An optimal Earth-Mars trajectory is available every 26 months, so naturally NASA tries to use those opportunities to launch its probes to the Red Planet. A major mission, the $475M Mars Scout, was slated for the 2011 launch window. The agency, however, found a "serious" conflict of interest in one of the panels formed to pick the contractor for the mission. Restarting the selection process will delay the flight until the 2013 window and add $40M to the cost. NASA won't say where the conflict occurred or whether it involved an individual, one of the institutions competing for the contract, or one of NASA's support contractors.
COMMENT: This is inexcusable. You're supposed to do your "due diligence" before you appoint panels for this kind of thing. When the details leak out, as I'm sure they will, I would not be surprised if the conflict was something that could have been discovered with an Internet search.