Earth.<\/p> The Galileo probe also showed that an upwelling of warm, slushy ice was indeed at work.<\/p> It detected an intrinsic magnetic field and measured directional changes consistent with the presence of a subsurface \u2018shell\u2019 of electrically conducting material, like a salty liquid ocean.<\/p> Elsewhere, the Hubble Space Telescope discovered Europa\u2019s thin oxygen atmosphere and in 2013\u20132017 saw water vapour emissions rising 100km (60 miles) high.<\/p> That furnished persuasive evidence of material ejected directly from the ocean.<\/p> In 2019, Hubble found sodium chloride (table salt), suggesting the ocean could be saltier and more Earth-like than originally thought\u2026 and more amenable to microbial life.<\/p> “Every scenario for life on Earth has liquid water,” Buratti explains.<\/p> “The search for life is top of the list: are we alone? But our understanding of how life originated and how it thrived has really evolved over the time that I\u2019ve been in this field.”<\/p> On Earth, life sprouted in the unlikeliest of places, notably hydrothermal vents in deep ocean trenches with no sunlight.<\/p> “Life formed in these thermal vents because the bacteria there are very primitive,” Buratti continues.<\/p> “They\u2019re at the base of the tree of life, so our understanding of where to look for life has changed.”<\/p> But Buratti remains cautiously guarded about finding life.<\/p> “It looks like the conditions for life are there,” she says. “We\u2019re empiricists and we don\u2019t have any evidence yet. Our mission\u2019s going to find evidence and work from there.”<\/p> A dedicated Europa mission has long held high-priority status.<\/p> Top-level goals include measuring the thickness of the crust, deciphering Europa\u2019s complex geology and ascertaining the nature, size, saltiness and composition of the ocean.\u00a0<\/p> In 1997, NASA proposed a radar-and-altimeter-equipped Europa Orbiter, but costs, power needs and a lengthy mission duration precipitated its 2002 cancellation.<\/p> A Jupiter Icy Moons Orbiter (JIMO) with ion or nuclear electric propulsion was scratched in 2005 as too ambitious.<\/p> Next came the US\/European Europa Jupiter System Mission (EJSM), including NASA\u2019s Jupiter Europa Orbiter.<\/p> It too was axed in 2011. But a kernel of EJSM survived.<\/p> Europe\u2019s share of that mission became the Jupiter Icy Moons Explorer (JUICE)<\/a>, launched in 2023.<\/p> And a US mission recommended by the National Research Council in 2013 led to the selection of nine science instruments in 2015 and approval of a voyage which in 2017 became known as Europa Clipper.<\/p> Europa Clipper’s name comes from 19th-century \u2018clippers\u2019: three-masted sailing ships that plied the world\u2019s oceans, delivering tea and other commodities.<\/p> But for NASA it has another meaning: Europa Clipper will not circle Europa.<\/p> Instead, it will orbit Jupiter, tweaking its trajectory to accomplish 44 fly-bys of the moon at distances from 26km (16 miles) to 2,700km (1,678 miles).<\/p> Europa\u2019s location deep inside Jupiter\u2019s radiation field would ordinarily fry Europa Clipper\u2019s electronics within months.<\/p> So to facilitate and survive a multi-year mission, it will \u2018clip\u2019 past the moon every few weeks \u2013 “rinse and repeat, many times,” says project scientist Robert Pappalardo of JPL \u2013\u00a0to spend as little time as needed in the high-radiation flux before heading outbound to safer distances to transmit data to Earth.<\/p> And that data will be collected with a comprehensive toolkit:<\/p> They will allow Clipper to image Europa\u2019s surface at resolutions of 50cm (20 inches) per pixel, directly sample water vapour plumes during low-altitude fly-bys, determine crust thickness and ocean And a 16-metre (52ft) ice-penetrating radar will \u2018sound\u2019 Europa\u2019s crust while an altimeter measures tides and surface roughness.<\/p> All told, it will map 95% of Europa at resolutions of 100 metres (330 feet): a sixfold increase in coverage at five times better quality than earlier missions.<\/p> Those nine instruments sit within Europa Clipper, the biggest spacecraft NASA has ever sent to a planet.<\/p> At 6.6 metres (20ft) tall and weighing 6,000kg (13,370lb), the SUV-sized Europa Clipper includes a 3-metre (10ft) high-gain antenna for communications and gravity measurements, and 24 thrusters for manoeuvres and the lengthy, six-hour-plus Jupiter orbit insertion engine burn.<\/p> And as clipper ships of old had large-area sails, so Europa Clipper\u2019s pair of five-piece solar arrays<\/a> are the biggest ever used at Jupiter.<\/p> Each extends to 14.2 metres (46.5ft) and the spacecraft spans an entire basketball court when fully deployed.<\/p> Though sunlight at the distance of Jupiter is only 4% as intense as it is near Earth, the arrays will generate 600 Watts of electrical power.<\/p>Past missions to Europa<\/strong><\/h2>
Life on Europa?<\/strong><\/h2>
How the Europa Clipper mission came about<\/strong><\/h2>
Europa Clipper orbit and science objectives<\/strong><\/h2>
Messages from Earth<\/strong><\/h2>