ARISS "mentor" helps the school and the volunteering ground station operators to prepare the contact between schools and astronauts on board the International Space Station.

ARISS is the common working group of the national amateur radio and amateur satellite radio societies involved in Amateur Radio operations on board the International Space Station (ISS).
Amateur Radio on International SpaceStation

ARISS-Europe is a subgroup of the ARISS working group.
ARISS-Europe plan, implement and co-ordinate amateur radio projects and activities on board the International Space Station, in agreement with the ARISS teams worldwide.

The space agencies have entrusted ARISS with the task to implement amateur radio contacts with schools for the astronauts on board the International Space Station.
School contact Ariss Europe Web Site