BUENOS AIRES (Reuters) - U.S. satellite communications company Iridium Communications Inc (IRDM.O) said on Sunday the last call from its device aboard a missing Argentine submarine was made at 1136 GMT on Wednesday,  the day the vessel vanished.  Argentina s Defense Ministry has said seven failed satellite calls on Saturday may have been from the submarine. In a statement to Reuters, Iridium referred to those reports and said no calls from the vessel were made on its network on Saturday but that there may be equipment from another satellite communications company aboard the submarine. 