The Galileo Challenge was a space and general science contest that the OCESS conducted every year. It took place every year around Easter break; currently it is on hiatus and its future remains uncertain. The Galileo Challenge consisted of about 50 multiple choice questions which focused on space sciences and astronomy, but also included questions about other branches of science. The prizes in the past have been insignificant, but in 2005-06, this crucial area was expanded with prizes from IBM, Carleton University, and a grand prize of a free tuition to the Da-Vinci science academy at Deep River.
The Galileo Challenge was open for all students from grades 9 and 10. Traditionaly, the participants for the Galileo Challenge come from Lisgar, though in its last few years the contest expanded to include participants from many schools around Ottawa. Elmwood and Colonel By both contributed participants.
For 2004-05, the first place winner was Nevin Hotson, who is now a Spacesim alumnus, while second place winner was David Reid. Third place went to Stefan De Young, who is currently serving a life sentence with Spacesim.
There was some contemplation of creating a senior grade science competition similar to the Galileo Challenge. However, after Jeff Gao's graduation, Education Commander Arthur Quang failed to continue it. Some wide-eyed idealists hope that 2009-10 commander Lyra Evans will resurrect this important legacy.