New York: NASA may have devoted many of its exploration resources to Mars recently, but the US space agency also has its eye on an icy moon of Jupiter that may be capable of supporting life.
The agency is thinking about ways to investigate the possible habitability of Europa, Jupiter`s fourth-largest moon. One concept that may be gaining traction is a so-called "clipper" probe that would make multiple flybys of the moon, studying its icy shell and suspected subsurface ocean as it zooms past.
"We briefed [NASA] headquarters on Monday, and they responded very positively," mission proponent David Senske, of NASA`s Jet Propulsion Laboratory in Pasadena, said.
The USD 2 billion 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.
Astrobiologists regard Europa, which is about 3,100 kilometres wide, as one of the best bets in our solar system to host life beyond Earth.
The moon is believed to harbour a large ocean of liquid water beneath its icy shell. 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.
NASA has long been interested in exploring the icy moon and its ocean. Several years back, the agency drew up an ambitious mission concept called the Jupiter Europa Orbiter (JEO), which would have made detailed studies of Europa and the incredibly volcanic Jupiter moon.
According to the 2011 Planetary Science Decadal Survey, the science returns from such a mission would have been impressive which outlined the scientific community`s goals in the field over the coming decade.
The decadal survey ranked JEO as the second-highest priority among large-scale missions, just behind Mars sample-return. But the report said its USD 4.7 billion price tag was just too high.
"The recommendation was, immediately go and do a de-scope. They loved the science, the science was great. But focus it," said Senske.
Researchers got to work developing a leaner, cheaper Europa mission that would fit under a firm USD 2 billion cost cap. They came up with two main options: the clipper and a Europa orbiter.