NASA is plotting a daring robotic mission to Jupiter's watery moon Europa, a place where astronomers speculate there might be life.

The set aside $15 million in its 2015 to start planning some kind of mission to Europa. No details were released but NASA chief financial officer Elizabeth Robinson said Tuesday that it would be launched in the mid-2020s.

Astronomers have long lobbied for a mission to Europa, but it would cost billions of dollars.

Last year, scientists discovered liquid plumes of water shooting up through Europa's ice. Now think it will be cheaper to explore by flying through those watery jets than circling the moon.

Harvard astronomer Avi Loeb said going to Europa would be more exciting than exploring dry Mars.