The National Aeronautics and Space Administration (NASA) will wait two years longer than scheduled and spend up to another $40 million to launch a $475 million probe to Mars because of an unspecified conflict of interest in the purchasing process, officials said Friday. The Mars Scout program had scheduled a 2011 launch of the Mars atmospheric probe and was going to select proposals for the mission from one of two Colorado research institutes. But a “serious” conflict of interest in one of the proposals forced NASA to disband the panel formed to choose the proposal, officials said. The space agency created a new panel, and that caused a delay in awarding the contract, Mars Exploration Program director Doug McCuistion said. Because Mars only comes close enough to Earth to launch probes every 26 months, NASA had to postpone the mission from 2011 to 2013, he said.