Artist rendering of NASA’s Europa Clipper spacecraft. Credit: NASA/JPL-Caltech

Jupiter’s icy moon takes a big step forward as engineers deliver a major component of the spacecraft.

Europa, Jupiter’s icy moon, almost certainly has a vast ocean beneath its icy shell. In fact, scientists believe this ocean contains more water than all of Earth’s oceans combined. The complex chemistry required for life as we know it to exist requires liquid water, making this ocean one of the key reasons astrobiologists want to study Europa.

NASA’s Europa Clipper will be equipped with science instruments needed to study Europa to see if it harbors conditions suitable for supporting life. It is expected to launch in 2024 and take several years to reach Jupiter. Once there, it will orbit the planet, during which it will soar past Europa some 45 times or so. During each flyby, it will scan the moon and then report the data back to Earth.

Now, the main body of NASA’s Europa Clipper spacecraft has just been delivered to the agency’s Jet Propulsion Laboratory (JPL) in Southern California. Over the next two years there, engineers and technicians will finish assembling the craft by hand before testing it to make sure it can withstand the journey to Jupiter’s icy moon Europa.

NASA’s Europa Clipper spacecraft is visible in a main clean room at JPL, as engineers and technicians inspect it just after delivery in early June 2022. Credit: NASA/JPL-Caltech/Johns Hopkins APL/Ed Whitman

The spacecraft body is the mission’s workhorse. Standing 10 feet (3 meters) tall and 5 feet (1.5 meters) wide, it’s an aluminum cylinder integrated with electronics, radios, thermal loop tubing, cabling, and the propulsion system. With its solar arrays and other deployable equipment stowed for launch, Europa Clipper will be as large as an SUV; when extended, the solar arrays make the craft the size of a basketball court. It is the largest NASA spacecraft ever developed for a planetary mission.

“It’s an exciting time for the whole project team and a huge milestone,” said Jordan Evans, the mission’s project manager at JPL. “This delivery brings us one step closer to launch and the Europa Clipper science investigation.”

This video captures the delivery of the core of NASA’s Europa Clipper spacecraft to the agency’s Jet Propulsion Laboratory in Southern California. The spacecraft’s body was designed and built by the Johns Hopkins Applied Physics Laboratory in collaboration with the Jet Propulsion Laboratory and NASA’s Goddard Space Flight Center. Credit: NASA/JPL-Caltech

Scheduled to launch in October 2024, the Europa Clipper will make nearly 50 flights aboard Europa, which scientists are confident harbors an inner ocean that contains twice as much water as Earth’s oceans combined. The ocean may currently have adequate conditions to support life. The spacecraft’s nine science instruments will collect data on Europa’s atmosphere, surface and interior—information that scientists will use to measure ocean depth and salinity, ice crust thickness, and potential plumes that might spew groundwater into space.

These devices have already begun to arrive at the Jet Propulsion Laboratory, where the phase known as assembly, testing and launch operations has begun since March. Ultraviolet spectrometer, called Europa-UVS, arrived in March. Next came the spacecraft’s Thermal Emission Imager, E-THEMIS, presented by the scientists and engineers leading its development at Arizona State University. E-THEMIS is an advanced infrared camera designed to map Europa’s temperatures and help scientists find clues about the moon’s geological activity — including areas where liquid water might be near the surface.

By the end of 2022, it is expected that most of the flight instrumentation and the rest of the scientific instruments will be completed.

NASA’s Europa Clipper spacecraft is disassembled in a main clean room at JPL, where engineers and technicians inspect it right after delivery in early June 2022. Credit: NASA / JPL-Caltech / Johns Hopkins APL / Ed Whitman

full package

The Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, designed the Europa Clipper object in collaboration with the Jet Propulsion Laboratory and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The flight system that APL designed, built and tested—using a team of hundreds of engineers and technicians—was the largest physical system ever built by APL,” said Tom Magner of APL, the mission’s assistant project manager.

Work on the main unit now continues at JPL.

“What arrived at JPL is essentially an assembly phase in and of itself. Under the leadership of APL, this delivery includes the work of that institution and two NASA centers. Now the team will take the system to a higher level of integration,” Evans said.

The main body of NASA’s Europa Clipper spacecraft appears in its cargo hold, right after arriving aboard a C-17 cargo plane at March Air Reserve Base in Riverside County, California. Image Credit: NASA/JPL-Caltech/Johns Hopkins APL/Ed Whitman

The main structure is actually two stacked aluminum cylinders dotted with threaded holes for mounting to the spacecraft payload: the radio frequency unit, radiation monitors, propulsion electronics, transducers, and wires. The RF subsystem will power eight antennas, including a massive 10-foot (3-meter) high-gain antenna. The structure’s network of electrical wires and connectors, called a harness, weighs 150 pounds (68 kilograms) by itself; If stretched, it would run nearly 2,100 feet (640 metres) – twice the circumference of a football field.

The heavy-duty electronics vault, designed to withstand the intense radiation of the Jupiter system, will be integrated with the spacecraft’s main chassis along with scientific instruments.

Inside the spacecraft’s main body are two tanks – one containing the fuel and one for the oxidizer – and tubes that will transfer their contents to an array of 24 engines, where they will be combined to create a controlled chemical reaction that produces thrust.

The main body of NASA’s Europa Clipper spacecraft appears in its cargo hold as it enters the agency’s Jet Propulsion Laboratory in Southern California. Image Credit: NASA/JPL-Caltech/Johns Hopkins APL/Ed Whitman

“Our engines have two purposes,” said Tim Larson of Jet Propulsion Laboratory, deputy project manager. “We use it for large maneuvers, including when we get close to Jupiter and need a large burnout to be captured in Jupiter’s orbit. But it’s also designed for smaller maneuvers to manage the spacecraft’s position and to fine-tune the flyby of Europa and other Solar System objects along the way.”

These maneuvers, large and small, will play a large role during the six-year, 1.8 billion-mile (2.9 billion km) journey into this ocean world, which Europa Clipper will begin to investigate in earnest in 2031.

More about the mission

Missions like Europa Clipper contribute to the field of astrobiology, interdisciplinary research on the variables and conditions of distant worlds that could harbor life as we know it. While the Europa Clipper is not a mission to detect life, it will conduct a detailed survey of Europa and check whether the icy moon, with its subsurface ocean, has the potential to support life. Understanding the habitability of Europe will help scientists better understand how life evolved on Earth and the possibility of finding life outside our planet.

The Jet Propulsion Laboratory, operated by the California Institute of Technology in Pasadena, California, directs the Europa Clipper mission development in partnership with APL for NASA’s Science Mission Directorate in Washington. The Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Europa Clipper mission program.