Europa Clipper Press Kit

1. Europa is one of the most promising places to look for currently habitable conditions beyond Earth.

Scientists think some worlds in our solar system, such as Mars, may have hosted life billions of years ago. But they suspect that the ingredients for life — water, chemistry, and energy — could exist at the moon Europa right now. Previous missions have found strong evidence of an ocean beneath the moon’s thick icy crust, potentially with twice as much liquid water as all of Earth’s oceans combined.

Europa may be home to organic compounds, which are essential chemical building blocks for life. Europa Clipper will help scientists confirm whether organics are there, and also help them look for evidence of energy sources under the moon's surface. Scientists also wish to know if Europa’s conditions have stayed consistent over about 4 billion years, which is the age of the solar system — long enough for life to possibly arise.

In the last few decades, scientists have found that other worlds in our solar system, in addition to the moon Europa, likely have oceans beneath icy crusts. If the Europa Clipper mission determines that Europa is habitable, it would mean there may be more habitable worlds in our solar system — and that we would learn a lot more about how they work as well as how widespread they may be.

The discoveries Europa Clipper makes will complement data from the ESA (European Space Agency) Jupiter Icy Moons Explorer (Juice) mission, which will focus its investigation on Ganymede, Europa’s neighboring moon.

2. The spacecraft will fly through the most punishing radiation environment of any planet in the solar system.

Jupiter is surrounded by a gigantic magnetic field 20,000 times as strong as Earth’s. As the magnetic field spins, it captures and accelerates charged particles from the surrounding area. This creates radiation — particles or energy that moves from one place to another — which can damage spacecraft and harm astronauts. Jupiter’s radiation environment is the strongest of any planet in our solar system (second only to our Sun’s), making it especially hazardous.

Europa Clipper’s engineers came up with two key ways to minimize potential radiation damage: shielding the spacecraft’s sophisticated electronics with a specially designed vault and limiting the time Europa Clipper spends in particularly dangerous parts of Jupiter’s radiation. Even with these mitigations, during each flyby of the moon the electronics of the Europa Clipper spacecraft are expected to experience an average radiation dose of a few thousand to tens of thousands of rads (units of radiation absorbed by an object or person). This means that during each flyby, the spacecraft will get exposed to the equivalent of several million chest X-rays.

3. Europa Clipper will orbit the planet Jupiter, studying Europa while flying by the moon multiple times during its tour.

Europa Clipper’s mission team designed a tour where the spacecraft makes looping orbits around Jupiter that bring it close to the moon Europa for 49 science-dedicated flybys. These orbits allow the spacecraft to spend less than a day in the dangerous radiation environment near Europa on each orbit. The spacecraft will zip out of the most intense radiation areas before it loops back to fly by Europa again two to three weeks later.

4. Europa Clipper brings NASA’s most sophisticated suite of science instruments yet to the Jupiter system.

To determine if Europa is habitable, Europa Clipper must assess the moon’s interior, composition, and geology. The spacecraft carries nine science instruments and a gravity experiment that uses the orbiter’s telecommunications system to complete these objectives.

One significant new tool Europa Clipper has is an ice-penetrating radar called the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). This instrument can bounce waves off any liquid water under the surface, creating a kind of CT scan of Europa’s ice shell.

The Mass Spectrometer for Planetary Exploration/Europa (MASPEX) is the most complex and capable instrument of its kind ever flown to the outer solar system. It can “sniff” and analyze Europa’s atmosphere and any gases erupting from beneath the surface.

Another instrument will also directly collect and examine dust at Europa: the SUrface Dust Analyzer (SUDA).

Four instruments will study the moon from a distance across a wide range of the light spectrum, from infrared through visible light to the ultraviolet. The Europa Thermal Emission Imaging System (E-THEMIS) will measure how the surface retains heat, which can provide information about the structure and materials present. It will also look for hot spots from erupting plumes or underground lakes. The Mapping Imaging Spectrometer for Europa (MISE) collects infrared light to determine the composition of the surface. It will produce the first detailed maps of the many materials and chemical compounds on the surface, including enigmatic reddish material that has intrigued scientists for decades. The dual-camera Europa Imaging System (EIS) will finish the job started by Voyager and Galileo to map the surface of Europa — at sufficiently high resolution to unravel the mystery of the moon’s intricate and baffling geology. In addition to investigating Europa’s surface composition, the Europa Ultraviolet Spectrograph (Europa-UVS) is a sensitive “plume finder” and will search for active eruptions like those detected by the Hubble Space Telescope.

Two instruments will study Jupiter’s magnetic field and charged particles, or plasma, trapped within that field to provide clues about the structure of Europa’s interior: the Europa Clipper Magnetometer (ECM) and the Plasma Instrument for Magnetic Sounding (PIMS). The ECM will measure minute changes in Jupiter’s magnetic field near Europa that can yield information about the size and salinity of Europa’s ocean. Enabling the ECM to fulfill its role, PIMS provides information about the plasma environment around Europa. Together, both instruments will also help scientists better understand Jupiter’s magnetic field and how it interacts with Europa.

A gravity and radio science experiment that analyzes frequency shifts in the spacecraft’s signals to Earth will be able to independently confirm an ocean at Europa and give scientists additional insight into Europa’s interior.

Because each opportunity to fly by Europa is precious, the mission plans for all science instruments to operate simultaneously during each pass. Scientists can then layer the data together to paint the full picture of Europa.

5. With antennas and solar arrays fully deployed, Europa Clipper is the largest spacecraft NASA has ever developed for a planetary mission.

When the spacecraft is completely stretched out, it will cover an area larger than a basketball court. That’s more than 100 feet (30.5 meters) end to end and about 58 feet (17.6 meters) across. The arrays need to be so big to collect enough sunlight to power the spacecraft’s instruments, electronics, heaters, and other subsystems despite sunlight at Jupiter being only about 4% of what Earth receives.

6. It’s a long journey to Jupiter.

Jupiter is on average some 480 million miles (about 770 million kilometers) from Earth, but Europa Clipper cannot fly directly to the solar system’s largest planet. Both planets are constantly in motion, and a spacecraft can carry only a limited amount of fuel. So mission planners are sending Europa Clipper past Mars and Earth, using the planets’ gravity as a slingshot to add speed to the spacecraft’s journey to Jupiter.

Europa Clipper will put about 1.8 billion miles (2.9 billion kilometers) on its odometer over the course of 5½ years. It will then use the gravity of the Jovian moon Ganymede to help slow down before firing its thrusters to get into orbit around Jupiter in 2030.

Europa Clipper team members have plenty to do during the journey, including testing science instruments and spacecraft subsystems, refining the software running on the spacecraft and instruments, and fine-tuning the details of the Jupiter tour so that the orbiter is fully ready on its first day there.

7. Institutions across the U.S. and Europe have contributed to Europa Clipper.

Currently there are about a thousand people across the U.S. working on the Europa Clipper mission. This includes about 650 people at NASA’s Jet Propulsion Laboratory in Southern California and at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. JPL leads the development of the mission in partnership with APL. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provided key contributions to the main spacecraft body, and NASA’s Kennedy Space Center in Florida is overseeing final integration and launch services. The Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, provides program management of the Europa Clipper mission.

Over 220 scientists work on the mission, including instrument leads at JPL, APL, the Southwest Research Institute, NASA Goddard, the University of Texas, the University of Michigan, the University of Colorado Boulder, and Arizona State University. Science team members are based across the U.S. and Europe.

European facilities have also played key roles: The spacecraft’s giant solar arrays were built in the Netherlands by Airbus, and the magnetometer sensors were tested in the countryside of Germany because scientists needed an extremely quiet location.

Since the mission was formally approved in 2015, more than 4,000 people have contributed to Europa Clipper, including teams who work for contractors and subcontractors.

8. More than 2.6 million of us are riding along with the spacecraft to Jupiter, bringing greetings from one water world to another.

As part of the Europa Clipper mission, people around the world are participating in a new version of the practice of sending a message in a bottle out into Earth’s ocean: The spacecraft is carrying a poem by U.S. Poet Laureate Ada Limón, co-signed by millions of people from nearly every country in the world, as it sails out into the cosmic ocean. The names have been stenciled in tiny letters on a dime-size microchip.

Both the microchip and Limón’s poem are on a tantalum metal plate on the electronics vault of the spacecraft, along with waveforms of people saying the word “water” in over 100 spoken languages. The poem — like the Europa Clipper mission — explores the connections between our two distant worlds, both full of mysteries. “O second moon,” Limón writes, “we, too, are made of water, of vast and beckoning seas. / We, too, are made of wonders…”