An in-depth exploration of Europa, Jupiter’s icy moon believed to be home to a vast subsurface ocean, has been confirmed by NASA as the space agency prepares to launch its exploratory spacecraft Europa Clipper in the 2020s.
"We are all excited about the decision that moves the Europa Clipper mission one key step closer to unlocking the mysteries of this ocean world," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters, in a statement. "We are building upon the scientific insights received from the flagship Galileo and Cassini spacecraft and working to advance our understanding of our cosmic origin, and even life elsewhere."
The search for water and oceanic conditions on other planets helps us understand the potential for life on other worlds. Following its launch, the radiation-tolerant spacecraft will orbit around Jupiter and conduct at least 45 close flybys of Europa at altitudes varying from 2,700 to 25 kilometers (1,675 to 16 miles) above the surface. The clipper will also fly by Jupiter’s two other large moons, Ganymede and Callisto.
Europa presents some of the strongest evidence for an ocean of liquid water beneath its icy crust, conditions that would make the moon favorable for life. First discovered in 1610 by Galileo, scientists conducting ground-based telescope observations more than three centuries later in the 1960s found evidence that Europa’s surface composition is mostly water ice. Subsequent flybys and observations found large, linear band-like features across the moon that suggest icy material had seeped into cracks on the surface. The Galileo mission of the 1980s and 90s confirmed earlier findings, adding to them hints that Europa is creating its own magnetic field.
But does that mean the icy moon has conditions suitable for life?
To answer these questions, scientists are turning to the Europa Clipper, a spacecraft equipped with some serious scientific gear. Cameras and spectrometers will allow scientists to capture high-resolution images of Europa’s surface to determine the moon’s composition. Ice-penetrating radar will help determine the thickness of the moon’s shell and search for subsurface lakes similar to those found beneath Antarctica. A magnetometer will determine the strength and direction of Europa’s magnetic field, which in turn will lend clues to the depth and salinity of the ocean. Thermal instruments will also be used to find recent eruptions of warmer water, while other instruments will look for water and tiny particles in the thin atmosphere.
"This is a giant step in our search for oases that could support life in our own celestial backyard," said Europa program scientist Curt Niebur. "We're confident that this versatile set of science instruments would produce exciting discoveries on a much-anticipated mission."
The Europa Clipper is set to launch as early as 2023, with a baseline commitment of 2025.