NASA has announced plans to launch a life-hunting mission to one of Saturn's moon, Enceladus.

The satellite is one of the two alien worlds that scientists suspect are harboring life. The other one is Jupiter's moon Europa, which is a target of another space probe mission in 2020.

Several concepts are already being evaluated by NASA's Discovery Program, which is an initiative to send highly focused but low cost missions to different destinations in the solar system, Space reports. One of the candidates is the Enceladus Life Finder (ELF), which proposes to send a space probe to Saturn by the end of 2021. 

"We think we have the highest chance of success of getting an indicator of [alien] life for really any mission at this point," ELF concept principal investigator Jonathan Lunine, said in the Space report.

Interest in Enceladus stems from its icy shells, which astrobiologists believe hide oceans of liquid water underneath, which can host alien life. This is supported by a discovery of the spacecraft Cassini in 2005, which revealed the existence of geysers in the satellite blowing water into space from its core, according to NASA.

Winners in the Discovery program will be revealed later this month. It is expected that the winner will be able to land the probe on Enceladus surface, a feat the Cassini spacecraft was not able to undertake. The landing will make it possible to gather samples that could provide clues about alien life. If the samples yield amino acids, fatty acids and methane, it would strongly argue for life within Enceladus, the ELF team was quoted as saying in the International Business Times report.