English: Excellent view of the lunar farside showing the crater Tsiolkovsky, as photographed by the crew of the Apollo 13 mission during their lunar pass. The view is looking southeast toward the lunar horizon. The approximate coordinates of Tsiolkovsky are 128.5 degrees east longitude and 20.5 degrees south latitude. The Apollo 13 crew members were forced to cancel their scheduled lunar landing because of an apparent explosion of oxygen tank number two in the Service Module (SM).