The computer was also put into use generating tracking commands for the receiver dish antenna in Ottawa that downloaded data from Alouette. The antenna could not track through "straight up", and had to be rotated 180 degrees to track back down to the opposite horizon. The movement was controlled by a simple system reading a paper tape. The computer produced tapes so the dish would be slowly rotated as it tracked the satellite, thereby guaranteeing no "dead time". Eventually a library of tapes was built up for any possible pass.