NASA plans to launch a mission to Jupiter's watery moon Europa, which has a climate that is believed to be a potential host for alien life.

The space agency set aside $15 million in its 2015 budget to start planning a mission to the planet's moon, which could occur in the mid-2020s, according to the India Times.

NASA Chief Financial Officer Elizabeth Robinson said the high radiation environment around Jupiter, as well as its distance from the Earth, could pose a challenge. When NASA sent Galileo to Jupiter in 1989, it took six years for the spacecraft to reach the planet.

Rensselaer Polytechnic Institute astronomer Laurie Leshin said it could be "a daring mission to an extremely compelling object in our solar system."

The icy surface of Europa houses as much water that is in all of the Earth's oceans and lakes. The water-abundant moon is thought to potentially harbor life.

The $15 million, which is a small portion of the $17.5 billion allocated NASA in the 2015 request, would fund early, "pre-formulation" work for the potential mission.

"I know people have asked about the total size [of the possible mission], and we're frankly just not sure at this point," Robinson said.

While the 2015 proposal is the first time Europa was included in the federal budget request, NASA has received funding for the potential mission to the moon in the past; Congress allocated a total of $155 million for the mission over the past two years.

Scientists say they may launch a probe called the Europa Clipper, which would orbit Jupiter but make dozens of flybys past Europa, using instruments to study the moon's ice shell and subterranean ocean. Officials estimate the Clipper could cost around $2 billion to launch.

Last year, scientists discovered liquid plumes of water shooting through Europa's icy exterior. NASA scientists Robert Pappalardo said that flying the Europa Clipper through the watery jets could make Europa cheaper to explore, opposed to only circling the planet or landing on its ice.

A major goal in the mission would be to search for life in the water under the moon's icy surface.