NASA planning mission to Jupiter's icy moon Europa
Though NASA is devoting many of its exploration resources to Mars these days, the agency is also thinking about ways to investigate the possible habitability of Europa, Jupiter's fourth-largest moon.
NASA scientists are planning for a "clipper" probe that would make multiple flybys of the moon, studying its icy shell and suspected subsurface ocean as it zooms past.
The 2-billion-dollar unmanned Europa Clipper, which could be ready to launch by 2021 or so, would also do vital reconnaissance work for a potential lander mission in the future, mission proponent David Senske, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., told SPACE.com.
Astrobiologists regard Europa, which is about 1,900 miles (3,100 kilometers) wide, as one of the best bets in our solar system to host life beyond Earth.
The moon is believed to harbor a large ocean of liquid water beneath its icy shell. Further, this ocean is likely in direct contact with Europa's rocky mantle, raising the possibility of all sorts of interesting chemical reactions, Senske said.
The irradiation of Europa's surface and tidal heating of its interior also mean the moon likely has ample energy sources - another key requirement for life as we know it.
The Clipper would carry a number of scientific instruments, including ice-penetrating radar, a topographical imager, a magnetometer, an infrared spectrometer, a neutral mass spectrometer and a high-gain antenna.
It would enter into orbit around Jupiter, then study Europa during dozens of flybys over the course of 2.3 years. On its closest passes, it would come within just 15 miles (25 km) of the moon's frozen surface.
These close encounters should help the probe crack some of Europa's most intriguing mysteries, such as the thickness of its ice shell and the saltiness and approximate depth of its ocean (as well as confirming that the ocean exists), Senske said.
This information, along with the spacecraft's detailed imagery of the moon's surface, could help guide a potential lander mission that would search for signs of Europan life sometime down the road.
The Clipper could probably be ready to launch between 2020 and 2022, Senske said.
Its journey to Europa would take about six years.