A dedicated mission to Jupiter's icy moon Europa, one of the best bets for life beyond Earth in our solar system, has inched a little closer to reality today.

The Obama Administration's 2015 NASA budget request (.pdf) asks for $17.5 billion for the agency, a slight drop from last year and more than a billion less than its 2010 peak of $18.7 billion. The request represents the things that the White House would like to see NASA pursue and includes funding for "pre-formulation work" on a mission that would fly by Europa, make detailed observations, and perhaps sample its interior ocean. Far bigger chunks of the budget are allocated to the development of a new manned spacecraft called Orion, the James Webb Space Telescope, successor to Hubble, and an extension of the International Space Station's lifespan to 2024.

"Clearly this is a statement by NASA that they recognize the priority and excitement of Europa exploration," said geologist Robert Pappalardo of JPL. It's the first time the White House has mentioned a Europa mission in its budget.

Europa is one of the solar system's most mysterious and badass moons. Beneath its icy crust, scientists think there is a vast ocean with more water in it than exists on all of Earth. Recently, scientists found evidence that a little bit of that water may be be erupting from geysers near the moon's south pole, sending plumes 200 kilometers into the air. Scientists would love nothing more than to send a spacecraft flying through these jets in order to sample their composition.

As far as robotic missions go, NASA has seemed obsessed lately with sending more and more probes to Mars. While the Red Planet is objectively awesome, some in the planetary science community have wondered if the other worlds in the solar system would be getting any attention at all. And the latest budget figures don't quite instill them with hope.

"I would not be overly optimistic until I see the words, 'We want to go to Europa'" from the administration, said planetary scientist Alyssa Rhoden of NASA's Goddard Spaceflight Center.

What Rhoden and other Europa researchers are really looking for is a definite commitment to the Europa Clipper mission, which is estimated to cost $2 billion and is not officially part of NASA's long-term plans. The mission has been planned for at least the last 15 years and is part of a back and forth tussle between the agency, the White House, and Congress in recent years.

Though the president proposes a budget each year, it's Congress that has the power of the purse. Line items in NASA's most recent congressional budgets provided $80 million per year for 2013 and 2014 to study instruments and mission plans for Europa Clipper. This move was spearheaded by Representative John Culbertson (R-Texas), who has a seat on the House Appropriations Committee and is keen to see the mission fly.

The president's 2015 budget likely allocates a few tens of millions to studying a Europa mission, though the exact number won't be revealed until March 10. The request seems to signal that the administration is more open to Europa Clipper, but also that they are not overly enthusiastic about it.

"That level of funding isn’t enough to start bending metal," said geophysicist Paul Hayne of NASA's Jet Propulsion Laboratory.

NASA's planetary science budget would likely need a boost of about $300 million per year for several years if Europa Clipper is going to really happen. For that, citizens interested in a mission to the icy world would need to advocate on its behalf.

"A mission to Europa takes vision," said Rhoden. "Exploring it is at the heart of what we do as NASA, and as scientists. But people need to make their voices heard or else it doesn’t happen."