NASA's Europa Clipper spacecraft will conduct a detailed survey of Jupiter's moon Europa to determine whether the icy moon could harbor conditions suitable for life. The spacecraft, in orbit around Jupiter, will make about 45 close passes over Europa, shifting its flight path for each flyby to soar over a different location so that it eventually scans nearly the entire moon.
After each flyby, the spacecraft will send its haul of data back to Earth. The time between flybys will also give scientists time to study the data and consider adjusting the timing and trajectory of future flybys if they find regions that spark curiosity and need more study.
Europa Clipper's altitude will vary from 1,675 miles to 16 miles (2,700 kilometers to 25 kilometers) above the moon's surface at closest approach. Most of the flybys will be below 60 miles (100 kilometers). The spacecraft also will swing by two other large Jovian moons — Ganymede and Callisto — to help shape and redirect its orbit.
The spacecraft will be about 20 feet (6 meters) in height and its solar arrays will stretch 72 feet (22 meters) from tip to tip. At liftoff, it will have a mass of about 13,228 pounds (6,000 kilograms) including fuel for the journey.
Europa Clipper's payload will include cameras and spectrometers to produce high-resolution images and compositional maps of Europa's surface and thin atmosphere, an ice-penetrating radar to search for subsurface water, and a magnetometer and gravity measurements to measure the moon's magnetic field and unlock clues about its ocean and deep interior.
The spacecraft will also carry a thermal instrument to pinpoint locations of warmer ice and perhaps recent eruptions of water, and instruments to measure the composition of tiny particles in the moon's thin atmosphere and surrounding space environment. In 2012, NASA's Hubble Space Telescope observed water vapor above Europa, providing the first strong evidence of water plumes. If the plumes exist — and if they're linked to a subsurface ocean — they will help scientists investigate the chemical makeup of Europa and the ocean's potential to harbor life.
Because Europa is bathed in radiation trapped in Jupiter's magnetic field, Europa Clipper's payload and other electronics will be enclosed in a thick-walled vault. This strategy of armoring up to go to Jupiter with a radiation vault was developed and successfully used for the first time by NASA’s Juno spacecraft. The vault walls — made up of titanium and aluminum — will act as a radiation shield against most of the high-energy atomic particles, dramatically slowing down the aging effect that radiation has on the spacecraft's electronics.