To participate teams need to be in an ESA member country:
http://www.esa.int/About_Us/Welcome_to_ ... ber_States
Check out the
Read the rules buttons at the bottom of the mission timeline pages:
One thing you could try is an international collaboration with a team who are in an ESA member country, only 50% of team members must have the nationality of an ESA member. CoderDojo have a forum thread for people seeking to do this:
https://forums.coderdojo.com/topic/480/ ... -challenge