Clarissa, a voice-operated computer assistant, will be used in space for the first time on Monday.

The program will initially talk astronauts on the International Space Station through tests of onboard water supplies. But its developers hope it will eventually be used for all computer-related work on the station.

The program “listens” to everything astronauts say and analyzes how to respond, using a “command grammar” of 75 commands based on a vocabulary of 260 words.