Europa will soon become the target of NASA probes searching for life on this giant moon of Jupiter. The space agency has selected nine science instruments to fly to the Jovian satellite, picked to help determine whether alien life could exist on this planetary body.
Strange straight lines on the surface of Europa, looking like cracks in ice, suggest a vast ocean could exist beneath the frozen crust.
The Galileo spacecraft orbiting around Jupiter has collected additional evidence that a vast ocean of liquid water exists beneath Europa's frozen surface. This body of water could be twice as large as all the oceans on Earth combined.
Energy to drive chemical reactions would be provided through tidal heating as tides pull on the satellite as it orbits around the gas giant. Astronomers believe this salt ocean may be in contact with the mantle of Europa, which could result in complex chemical reactions. Hydrothermal vents may also exist on the ocean floor, adding energy and complex molecules to the water. This combination of conditions could make Europa one of the most likely places in the solar system to find alien life.
"Europa has tantalized us with its enigmatic icy surface and evidence of a vast ocean, following the amazing data from 11 flybys of the Galileo spacecraft over a decade ago and recent Hubble observations suggesting plumes of water shooting out from the moon," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate.
A NASA mission planned for exploration of Europa will orbit Jupiter, making 45 flybys of the satellite over three years, at distances of just 16 miles to 1,700 miles away from the moon. The flight is currently scheduled for launch sometime in the first half of the 2020's.
Instruments the solar-powered spacecraft will carry include cameras as well as spectrometers to determine the composition of the surface, including the mysterious brown material seen rising from the cracks. A magnetometer will record the magnetic field of Europa to measure the salinity of any subsurface ocean. Ice-penetrating radar will determine if water on the moon is found in large oceans, or isolated lakes, like those found under Antarctica. It also will carry a thermal instrument to search for recent eruptions of water, and others to look for evidence of water particles in the thin atmosphere.
"If we can determine what that brown gunk is, we can then understand what is in the water - what is in the oceans of Europa - and that is an incredibly important question to answer if we're trying to figure out if this place is habitable," Curt Niebur, Europa program scientist, said.
Cameras aboard the vehicle will be able to photograph nearly 90 percent of the surface of Europa down to a resolution of just 164 feet. This compares with the Galileo mission, which photographed 10 percent of the surface of the satellite, at a resolution of 650 feet.
Europa, with a diameter of 1,900 miles, is the smallest of Jupiter's four giant moons and the sixth-largest satellite in the solar system. It was discovered by pioneering astronomer Galileo Galilei on Jan. 8, 1610.