Pupils at Woolmer Hill School, Haslemere in Surrey, are taking part in the special mission.
They were chosen because a musician called Greg Lake sent his children to school there.
He's now involved with a US space project Team Encounter.
The aim is to launch "humanity's first starship" in 2004.
It's hoped the probe may one day come into contact with aliens who will be able to decode the messages and learn about Earth.